DAT BIOLOGY SECTION

Matter

Anything that takes up space and has mass

Element

pure substance that has specific physical/chemical properties and cannot be broken down into a simpler substance

Intramolecular forces

attractive forces that act on atoms within a molecule

Intermolecular forces

forces that exist between molecules and affect physical properties of the substance

Monomers

single molecules that can potentially polymerize

polymers

substances made up of many monomers joined together in chains

Carbohydrates contain:

carbon, hydrogen, and oxygen atoms (CHO)

monosaccharides

carbohydrate monomers with empirical formula of (CH2O)n. “n” is the number of carbons

disaccharides

contain 2 monosaccharides joined together by glycosidic bond.

What is the result of a dehydration (condensation) reaction?

a disaccharide

Hydrolysis reaction

covalent bond is broken by the addition of water

Sucrose

disaccharide made of glucose and fructose

Lactose

disaccharide made of galactose and glucose

Maltose

Disaccharide made of glucose and glucose

Polysaccharides

contain multiple monosaccharides connected by glycosidic bonds to form long polymers

Starch

form of energy storage for plants and is an alpha bonded polysaccharide

Linear starch

Amylose

Branched starch

Amylopectin

Glycogen

form of energy storage in animals and is an alpha bonded polysaccharide. Has much more branching than starch

Cellulose

structural component in plant cell walls, and is a beta bonded polysaccharide. linear strands packed rigidly in parallel

Chitin

structural component in fungi cell walls and insect exoskeletons. It is a beta bonded polysaccharide with nitrogen added to each monomer

What do proteins contain?

Carbon, hydrogen, oxygen and nitrogen atoms (CHON)

What do atoms in proteins combine to form?

Amino acids

Amino acids link together to build what?

Polypeptides (or proteins)

Proteome

all the proteins expressed by one type of cell under one set of conditions

Amino acids

monomers of proteins and have this structure:

How many different kinds of amino acids are there?

20, each have a different R-group

Polypeptides

polymers of amino acids and are joined by peptide bonds through dehydration condensation reactions. Hydrolysis reactions break peptide bonds

N-terminus (amino terminus) of polypeptide

side that ends with the last amino acid’s amino group

C-terminus (carboxyl terminus)

side that ends with the last amino acid’s carboxyl group

conjugated proteins

proteins composed of amino acids and non-protein components. Includes: metalloproteins and glycoproteins

Metalloproteins

(ex: hemoglobin) proteins that contain a metal ion cofactor

Glycoproteins

(ex mucin) proteins that contain a carbohydrate group

Primary protein structure

sequence of amino acids connected through peptide bonds

Secondary protein structure

intermolecular forces between the polypeptide backbone (not R-groups) due to hydrogen bonding. Forms alpha helices or beta pleated sheets

Tertiary protein structure

3D structure due to interactions between R groups. Can cause hydrophobic interactions based on R groups

Disulfide bonds

created by covalent bonding between the R groups of 2 cysteine amino acids. Hydrogen bonding and ionic bonding between R groups also hold together the tertiary structure

Quaternary protein structure

multiple polypeptide chains come together to form one protein

protein denaturation

Describes loss of protein function and higher order structures. Only primary structure is unaffected

What causes denature of proteins?

result of high or low temperatures, pH changes, and salt concentrations

Protein function— Storage:

Reserve of amino acids

Protein functions— Hormones:

Signaling molecules that regulate psychological processes

Receptors

proteins in cell membranes which bind to signal molecules

Protein function— structure:

Provide strength and support to tissues

Protein function— immunity

antibodies that protect against foreign substances

Enzymes

regulate rate of chemical reactions

How do catalysts increase reaction rates?

lowers activation energy of reaction, they reduce the energy of the transition rate. They DO NOT shift a chemical reaction or affect spontaneity

transition state

unstable conformation between the reactants and the products

active site

specific for the substrate that it acts upon

specificity constant

measures how efficient and enzyme is at binding to the substrate and converting it to a product

induced fit theory

describes how the active site molds itself and changes shape to fit the substrate when it binds

Ribozyme

RNA molecule that can act as an enzyme (non-protein enzyme)

cofactor

a non-protein molecule that helps enzymes perform reactions

coenzyme

organic cofactor (i.e. vitamins)

Holoenzymes

enzymes bound to their cofactors

Apoenzymes

enzymes that are not bound to their cofactors

Prosthetic groups

cofactors that are tightly or covalently bonded to their enzymes

How do enzymes catalyze reactions?

conformational changes, presence of acid or base groups, induced fit, electrostatic attractions

Phosphatase

cleaves phosphate group off a substrate molecule

Phosphorylase

directly adds a phosphate group to a substrate molecule by breaking bonds within a substrate molecule

Kinase

indirectly adds phosphate group to a substrate molecule by transferring a phosphate group from an ATP molecule. These enzymes do not break bonds to add phosphate group

Feedback regulation of enzymes

end product of enzyme-catalyzed reaction inhibits enzymes activity by binding to allosteric site

Competitive inhibition

occurs when competitive inhibitor competes directly with the substrate for active site binding. Adding more substrate can increase enzyme action

Noncompetitive inhibition

occurs when noncompetitive inhibitor binds to allosteric site that modifies active site. Rate of enzyme action cannot be increased by adding more substrate

Lipids

contain carbon, hydrogen and oxygen atoms (CHO). Have long hydrocarbon tails that make them very hydrophobic

triacylglycerol (triglyceride)

lipid molecule with glycerol back bone (3 carbons and 3 hydroxyl groups) and 3 fatty acids (long hydrocarbon tails)

Saturated fatty acids

have no double bonds and as a result pack tightly (solid at room temp)

Unsaturated fatty acids

have double bonds, can be divided into monounsaturated (1 double bond) and polyunsaturated fatty acids (2 or more double bonds)

Cis-unsaturated fatty acids

have kinks that cause the hydrocarbon tails to bend, they do not pack tightly

Trans-unsaturated fatty acids

have straighter hydrocarbon tails. they pack tightly

phospholipids

lipids with a glycerol backbone, one phosphate groups, and 2 fatty acid tails

What group is polar in phospholipids? which is non-polar?

phosphate group is polar, fatty acids are nonpolar

amphipathic

both hydrophobic and hydrophillic

What lipid molecule is amphipathic?

cholesterol

What factors influence membrane fluidity?

temperature (high temp increase fluidity, low decreases), cholesterol (holds membrane together at high temps, keeps membrane fluid at low temps), and degrees of unsaturation (sat. fatty acids pack more tight than un sat.)

Lipoproteins

allow transport of lipid molecules in bloodstream due to outer coat of phospholipids, cholesterol and proteins

Low-density lipoproteins (LDLs)

low protein density, work to deliver cholesterol to peripheral tissues. sometimes considered “bad cholesterol”— can cause hear disease, vessel blockage

High density lipoproteins (HDLs)

high protein density and take cholesterol away from peripheral tissues. “good cholesterol”— delivers cholesterol to liver to make bile, reducing blood lipid levels