Exam 3

Question 1

Biological Membrane

Answer 1

lipid bilayer containing protein which completely surrounds and isolate biomolecules

Question 2

Ionophores

Answer 2

a biomolecule which facilitates the movement of ions across a biological membrane

Question 3

lipid

Answer 3

biomolecules which are insoluble or partially soluble in water and usually extractable by organic (non polar) solvents

Question 4

Cascade

Answer 4

a series of biochemical reactions which amplify so that the number of final products is orders of magnitude greater than the number of initiating molecules

Question 5

Effector enzymes

Answer 5

an enzyme component of a signal transduction pathway which is bound to a membrane, activated by a transducer and produces a second message

Question 6

Receptor

Answer 6

a transmembrane protein component of a signal transduction pathway to which an external signal molecule will bind to and cause a conformational change and subsequently activate a transducer molecule

Question 7

Second Messenger

Answer 7

a molecule which is part of a signal transduction pathway and which was produces as a consequence of the binding of the extracellular signal

Question 8

signal transduction

Answer 8

usually combined with the word signal to refer to the transfer of information from one side of a membrane to another

Question 9

Nucleic Acid

Answer 9

biopolymers consisting of nitrogenous bases which are linked to ribose or deoxyribose linked by phosphodiester bonds

Question 10

mRNA

Answer 10

is a class of RNA molecules which carries a copy of the sequence of nucleic acid bases from the DNA to the ribosomes where these sequences are translated into a series of linked amino acids to form proteins.

Question 11

tRNA

Answer 11

this is a series of RNA molecules composed of 75-95 nucleotides, which are charged with an amino acid by the appropriate tRNA synthetase enzyme and which carry that activated amino acid to the ribosome. (transfer ribonucleic acid)

Question 12

snRNA

Answer 12

this is a series of RNA molecules ranging in size from about 100-300 nucleotides long. (small nuclear ribonucleic acid)

Question 13

rRNA

Answer 13

this series of RNAs combine with proteins to form ribo-somes. (ribosomal ribonucleic acid)

Question 14

Tm

Answer 14

the temperature at which a particular molecular transition is 50% completed.

Question 15

annealing

Answer 15

as the process by which two strands of complementary nucleic acid bases Bind to each other. (Kinetic Process, rate dependent upon concentration of strands in solution, length of these strands, and the uniqueness of the sequences)

Question 16

melting

Answer 16

the process by which two strands of complementary nucleic acid bases Separate from each other. (Thermodynamic Process involving Tm, dependent upon percent composition of cytosine/guanine base pairs)

Question 17

Endonuclease

Answer 17

a nuclease which cleaves an internal phosphodiester bond

Question 18

exonuclease

Answer 18

a nuclease which removes one nucleotide from one end of a nucleic acid

Question 19

high energy bond

Answer 19

this phrase refers to the phosphoanhydride bond found in ATP and ADP which has more energy of hydrolysis than what one might expect based on the bond energies

Question 20

restriction enzyme

Answer 20

protein endonucleases, which cleave at a specific DNA sequence, which is typically a palindrome.

Question 21

domain

Answer 21

a substructure of the tertiary structure that can evolve, function, and exist independently of the rest of the protein chain.

Question 22

motif

Answer 22

a unique combination or folding of secondary structures.

Question 23

enthalpy

Answer 23

the measure of the amount of heat generated under constant pressure

Question 24

entropy

Answer 24

the measure of the disorder of a system

Question 25

Gibb’s free energy

Answer 25

is the amount of energy available to do chemical work

Question 26

transducer

Answer 26

a protein component of the signal transduction pathway, which is activated by a receptor and in turn alters the activity of an effector enzyme

Question 27

Denaturation

Answer 27

the process by which a biomolecule loses its biological function

Question 28

electrophoresis

Answer 28

a technique of separation based on the movement of charged molecules in the prescence of an electric field

Question 29

PAGE

Answer 29

PolyAcrylamide Gel Electrophoresis

separation and/or analysis of proteins

Question 30

Isomers

Answer 30

two different chemical compounds which have the same chemical composition but are physically distinct and separable

Question 31

Anomers

Answer 31

a chiral center which is not initally present in a molecule and which is created by intramolecular bonding

Question 32

Enantiomers

Answer 32

2 stereoisomers in which all the chiral center are switched

Question 33

Epimers

Answer 33

2 stereoisomers which differ only in one chiral center

Question 34

diastereomers

Answer 34

stereoisomers which contain more than 1 chiral chenter but are not mirror images of echer other

Question 35

proteins

Answer 35

polymer of alpha amino acids linked by a peptide (amide) bond

Question 36

cooperativity

Answer 36

occurs when the change in one parameter influences the change in similar parameters

Question 37

V_o (intial velocity)

Answer 37

-d[S]/ d[t] when t = 0

the rate of change in the concentration of substrate or product per unit of time at the beginning of the reaction where little product is formed and when the back reaction is negligible

Question 38

V_max

Answer 38

k_cat [E_t]

the rate of enzyme catalyzed reaction with saturating concentration of substrates and is the product of the catalytic rate constant or turnover number and the total enzyme concentration

Question 39

Km

Answer 39

(k_-1 + k_-2) / k₁

_{the concentarion of substrate which yields half of the maximum velocity for an enzyme catalyzed reaction or is the concentration when the initial velocity is equal to half of the maximum velocity}