Chapter 1 Test Biology 12

Water

Water

• Most abundant chemical in the body.

• Very small molecule.

• Polar as hydrogen is positive and oxygen is negative allowing it to pull other molecules apart.

• Surrounds the solute

Hydrophobic Interactions

• Water fearing/hating.

• Non-polar molecules will clump together in fear of polar molecules.

Cohesion

Molecules sticking to themselves. When water forms dome shape.

Adhesion

Molecules sticking to other molecules. When water climbs glass.

Water Heat Capacity

Water absorbs and releases heat energy slowly, and can hold a great deal of heat energy. This helps organisms maintain body temperature in the safe range.

What are the main chemical bonds in biology?

Covalent bonds.

Macromolecules

• Most living things contain carbon.

• 96% of the body is C, H, O, and N.

• C, H, O, N, make carbohydrates, nucleic acids, proteins, and lipids.

Small similar repeating molecular structures.

Monomers

Monomers

• Can exist individually.

• Subunits form polymer.

Macromolecules function/structure.

• Polymers made up of monomers.

• Monomers are small units.

• Polymers are long chains (large molecules).

Carbohydrates

• Major source of energy and make up 50-55% of calories in a healthy diet.

• Most important nutrient.

• Carbon, Hydrogen, and Oxygen.

• Fruit, candy, cakes, bread, pasta, potatoes, rice, vegetables.

Carbohydrate types

• Monosaccharides.

• Disaccharides.

• Polysaccharides.

Monosaccharides

• Simple sugars.

• Monomers.

• Glucose, fructose, galactose, ribose.

• Fruits, candy, cakes, raisins, contains three to seven carbons.

• CH2O

• Form rings due to adhesive component of water.

Disaccharides

• Simple Sugars, (double sugars).

• Monomers.

• Sucrose (table sugar), maltose, lactose.

• Formed via dehydration synthesis (formation of water).

• C12H22O11

• Glucose + Glucose = maltose,

  glucose + fructose = sucrose.

Polysaccharides

• Complex sugars.

• Polymers.

• Starch, glycogen, cellulose, chitin.

• Structural or storage molecules.

• (C6H10O5)n

Simple Carbohydrates

Found in fruits, milk, vegetables, cake, candy, and other refined sugar products. Provide energy but lack vitamins, minerals, and fibre.

Complex Carbohydrates

Found in bread, legumes, rice, pasta, and starchy vegetables. Provide vitamins, minerals, and fibre.

Sweetness

• Certain molecules, including non-sugar, are sweet as they bind to “sweet” receptors of the tongue.

Starch

• Plant storage.

• Polymer composed of 2000-6000 glucose molecules.

Glycogen

• Animal starch storage.

• Stored in liver and muscle.

• More highly branched than starch.

• Extra glucose molecules are stored and when the body needs more energy, glycogen is converted back into glucose units.

Cellulose

• Fibre.

• Structural polysaccharides.

• Found in the cell wall of plants.

• Most abundant compound on Earth.

• Many glucose molecules linked, (different from starch).

• Cannot be digested and has no nutritional value. But is very important for digestion as it holds water in large intestine and aids in excretion of waste.

Function of Carbs in the Cell

1. Primary source of energy.

2. Storage food.

3. Framework/structure in body.

4. Sweetener.

5. Dietary fibre.

6. Regulation of blood glucose.

7. Raw material for industry.

8. Cell recognition - selection of cells to make tissues, and rejection of foreign cells.

Carbohydrate bonds

Glycosidic bonds.

How do monosaccharides form disaccharides?

Two monosaccharides are attached via dehydration/hydrolysis reactions. GLYCOSIDIC BONDS.

Isomers

Same number of atoms of each element but have distinct arrangements of atoms.

Dehydration synthesis

Remove water, bond together.

Hydrolysis

Add water, break apart.

Oligosaccharide

Component of fibre from plant tissues.

Glycosidic bond

Covalent bond formed between carbohydrate and another molecule.

Intermolecular Force of Attraction

Attraction and repulsion between the same molecules. Example H2O cohesion.

Proteins

• Most structurally and functionally diverse molecules due to different arrangements of amino acids.

