Proteins

Question 1

proteins functions

Answer 1

enzymes
defensive (antibodies)
hormonal and regulatory (physiologial processes)
Receptor (receive and respond to molecular signals)
storage
structural
transport
genetic regulatory

Question 2

chemical structures

Answer 2

polypeptide chain
chains folded into 3D shapes defind by amino acid sequence

Question 3

structural formula

Answer 3

HN3+ - C - COO-
C attached to R and H
C is an alpha carbon

Question 4

which two isomeric forms do amino acids exist in

Answer 4

D amino acids (right)
L amino acids (left) - in organisms

Question 5

methionine functions

Answer 5

initiates chains of amino acids

Question 6

Proline

Answer 6

causes kinks in chains of amino acids

Question 7

Cysteine

Answer 7

links amino acid chains together

Question 8

Disulphide bridges

Answer 8

Terminal SH of cysteine react with another cysteine to form disulphide bridge
needed for protein folding

Question 9

How do the amino acids bond together

Answer 9

covalently in a condensation reaction by peptide bonds
peptide bond is inflexible = no rotation

Question 10

What is the protein primary structure

Answer 10

amino acid sequence

Question 11

alpha helix protein secondary structure

Answer 11

right handed coil resulting
H2 bonding between N-H groups on one amino acid and C=O groups on another

Question 12

beta pleated sheet protein secondary structure

Answer 12

two or more polypeptide chains are aligned
H2 bonding from between chains

Question 13

tertiary structure of proteins

Answer 13

contains beta pleated sheet, alpha helix, h2 bonding and disulfide bridge
folded

Question 14

what is tertiary structure determined by

Answer 14

• Disulfide bridges
• Hydrogen bonds
• Aggregation of hydrophobic side chains
• van der Waals forces
• Ionic bonds

Question 15

what conditions affect secondary and tertiary structure

Answer 15

High temperature
* pH changes
* High concentrations of polar molecules
* Nonpolar substances

Question 16

potential energy

Answer 16

stored energy
chemical bonds, conc gradient, charge imbalance

Question 17

metabolism definition

Answer 17

sum total of all chemical reactions in an organism

Question 18

anabolic reactions def

Answer 18

complex molecules made from simple molecules, energy input is required

Question 19

catabolic reactions

Answer 19

complex molecules broken down to simpler ones and energy released

Question 20

what principles affect biological energy transformations

Answer 20

law of thermodynamics
understand how cells harvest and transform energy

Question 21

What is the first law of thermodynamics

Answer 21

enegry is neither created nor destroyed

Question 22

second law of thermo

Answer 22

energy converted from one form to another, some energy unavailable to do work
no energy transformation is 100% efficient
(some energy is not usable)

Question 23

what is entropy

Answer 23

chaos and disorder in a system
takes energy to impose order on system, unless energy applied to system it will be disordered

Question 24

equation for figuring out total energy

Answer 24

total energy = usable energy + unusuable energy

Question 25

gibbs equation

Answer 25

ΔG = ΔH – TΔS * If ΔG is negative, free energy is released * If ΔG is positive, free energy is consumed * If free energy is not available, the reaction does not occur.

Question 26

exergonic vs endergonic

Answer 26

exergonic = reactions release energy (–ΔG) endergonic = reactions consume free energy (+ΔG)

Question 27

Exergonic and endergonic reactions on graph

Answer 27

Ex = reactions and products, S shape curve from high to low (energy released) En = low to high (energy gained)

Question 28

three mechanisms used for enzymes to work

Answer 28

Orientation physical strain chemical change of the substrate

Question 29

orientation

Answer 29

enzymes orient substrate molecules, bringing together the atoms that will bond

Question 30

Physical strain

Answer 30

enzymes stretch the bonds in substrate molecules, making them unstable

Question 31

chemical charge

Answer 31

enzymes can temporrily add chemical groups to substrates

Question 32

what is a lysozyme

Answer 32

enzyme found in egg white, saliva and tears acts as antibiotic because it catalyses the cutting of polysaccharide chains in bacterial cell walls so they rupture

Question 33

what reaction does lysos=zyme catalyse

Answer 33

hydrolysis reaction = forms water that is spontaneous but not instantaneous

Question 34

how are enzyme reactions organised

Answer 34

metabolic pathways that are interconnected maintaining internal homeostasis

Question 35

feedback inhibition

Answer 35

final products from metabolic pathways act as a noncompetitive inhibitor of the first enzyme which shuts down the pathwya

Question 36

how to figure out optimal temp and maximum rate of graph

Answer 36

maximum rate is height of peak optimum temp = reaction rate is 0 line directly below curve

Question 37

what are ribozymes

Answer 37

RNA molecules that exhibit enzymatic activity enzymes are proteins ribozymes are made from rna forms cleaved mRNA