Gene Expression Final Review

Question 1

Given the equation: deltaG = 2.303RTlog[Ci]/[Co] + ZF deltaEm:

Assuming that Na+ ions are 15 times more concentrated outside the cells than inside the cells what will be the free energy for the transport of Na+ ions through the membrane?

Answer 1

-3.26 Kcal/mol

Question 2

Using this equation: 2.303RTlog[Ci]/[Co] + ZF deltaEm:
getting a negative value for free-energy means:

Answer 2

the specific solute/ion will diffuse into the cell

Question 3

For calculation of free energy for the diffusion of uncharged solutes across a membrane we need to use

Answer 3

Another, more simpler equation

Question 4

The octanol-water partition coefficient is generally in direct correlation with:

Answer 4

The permeability of the membrane for solutes

Question 5

The _____ of molecules is a variable that affects their permeability by diffusion across the membrane>

Answer 5

size

Question 6

Hypertonic solution is a solution that _______

Answer 6

has a higher solute concentration than the cell

Question 7

The water is crossing the membrane by ______

Answer 7

All are correct (osmosis, aquaporin channel, diffusion)

Question 8

Channels can transport ions ____

Answer 8

Bidirectionally

Question 9

The potassium ion channel (KcsA) is a ____

Answer 9

voltage-gated channel

Question 10

The selectivity filter in the potassium ion channel selects ____

Answer 10

specifically for potassium ions and against sodium and other ions

Question 11

Facilitated diffusion such as transporting glucose is a form of:

Answer 11

Positive transport which has enzyme like kinetics

Question 12

The Na+/K+ pump _____

Answer 12

Transfers 2 potassium ions in and 3 sodium ions out in each cycle.

Question 13

The Na+/K+ pump _____

Answer 13

Utilizes ATP as a source of energy, and can transfer solutes from a lower concentration to a higher one.

Question 14

The H+/ATPase pumps in the parietal cells ____

Answer 14

pumps protons in the stomach chamber once translocated to the membranes by the activity of hormones and then histamines

Question 15

Which of the following are organelles are part of the endomembrane system?

Answer 15

Endoplasmic reticulum, Golgi complex, endosomes, lysosomes, vesicles

Question 16

BIP and calnexin are ______

Answer 16

chaperones

Question 17

The Davson-Danielli model is:

Answer 17

a model that included proteins as part of the membranes because lipid solubility alone couldn’t explain membrane permeability

Question 18

Which of the following statements characterizes phosphoglycerides THE BEST?

Answer 18

They have a polar head group including phosphate, a glycerol backbone, and two fatty acid chains

Question 19

Liposomes can be used to specifically deliver _____

Answer 19

aqueous-soluable and lipid-soluable drugs

Question 20

Which of the following statements is INCORRECT?
Glycolipids ______

Answer 20

are lipids that are non-covalently linked to carbohydrates

Question 21

Freeze-fracture replication is a method that ______

Answer 21

is used to explore the distribution of membrane associated integral proteins

Question 22

The protein Lucky, with 3 transmembrane domains, has at the N-terminus of it the sequence residues: GRKHKRRLKR. The C-terminus of Lucky has the following residue sequence: TADMGENGRSP (K=lysine and R=arginine, both basic and positively charged). Where would the N-terminus and the C-terminus of the protein Sunshine be localized on your prediction?

Answer 22

N-terminus inside the cell and C-terminus outside the cell

Question 23

EPR - electron paramagnetic resonance is a method that allows _____

Answer 23

to determine the spacial and temporal organization of transmembrane domains of integral proteins

Question 24

Which of the following statements if INCORRECT?
Lipid anchored proteins ____

Answer 24

always need an oligosaccharide to link them to a membrane lipid

Question 25

Membrane fluidity and lipid movement is important for:

Answer 25

cell movement

Question 26

Which of the following amino acid/s can from a hydrogen bond in a physiological pH

Answer 26

Cystine

Question 27

Which of the following statements is correct?

