Download - Introduction to Life
Introduction to life
By:-Ms. Smita Shukla
Assistant Professor
Biology is the study of life and living organisms, from one-celled creatures to the most complex living organism of all — the human being. Biology includes the study of genes and cells that give living things their special characteristics.
All living things share some basic properties.Cellular OrganizationReproductionMetabolism (Obtain and Use Energy)HomeostasisHeredityResponsivenessGrowth and DevelopmentAdapt Through Evolution
Unicellular OrganismsEntire organism is made up of one single cellBacteria and protists
Smallest unit capable of all life functions
Multicellular OrganismsThe organism is made up of many cellsCells have specialized functions within the organism
Reproduction is the process of producing new organisms of the same type
Asexual ReproductionA single parent organism reproducing by itself
Sexual ReproductionTwo different parent organisms contribute genetic information Involves the combination of male and female sex cells
Living organisms need energy to grow, develop, repair damage, and reproduce
Anabolism
The process of building up complex substances from simpler substances Building up cells and cellular components Photosynthesis
CatabolismThe process of breaking down complex substances into simpler substances to release energy Digestion Cellular Respiration
MetabolismThe total of all chemical reactions in an organism Anabolism + Catabolism = Metabolism
A stable state of conditions in the body that are necessary for life
Body temperatureBlood volumepH balance (Blood7.34–7.45)Water balance
Genes carry hereditary information
Genes are composed of DNA
Heredity is the reason children resemble their parents
“Mutations change DNA code and can be passed from generation to generation”.
Organisms react to stimuli:LightTemperatureOdorSound GravityHeatWaterPressure
An example is a plant’s leaves and stems growing toward light
Growth means to get bigger in size
Development involves a change in the physical form or physiological make-up of an organism
AdaptationA process that enables organisms to become better suited to their environment Species obtain adaptations through evolution over great periods of time
An Example of Adaptation
Desert plants have succulent waxy leaves and stems to store water and reduce water loss
What is classification?
Classification is the grouping of living organisms according to similar structures and functions.
Aristotle grouped animals according to the way they moved.
As living things are constantly being investigated, new attributes are revealed that affect how organisms are placed in a standard classification system.
Taxonomy is the branch of biology concerned with the grouping and naming of organisms.
Biologists who study this are called taxonomists.
People wanted to organize their world so they began grouping, or classifying everything they saw.
To help us see relationships, similarities and differences.
To help us organize all the organisms we discover . . .
To give every species a name based on a standard method so scientists from different countries can talk about the same animal without confusion.
Carolus Linnaeus was a Swedish botanist. Developed a 7-level (taxa) classification system based on similarities between organisms.
Developed by Carolus Linnaeus.
Two-name system:First name is the organism’s genus.Second name is the organism’s species.
The first letter of the genus is ALWAYS capitalized.
The first letter of the species is NEVER capitalized.
Scientific names of organisms are always italicized or underlined
29
Classification of Groups
• Taxon ( taxa-plural) is a category into which related organisms are placed
• There is a hierarchy of groups (taxa) from broadest to most specific
• Domain, Kingdom, Phylum, Class, Order, Family, Genus, species
copyright cmassengale
DomainKingdomPhylumClassOrderFamilyGenusSpecies
31
Hierarchy-Taxonomic Groups
• Domain• Kingdom• Phylum (Division – used for plants)• Class• Order• Family
• Genus• Species
BROADEST TAXON
Most Specific
copyright cmassengale
32copyright cmassengale
HISTORY OF CLASSIFICATION
ARISTOTLEDIVIDED LIVING THINGS INTO TWO KINGDOMS
CAROLLUS LINNAEUS DEVELOPED THE CLASSIFICATION ON SIMILAR PROPERTIES, FOUND BINOMIAL NOMENCLATURE AS A SYSTEM TO GIVE A SCIENTIFIC NAME
ROBERT WHITTAKER HE GAVE FIVE KINGDOMS SYSTEM
Domains
Domains are the broadest taxonomic classification of living organismsThe three Domains:
Archaea Bacteria Eukarya
35
• Broadest, most inclusive taxon• Three domains• Archaea and Eubacteria are unicellular prokaryotes (no nucleus or membrane-bound organelles)
• Eukarya are more complex and have a nucleus and membrane-bound organelles
Domains
copyright cmassengale
Domains are Divided into Kingdoms
Archaea----- ArchaebacteriaBacteria ------ Eubacteria Eukarya ------- Protist Fungi Plantae Animalia
How does it work?
There are 6 broad kingdomsEvery living thing that we know of fits into one of the six kingdomsEach level gets more specific as fewer organisms fit into any one group
38
ARCHAEA
• Probably the 1st cells to evolve• Live in HARSH environments• Found in:
– Sewage Treatment Plants– Thermal or Volcanic Vents– Hot Springs or Geysers that are acid– Very salty water (Dead Sea; Great Salt Lake)
copyright cmassengale
39
ARCHAEAN
copyright cmassengale
40
EUBACTERIA• Some may cause DISEASE• Found in ALL HABITATS except harsh ones
• Important decomposers for environment
• Commercially important in making cottage cheese, yogurt, buttermilk, etc.
copyright cmassengale
41
Live in the intestines of animals
copyright cmassengale
42
Domain Eukarya is Divided into Kingdoms
• Monera (true bacteria (eubacteria) and cyanobacteria (blue-green algae).
• Protista (protozoans, algae…)• Fungi (mushrooms, yeasts …)• Plantae (multicellular plants)• Animalia (multicellular animals)
copyright cmassengale
By: ROBERT WHITTAKER
KINGDOM MONERA • Unicellular• Prokaryotic• Cell wall is non cellulosic• Nutrition - autotrophic or heterotrophic•Locomotion – flagella, gliding or non motile.•Reproduction – conjugation, transduction and transformation
Bacteria Bacteria types
45
Protista•Most are unicellular•Some are multicellular•Some are autotrophic, while others are heterotrophic•Aquatic
copyright cmassengale
46
Fungi• Multicellular, except yeast
• Absorptive heterotrophs (digest food outside their body & then absorb it)
• Cell walls made of chitin
copyright cmassengale
Yeast Sporangial forms
Amanita musaria Bracket fungi
48
Plantae•Multicellular•Autotrophic•Absorb sunlight to make glucose – Photosynthesis•Cell walls made of cellulose
copyright cmassengale
Bryophytes
Polytricum sp. female gametopytes Polytricum sp. male gametopytes
Pteridophytes
Fern (Nephrolepis)
Gymnosperms
Thuja Pine
Angiosperms
53
Animalia• Multicellular• Ingestive
heterotrophs (consume food & digest it inside their bodies)
• Feed on plants or animals
copyright cmassengale
54copyright cmassengale
55copyright cmassengale
Organizational Hierarchy of LifeMost Complex
LeastComplex sub-atomic particles
atommoleculemacromoleculeorganellecelltissueorganorgan systemorganismpopulationcommunityecosystembiosphere
protons, neutrons, electronsnitrogen
nucleotideDNAnucleusneuronnervous tissuebrainnervous systemfishschool of fishcoral reef populations
coral reef (living + nonliving)inhabitable regions of earth
Biological Levels of Organization
Basic Concept of Cell & its Function
What are Cells?• What is a cell?• Where do we find cells?Cell: “A cell is a basic unit of structure and
function of life. In other words, cells make up living things and carry out activities that keep a living thing alive”.
Cells Continued• What makes a cell?• A cell is a living thing.• Cells are able to make more cells like themselves.
• Interesting Fact: “New cells can only come from existing cells (cells that are already made)”.
