Name:______Practice Test______
Unit Test 40 points Comprehensive Test 40 points
Multiple Choice: Choose the one best answer, circle the answer on your test and fill in the appropriate blank on your scantron. 1 point each
Unit Test:
1) Which amino acid’s functional group is used to create N-linkages that attach carbohydrates to membrane proteins? a) Serine b) Threonine c) Asparagine d) Cysteine
2) The removal of extracellular calcium would be most likely to prevent which cellular adhesion molecule from functioning? a) N-CAMs b) Selectins c) Integrins d) Cadherins
3) ______create belt-like seals between epithelial cells that prevent migration of proteins between the basolateral and apical sides.
a) Tight Junctions b) Desmosomes c) Hemidesmosomes d) Gap Junctions
4) Toxins in the body are often metabolized by the P-450 enzyme system which is located where?
a) Smooth endoplasmic reticulum b) Nucleus c) Mitochondrial matrix d) All of above
5) The membrane of the nuclear envelope is continuous with the….
a) Plasma membrane b) Membrane of Golgi Apparatus c) Endoplasmic reticulum d) All of above
6) Ribosomal proteins and rRNA that make up large and small ribosomes are assembled in what part of a cell?
a) Nucleus b) Golgi apparatus c) Smooth endoplasmic reticulum
7) The two membrane bilayers of the nuclear envelope is continuous with the….
a) Plasma membrane b) Membrane of Golgi Apparatus c) Endoplasmic reticulum d) All of above
8) Which of the following is not present in the DNA double helix?
a) Guanine b) Cytosine c) Uracil d) Adenine e) Thymine
9) Importin and exportin permit the nucleus of a eukartotic cell to tightly regulates transport of what?
a) Small molecules such as nuceotides b) Large molecules such as proteins
10) Only about 10% of the RNA in a typical eukaryotic cells is what type?
a) mRNA b) tRNA c) rRNA d) snRNA
11) Three eukaryotic transcription factors _____, ______, then ______must bind to the promoter region of DNA before RNA polymerase II can optimally bind. a) D, A, B b) F, E, H c) 1, 2, 3
12) In eukaryotes, which required promoter sequence is located the closest to the initiation site on the DNA upstream of the gene in question?
a) GC box b) TATA box c) CAAT box d) Enhancers/Suppressors
13) When RNA is transcribed from DNA, the new bases for RNA are added to the ____end of the nascent chain.
a) 5’ phosphate b) 5’ hydroxyl c) 3’ phosphate d) 3’ hydroxyl
14) Which one of these methods is NOT used to post-transcriptionally modify eukaryotic RNA?
a) Remove introns b) Add methyl-groups to 5’-end c) Add 3’-poly-A tail
d) Addition of Ubiquitin e) All of above are important post transcriptional RNA modifications
15) Which ribosomal binding site could contain a t-RNA that either had an amino acid attached by an ester to its 3’ end or an empty 3’-end? a) A or Aminoacyl-cite b) P or peptidyl-site c) E or exit site
16) a) True b) False: The same transcription factors are expressed at the same level in all eukaryotic cells.
17) Addition of ubiquitin to nascent ______causes its half life to be ______.
a) RNA, decreased b) RNA, increased c) protein, decreased d) protein, increased
18) a) True b) False: With respect to mRNA translation, eukaryotic and prokaryotic cells both use the same 40S and 60S ribosomal subunits, each of which consists of a many individual rRNA and protein fragments.
19) a) True b) False: With respect to the exact identity of the amino acid it carries, the third base on tRNA can be quite variable and it means that several different anticodons can deliver the same amino acid to a location of a nascent protein (20 amino acids and 61 amino acid codons).
20) a) True b) False: Ribosomes are called “ribozymes” because the RNA in a ribosome helps mRNA and tRNA interact with the ribosomal proteins where the ribosomes enzyme function (true binding site) is located.
