topic two: biochemistry carbohydrateslipidsproteins nucleic acids

Topic Two: BiochemistryTopic Two: BiochemistryCarbohydratesCarbohydrates

LipidsLipidsProteinsProteins

Nucleic AcidsNucleic Acids

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Four Types of Organic MoleculesFour Types of Organic Molecules• There are 4 major types of organic molecules important in biology.

Carbohydrates

monosaccharides, disaccharides,

polysaccharidesLipids

Triglycerides, Phospholipids,

Waxes, Steroids

Proteins

Primary, Secondary, Tertiary, Quaternary

Nucleic Acids

DNA, RNA

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MetabolismMetabolism• Metabolism: All the chemical

reactions that occur in the body.– Can be catabolic or anabolic– Over 200,000 reactions occur in your Over 200,000 reactions occur in your

body cellsbody cells• Monomers are basic subunits used

to build larger molecules. – Eg. Amino acids

• Polymers are molecules composed of many monomers bonded together– Eg. Many amino acids bond together

to form a protein.

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Catabolic vs. Anabolic ReactionsCatabolic vs. Anabolic ReactionsCatabolic Reactions:• Larger molecules

(polymers) break down into smaller units (monomers)

• Ex. Digestion (breaking down food)

Anabolic Reactants:• Small units (monomers)

combine to make larger molecules (polymers)

• Ex. Plants and photosynthesis

Catabolic Reactions

Anabolic Reactions

Polymers Polymers

Monomers

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Monomer:

Amino acid

Polymer:

Protein

Ex: Proteins in the human body

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HydrolysisHydrolysis

• Larger molecule is broken down using water• Water is taken up at the broken bond site

+

H2O

“water” “to cut”

CATABOLIC !!

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Dehydration SynthesisDehydration Synthesis

• Larger molecules are formed by removing water

+

H2O

“To take water out” “To make”

ANABOLIC !!

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Catabolic vs. Anabolic ReactionsCatabolic vs. Anabolic Reactions

How to Remember these terms:CHAD: Catabolic – Hydrolysis,

Anabolic – Dehydration Synthesis

• Carbohydrates are the body’s most important source of energy!

• The human body cannot make carbohydrates itself

• We must consume plants for carbohydrates.

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Topic 2-2: CarbohydratesTopic 2-2: Carbohydrates

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Characteristics of CarbohydratesCharacteristics of Carbohydrates• A carbohydrate can be a single sugar or

polymer of many sugars• Carbohydrates are composed of carbon

(C), hydrogen (H), and oxygen (O)– Ratio of carbon, hydrogen, oxygen =

1:2:1– Ex. Glucose C6H12O6

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Two Purposes of CarbohydratesTwo Purposes of CarbohydratesStructural

Major structural component of cell organelles, membranes, cell wall

Ex. cellulose

Energy

Produced by photosynthesis, carbohydrates are the major energy source for cells. Energy is released

through cell respiration

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Types of CarbohydratesTypes of CarbohydratesMonosaccharides

“1 sugar unit”

Ex: glucose/fructose

Disaccharides

“2 sugar units”

Ex: sucrose

Polysaccharides

“many sugar units”

Ex: starch/ glycogen

Classified by the

number of sugar

units they contain

How are disaccharides and polysaccharides formed?

Dehydration Synthesis!!

CarbohydratesCarbohydrates

+

H2O

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MonosaccharidesMonosaccharides• Monosaccharides

are made of single sugar units

• Examples include:– glucose– fructose

– These are all isomers • Same chemical

formula C6H12O6

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Types of MonosaccharidesTypes of Monosaccharides

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Use the chart to help fill in your workbooksUse the chart to help fill in your workbooks Monosaccharide Origin Purpose

Glucose

Fructose

From food, found in human blood plasma + all cells

Main source of fuel for cells

Found in fruits and honey. Twice as sweet as glucose

Sweetest naturally occurring carbohydrate. Used for sweeteners.