Some HISTORY for you• In 1660s there was a man named Robert
Hooke. Robert lived in Britain and was a scientist. He was the first person to observe cells.
• Robert took a piece bark from an old oak tree and looked at it through a microscope.
• The bark looked like it was made up of many small rooms (kind of like a house with many bedrooms). He named the rooms, or structures, he saw under the microscope as cells. Therefore, he Coined the term cell
• THIS IS HOW THE WORD CELLS CAME TO BE!!
The Cell TheoryCell Theory:1. All living things are composed of cells.2. Cells are the basic units of structure and
function in living things.3. New cells are produced from existing cells.
Schleiden
Schwann Virchowwww.nerdscience.com
« Omnis cellula e cellula »
• Cells are the basic units of organisms–Cells can only be observed under microscope
• Two basic types of cells:
Animal Cell Plant Cell
Plant Cell
–Made of cellulose which forms very thin fibres–Strong and rigid–In plant cells only
• Cell wall
– Protect and support the enclosed substances (protoplasm)
– Resist entry of excess water into the cell
– Give shape to the cell
• Cell wall
Plant Cell
–A dead layer–Large empty spaces present between cellulose fibres
freely permeable
• Cell wall
Plant Cell
–Lies immediately against the cell wall
–Made of protein and lipid Selectively permeable
• Cell membrane
Plant Cell
–A living layer–Can control the movement of materials into and out of the cell
• Cell membrane
Plant Cell
–Jelly-like substance enclosed by cell membrane
–Provide a medium for chemical reactions to take place
• Cytoplasm
Plant Cell
–Contains organelles and granules :•e.g. chloroplast
•e.g. mitochondria
• Cytoplasm
Plant Cell
Organelles
very small size – can only be observed under electron microscope
has specific functions in cytoplasm
–Contains the green pigment chlorophyll•To trap light energy, to make food by photosynthesis
Plant Cell
• Chloroplast
–Contain starch grains (products of photosynthesis)
• Chloroplast
Plant Cell
–Rod shape–For respiration
Plant Cell• Mitochondrio
n( mitochondria )
–Active cells ( eg. sperms, liver cells) have more mitochondria
Plant Cell• Mitochondrio
n( mitochondria )
–Starch granules
–Oil droplets–Crystals of insoluble wastes
Plant Cell
• Non-living granules
– large central vacuole
– Surrounded by tonoplast
– Contains cell sap• a solution of chemicals (sugars, proteins, mineral salts, wastes, pigments)
Plant Cell• Vacuole
–Control the normal activities of the cell
–Bounded by a nuclear membrane
–Contains thread-like chromosomes
Plant Cell
• Nucleus
–Each cell has fixed number of chromosomes• Chromosomes carry genes–genes control cell characteristics
• Nucleus
Plant Cell
mitochondrion
nucleus
glycogen granule
cell membrane
cytoplasm Animal cell
• No cell wall and chloroplast
• Stores glycogen granules and oil droplets in the cytoplasm
vacuole
Different kinds of animal cells
white blood cell
red blood cell
cheek cells
sperm
nerve cell
muscle cell
Amoeba
Paramecium
Similarities between plant cells and animal
cellsBoth have a cell membrane surrounding the cytoplasm
Both have a nucleus
Both contain mitochondria
Differences between plant cells and animal cells
Animal cells Plant cellsRelatively smaller in
sizeIrregular shape
No cell wall
Relatively larger in size
Regular shape
Cell wall present
Animal cells Plant cellsVacuole small or
absentGlycogen granules as food
storeNucleus at the centre
Large central vacuoleStarch granules
as food store
Nucleus near cell wall
Differences between plant cells and animal cells
Structure Animal cells Plant cellscell membrane Yes yes
nucleus Yes yesnucleolus yes yesribosomes yes yes
ER yes yesGolgi yes yes
centrioles yes nocell wall no yes
mitochondria yes yescholorplasts no yes
One big vacuole no yescytoskeleton yes Yes
Two Major Cell Types
Cell Type Example
Prokaryotic Bacteria
Eukaryotic ProtistsFungiPlantsAnimals
Eukaryotic Cell(plant)
The distinction between prokaryotes and eukaryotes is considered to be the most important distinction among groups of organisms. Eukaryotic cells contain membrane-bound organelles, such as nucleus, while prokaryotic cells do not.
Differences in cellular structure of prokaryotes and eukaryotes include the presence of mitochondria and chloroplasts, the cell wall, and the structure of chromosomalDNA.
Prokaryotes were the only form of life on Earth for millions of years until more complicated eukaryotic cells came into being through the process of evolution.
Prokaryotic Cells
• In Greek:–Pro = before– karyotic = nucleus
• Cell that do not have a nucleus
• Bacteria
Eukaryotic Cells
• In Greek:– Eu = True–Karyotic = nucleus
• Cell that have a nucleus
What are cell parts and
their functions?
In this PowerPoint you will learn the following:
• Different cell parts•What function each part has
Even if cells are very tiny, they are made up of smaller parts, and the parts do different jobs.
Cell organelles are of 2 types..• Membranous Organelles:
1. Rough Endoplasmic reticulum.2. Smooth endoplasmic reticulum.3. Mitochondria.4. Golgi.5. Lysosomes.
• Non membranous Organelles.
1. Ribosomes.2. Cytoskeletal structures.
As you can see cells have many parts.
Cell wall • Only found surrounding plant, fungal and
bacterial cells• Its purpose is to shape and protect the cell like
the outside wall of a shopping mall, which provides shape and protection for it.
• “Supporter and Protector”
Cell membrane
The cell membrane holds and protects the cell. It controls what substances come into and out of the cell like an entrance you have to pass to get into the shopping mall.
“Gate of the Cell”.
Surrounds all cells.
In a plant cell, it lies beneath the cell wall.
In animal cells, it is the outer boundary (made of Cell Membranecholesterol)
Cell membrane Provides cell with– Protection– Control of movement ofmaterials in/out of cell– Support– Maintains condition of cell
Function• Regulates the movement of materials from one
environment to the other.
• Transports raw materials into the cell and waste out of the cell.
• Prevents the entry of unwanted matter and the escape of needed materials.
• Maintain a steady environment: Homeostasis
Cytoplasm
• The cytoplasm is the watery, gel-like material in which cell parts move and cell activities take place like the hallways of the mall where people move.
• “Area of Movement”
Found in both plant andanimal cells• Clear, thick, jelly-likeMaterial.
• Located beneath cellMembrane.
• Supports and protects cellOrganelles.
• It’s like the sidewalks thatare found throughout acity!
Cytoplasm
Mitochondria • Mitochondria produces most of the energy for the
cell, like an electrical system of the shopping mall, which supplies electrical energy.
• “Powerhouse of the cell”
Found in both plant andanimal cells.
Looks like a jellybean
Breaks down sugarmolecules to release usable energy.
Has inner foldings(Cristae) that increasethe internal surface area.
It’s like a city’s powerplant!
Mitochondria are the only organelles to have their own genetic material.
In EM it can be seen that mitochondria are bounded by double unit membrane.These membrane are separated by narrow intramembranous space
Inner membrane is four or five times larger than outer membrane.
Outer membrane is fairly permeable, inner membrane is highly selective.
Interior of the mitochondrian is filled with mitochondrial matrix of slightly higher electron density than the surrounding cytoplasm.
Mitochondria are renewed on a continuous basis throughout the cell cycle.
The number and size of mitochondria give an indication of the energy requirements.
Mitochondria primarily concerned with the chemical process by which energy is made available to the cell in the form of ATP.