• Long chains of amino acids bonded via peptide bonds.

• Type of protein is determined by arrangement of amino acids.

• 42% of dry body weight.

Amino Acids

• Contains amino group, carboxyl group, R group (distinguishes each of the 20 amino acids.

• Humans produce 11 amino acids, other 9 are obtained via food.

Levels of Protein

• Primary - linear sequence of amino acids (a-a-a-a-a)

• Secondary - linear sequence after it folds on itself due to hydrogen bonding.

• Tertiary - when folded sequence begins to bend within itself due to hydrophobic effect.

• Quaternary - when there are more than one polypeptide chain.

Primary level of protein (1 degree)

Linear sequence of amino acids determined by DNA.

Covalent peptide bonds between a-a-a-a…

Amino Acid bonding

• Cells link amino acids together by dehydration synthesis.

• The bonds between amino acids and monomers are called peptide bonds.

Secondary level of protein (2 degree)

• Twisting and folding of linear primary structure.

• Hydrogen bonds between charged a-a-a-a.

• Forms alpha helix, triple helix, and beta pleated sheet.

Tertiary protein structure (3 degree)

• Folding of secondary structure into a complex 3-D shape.

• Amphiphilic forces (hydrophobic/phillic), disulfide bridges, H-bonds, ionic bonding.

• Forms globular proteins.

Quaternary protein structure (4 degree)

• Combining of two or more tertiary subunits.

• Amphiphilic forces, Van Der Waal’s forces, H-bonding, R-group interactions.

• Large globular proteins. (hemoglobin)

Simple vs. Conjugated Proteins

• Simple proteins

  • contains only amino acids

• Conjugated proteins

  • amino acid with another component

  • glycoprotein, nucleoprotein, lipoprotein, phosphoprotein,

Proteins are involved in…

1. Enzymes (anabolic or catabolic)

2. Transport (RBC), passage of molecules into cell.

3. Structural (cartilage, nails, hair,).

4. Hormones (insulin, oxytoxin).

5. Contractile structures (muscle).

6. Defence (antibodies),

7. Builds DNA

Denaturation

Breaking of weak bonds in proteins. Causes:

• Temperature

• pH

• Salt concentrations

• Heavy metals

Hydrophobic and hydrophillic amino acids

Amino acids with polar or ionic functional groups make stronger intermolecular forces of attraction and are hydrophillic.

Amino acids with non-polar functional groups are weaker intermolecular forces and are hydrophobic.

Chain of amino acids

polypeptide (primary structure)

Side group/R-group

Represents one of the 20 amino acid side chains.

Fair test

Test of urine to see amino acid balance.

Neurotransmitter

Chemical signals produced by neurons in the nervous system. Dopamine.

Receptor

The receptor of chemical signal is a protein.

Lipids

• Composed of C, H, and O but contain more H than carbohydrates.

• Not true polymers only grouped because the are non-polar.

• Store more energy than carbs.

• Saturated, Unsaturated, trans fats.

• Oils, waxes, fats, phospholipids, steroids.

Types of Lipids

1. Fats

2. Phospholipids

3. Steroids

4. Waxes

Fats

• Triglyceride consisting of one glycerol molecule linked to three fatty acids.

• 3 types

  • Saturated

  • Unsaturated/monosaturated

  • Polyunsaturated/trans fats

Triglycerides

• One glycerol + three fatty acids (saturated, unsaturated, trans)

Saturated Fats

• C-C single bonds, H-bonded.

• Max H bonded= reduced.

• Have higher melting point.

• Solid at room temp.

• Mostly animal sources (dairy, lard, blubber.)

• Least healthy

Unsaturated fat

• C=C double bonds (less than max. H-bonded).

• less h-bonded = oxidized.

• Lower melting point.

• Liquid at room temperature.

• Can be monounsaturated or polyunsaturated.

• Mostly plant sources (vegetable oils).

• Healthier form of lipid.

Trans Fat

• Comes from adding hydrogen to vegetable oil via hydrogenation.

• Makes fat more solid and less likely to go bad.

'“Good” and “Bad”

Good= unsaturated fats

Bad= saturated fats

Worst= trans fats

Fats are rich in kilojoules so should be consumed in moderation.

