Cell Bio Final (Previous Exam Questions)
Select all of the following that are true during the enzymatic transfer of electrons and protons from FADH2 to Fe3+.
- Fe 3+ is reduced to Fe 2+ - FADH2 is oxidized - two protons are released into the medium
From the list below, select all the categories into which plasma membrane receptors can be conveniently classified.
- ion channel receptors - receptors linked to G-proteins - catalytic receptors
From the list below, select all the conversions that generate CO2.
- isocitrate to alpha-ketoglutarate - alpha-ketoglutarate to succinyl coA - pyruvate to acetyl coA
From the list below, select all the processes that generate CO2.
- pyruvate processing - TCA cycle
There are only two ways cells make ATP. From the list below, check those two.
- substrate level phosphorylation - oxidative phosphorylation
Consider a protein inserted into the ER membrane during translation (i.e., co-translational import). A lumenal segment of such a protein may later be found in which of the following places?
- the lumen of a Golgi cisterna - the lumen of a vesicle *there may be more correct answers. idk mane*
On a Hanes-Woolf plot [S]/v is plotted as a function of [S]. On this type of plot the x-intercept represents _______ .
-Km
How much 2 M ethanol would you add to make 100 mL of 02.5 mM ethanol?
0.0125 mL
You spin down 2.0 mL of cell suspension, bring the pellet up in 100 microliters of PBS, then add 10 microliters of trypan blue directly to the smae tube. What is the dilution factor?
0.055
If you dilute 5.0 mL of a citrate solution that is 5 mg/mL to a total volume of 100 mL, what is the citrate concentration of the final solution?
0.25 mg/mL
How many ATP molecules are produced for each "turn" of the TCA cycle?
1
The equation describing the regression line of a LIneweaver Burk plot is y = 0.25x - 0.1. What is the numerical value of Km?
1
How much of a solution that is 7.65 mg urea/mL do you need to have 12 mg of urea?
1.57 mL
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?
100%
A linear regression through the data of a standard curve plotting protein concentration as a function of absorbance has a slope of 0.4 absorbance units (AU)/mg protein/mL and a Y-intercept of 0.1 AU. What is the protein concentration of a sample that yields an absorbance of 0.9 AU?
2.0
If there are 20 chromatids in a cell, how many centromeres are there?
20
You have counted your cell culture and found that three "red" squares (1 x 1 x 0.1 mm) gave you counts of 98, 104, and 125 ells, respectively. The dilution factor is 0.25. What is the density of your culture?
272,500 cells/mL
How much protein is contained in 3.78 mL of a solution that is 1 g/L?
3.78 mg
Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells?
32
What is the equilibrium potential for sodium when its concentration inside the cell is 34 mM and outside the cell is 165 mM?
40 mV
After being oxidized completely to H2O and CO2, how many CO2 molecules are produced by one molecule of glucose?
6
How many oxygen molecules (O2) are required each time a molecule of glucose (C6H12O6) is completely oxidized to carbon dioxide and water via aerobic respiration?
6
Which of the following is/are NOT TRUE of ATP?
ATP is found only in mitochondria
How would you make 50 mL of 0.50 mM glutamate (MW = 147.1)?
Add 3.68 mg of glutamate to a 50 mL volumetric flask and bring up to 50 mL?
Phylogenetically, cells are divided into three broad domains, ______.
Bacteria, Archaea, and Eukaria
Codons are three-base sequences that specify the addition of a single amino acid. How do eukaryotic codons and prokaryotic codons compare?
Codons are a nearly universal language among all organisms.
In eukaryotic cells, chromosomes are composed of _____.
DNA and proteins
Which is the correct order of protein movement through the endomembrane system?
ER, golgi, lysosome
The phase of the cell cycle that varies most in duration in various cell types is _____.
G1
Which of the following statements about NAD+ is true?
NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle
In addition to ATP, what are the other end products of glycolysis?
NADH and pyruvate
What is the difference between a synthase and a synthetase?
One uses ATP, the other does not
Under normal cellular conditions, pyruvate may be converted into all of the following EXCEPT this one.
PEP
Which of the following is NOT one of the steps of cellular respiration?
RNA processing
The phase of the cell cycle associated with the doubling of the amount of DNA in the cell is _________ phase.
S
Which of the following are true based on what we know today? (about prokaryotes)
Some prokaryotes can have cytoskeletal elements and internal, membrane-bound organelles.
What does it mean to say that a signal is transduced?
The physical form of the signal changes from one form to another.
*True or False?* Ion gradients across the membrane drive numerous cellular functions.