ATP is often referred to as the energy “currency of cell”
Main site of aerobic respiration.
• This DNA is inherited maternally.
• Mitochondria are also significant participants in many versions of apoptosis, and altered mitochondrial function appears to be associated with various cancerous changes in cells.
• In cell hypertrophy- increase in number of mitochondria in cells
• In cell atrophy- decrease in no. of mitochondria's in cells.
Mitochondrial DNA
Chloroplast • Chloroplast is only in plant cells, like the cell wall. It
contains chlorophyll, which captures energy from sunlight and uses it to produce food for the cell like the pizza shop in the mall that makes food.
• “Food Producers”
• Green in color due to chlorophyll.
Vacuoles • The vacuoles store food, water, and chemicals, like
water tank and pipes of the mall, which store water.
• “Storage Tanks”
Found in both plant andanimal cells– In plant cells: veryfew and very largeVacuoles– In animal cells:many little ones
Fluid-filled sacs
Vacuoles
Identified in 1833 byRobert Brown
Found in both plantand animal cells
NucleusLarge, oval shapeCentrally located in cellControls cell activitiesContains geneticinformation (DNA)
Nucleus • Nucleus regulates and controls cell activities,
acting like the “brain” of the cell, like the mall office, which regulates and controls activities of the shopping mall.
• “Control Center”
NUCLEUS
• Most prominent organelle.
• All cells in the body contain nucleus except mature RBCs & uppermost layer of skin.
Cell Nucleus: Functions
• Bag of chromosomes: It contains most of the cell's genetic material.
• Storage of DNA, DNA maintenance• Replication & repair of DNA• Site of transcription & post transcriptional
processing/ modification
The control center of a cell:- Controls the activities of cell
by regulating gene expression.
- Production of ribosomal subunits in the nucleolusNucleolus: Actively transcribing region of nucleus• Synthesis of rRNA• Formation of ribosome
subunits
Nuclear membrane • The nuclear membrane protects the nucleus and also
allow substances to pass in and out of the nucleus, as the cell membrane does the same for the cell; like the main office; like the walls of the mall and its entrance, which protect the office and let workers in and out.
• “Gate of the Nucleus”
FUNCTIONS CONT.Nuclear membrane Compartmentalizes the
nucleus
Nuclear poreTransport of molecules between the cytoplasm and the nucleus
Chromatin DNA Replication and transcription
Nuclear matrixReplication, DNA repair and transcriptional process
NucleolusSynthesis of rRNA and ribosomes
Chromosomes
• The chromosomes direct the activities of cells like a mall office director who works in the office and directs all the activities of the shopping mall.
• “Director of the Cell”
Golgi ApparatusDiscovered in 1898 byCamillo Golgi
Found in both plant andanimal cells
Looks like a flattenedstack of membranes (orpancakes!)
Processes and packagesmolecules, like lipidsand proteins, that weremade by the cell
RibosomesFound in both plantand animal cells
Can be attached to theEndoplasmic Membraneor floating free in the cytoplasm
Ribosomes:-• Produces proteins• The smallest organelles• It’s like the brick yardthat supplies a city withwhat it’s made of!
Endoplasmic ReticulumFound in both plant andanimal cells• Network of tubes• Transports materialsthroughout the cellEndoplasmic Reticulum
Two types– Smooth (no ribosomes)– Rough (covered withribosomes)• It’s like a city’s highwaysystem!
‘The Cell’s Delivery System’
Chapter 2Introduction to Biomolecules
Biomolecules Definition
• Biomolecules are molecules that occur naturally in living organisms.
• Biomolecules include macromolecules like proteins, carbohydrates, lipids and nucleic acids.
• It also includes small molecules like primary and secondary metabolites and natural products.
• Biomolecules consists mainly of carbon and hydrogen with nitrogen, oxygen, sulphur, and phosphorus.
• Biomolecules are very large molecules of many atoms, that are covalently bound together.
Classes of Biomolecules
There are four major classes of biomolecules:
• Carbohydrates• Lipids• Proteins• Nucleic acids
Carbohydrates
• Carbohydrates are often known as sugars, they are the 'staff of life' for most organisms.
• They are the most abundant class of biomolecules in nature, based on mass.
• Carbohydrates are also known as saccharides, in Greek sakcharon mean sugar or sweetness.
• Carbohydrates consist of the elements carbon (C), hydrogen (H) and oxygen (O) with a ratio of hydrogen twice that of carbon and oxygen. General formula of carbohydrate is Cn H2n On
• In their basic form, carbohydrates are simple sugars or monosaccharides.
• These simple sugars can combine with each other to form more complex carbohydrates.
• The combination of two simple sugars is a disaccharide.
• Carbohydrates consisting of two to ten simple sugars are called oligosaccharides, and those with a larger numbers are called polysaccharides.
Sugars• Sugars are white crystalline carbohydrates
that are soluble in water and generally have a sweet taste.
Classification of Carbohydrates
• The carbohydrates are divided into three major classes depending upon whether or not they undergo hydrolysis, and if they do, on the number of products formed.
Monosaccharides• The monosaccharides are polyhydroxy
aldehydes or polyhydroxy ketones which cannot be decomposed by hydrolysis to give simpler carbohydrates.
• Examples are glucose and fructose, both of which have molecular formula, C6H12O6.
• Many saccharide structures differ only in the orientation of the hydroxyl groups (-OH).
• This slight structural difference makes a big difference in the biochemical properties, and in the physical properties such as melting point .
• A chain-form monosaccharide that has a carbonyl group (C=O) on an end carbon forming an aldehyde group (-CHO) is classified as an aldose. When the carbonyl group is on an inner atom forming a ketone, it is classified as a ketose.
• On the basis of number of carbon atoms monosaccharide are further classified into following small units:
(i) Trioses (C3 H6 O3) – It contain 3 carbon molecule. Examples are: Glyceraldehyde and and Dihydroxy acetone.
Glyceraldehyde
(ii) Tetroses(C4 H8 O4) – It contain 4 carbon molecules. Examples are: Erythrose, Erythrulose.
D-Erythrose D-Threose D-Erythrulose
(iii) Pentoses (C5 H10 O5) – It contain 5 carbon molecules. Examples are: Ribose, Ribulose, Arbinose,Xylulose, Deoxyribose.
D-Ribose D-Arabinose D-Xylose D-Lyxose
• The ring form of ribose is a component of ribonucleic acid (RNA).
• Deoxyribose, which is missing an oxygen at position 2, is a component of deoxyribonucleic acid (DNA)
• In nucleic acids, the hydroxyl group attached to carbon number 1 is replaced with nucleotide bases.
Ribose Deoxyribose
(iv) Hexoses(C6H12O6) – It contain 6 carbon molecules. Examples are: Glucose, Mannose, Fructose, Galactose etc…
D-Glucose D-Mannose D-Galactose
• Structures that have opposite configurations of a hydroxyl group at only one position, such as glucose and mannose, are called epimers.
• Glucose, also called dextrose, is the most widely distributed sugar in the plant and animal kingdoms and it is the sugar present in blood as "blood sugar".
• Fructose, also called levulose or "fruit sugar", is shown here in the chain and ring forms. Galactose is a constituent of agar-agar. It is also called brain sugar.
• Fructose and glucose are the main carbohydrate constituents of honey.
D-FructoseFructose
(v) Heptoses (C7 H14 O7) – It contain 7 carbon molecules. Examples are: Sedoheptulose.
Sedoheptulose has the same structure as
fructose, but it has one extra carbon. Sedoheptulose is found in carrots.
D-Sedoheptulose
• Many simple sugars can exist in a chain form or a ring form, as illustrated by the hexoses above.