Saturated foods

Whole milk, butter, cheese, and ice cream, red meat, chocolate, coconuts, coconut milk, coconut oil.

Unsaturated

Olives, olive oil, canola oil, peanut oil, cashews, almonds, peanuts, nuts, avocados, corn, soybean, safflower, fish.

Trans

Margarine, vegetable shortening, partially hydrogenated vegetable oil, deep fried chips, fast food, commercially baked goods.

Phospholipids: Components of cell membrane

• Similar to triglyceride.

• Phosphate replaces third fatty acid.

• R group is attached to phosphate.

• “Head” is polar (hydrophilic).

• “Tail” is non-polar (hydrophobic).

Phospholipids

Composed of R-group which may contain nitrogen, phosphate and 2 fatty acids. It is amphiphilic.

Micelle phospholipid

Found in cell membrane and creates pores in cell membrane.

Liposome phospholipid

Used in drug delivery

Amphiphilic

When a substance has both hydrophobic and hydrophilic parts in it. Polar and non-polar functional groups.

Steroids

• Found in:

  • Animal tissues,

  • All cell membranes

• Structure:

  • 17 carbons in 4 rings

• Precursor for:

  • Sex hormones,

  • Vitamins A & E

  • Bile salts (emulsify fats)

Waxes

• Long chain fatty acids + long chain alcohols

• Cutin on leaves and insects, beeswax.

Uses of Fats

• Energy store,

• Major component of cell membrane,

• Thermal insulation,

• Protective cushion around major organs,

• Water-repelling coating for skin, fur, feather, and leaves (Wax),

• Steroids: Hormones (regulates sexual function, reduce inflammation, skin treatments, increase muscle mass)

Glycerol

Three carbon atoms of which have hydroxyl group bonded to each.

Ester linkage

Carboxylic acid bonded to alcohol.

Glycolipid

Lipids with carbohydrate attached by a glycosidic bond.

Transmembrane protein

Proteins embedded within lipids exposed on both sides of the membrane.

Nucleic Acids

• Information-Rich polymers of nucleotides.

• Blueprints for proteins.

• Control the life of a cell, DNA contains genetic info of organism.

Types of Nucleic Acid

1. DNA, Deoxyribonucleic acid

2. RNA, Ribonucleic acid

Nucleotides

• Monomers of nucleic acid.

• Phosphate group, sugar, and nitrogenous base.

Nucleotide bonds

Ester bond = Phosphate & sugar

Glycosidic bond = Sugar & base

Sugar and phosphate form backbone of nucleic acid

Nitrogenous Bases (held together via hydrogen bonds)

• 4 Types

  • Adenine

  • Thymine

    • Adenine and Thymine go together

    • Thymine is replaced with uracil in RNA

  • Guanine

  • Cytosine

    • Guanine and Cytosine go together

Purines

Adenine and Guanine

Pyrimidines

Cytosine, Uracil and Thymine

DNA Structure

• Two polynucleotides twisted into double helix.

• Four kinds of n-bases carry genetic code.

• Chain of nucleotides linked by covalent bonds.

• Condensation reaction creates phosphodiester bond.

• Antiparallel.

• held together via hydrogen bonds.

• Complimentary base pairing.

DNA vs RNA - Deoxyribonucleic acid

• Main genetic component of all cells.

• Double chains

• 2-Deoxyribose sugar

• Adenine, Thymine, Guanine, Cytosine.

• Contains instructions to make RNA (transcription).

• Located in nucleus of mitochondria.

• DNA self replicate.

• Usually 2 polymers of nucleotides.

DNA vs RNA - Ribonucleic acid

• Single chains,

• Ribose sugar

• Adenine, uracil, guanine, cytosine.

• Holds instructions for making proteins for cellular structure and function (translation).

• Located in the cytoplasm, nucleus and ribosomes.

• RNA does not replicate.

Adenosine triphosphate ATP

Small package of energy in the form of a nucleic acid.

Nucleic acid structure

Forms 3-D structure due to intermolecular forces.

Autotroph

Organism that produces its own food.

Heterotroph

Organism that cannot produce its own food.