True
Zinc, an essential trace element for most organisms, is present in the active site of the enzyme carboxypeptidase. The zinc most likely functions as____.
a cofactor necessary for enzyme activity
The molarity of a solution is___
a measure of solute concentration
What is a nuclear localization signal?
a sequence of amino acids that signals for a protein to enter the nucleus
Different body cells can respond differently to the same peptide hormones because _____.
a target cell's response is determined by the receptors it possesses
Which component(s) of the cytoskeleton is/are polar?
actin and microtubules
Cyclins modulate the progression of cells through the cell cycle by
activating protein kinases that are critical regulators of cell division.
In the article by Hediger, membrane-associated transporters were divided into two categories, _______ and ________.
active, passive
Which enzyme is desginated EC 1.1.1.1?
alcohol dehydrogenase
Which of the following is NOT a tenet of the cell theory?
all cells have a membrane bound nucleus
The nucleus contains
all of the above (DNA, protein, chromatin)
Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in ______.
all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors
Consider the number of carbon atoms in the molecules listed below. Which one does not belong with the others?
alpha-ketoglutarate
Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because they _____.
amplifiy the original signal many times
Cyclin-dependent kinase (Cdk) is _____.
an enzyme that attaches phosphate groups to other proteins
____ bind two or more ions or molecules and transport them in opposite directions across a membrane.
antiporters
According to Robinson, the deepest branch of the evolutionary tree is between ______ and _______.
archaea, bacteria
Ribosomes____
are made of RNA and protein and synthesize all the proteins in a cell
Cells are small in part b/c _____.
as they get larger it becomes more difficult to keep the concentrations of reactants relatively high and the surface area is unable to meet the demands of the increased volume
In the term " DG ", the " ' " symbol indicates that the reaction was carried out
at pH = 7.0
A mutation in yeast makes it unable to convert pyruvate to ethanol. How will this mutation affect these yeast cells? The mutant yeast cells wil _____ .
be unable to grow anaerobically
In the equation describing Fick's law, why is it possible to replace term dc/dx with term (Co-Ci) when considering biological systems?
because in biological systems dx is a constant
How might a change of a single amino acid at a site distant from the active site of an enzyme alter an enzyme's substrate specificity?
by changing the conformation of the enzyme
Consider this pathway: epinephrine → G protein-coupled receptor → G protein → adenylyl cyclase → cAMP. The second messenger in this pathway is _____.
cAMP
Cellulose belongs to which of the following groups of macromolecules?
carbohydrates
Of the following molecules, which passes through a lipid bilayer most readily?
carbon dioxide
The simplest structure shared among all living organisms is the___.
cell
Glycosylated proteins and lipids within the plasma membrane are important for
cell recognition and protection
In the cells of some organisms, mitosis occurs without cytokinesis. This results in _____.
cells with more than one nucleus
Cells are _____.
characteristic of prokaryotic and eukaryotic organisms
Which of the following does NOT pass through nuclear pores?
chromosomes
Which of the following chemical bonds is the strongest?
covalent
Kinetochore microtubules assist in the process of splitting centromeres by _____.
creating tension by pulling toward opposite poles
Mitosis separates chromosomes. Cytoplasm is divided between two daughter cells by _____.
cytokinesis
When the size of a cell increases, the surface area/volume ratio ____
decreases
In the equation describing Fick's Law, the variable "D" represents the ______.
diffusion coefficient
The activation of receptor tyrosine kinases is characterized by _____.
dimerization and phosphorylation
Tumor-supressor genese ____.
encode proteins that help prevent uncontrolled cell growth
This organelle is involved in protein synthesis.
endoplasmic reticulum
During normal glycolysis, glucose-6-phosphate is converted into _________.
fructose-6-phosphate
Yeast cells that have defective mitochondria incapable of respiration will be able to grow by catabolizing which of the following carbon sources for energy?
glucose
Which amino acid was produced in Stanley Miller's experiment?
glycine
Which of the following occurs in the cytosol of a eukaryotic cell?
glycolysis and fermentation
In general, an enzyme with a low afifnity
has a high reaction rate
An exothermic reaction______
has a negative DG and proceeds spontaneously
Neurons and some other specialized cells divide infrequently because they _____.
have entered into G0
Which of the following is/are true of Robert Remak?
he was one of the first to postulate that all cells arise from preexisting cells
What is the difference between a biphosphate and a diphosphate?
in a diphosphate, the phosphates are directly attached to one another
In the cell cycle, a mitotic Cdk is present during _________ phase.
in all phases on this list
The product of the p53 gene _____.
inhibits the cell cycle
During ATP synthesis by the F0F1 ATPase, protons flow from the __________ into the ________.