• The ring form is favored in aqueous solutions, and the mechanism of ring formation is similar for most sugars.
• The rearrangement produces alpha glucose when the hydroxyl group is on the opposite side of the -CH2OH group, or beta glucose when the hydroxyl group is on the same side as the -CH2OH group.
α-D-Glucose β-D-Glucose
• Monosaccharides forming a five-sided ring, like ribose, are called furanoses. Those forming six-sided rings, like glucose, are called pyranoses.
Furanose Pyranose
Oligosaccharides
• These sugars are formed by linking of 2-10 units of monosaccharides.
• In Oligosaccharides ,aldehyde or ketone group of one monosaccharide are linked with alcoholic group of another monosaccharide to form Glycosidic bond
(C-O-C).
• The most abundant oligosaccharides are disaccharides, formed by two monosaccharides, and especially in the human diet the most important are sucrose (common table sugar), lactose and maltose.
(i) Disaccharides:
• Carbohydrates which upon hydrolysis give two molecules of the same or different monosaccharides are called disaccharides. Three particular disaccharides are: Sucrose, Maltose & Lactose.
(a) Sucrose: Also called saccharose, is ordinary table sugar refined from sugar cane or sugar beets. When Sucrose is hydrolyzed, it yields one unit of glucose and one unit of fructose.
Sucrose
(b) Maltose (also known as malt sugar): It occurs in the body as an intermediate product of starch digestion. When maltose is hydrolyzed, it yields two molecules of glucose.
Maltose
(c) Lactose ( also known as milk sugar): This disaccharide is found only in milk. When lactose is hydrolyzed it yields one unit of glucose and one unit of galactose.
Lactose
(ii) Trisaccharides:(a) Raffinose: Also called melitose, is a trisaccharide that is widely found in legumes and vegetables, including beans, peas, cabbage etc..
• It consists of galactose connected to sucrose via a 1α→6 glycosidic linkage.
• Humans cannot digest saccharides with this linkage and the saccharides are fermented in the large intestine by gas-producing bacteria.
Raffinose
Polysaccharides• Polysaccharide, also called glycan, the form in
which most natural carbohydrates occur.
• Polysaccharides may have a molecular structure that is either branched or linear.
• Linear compounds such as cellulose often pack together to form a rigid structure; branched forms (e.g., gum arabic) generally are soluble in water and make pastes.
• Polysaccharides composed of many molecules of one sugar or one sugar derivative are called homopolysaccharides (homoglycans).
• Homopolysaccharides composed of glucose include glycogen and starch, the storage carbohydrates of animals and plants respectively; and cellulose, the important structural component of most plants.
• Polysaccharides consisting of molecules of more than one sugar or sugar derivative are called heteropolysaccharides (heteroglycans). Most contain only two different units and are associated with proteins; like Peptidoglycan, proteoglycans etc..
• Hetropolysaccharides provide extracellular support for organisms of all kingdoms.
• The polysaccharides described below play important roles in nutrition, biology, or food preparation.
Types of polysaccharides:(i) Starch: Starch is the major form of stored
carbohydrate in plants. Starch is composed of a mixture of two substances: amylose, an essentially linear polysaccharide, and amylopectin, a highly branched polysaccharide.
• Both forms of starch are polymers of α-D-Glucose. Natural starches contain 10-20% amylose and 80-90% amylopectin.
• Amylose forms a colloidal dispersion in hot water (which helps to thicken gravies) whereas amylopectin is completely insoluble.
a) Amylose molecules consist typically of 200 to 20,000 glucose units which form a helix as a result of the bond angles between the glucose units.
Amylose
b) Amylopectin differs from amylose in being highly branched.
Short side chains of about 30 glucose units are attached with 1α→6 linkages approximately every twenty to thirty glucose units along the chain. Amylopectin molecules may contain up to two million glucose units.
Examples of starch are: Dextrins, Syrups, High fructose corn syrup(HFCS), Polydextrose etc..
(ii) Glycogen: Glucose is stored as glycogen in animal tissues by the process of glycogenesis.
Glycogen is a polymer of α-D-Glucose identical to amylopectin, but the branches in glycogen tend to be shorter (about 13 glucose units)
Glucose chains are organized globularly like branches of a tree originating from a pair of molecules of glycogenin, a protein with a molecular weight of 38,000 that acts as a primer at the core of the structure.
Glycogen is easily converted back to glucose to provide energy.
(iii) Dextran: Dextran is a polysaccharide similar to amylopectin, but the main chains are formed by 1α→6 glycosidic linkages and the side branches are attached by 1α→3 or 1α→4 linkages.
Dextran is an oral bacterial product that adheres to the teeth, creating a film called plaque.
It is also used commercially as food additives..
Dextran
(iv) Cellulose: Cellulose is a polymer of β-D-Glucose, which in contrast to starch, is oriented with -CH2OH groups alternating above and below the plane of the cellulose molecule thus producing long, unbranched chains.
The absence of side chains allows cellulose molecules to lie close together and form rigid structures.
Cellulose is the major structural material of plants.
Wood is largely cellulose, and cotton is almost pure cellulose.
Cellulose can be hydrolyzed to its constituent glucose units by microorganisms that inhabit the digestive tract of termites and ruminants.
Cellulose
(v) Hemicellulose: The term "hemicellulose" is applied to the polysaccharide components of plant cell walls other than cellulose, or to polysaccharides in plant cell walls which are extractable by dilute alkaline solutions.
Hemicelluloses comprise almost one-third of the carbohydrates in woody plant tissue.
The chemical structure of hemicelluloses consists of long chains of a variety of pentoses, hexoses.
Hemicelluloses may be found in fruit, plant stems & grain. Although hemicelluloses are not digestible, they can be fermented by yeasts and bacteria.
• The polysaccharides yielding pentoses on hydrolysis are called pentosans. Xylan is an example of a pentosan consisting of D-xylose units with 1β→4 linkages.
Xylan
(vi) Chitin: Chitin is an unbranched polymer of N-Acetyl-D-glucosamine.
It is found in fungi and is the principal component of arthropod and lower animal exoskeletons, e.g., insect, crabs etc..
It may be regarded as a derivative of cellulose, in which the hydroxyl groups of the second carbon of each glucose unit have been replaced with acetamido (-NH(C=O)CH3) groups.
Chitin
(vii) Pectin: Pectin is a polysaccharide that acts as a cementing material in the cell walls of all plant tissues. Pectin is the methylated ester of polygalacturonic acid, which consists of chains of 300 to 1000 galacturonic acid units joined with 1α→4 linkages.
Pectin is an important ingredient of fruit
preserves, jellies, and jams.
Pectin is a polymer of α-Galacturonic acidwith a variable number of methyl ester (-COOCH3) groups.
Functions of Carbohydrates
Carbohydrates have six major functions within the body:
• Providing energy and regulation of blood glucose• Sparing the use of proteins for energy• Breakdown of fatty acids and preventing ketosis• Biological recognition processes i.e. they are essential for cells to communicate with each other.
• Flavor and Sweeteners• They have the potential to reduce the risks of many chronic diseases.
Lipids: Fats & Oils
LIPIDS• Lipids are naturally occurring hydrophobic
molecules.
• They are heterogeneous group of compounds related to fatty acids. They include fats, oils, waxes, phospholipids, etc.
• They make up about 70% of the dry weight of the nervous system. Lipids are crucial for the healthy functioning of the nerve cells.
• Lipids are greasy or oily organic substances; lipids are sparingly soluble in water and are soluble in organic solvents like chloroform, ether and benzene.