Answer 27

some proteins don't have tertiary structure

Question 28

Proteins that are stably associated with each other are considered:

Answer 28

a stable multiprotein complex

Question 29

A heterotrimer is a:

Answer 29

protein that is made up of three subunits some of them are different

Question 30

Given are four in vitro reactions that their K'eq values are as follows: 1. 10^-2 2. 10^-4 3. 10^2 4. 10^4 Which of these reaction will have the highest negative standard free energy?

Answer 30

reaction 4

Question 31

When a restriction enzyme has a positive standard free energy, what does it tell us about this reaction?

Answer 31

It is and endergonic reaction

Question 32

The forward reaction of ATP+H2O > ADP +Pi in the cell has a standard free energy deltaG= -11.5 kcal/mol. What will be the deltaG" of the backward reaction in vivo?

Answer 32

It will be 11.5 kcal/mol

Question 33

Enzymes cannot make an unfavorable/endergonic reaction to favorable. What is your response to this statement?

Answer 33

It is incorrect

Question 34

If a single enzyme can catalyze 560 reaction during 8 seconds, at saturating substrate concentrations, the turnover number of this enzyme is:

Answer 34

70

Question 35

The active site of the enzyme is ______

Answer 35

the site of the enzyme directly involved in binding the substrate/s

Question 36

Changing substrate reactivity by maintaining precise substrate orientation is ______

Answer 36

one of the mechanism by which enzymes catalyze reactions and reduce the activation energy

Question 37

When comparing an enzymatic reaction in the presence of competitive enzyme inhibitor to the uninhibited reaction, the inhibited reaction will _________

Answer 37

have the same Vmax but higher Km

Question 38

If in a certain double stranded DNA, 35% of the bases are thymine, what would be the percentage of guanine in the same DNA strand?

Answer 38

15%

Question 39

In a thermal denaturation curve of two different double stranded DNA species (with the same size of DNA fragments), one Tm was 82*C, and the second Tm was 85*C. Can we tell which double stranded DNA had more cystine-guanine base pairs relatively to adenine-thymine base pairs?

Answer 39

Yes, we can tell, and it's the DNA with higher Tm

Question 40

Susan is suing Jerry in court trying to prove his paternity ver her child. What type of biological assay can be used to prove her case?

Answer 40

DNA fingerprinting utilizing minisatellite DNA variability

Question 41

What does RNA Pol 1 transcribe?

Answer 41

rRNA

Question 42

What does RNA Pol 2 transcribe?

Answer 42

mRNA, snRNA, snoRNA

Question 43

What does RNA Pol 3 transcribe?

Answer 43

rRNA, tRNA, snRNA

Question 44

Which is NOT a function of the cytoskeleton?

Answer 44

transcribing DNA

Question 45

The enzyme that attached appropriate amino acid onto its tRNA is:

Answer 45

Amino acyl tRNA synthetase

Question 46

Which gene below A or B is more likely to be turned ON? A: unmethylated B: methylated

Answer 46

A

Question 47

The antibiotic erythromycin disrupts protein synthesis by preventing ribosomal translocation (movement of the ribosome relative to the mRNA). It does not affect any other step in protein synthesis. Suppose you are doing a translation reaction in vitro and you add erythromycin just before the 3rd polypeptide bond is about to be formed. You wait a few minutes and look at the ribosome. Which factor is most likely inhibited by erythromycin? The carboxyl end of amino acid #3 should now be covalently attached to:

Answer 47

1. EF-G 2. the charged tRNA bound to A site

Question 48

The cytoskeleton is made up of three different components: microtubules consisting of tubulin, intermediate filaments consisting of various proteins with similar structure, and microfilaments consisting of actin (also call actin filaments). Together they play a critical role in cellular structure, support and spatial organization, intracellular transport, contractility and motility, and cell adhesion. Connect the following cytoskeletal functions to the component(s) most responsible for them. 1. Intracellular transport 2. Contractiliity and Motiliity 3. Cell adhesion

Answer 48

1. microtubules and microfilaments 2. microfilaments only 3. intermediate filaments and microfilaments