21) “Wobble” in tRNA anti-codons refers to the fact that the ______base in its anticodon can be variable with respect to coding for a specific amino acid. a) First b) Second c) Third
22) a) True b) False: Enhancers and silencers can be located thousands of bases away from the TATA box and the +1 initiation site on DNA.
23) a) True b) False: Termination of mRNA translation occurs when the anticodon of a special termination tRNA binds the mRNA stop codon at the ribosomal P-site.
24) Which of the following provides a way to modify gene expression in the present and future generations?
a) Gene amplification b) Gene rearrangement
c) Selective DNA base methylation d) All of above
25) Which type of genome level DNA modification helps some malarial parasites become resistant to drugs by creating more enzymes for degrading the antibiotic medications used against it.
a) Gene amplification b) Gene rearrangement
c) Selective chromatin unwinding d) Selective DNA base methylation
26) A) True B) False: Thyroxine, cortisol, testosterone and estradiol are all lipid soluble hormones that must bind directly to the DNA at the TATAA-Box in order for them to modify transcription of a gene.
27) A) True B) False: In eukaryotes DNA in a gene can be extensively rearranged, this process is important in the development of acquired immunity and the development of antibodies.
28) What type of transcriptionpermits a protein to be secreted into the blood at the same rate all the time?
a) Constituitive b) Benign c) Transcriptional d) Regulated
29) What protein directly permits a cell to internalize portions of its plasma membrane by a process called receptor-mediated endocytosis? a) Sarcoplasmic b) Antrgrade transport c) Clathrin
30) Which of the following is a specialized structure that stores calcium and releases it upon demand in a skeletal or cardiac myocyte? a) Endoplasmic reticulum b) Sarcoplasmic reticulum c) Retrograde transport
Comprehensive Multiple Choice Questions:
31) A) True B) False: With respect to the surface to volume ratio, a large flat cell has better gas exchange than a large spherical cell.
32) If a red blood cell was put into isotonic saline what would be most likely to occur?
A) Crenation B) Unequal osmosis C) Lysis D) Hypertonicity e) Nothing in particular
33) A) True B) False: A chemical reaction that has a large Positive value (+6.5) for its Delta G could run (go forward) if ATP is hydrolyzed to ADP and Pi at the same time.
34) Which molecule would be the most amphipathic?
A) Cholesterol B) Triglyceride C) The amino acid Lysine D) Membrane phospholipid
35) What kind of enzyme could remove a phosphate group from the serine of its target protein?
A) Phosphatase B) Isomerase C) Nuclease D) Kinase
36) Consider a transmembrane protein, the R-groups facing the extra cellular side tend to be _____charged, those facing the membrane lipids tend to be _____charged and those facing the intracellular side tend to be ______charged.
a) Neutrally, Negatively, Positively b) Negatively, Positively, Neutrally c) Positively, Neutrally, Negatively
37) If the Keq for a reaction was 100, would the reaction favor a larger number of products or reactants when equilibrium was reached?
a) Reactants b) Products c) Keq was reached because BOTH reactants and products are at 1 M
38) True/False: Enzymes do NOT do what?
a) Increase the speed of reactions b) Decrease the reaction activation energy
c) Change Keq d) Stabilize the transition state
39) If the movement of glucose across a membrane could be saturated (you observed a saturated maximum transport rate into the cell). You would conclude that glucose transport is occurring via….
a) Simple diffusion b) Facilitated transport c) Osmosis
40) If transport of a material across a plasma membrane occurred only if ATP could be produced in the cell what type of transport was involved?
a) Facilitated Diffusion b) Passive Diffusion c) Active Transport d) Antiport transport
41) If the same number of sodium ions and glucose molecules appeared inside a cell , transport by a ______carrier would be suspected. a) Antiport b) Symport c) Uniport
42) The Na+/K+-ATPase pumps ____sodium ions out of a cell and ___potassium ions into a cell for each ATP used. a) 1,1 b) 2,3 c) 3,2 d) 3,3 e) 2,2
A B C D
43) Glycolysis stops if which of the above molecules is not available in the cytosol.