• Lipids are important constituent of of the diet because they are a source of high energy value.
• Lipids combined with proteins are important constituents of the cell membranes and mitochondria of the cell. Lipids are not generally macromolecules.
Classification of Lipids
• They may be classified based on their physical properties at room temperature (solid or liquid, respectively fats and oils), on polarity, or on their essentiality for humans, but the preferable classification is based on their structure.
Types of Lipid
1. Triglycerides [Fats & Oils]
2. Waxes3. Phospholipids4. Steroids5. Glycolipids6. Lipoproteins7. Terpenes
Based on structure, they can be classified in three major groups.
1. Simple Lipids or Homolipids
• These are esters of fatty acids with various alcohols.
(A)Fats and Oils: Esters of fatty acids with glycerol. The difference between fat and oil is only physical. Thus, oil is a liquid while fat is a solid at room temperature.
These triglycerides (or triacylglycerols) are found in both plants and animals, and compose one of the major food groups of our diet.
Fats & Oils•the commonest lipids in nature
•the constituents of fats are:-
fatty acids (alkanoic acids)
glycerol (propane 1-2-3 triol)
(B)Waxes: Esters of fatty acids(usually long chain)with alcohols other than glycerol. These alcohols may be aliphatic or alicyclic. Cetyl alcohol [CH3(CH2)15OH] is most commonly found in waxes.
The name cetyl derives from the whale oil (Latin: cetus) from which it was first isolated.
Example: Beeswax(insect wax), Carnauba wax (important plant wax; also a complex mixture ; hardest known wax)
Fatty acids- general formula: R.COOH
- most have an even number of C - most commonly 16-18
C16H32O2
R
- fatty acids may be: saturated or unsaturated
Saturated fatty acid[Single bonds only]
Unsaturated fatty acid[Double bonds]
Stearic acid, C17H35COOH –Saturated fatty acid Oleic acid, C17H33COOH –
Unsaturated fatty acid
The more double bonds present, the more bent the molecule is
Properties of SaturatedFatty Acids
• Contain only single C–C bonds• Closely packed • Strong attractions between chains• High melting points• Solids at room temperature
201
Properties of UnsaturatedFatty Acids
• Contain one or more double C=C bonds• Nonlinear chains do not allow molecules
to pack closely• Few interactions between chains• Low melting points• Liquids at room temperature
202
Fatty Acids
• The Length of the Carbon Chain– long-chain, medium-chain, short-chain
• The Degree of Unsaturation– saturated, unsaturated,
monounsaturated, polyunsaturated• The Location of Double Bonds–omega-3 fatty acid, omega-6 fatty acid
Monounsaturated Fatty Acid(MUFA)
One carbon-carbon double bond
Polyunsaturated Fatty Acid(PUFA)
More than one carbon-carbon double bond
Location of Double Bonds• PUFA are identified by position of the double bond nearest the methyl end (CH3) of the carbon chain; this is described as a omega number;
• If PUFA has first double bond 3 carbons away from the methyl end=omega 3 FA
• 6 carbons from methyl end=omega 6 FA
Cis and Trans Fatty Acids
• Because of the presence of doubles bond in aliphatic hydrocarbon chain of unsaturated fatty acids, they can exhibit geometrical isomerism also called as cis-trans isomerization.
• Naturally occurring fatty acid exhibit cis-configuration which can be modified to artificial configuration known as trans.
• In cis-form the hydrogen atoms of double bonded carbon atom oriented on same side, however in trans form they oriented in opposite direction.
• The differences in geometry of trans and cis-unsaturated fatty acids play an important role in biological processes.
• Cis and trans forms of fatty acids show different physical and chemical properties just like other organic geometrical isomers.
• Trans isomers show high melting points due to closely packed structure compare to cis isomers.
• The configuration of unsaturated fatty acids not only affects their physical properties but also their health implications.
Some other differences between cis and trans-fatty acids are as follows.
2. Compound Lipids or Heterolipids
• Esters of fatty acids containing groups in addition to an alcohol and a fatty acid.
(a)Phospholipids: Lipids containing, in addition to fatty acids and an alcohol, a phosphoric acid residue.
• They frequently have nitrogen containing bases and other substituent's, e.g., in glycerophospholipids the alcohol is glycerol and in sphingophospholipids the alcohol is sphingosine.
(b) Glycolipids (glycosphingolipids): Lipids containing a fatty acid, sphingosine, and carbohydrate.
(c) Other complex lipids: Lipids such as sulfolipids and aminolipids. Lipoproteins may also be placed in this category.
215
3. Precursor and derived lipids:• This group includes:– Fatty Acids.–Glycerol.–Cholesterol.– Steroid hormones.– Fatty aldehydes.– Fat soluble vitamins [ A D E K].– Some other alcohols.
Derived lipids• Derived lipids are the substances derived from
simple and compound lipids by hydrolysis.
• These includes fatty acids, alcohols, monoglycerides and diglycerides, steroids, terpenes, carotenoids.
• The most common derived lipids are steroids, terpenes and carotenoids.
• Steroids do not contain fatty acids, they are nonsaponifiable, and are not hydrolyzed on heating.
• They are widely distributed in animals, where they are associated with physiological processes.
• They performs various functions such as hormones and contributes to the structure of cell membranes.
Steroids• Steroids are: Lipids containing the steroid
nucleus, which is a fused structure of four rings.
• Found in cholesterol, bile salts, hormones, and vitamin D.
a. Cholesterol • The most abundant steroid in the body.
•Contains 27 carbon atoms.
• At C3 there is a –OH group; so it is an alcohol. Composed of the steroid nucleus with methyl groups, an alkyl chain, and a hydroxyl group attached.
b. Bile Salts• Are synthesized from cholesterol and stored
in the gall bladder.
• Emulsify fats and oils to give a greater surface area for lipid digesting enzymes.
Terpenes• In majority are found in plants. Example:
natural rubber. Gernoil, etc.
• Are volatile organic compounds which are odoriferous constituents of essential oils.
• They contain carbon, hydrogen and oxygen and are not aromatic in character.
Carotenoids• Carotenoids are tetraterpenes. They are widely distributed in both plants and animals.
• They are exclusively of plant origin.
• Due to the presence of many conjugated double bonds, they are colored red or yellow. Example: Lycopreene, carotenes, Xanthophylls.
Function of Lipids
Lipids perform several biological functions:
• Lipids are storage compounds, triglycerides serve as reserve energy of the body.
• Lipids are important component of cell membranes structure in eukaryotic cells.
• Lipids regulate membrane permeability.
• They serve as source for fat soluble vitamins like A, D, E, K.
• As lipids are small molecules and are insoluble in water, they act as signalling molecules.
• Cholesterol maintains fluidity of membranes by interacting with lipid complexes.
• Layers of fat in the subcutaneous layer, provides insulation and protection from cold. Body temperature maintenance is done by brown fat.
Summary LipidsIt’s sub types: ClassificationFatty AcidsTypes of fatty acidsCompound and derived lipidsFunctions of lipids
Proteins
What is a Protein?
The word protein came from a Greek word “Proteios”Proteins are like long necklaces with differently
shaped beads. Each "bead" is a small molecule called an amino acid.
Compounds composed of carbon, hydrogen, oxygen, and nitrogen and arranged as strands of amino acids
• Proteins are a class of most important compounds that are found in living organisms.
• Proteins are the main constituents of our body such as muscles, skin, hair and nails.
• Protein carry all vital life processes in the human system.
• Proteins are a vast class of substances of almost unbelievable diversity in structure and function.
What is Amino Acid?