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DisaccharidesDisaccharides• Formed by the joining of two monosaccharides

– Process called dehydration synthesis (water molecule is extracted from the two monosaccharide sugar molecules that come together)

Disaccharides: aka double sugars!!!

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Disaccharides - SucroseDisaccharides - Sucrose

Ex: glucose + fructose make sucrose and water The reverse process is called HYDROLYSIS (uses water)

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Three Common DisaccharidesThree Common DisaccharidesDisaccharide(ISOMERS)

Monomers General comments

Sucrose Glucose + Fructose From sugar cane plant, used as table sugar

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PolysaccharidesPolysaccharides: : AKA AKA Complex CarbohydratesComplex Carbohydrates

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PolysaccharidesPolysaccharides• Formed by the union of many monosaccharides by

dehydration synthesis

Major Role a) Energy Major Role a) Energy StorageStorage

energy storage molecles in organisms are starch (plants) glycogen (animals)

liver

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PolysaccharidesPolysaccharides

Major Role b) Structural Major Role b) Structural SupportSupport

such as cellulose (plants) and chitin (exoskeletons)

Important PolysaccharidesImportant Polysaccharides

What are the two important polysaccharides used for energy storage in

organisms?

STARCH (PLANTS) and GLYCOGEN (ANIMALS)

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StarchStarch• Monomers used: glucose• Function: energy storage in

plants• Other: Glucose molecules

that are not required for growth or energy in the cell are linked together to form starch

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GlycogenGlycogen

• Monomers used: glucose• Function: Storage of glucose in

animals (liver and muscle cells)– High Blood Glucose -Glycogen formed in

the liver– Low Blood Glucose -Glycogen is broken

down • Other: When energy is needed by

the cell, stored glycogen is broken down into glucose molecules to be used for energy

Darker meats mean most of the stored

glycogen has broken down into lactic acid

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CelluloseCellulose• Monomers used: glucose • Function: Main structural

material in plant cell walls• Other: The bonds between the

glucose molecules are difficult to break, so cellulose is not easily digested. – Cotton, wood and wood products like

paper are almost entirely made of cellulose!

– Digestion in cows, horses, goats and termites is done by microorganisms that live in their digestive tracts

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Why can’t we digest Why can’t we digest cellulose??cellulose??

• Humans don’t have cellulase – an enzyme to break down cellulose)

• But… we still need cellulose (aka fiber) to hold water in the large intestine, and help eliminate wastes

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Topic 2-3: LipidsTopic 2-3: Lipids• Lipids are insoluble (do not dissolve) in water • Contains carbon, hydrogen, and oxygen

• Ratio of H to O is greater than 2 to 1• Examples include

– triglycerides– phospholipids– steroids

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Purposes of LipidsPurposes of Lipids• Long Term Energy Storage

– Lipids are long term energy storage molecules

• contain more than twice the calories compared to carbohydrates or proteins

• Structural Material–cell membranes–cushion for organs–carriers for vitamins–raw materials for synthesis of hormones–insulators

Types of Lipids: TriglyceridesTypes of Lipids: Triglycerides• Triglycerides

– Commonly known as fat– Formed from one glycerol and 3 fatty acids by

dehydration synthesis

glyc

erol

Fatty Acid #1

Fatty Acid #2

Fatty Acid #3

O

O

O

Triglyceride (fat)

Total = 3 waters produced

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2 Types of Fatty Acids:2 Types of Fatty Acids:• SATURATED FAT

– Source: usually from animals

– Single/double bond: only single bonds between carbon atoms

– Reactivity: Very Stable -- hard to break down

– Solid/liquid: solid or semi-solid at room temperature

– Example: butter

UNSATURATED FAT• Source: usually from plants• Single/double bond:

unsaturated fatty acids have some double bonds between carbon atoms

• Reactivity: more reactive than fats and easy to break down

• Solid/liquid: liquid at room temperature

• Example: Canola oil

Types of Fatty AcidsTypes of Fatty Acids

http://www.youtube.com/watch?v=RiYOuI7iyp8&safety_mode=true&safe=active

Bill Nye- clots 4:30 – 6:18http://www.youtube.com/watch?v=YlCX2NCEgcM&safety_mode=true&safe=active