A B C or D
44) For eukaryotic cells glycolysis occurs in the ______and the tricarboxylic acid cycle occurs in the ____.
a) Mitochondria, Phospholipid bilayer b) Cytosol, Golgi apparatus
c) Cytosol, Smooth endoplasmic reticulum d) Cytosol, Mitochondria
45) a) True b) False: Carbon fixation for glucose production by plant cells occurs during the Dark Reaction only if pre-existing carbohydrates are ready to accept the carbon dioxide.
46) a) True b) False: Allosteric regulation occurs when a compound forms a non-covalent bond with the target enzyme, causing a temporary change in its function.
47) a)True/b) False: Photosynthesis drives the dark reactions that represent carbon fixation. Fixation occurs when five carbon Ribulose-1,5-bisphosphates acceptcarbon dioxides and become 3-phosphoglycerates.
Simplified GHK Equation Vm=2.303RT/F log Pk(K)o+Pna(Na)o
Pk(K)i+Pna(Na)i
48) If the sodium permeability is increased a cell will become more? a) Depolarized b) Hyperpolarized
49) a)True b)False: Saltatory conduction of an action potentials is fastest because it uses gaps in the myelin to expose sodium and potassium voltage-gated channels at Nodes of Ranvier.
50) a)True/b)False: Voltage gated channels have a gate that closes a few milliseconds after the gates open during depolarization, this limits the duration of membrane potential depolarization.
PLEASE CONTINUE ON BACK OF SAME SCANTRON SHEET
51) Binding of epinephrine to its Beta-1 receptor causes what subunit of a G-protein to dissociate and stimulate adenylyl cyclase to produce cAMP?
a) Alpha-GTP b) Beta-GTP c) Gamma-GTP d) Calmodulin
52) Diacylglycerol and inositol triphosphate are two second messengers that are produced by the same enzyme. What enzyme produces these two second messengers?
a) Adenylyl cyclase b) Guanylyl cyclase c) Calmodulin
d) Tyrosine kinase e) Phospholipase-C
53) Which of the following can increased calcium permeability leading to contraction or exocytosis?
a) Inositol triphosphate b) Voltage-gated channels c) Calcium d) All of above
54) Which of the following moves a vesicle along a microtubule towards its positive (elongating) end.
a) Myosin b) Kinesin c) Keratin d) Calodulin
55) How many of the items indicted below would be produced if stearate (a 18 carbon long fatty acid) underwent beta-oxidation (BUT NOT TCA) in the mitochondrial matrix?
Acetyl-CoA= NADH= FADH2=
a) 18, 18, 8 b) 9, 8, 8 c) 8, 9, 9
56) How many of the items below are produced when one acetyl-CoA enters the citric acid cycle and is completely oxidized?
NADH= __ FADH2= __ GTP= CO2= __ Oxaloacetate= Pyruvate= .
a) 3, 1, 1, 2, 1, 0 b) 2, 2, 2, 4, 2, 0 c) 6, 6, 6, 4, 2, 2
57) In skeletal muscle, what cation binds to troponin and displaces tropomyosin from actin, thereby exposing actin to the myosin head?
a) Sodium b) Potassion c) Calcium d) Bicarbonate
58) In smooth muscle, phosphorylation of what enzyme by ______permits contraction to occur.
a) Calmodulin b) Tyrosine kinase c) Myosin light chain kinase d) Myosin phosphatase
Unit Written Questions:10 points
Please write your answers on the paper provided:
Abbreviations for the 20 different amino acids: Phenylalanine-Phe, Leucine-Leu, Isoleucine-Ile, Methionine-Met, Valine-Val, Serine-Ser, Proline-Pro, Threonine-Thr, Alanine-Ala, Tyrosine-Tyr, Histidine-His, Glutamine-Gin, Asparagine-Asn, Lysine-Lys, Aspartate-Asp, Glutamate-Glu, Cysteine-Cys, Tryptophan-Tyr, Arginine-Arg, and Glycine-Gly.