• Amino acids are derivatives of carboxylic acids formed by substitution of -hydrogen for amino functional group
What do Amino Acids Do? Amino acids are essential to life, have a role in
metabolism, and are important in nutrition. They form short polymer chains called peptides, as
well as longer chains that are called polypeptides or proteins.
About 75 percent of the human body is made up of chains of amino acids, which is why they are so vital to how your system functions.
All the chemical reactions that occur in the body depend on amino acids and the proteins they build.
Amino Acids• Amino Acids are the building units of proteins. Proteins are polymers of amino acids linked together by what is called “ Peptide bond”.
• There are about 300 amino acids occur in nature. Only 20 of them occur in proteins.
• Each amino acid has 4 different groups attached to α- carbon ( which is C-atom next to COOH). These 4 groups are : amino group, COOH gp, Hydrogen atom and side Chain (R)
R
• At physiological PH (7.4), -COOH gp is dissociated forming a negatively charged carboxylate ion (COO-) and amino gp is protonated forming positively charged ion (NH3+) forming Zwitter ion
• Amino acid structures differ at the side chain (R-groups).
• Abbreviations: three or one letter codes
• Amino acids (except glycine) have chiral centers:
• There are 20 commonly occurring amino acids that make up proteins, and the order of amino acids in proteins determines its structure and biological function.
Classification of amino acids
• Amino acids are classified into different ways based on polarity, structure, nutritional requirement, metabolic fate, etc.
• Generally used classification is based on polarity.
• Amino acid polarity chart shows the polarity of amino acids.
Classification on polarity basis
Based on polarity, amino acids are classified into four groups as follows,
• Non-polar amino acids.• Polar amino acids with no charge.• Polar amino acids with positive charge.• Polar amino acids with negative charge.
Classification of ProteinsProteins ate divided into three main classes :
1. Simple proteins2. Conjugated proteins3. Derived proteins
Classification of Proteins
Simple proteins• The simple proteins are those which are made of amino acid units only, joined by peptide bond.
• Upon hydrolysis they yield mixture of amino acids or their derivatives. They include the following groups:-
(a) Albumins: These are water soluble-proteins found in all body cells and also in the blood stream. Examples are: lacto albumin found in milk ; serum albumin found in blood and egg albumin found in egg.
(b) Globulins: These are insoluble in water but are soluble in dilute salt solutions of strong acids and bases. Examples of globulins are lactoglobulin found in milk and ovoglobulin in egg yolk.
(c) Glutelins: These are soluble in dilute acids and alkalis. The
protein glutenin of wheat and oryzenin of rice is an example. They occur only in plant material.
(d) Histones: These are water soluble proteins in which basic amino acids predominates. They are rich in arginine or lysine. In eukaryotes the DNA of the chromosomes is associated with histones to form nucleoproteins.
(e) Protamines: These are water soluble basic polypeptides with a low molecular weight (about 4,000 Daltons).
Protamines are found bound to DNA in spermatozoa of some fishes. Examples of protamines are salmine (in salmon) and sturine (in sturgeons)
Conjugated proteins• These consist of simple proteins in
combination with some non-protein component.
• The non-protein groups are called prosthetic groups. Conjugated protein includes the following group:-
(a) Nucleoproteins: (Protein + nucleic acid). Nucleoproteins are proteins in combination with nucleic acids. Examples are: Nucleohistone.
(d) Chromoproteins: These are proteins in combination with a
prosthetic group that is a pigment. Examples are the respiratory pigments hemoglobin.
(c) Phosphoproteins (Protein+phosphate): Phosphoproteins are proteins in combination with a phosphoric acid residue as a prosthetic group.
Examples of phosphoproteins are casein of milk and vitellin in egg yolk.
(e) Lipoproteins: These are proteins conjugated with lipids. There are different types of lipoproteins, high density lipoproteins (HDL), low density lipoproteins(LDL); Very low density lipoprotein(VLDL).
(f) Metalloproteins: These are proteins conjugated to metal ion
(s). Example : The heme protein, which contain iron are classed as chromoproteins also are metalloproteins.
Derived proteins
They are substances resulting from the decomposition of simple and conjugated proteins as in peptones, peptides.
Derived proteins are subdivided into primary derived proteins and secondary derived proteins.
Derivatives of proteins due to action of heat, enzymes, or chemical reagents.
a) Primary Derivedb) Secondary Derived
Primary derived proteins – • Proteans, • Metaproteins and • Coagulated proteins. Example: cooked egg albumin etc..
Secondary derived proteins – • Proteoses, • Peptones and • Polypeptides.
STRUCTURE OF PROTEINS
Four different levels of structure –
Primary,
Secondary,
Tertiary and
Quaternary
PRIMARY STRUCTURE
Secondary Structure
Tertiary & Quaternary Structure Structure
Protein FunctionsAntibodies
Contractile Proteins
Enzymes
Hormonal Proteins
Transport Proteins
Storage Proteins
Structural Proteins
NUCLEIC ACIDS
It’s Composition
DNA
RNA
Composition of DNA
• A pentose sugar – Deoxy ribose sugar
• Nucleotides – A,T,G,C
• A phosphate
Pentose sugar in DNA• Deoxyribose sugar– 4 C atoms and oxygen molecule forms the ring– 5th C atom is outside the, part of CH2 group– 3 OH groups at positions 1,3,5
Nitrogen Bases• There are four nitrogen bases making up four different nucleotides.
Adenine
Guanine
Thymine
CytosinePyrimidines
PurinesA
C
G
T
N base
Nucleic Acid Composition phosphate
nucleotide
N base
PO4
SugarSugar
PO4
N baseThe numbers are the positions of the carbons on the sugar.
(the 3’ end)
5
4
3 2
1
(the 5’ end)
sugarnitrogen base
DeoxyriboNucleic Acid
Nucleosides & Nucleotides• Nucleotide = a nitrogenous (nitrogen-containing) base + a pentose + a phosphate
• Nucleoside = a nitrogenous (nitrogen-containing) base + a pentose
A molecule of DNA is formed by millions of nucleotides joined together in a long chain
PO4
PO4
PO4
PO4
sugar-phosphate backbone
+ bases
Joined nucleotides
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
PO4
Double stranded DNA
The bases always pair up in the same way
Adenine forms a bond with Thymine
And cytosine bonds with guanine
Adenine Thymine
Cytosine Guanine
The paired strands are coiled into a spiral called
A DOUBLE HELIX
sugar-phosphatechain
Bases
Formation of Phosphodiester bonds to make a polynucleotide strand
Structure of DNA: Watson & Crick model
Erwin Chargaff
A AA AA A
AT
T
T
T TT
T
CCC G G
G
The Properties of DNA
Types of DNA
DNA as a genetic material
Is the Genetic Material Protein or DNA
Direct evidences come from :
• Frederick Griffith’s (1928) experiment.
• Hershey and Chase (1952 ) experiment.
Frederick Griffith’s (1928) experiment.
STEPS IN THE EXPERIMENT
1 LIVE SIII
2 LIVE RII
3 H K S III 4 H K S III & LIVE RII
Strains of Streptococcus pneumoniae injected to mice
Griffith’s Experiment
RII SIII Transformation takes place in step 4 gives clue for DNA as
“genetic material”
1
2
3
4
Hershey & Chase Experiment
(1952)
Life Cycle of T-2 Phage
Phage is made of DNA and protein coatOnly DNA enters
in the Bacterial cell and protein coat is left out side
288
Events which take place in life cycle of bacteriophage
HERSHEY & CHASE CONCLUSION
Summary of Hershey & Chase (1952 ) experiment
End of Presentation
RNA STRUCTURE AND FUNCTIONS
What we will be discussing?
