Biological Molecules Project Biology 12 by Coleman Everest

WATER• Earth’s ability to support life is based on the presence of liquid water. It makes up approximately 60% of the human body and 60% - 70% of all life forms.

• A water molecule consists of two positively charged hydrogen atoms and one negatively charged oxygen atom. Water molecules are held together by weak attractive forces called hydrogen bonds.

• H2O is a polar molecule because the electrons are unevenly distributed meaning the hydrogen ends of the molecule have a slight positive negative charge and the oxygen end has a mild negative charge. This weak attraction is enough to create hydrogen bonds, but a whole water molecule is electrically neutral.

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Water as a solvent-Solvent for all polar molecules and ionic compounds, dissolves more than any other liquid. -Acts as a “chemical wedge”; can break apart and form new bonds; facilitates many chemical reactions in biological systems in the human body.

Water as a temperature regulator -Water temperature changes slowly; no drastic changes. -High boiling point (100 degrees Celsius)

Water as a lubricant-A vital, natural lubricant.-Humans need water to produce the bodily fluids that allow us to blink, circulate blood, swallow, and do the horizontal monster mash.

Acids, Bases, & BuffersAcids, bases and buffers all have important roles in the biological systems within the human body, with particular regard to maintaining chemical balance.

Acids (substances with a pH lower than 7): essential to the digestive system. Hydrochloric Acid in our stomach helps us break down food particles so that nutrients can be extracted.

Bases (with a pH greater than 7): blood must maintain a pH of about 7.35-7.45, (a slight base) in order for hemoglobin to be carried.

Buffers are chemical combinations present throughout the systems of the human body that keep pH levels regular. Buffers resist changes in pH (from, for example, a poorly balanced diet) because they can take up hydrogen or hydroxide ions produced through the dissociation of water molecules. (see below)

shows how dissociated

hydrogen and hydroxide ions can bond with

other chemicals to form acids or

bases.

The scale used to measure the acidity or alkalinity of substances is pH (0-14), 0 being very acidic and 14

being very alkali. Water is considered neutral at about 7.

CarbohydratesAll carbohydrates contain hydrogen, oxygen and carbon. The 3 main types of carbohydrates are monosaccharides, disaccharides and polysaccharides. (saccharide = sugar) The carbohydrates in one’s diet allow cells to produce energy.

Dehydration synthesis - A simple process by which monosaccharides become di- or polysaccharides: Dehydration (removal of water) occurs when two carbohydrates are brought together to form a new

carbohydrate. Water is left over as a by-product of the synthesis, taking a hydrogen (H) and a hydroxide (OH)

from either carbohydrate. Hydrolysis is the reverse of this process in which water

is added to a compound in order to break it down.

Dehydration Synthesis

Monosaccharide(Simple sugars)

CnH2nOn

Glucose (pictured)Ribose

FructoseDeoxyribose

Disaccharides(Double sugars)

Sucrose/table sugar(pictured)

MaltoseLactose

Polysaccharides(Complex sugars)

StarchCellulose (pictured)

Glycogen

type structure examples

Starch: Storage form of sugar in

plants. Helps maintain structural integrity. Contains double

bonds.

Cellulose: Found only in plants - forms cell walls and gives them their rigidity.

Contains inra- intermolecular

hydrogens bonds. An insoluble fiber.

Glycogen: Storage form of sugar in animals. Contains

double bonds.

ProteinsProteins are organic compounds made

up of one or several polypeptides. Amino acids (monomers) are

bonded together in certain ways to form different proteins. There are a total of 20 individual amino acids, all with a nitrogen-based amino group. Peptide bonds, which form through

dehydration reactions, link amino acids in a protein.

Amino Group

Carboxylic acid group.

Side chain Main Functions of Proteins•Source of energy• Builds / repairs body tissues (muscle, etc.)• Makes up enzymes & hormones • Maintains healthy hair, nails, skin

StructurePrimary: a sequence of amino acids held together by peptide bonds. Secondary: forms as a result of weak attractive forces between adjacent amino acids.Tertiary: globular proteins that hold their shape due to disulphide bonds between folded strands. Many enzymes have this structure.Quaternary: made of several polypeptides coming together to form a larger molecule. Hemoglobin has this structure and is made up of 4 polypeptides.

Nucleic AcidsNucleotides (a type of monomer) form polymers called nucleic acids.

DNA RNAThe genetic material itself involved in using genetic information

Double alpha helix structure Linear (single-stranded) structure

The nucleotides are made up of a 5-carbon sugar, a

phosphate, and a nitrogenous base.

The four types of nitrogenous bases in DNA

fall into two categories.

Purine bases• Adenine (A)• Guanine (G)

Pyrimidine bases• Thymine (T)• Cytosine (C)

The four types of nitrogenous bases in RNA

fall into two categories.

Purine bases• Adenine (A)• Guanine (G)

Pyrimidine bases• Uracil (U)• Cytosine (C)

Ribonucleic AcidDeoxyribonucleic Acid

ATP: a single nucleotide which acts as a “mobile energy source” for all cells in the body.

DNA has a double helix structure, consisting of a sugar-phosphate backbone (purple),

held in helix formation by complimentary base pairings (T-A, C-G) and hydrogen bonding.

LipidsOils, fats, waxes, steroids and phospholipids are all classified as lipids.

Fatty acids are made of long hydrocarbon chains ending in an acid group.

Saturated• single bonds between carbons allows for more hydrogens to be bonded, saturating the carbons with hydrogen. Found only in animal fats, which are solid at room temperature.

Unsaturated• Has some double bonds between carbons, allowing for less hydrogen atoms. Found in plant oils. Hydrogens can be added, making them saturated.

There are two types of fatty acid.

Fats and oils (neutral fats) provide energy storage. They consist of 3 fatty acids attached to one glycerol molecule and are known as triglycerides. Oils, liquid at room temperature, store energy in plants, and fats, solid at room temperature do the same in animals. Fats and oils are not water soluble, and are stored in body tissue.

GlycerolFatty acids

PhospholipidsA certain kind of fat that

has a phosphate group substituted for one of the three fatty acids attached to the glycerol molecule. A

phospholipid molecule consists of a polar

(hydrophilic) “head” consisting of glycerol, nitrogen phosphate

groups. and and non-polar (hydrophobic)

“tail”, consisting of two fatty acids.

Steroids“Circular fats”, steroids are structured very

differently than other lipids. Rather than having a glycerol and 3 fatty acids, steroids

consist of four carbon rings with other groups of atoms (OH-, etc.) added. Some common steroids in the human body are testosterone, estrogen, and cholesterol.

Cholesterol

Testosterone

the end

Bibliography

In Class Notes

General & Human Biology: http://mhhe.com/biosci/genbio/espv2/data/cells/001/index.html

Open School BC Biology 12 Course Resource: http://openschool.bc.ca/courses/biology/bi12/mod1.html

Chemical Compound Outline (Part I): http://waynesword.palomar.edu/chemid1.htm

Kimball's Biology Pages:http: //users.rcn.com/jkimball.ma.ultranet/BiologyPages/

An On-Line Biology Book: http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookTOC.html