Bill Nye- Fat is bad. Fruit, veg good 1:53 – 3:23

https://www.youtube.com/watch?v=KG_ybdk1VaE ASAP Science – butter vs. margarine 3:09

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Types of Lipids: PhospholipidsTypes of Lipids: Phospholipids• Phospholipids are a major component of cell membranes• Formed from one glycerol, two fatty acids and one

phosphate

glyc

erol

Fatty Acid #1

Fatty Acid #2

Phosphate

O

O

O

Hydrophilic

Hydrophobic

Cell MembraneCell Membrane

– Phosphate replaces one of the fatty acids • Phosphate is hydrophilic (polar)• Fatty acid tails are hydrophobic (nonpolar)

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Types of Lipids: Steroids

• Structure = four fused carbon rings• Function = building material for hormones, bile etc• Common examples are cholesterol and testosterone

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Effects of Steroids

• Read: “The Cholesterol Controversy” • Answer questions 1 – 5 in your workbook

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Homework Assignment

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Cholesterol ControversyCholesterol Controversy1. What is Cholesterol?• Cholesterol is a waxy steriod of fat. (abundant

in animal fats, brain and nerve tissue, meat and eggs)

• functions in the body as a membrane constituent and as a precursor of steroid hormones and bile acids.

2. Why has cholesterol been so important to health conscious consumers?

• levels in the blood are associated with arteriosclerosis, gall stones and heart disease!

• People with a certain genetic makeup are predisposed to arteriosclerosis…Can lead to heart disease!!!!!

Arthrosclerosis

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LDLs vs. HDLsLDLs vs. HDLs3. What do HDL and LDL stand for?• HDL = High Density Lipoprotein, • LDL = Low Density Lipoprotein 4. What is the function of HDL’s and LDL’S?Low-density lipoprotein is the major cholesterol carrier in the blood • LDL’s are “bad cholesterol”• High levels of LDLs have been associated with the clogging of arteries known as a

plaque• Plaque restricts blood flow to the heart + brain & can lead to heart attack or stroke

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• HDLs (which are good!) carry LDLs back to the liver, which begins breaking it down

• High density lipoproteins lower blood cholesterol• eating a balanced diet, exercising, and stopping tobacco

use, medications can increase HDLs!!

State the function of HDLs & LDLsState the function of HDLs & LDLs

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Cholesterol & DietCholesterol & Diet• People get cholesterol in two

ways– The liver produces cholesterol– Foods contain cholesterol – especially

egg yolks, meat, poultry, fish, seafood and whole-milk dairy products

• Typically the body makes all the cholesterol it needs (no need to consume)

• What increases blood cholesterol?– Consuming saturated fatty acids– Eating trans fats– Both may lead to heart disease

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Cholesterol & DietCholesterol & Diet5. How can you decrease your

cholesterol intake?• keeping dietary intake of saturated

fats low can significantly lower your dietary cholesterol

• Eat no more than six ounces of lean meat, fish and poultry per day and use fat-free and low-fat dairy products

• vegetable sources such as beans are good substitutes for animal sources of protein

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Cholesterol & ExerciseCholesterol & Exercise5. How can you decrease your

cholesterol?• Exercising lowers LDLs• Being overweight tends to increase

the amount of low-density lipoprotein (LDL) in your blood.

• Fibre and cellulose lower LDLs• Higher intensity exercise lowers the

LDLs more than moderate exercise does. It also raises HDLs more.

NOTE:Genetics, weight, age, gender, and diet

all contribute to an individual's cholesterol profile.

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Triglicerides videoTriglicerides video

http://www.youtube.com/watch?v=VGHD9e3yRIU