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59) 5 pt: Examine the mRNA below and determine the protein (aa sequence) that would result from successful translation by a ribosome.
a) # of amino acids ______
b) # of codons?_____ c) # of peptide bonds in protein?_____
d) Find the start codon and show the specific amino acids (names) in the specific sequence of the peptide resulting from translation of this mRNA.
5’-AGCCUUAUGAGGCAGGGGAUGACCGAGCGCUAAGGCCGG-3’
60) 2pt: The mRNA above was transcribed from a single template strand of DNA that was unwound from a double helix. What was the base sequence of this template ssDNA?
61) 3 pt: Compare and contrast the function of the smooth endoplasmic reticulum, the rough endoplasmic reticulum and free ribosomes that are not bound to the ER? 20-40 words
Comprehensive Written Questions (12 points)
Choose 4 of the following 6 questions (3 pts each)
Please write answers on the paper provided
Useful Formulas: Keq= [products]/[reactants] R=1.987 cal/mol K T=298 K
MM kinetics: v= Vmax [S]/(Km+[S]) LB Kinetics: 1/v= (Km/Vm)(1/[S]) + 1/Vmax
∆G= ∆G’o + 2.303 RT log [products]/[reactants] Remember!!!!! 2.302(log X) = ln X
59) Consider this reaction in a skeletal muscle cell:
Phosphocreatine + ADPCreatine + ATP
Phosphocreatine= 28 mM, Creatine = 8 mM, ADP=1 mM, ATP=8 mM, PO4=8mM
A) What is the standard ∆G’o for this reaction?
Show math, and final mathematical answer in CORRECT UNITS in correct formula.
B) Show the formula with numbers set in proper units that would permit you to properly calculate the physiological delta G for the reaction under the conditions described above if you have access to a good calculator.
62) Draw and label the Michealis-Menton Plot for an enzyme-linked reaction and show the relationship of Vmax and Km.
A) Normal Reaction (Km and Vm)
B) Plot of reaction in the presence of a competitive inhibitor (Km ci and Vm ci)
C) Plot of reaction in presence of a non-competitive inhibitor (Km nci and VM nci)
D) Can an enzymes Vm ever in practice be reached? Yes or No
Draw a plot like this on your answer sheet
RxnVelocity
[S]
63) What is the Fluid Mosaic Model of a cell membrane? What are the characteristics of membrane lipids and proteins that make this model work? (20-40 words with diagrams if this helps)
64) With respect to glycolysis, many of the chemical reactions have a positive ∆G’o value. Describe three things that a cell could use to improve product formation? (20-40 words)
65) With respect to second messenger systems, why is intracellular amplification needed so that a hormone such as insulin can change cellular function? Name and describe a hormone that does not require amplification and how it functions in this regard. (20-40 words with diagrams if this helps)
66) Consider microtubules and microfilaments: compare and contrast their structure (subunits) and function (describe two cellular functions that each is responsible for).
(20-40 words with diagrams if this helps)
Unit Extra Credit (2 pts 4 X ½ pt):Draw/Name and amino acid that would do the following:
a) Associate with the hydrophobic core of the lipid bilayer
b) Could be phosphorylated by a kinase
c) Would have a charged R-group that could attract calcium
d) Would permit collagen to form tight bundles due to its small size
Comprehensive Extra Credit (up to 4 pts): Create adiagram/flow chartthat namesthe substrates, products, organelles and enzyme complexes that permit a single glucose molecule in the cytosol of a well oxygenated eukaryotic cell (cardiac cell) to be completely oxidized in a mitochondria to carbon dioxide, generate a proton gradient for ATP synthesis, as well as consume oxygen and ultimately produce of water. (chemical structures optional)