Gene Expression Final Review Flashcards
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?
-3.26 Kcal/mol
Using this equation: 2.303RTlog[Ci]/[Co] + ZF deltaEm:
getting a negative value for free-energy means:
the specific solute/ion will diffuse into the cell
For calculation of free energy for the diffusion of uncharged solutes across a membrane we need to use
Another, more simpler equation
The octanol-water partition coefficient is generally in direct correlation with:
The permeability of the membrane for solutes
The _____ of molecules is a variable that affects their permeability by diffusion across the membrane>
size
Hypertonic solution is a solution that _______
has a higher solute concentration than the cell
The water is crossing the membrane by ______
All are correct (osmosis, aquaporin channel, diffusion)
Channels can transport ions ____
Bidirectionally
The potassium ion channel (KcsA) is a ____
voltage-gated channel
The selectivity filter in the potassium ion channel selects ____
specifically for potassium ions and against sodium and other ions
Facilitated diffusion such as transporting glucose is a form of:
Positive transport which has enzyme like kinetics
The Na+/K+ pump _____
Transfers 2 potassium ions in and 3 sodium ions out in each cycle.
The Na+/K+ pump _____
Utilizes ATP as a source of energy, and can transfer solutes from a lower concentration to a higher one.
The H+/ATPase pumps in the parietal cells ____
pumps protons in the stomach chamber once translocated to the membranes by the activity of hormones and then histamines
Which of the following are organelles are part of the endomembrane system?
Endoplasmic reticulum, Golgi complex, endosomes, lysosomes, vesicles
BIP and calnexin are ______
chaperones
The Davson-Danielli model is:
a model that included proteins as part of the membranes because lipid solubility alone couldn’t explain membrane permeability
Which of the following statements characterizes phosphoglycerides THE BEST?
They have a polar head group including phosphate, a glycerol backbone, and two fatty acid chains
Liposomes can be used to specifically deliver _____
aqueous-soluable and lipid-soluable drugs
Which of the following statements is INCORRECT?
Glycolipids ______
are lipids that are non-covalently linked to carbohydrates
Freeze-fracture replication is a method that ______
is used to explore the distribution of membrane associated integral proteins
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?
N-terminus inside the cell and C-terminus outside the cell
EPR - electron paramagnetic resonance is a method that allows _____
to determine the spacial and temporal organization of transmembrane domains of integral proteins
Which of the following statements if INCORRECT?
Lipid anchored proteins ____
always need an oligosaccharide to link them to a membrane lipid
Membrane fluidity and lipid movement is important for:
cell movement
Which of the following amino acid/s can from a hydrogen bond in a physiological pH
Cystine
Which of the following statements is correct?
some proteins don’t have tertiary structure
Proteins that are stably associated with each other are considered:
a stable multiprotein complex
A heterotrimer is a:
protein that is made up of three subunits some of them are different
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?
reaction 4
When a restriction enzyme has a positive standard free energy, what does it tell us about this reaction?
It is and endergonic reaction
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?
It will be 11.5 kcal/mol
Enzymes cannot make an unfavorable/endergonic reaction to favorable.
What is your response to this statement?
It is incorrect
If a single enzyme can catalyze 560 reaction during 8 seconds, at saturating substrate concentrations, the turnover number of this enzyme is:
70
The active site of the enzyme is ______
the site of the enzyme directly involved in binding the substrate/s
Changing substrate reactivity by maintaining precise substrate orientation is ______
one of the mechanism by which enzymes catalyze reactions and reduce the activation energy
When comparing an enzymatic reaction in the presence of competitive enzyme inhibitor to the uninhibited reaction, the inhibited reaction will _________
have the same Vmax but higher Km
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?
15%
In a thermal denaturation curve of two different double stranded DNA species (with the same size of DNA fragments), one Tm was 82C, and the second Tm was 85C.
Can we tell which double stranded DNA had more cystine-guanine base pairs relatively to adenine-thymine base pairs?
Yes, we can tell, and it’s the DNA with higher Tm
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?
DNA fingerprinting utilizing minisatellite DNA variability
What does RNA Pol 1 transcribe?
rRNA
What does RNA Pol 2 transcribe?
mRNA, snRNA, snoRNA
What does RNA Pol 3 transcribe?
rRNA, tRNA, snRNA
Which is NOT a function of the cytoskeleton?
transcribing DNA
The enzyme that attached appropriate amino acid onto its tRNA is:
Amino acyl tRNA synthetase
Which gene below A or B is more likely to be turned ON?
A: unmethylated
B: methylated
A
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:
- EF-G
- the charged tRNA bound to A site
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
- microtubules and microfilaments
- microfilaments only
- intermediate filaments and microfilaments