RNAIntroductionStructure Different types & functionsConclusion
Structure of RNA
THE NUCLEOTIDE: RNA OH
O=P-O-5CH2 BASE
OH O 4C 1C
H H H H 3C 2C
OH 0H
AdenineGuanineCytosineUracil
Synthesis
Types of RNAMessenger RNA (mRNA)carries information from DNA to the ribosome
Transfer RNA (tRNA)involved in the process of translation
Ribosomal RNA (rRNA)
RNA Types
Messenger RNA (mRNA)
Comprises only 5% of the RNA in the cell
Ribosomal RNA (rRNA)
Transfer RNA (tRNA)
Functions of different RNA
RNA V/S DNA
Differences between RNA and DNAS.No. RNA DNA1) Single stranded mainly except
when self complementary sequences are there it forms a double stranded structure (Hair pin structure)
Double stranded (Except for certain viral DNA s which are single stranded)
2) Ribose is the main sugar The sugar moiety is deoxy ribose
3) Pyrimidine components differ. Thymine is never found(Except tRNA)
Thymine is always there but uracil is never found
4) Being single stranded structure- It does not follow Chargaff’s rule
It does follow Chargaff's rule. The total purine content in a double stranded DNA is always equal to pyrimidine content.
Differences between RNA and DNAS.No. RNA DNA5) RNA can be easily destroyed by
alkalies to cyclic diesters of mono nucleotides.
DNA resists alkali action due to the absence of OH group at 2’ position
6) RNA is a relatively a labile molecule, undergoes easy and spontaneous degradation
DNA is a stable molecule. The spontaneous degradation is very slow. The genetic information can be stored for years together without any change.
7) Mainly cytoplasmic, but also present in nucleus (primary transcript and small nuclear RNA)
Mainly found in nucleus, extra nuclear DNA is found in mitochondria, and plasmids etc
8) The base content varies from 100- 5000. The size is variable.
Millions of base pairs are there depending upon the organism
S.No. RNA DNA9) There are various types of RNA –
mRNA, r RNA, t RNA. These RNAs perform different and specific functions.
DNA is always of one type and performs the function of storage and transfer of genetic information.
10) No variable physiological forms of RNA are found. The different types of RNA do not change their forms
There are variable forms of DNA (A, B and Z)
11) RNA is synthesized from DNA, it can not form DNA(except by the action of reverse transcriptase). It can not duplicate (except in certain viruses where it is a genomic material )
DNA can form DNA by replication, it can also form RNA by transcription.
12) Many copies of RNA are present per cell
Single copy of DNA is present per cell.
VITAMINS
• Organic (carbon-containing) compounds that are essential in small amounts for body processes
• Do not provide energy• Enable the body to use the energy provided
by fats, carbohydrates, and proteins• Mega doses can be toxic.
Classification of Vitamins
Vitamin AAlternative Names:Retinol; Retinal; Retinoic acid; Carotenoids
• Is a fat-soluble vitamin.
• Preformed vitamin A is found in animal products .
• Pro-vitamin A is found in plant-based foods
Vitamin A (and carotenoids)• Functions:– Normal vision– Protects from
infections– Regulates
immune system
– Antioxidant (carotenoids)
• Food sources:– Liver– Fish oil– Eggs– Fortified milk or
other foods– Red, yellow, orange,
and dark green veggies (carotenoids)
Excess Birth defects, hair
loss, dry skin, headaches, nausea,
dry mucous membranes, liver damage, and bone and joint pain
Deficit Night blindness, dry, rough skin, increased
susceptibility to infections
Vitamin DAlternative Name: Calciferol
Regulation of Calcium metabolism
Vitamin D (the sunshine vitamin)
Functions:–Promotes absorption
of calcium and phosphorus–Helps deposit those in
bones/teeth–Regulates cell growth–Plays role in immunity
Sources:– Sunlight (10 – 15
mins 2x a week)– Salmon with bones–Milk– Orange juice
(fortified)– Fortified cereals
Excess Deposits of calcium
and phosphorus in soft tissues, kidney, and heart damage.
Deficit Poor bone and tooth
formation, rickets which causes malformed bones and pain in infants
Osteomalacia (softening of bones)
Osteoporosis (brittle, porous bones)
VITAMIN EAlternative Name: TocopherolFunctions: AntioxidantEnhances immune systemRetards spoilage of commercial foods
Sources of Vitamin E• Vegetable oils: corn,
soybean, and products made from them.
• Wheat and green leafy vegetables
Excess Relatively
nontoxic, fat-soluble vitamin
Excess stored in adipose tissue
Avoid long-term mega doses.
Deficit
Serious neurological defects can occur from mal absorption.
Vitamin KAlternative Name: Phylloquinone Made up of several compounds essential for
blood clotting.
Vitamin K is destroyed by light and alkalis.
Functions of Vitamin K
Formation of prothrombin for clotting of blood
Sources of Vitamin K• Green leafy vegetables such as broccoli,
cabbage, spinach
• Bacteria in small intestine synthesizes some vitamin K, but must be supplemented by dietary sources.
Excess Anemia can result
from excessive amounts of synthetic vitamin K.
Deficit Defective blood
coagulation, which increases clotting time and makes client prone to hemorrhage.
Water-Soluble Vitamins• Vitamin B complex and C• Dissolve in water• Easily destroyed by air, light, and cooking
Vitamin B1 Alternative Name: Thiamin
Function: Used in metabolism of carbohydrates for energy.
muscle and nerve function, and hydrochloric acid production in the stomach
Sources of Vitamin B1
• Whole grains, • Rice, • Pasta, • Fortified cereals, • Meat and pork.
DeficiencyRare- BeriberiLoss of muscle function, Nerve damage,Mental confusion
Vitamin B2
Alternative Name: RiboflavinFunction:Helps in energy production, Making niacin( Vit. B3), Red blood cell formation & human growth.
Sources of Vitamin B2
• Dairy, • Eggs, • Green leafy vegetables, • Nuts, meat, • Legumes, and • Enriched flour
DeficiencyUncommon- anemia,mouth sores, sore throat, swelled mucous membranes& skin disorders.
Vitamin B3
Alternative Name: NiacinFunction:Used in metabolism, to produce hormones, enzyme & nerve function & reducing cholesterol
Sources of Vitamin B3
• Pork,• Fish, beef, • Peanut butter, • Legumes, • Enriched and fortified grains
DeficiencyPellagra is characterized by the 4 D’s: Dermatitis, Diarrhea, Dementia & Death
Vitamin B5
Alternative Name: Pantothenic AcidFunction:Used to make blood cells, cholesterol,
hormones ,metabolize fat & carbohydrates
Sources of Vitamin B5
• Poultry, fish, • Cereals, • Unprocessed foods.
Deficiency• Very rare- only seen in severe malnutrition. Symptoms are:• Headache, • fatigue, • burning & numbness of feet
Vitamin B6
Alternative Name: PyridoxineFunction: Protein metabolism, Blood cell formation, Immune system function, and Niacin production
Sources of Vitamin B6
• Chicken, • Pork, fish, • Grains, • Nuts & legumes
Deficiency• Dermatitis• Fatigue• Anemia
Vitamin B7
Alternative Name: BiotinFunction: Used in fatty acid synthesis, also other functions.
Maintaining a strong immune system & proper working of the nervous system.
Sources of Vitamin B7
• Generally produced in the intestine, in the presence of healthy intestinal flora.
• Cereals, • Pulses & legumes, • Vegetables, nuts
DeficiencyPain, Tiredness, Lack of appetite, Muscular weakness,
Vitamin B9
Alternative Name: Folic AcidFunction: For synthesis of glycine, methionine,
nucleotides etc..Important for rapidly dividing cells
Sources of Vitamin B9
• Broccoli,• Citrus Fruits,• Beans, Peas• Avocado,• Spinach
DeficiencyLinked to neural tube defects in fetus,
Inflammation of mouth & tongue, poor growth, depression & mental confusion,
Megaloblastic anemia
Vitamin B12
Alternative Name: CyanocobalaminFunction: B12 is also used in regenerating folateHelps in the formation of red blood cells
Sources of Vitamin B12
• Meats (beef liver)• Meat, • Poultry, • Eggs,• Milk and other dairy foods
DeficiencySore tongue,Stomach upset and weight lossRapid heartbeat and breathingWeakness, tiredness
Vitamin C
Alternative Name: Ascorbic AcidFunction: An antioxidant vitamin,For healthy teeth, gums and blood vessels;Improves iron absorption and resistance to
infection
Sources of Vitamin C
• Fresh vegetables & fruits,• Broccoli,• Cauliflower, lemon, cabbage, pineapples,
strawberries, citrus fruits.
DeficiencySore tongue,Stomach upset and weight lossRapid heartbeat and breathingWeakness, tiredness
ENZYMES
What Are Enzymes?• Most enzymes are
Proteins (tertiary and quaternary structures)
• Act as Catalyst to accelerates a reaction
• Not permanently changed in the process
Enzymes• Are specific for what
they will catalyze• Are Reusable• End in –ase
-Sucrase-Lactase-Maltase
How do enzymes Work?
Enzymes work by: weakening bonds
which lowers activation energy
Enzymes lower the activation energy of a reaction
Final energy state of products
Initial energy stateof substrates
Activation energyof uncatalysed reactions
Activation energyof enzyme catalysedreaction
Progress of reaction (time)
Ener
gy le
vels
of m
olec
ules
Enzyme-Substrate Complex
The substance (reactant) an enzyme acts on is the substrate
EnzymeSubstrate Joins
Active Site• A restricted region of an enzyme
molecule which binds to the substrate.
EnzymeSubstrate
Active Site
Enzymes lower activation energy by forming an enzyme/substrate complex
Substrate + Enzyme
Enzyme/substrate complex
Enzyme/product complex
Product + Enzyme
Classification of Enzymes
EC 1. Oxidoreductases
EC 2. Transferases
EC 3. Hydrolases
EC 4. Lyases
EC 5. Isomerases
EC 6. Ligases
Theories for Enzyme- Substrate Binding
Two Theories have been proposed to explain the interaction of enzyme and substrate LOCK & KEY MODEL
INDUCED – FIT THEORY
Lock and Key
Lock-and-key hypothesis assumes the active site of an enzyme is rigid in its
shape
How ever crystallographic studies indicate proteins are flexible.
380
Induced Fit• A change in the
shape of an enzyme’s active site• Induced by the
substrate
The Induced-fit hypothesis suggests the active site is flexible and only assumes its catalytic conformation after the substrate molecules bind to the site.
When the product leaves the enzyme the active site reverts to its inactive state.
What Affects Enzyme Activity?
Enzyme activity
How fast an enzyme is workingRate of Reaction
Rate of Reaction = Amount of substrate changed (or amount product formed) in a given period of time.
Enzyme activity
Four Variables
TemperaturepH
Enzyme Concentration
Substrate Concentration
Rate
of R
eacti
on
Temperature
0 20 30 5010 40 60
40oC - denatures
5- 40oC Increase in Activity
<5oC - inactive
Effect of heat on enzyme activityIf you heat the protein above its optimal
temperature bonds break
meaning the protein loses it secondary and tertiary structure
Effect of heat on enzyme activty
Denaturing the proteinACTIVE SITE CHANGES SHAPE
SO SUBSTRATE NO LONGER FITS
Even if temperature lowered – enzyme can’t regain its correct shape
Rate of R
eaction
pH
Rate
of R
eacti
on
pH
1 3 42 5 6 7 8 9
Rate
of R
eacti
on
Enzyme Concentration
Rate
of R
eacti
on
Enzyme Concentration
Enzyme Concentration
Rate
of R
eacti
on
Substrate Concentration
Rate
of R
eacti
on
Substrate Concentration
Substrate Concentration
Rate
of R
eacti
on
Substrate Concentration
Substrate Concentration
Active sites full- maximum turnover
Cofactors and Coenzymes
• Inorganic substances (zinc, iron) and vitamins (respectively) are sometimes need for proper enzymatic activity.
• Example:Iron must be present in the quaternary structure
- hemoglobin in order for it to pick up oxygen.
Two examples of Enzyme Inhibitors
a. Competitive inhibitors: are chemicals that resemble an enzyme’s normal substrate and compete with it for the active site.
EnzymeCompetitive inhibitor
Substrate
Inhibitorsb.Noncompetitive inhibitors:
Inhibitors that do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, which in turn alters the active site.
Enzymeactive site altered
NoncompetitiveInhibitor
Substrate
Applications of Enzymes
Enzymes in industry• There are many uses of enzymes in industry.
Examples of these are:• Clothes/dishwashing detergents• Baby food• Starch(HFCs)• Glucose(Fructose-Slimming Aid)• Medical Diagnosis• Diabetes Control• Curing Disease
Enzymes in Clothes/Dishwasher Detergents
• People use biological detergents to remove stains.• Biological washing powders contain proteases and
lipases.• These enzymes break down proteins and fats in the
stain.AdvantagesEnzymes give you a cleaner wash.Work at lower temperatures-this means you use less electricity.
DisadvantagesIf water too hot, enzymes become denatured.
Enzymes in baby food
• Proteases are used to make baby food.• Proteases ‘pre-digest’ some of the protein in
the food.
AdvantagesTreating food with protease enzymes make it easier for a baby’s digestive system to cope with it.
Starch(HFCS)
• Carbohydrases are used to convert starch into sugar (glucose) syrup.
Did You Know?HFC stands for High Fructose Corn Syrup.
Enzymes In Slimming Aids
• The enzyme, isomerase, is used to change glucose syrup to fructose syrup. Glucose and fructose contain exactly the same amount of energy.
Enzymes To Diagnose Disease
Enzymes To Diagnose and Control Disease
• A common test for sugar in the urine relies on a color change on a test strip. The test strip contains a chemical indicator and an enzyme.
Enzymes to cure disease
If you have a heart attack. An enzyme called streptokinase will be injected into your blood as soon as possible.
Introduction
Functions of Hormones
Characteristics of Hormones
Mechanism of Hormones
All hormones in the human body can be divided into lipid-derived, amino acid-derived, and peptide hormones.
Key Points• Most lipid hormones are steroid hormones, which
are usually ketones or alcohols and are insoluble in water.
• Steroid hormones (ending in '-ol' or '-one') include estradiol, testosterone, aldosterone, and cortisol.
• The amino acid-derived hormones (ending in '-ine') are derived from tyrosine and tryptophan and include epinephrine and norepinephrine (produced by the adrenal medulla).
Key Points• Amino acid-derived hormones also include thyroxin (produced
by the thyroid gland) and melatonin (produced by the pineal gland).
• Peptide hormones consist of a polypeptide chain; they include molecules such as oxytocin (short polypeptide chain) or growth hormones (proteins).
• Amino acid-derived hormones and protein hormones are water-soluble and insoluble in lipids.
Plant & Animal Hormones
Plant Hormones• AUXIN• CYTOKININ• GIBBERELLIN• ETHYLENE
Animal Hormones