intermembrane space, matrix
In a cell of a kelp plant the concentration of K+ is much greater inside the cell that outside the cell. The equilibrium voltage for K+ is -73 mV. You measure Vm and get a reading of -90 mV. In this situation, in which direction will K+ tend to flow?
into the cell
Metabolism ____________.
is the total of all the reactions occurring within a cell
Gramicidin is an antibiotic that increases the permeability of bacterial cell walls to inorganic ions. What is the most likely mode of action of gramicidin?
it forms a channel in the membrane
Rough ER is called "rough" because_____
it is covered with ribosomes
Which of the following is true of the genetic code?
it is redundant
Why is the Lineweaver-Burke plot important in enzyme kinetics?
it makes it easier to determine Vmax
Which of the following is/are NOT TRUE of facilitated passive diffusion?
it requires ATP
Why can glycolysis be described as having an energy investment phase and an energy payoff phase?
it uses stored ATP and then forms a net increase in ATP
Microtubules often perform their role in movement in association with the motor protein ______ .
kinesin
Consider the equation y=(ax)/(x+k). A graph of 1/y as a function of 1/x will be _______ .
linear
Glycolysis is active when cellular energy levels are ____; the regulatory enzyme, phosphofructokinase, is _____ by ATP.
low; inhibited
Translation requires _____.
mRNA, tRNA, and rRNA
At the most fundamental level, what do enzymes do?
make and break chemical bonds
What is the common name for Callithrix jacchus?
marmoset
The F0 unit of the F0F1 ATPase resides in the inner mitochondrial membrane and the F1 unit resides in the ___________.
matrix
Which of the fundamental properties of life do viruses NOT possess?
metabolism & irritability
The major structural elements of the cytoskeleton are
microtubules, microfilaments, and intermediate filaments
In post-translational import a "transit sequence" targets proteins to which of the following organelle(s)?
mitochondria & cholorplasts
Energy released by the electron transport chain is used to translocate H+ into which location in eukaryotic cells?
mitochondrial intermembrane space
The first gap in the cell cycle (G1) corresponds to _____.
normal growth and cell function
Which of the following structures are involved in ribosome synthesis?
nucleolus
This organelle has a double membrane system.
nucleus
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration?
oxidation of pyruvate to acetyl CoA and the citric acid cycle
What kind of molecules serve as electron acceptors in cellular respiration?
oxidized molecules with low potential energy
Which of the following processes includes all others?
passive transport
Which of the following is the major lipid found in membranes?
phospholipids
Which of the following is not a "logical" reason for cells to phosphorylate glucose?
phosphorylated glucose is a competitive inhibitor of glyceraldehyde-3-phosphoate dehydrogenase
mRNAs are smaller than the length of the DNA that codes for them because _____.
post-transcriptional modification removes the introns
The primary function of an enzyme or any biological catalyst is to ____.
reduce the energy of activation and increase the rate of a reaction
Which of the following is NOT a function of cell membranes?
regulate the transfer of genetic information in the form of DNA and RNA
A gap junction is a channel that connects adjacent cells. Which one of the following CANNOT pass through a gap junction?
ribosomes
All form of life on Earth possess these structures at some point in their lives.
ribosomes
Biological membranes___
separate "inside" from "outside" and allow eukaryotes to compartmentalize
A primary objective of cell fractionation (including differential centrifugation) is to ____.
separate the major organelles
A cell with an extensive are of smooth endoplasmic reticulum is specialized to _____.
synthesize large quantities of lipids
In the NCBI database, the file designated "M10098.1" is the sequence for __________.
the Human 18S RNA gene
In human and many other eukaryotic species' cells, the nuclear membrane has to disappear to permit _____.
the attachment of microtubules to kinetochores
Enzyme and product do not reform the ES complex b/c
the enzyme does not recognize the product
What is the equilibrium potential for a given ion in a given chemical environment?
the membrane voltage at which the net flux of the ion is 0
For living organisms, which of the following is an important consequence of the first law of thermodynamics?
the organism ultimately must obtain all of the necessary energy for life from its environment
Ions diffuse across membranes through specific ion channels down ___
their electrochemical gradient
BRCA1 and BRCA2 are considered to be tumor-suppressor genes because _____.
their normal products participate in repair of DNA damage
Which of the following is/are true of the signal recognition particle?
they are composed of both protein and RNA and they bind to a sequence of amino acids in proteins
Which of the following is/are true of enzymes?
they can convert endothermic reactions into an exothermic reaction
Which of the following statements is TRUE of membrane phospholipids?
they freely move laterally within the membrane
Why are fermentation reactions important for anaerobic cells?
they regenerate NAD+ so that glycolysis can continue to operate
In glycolysis, for each molecule of glucose oxidized to pyruvate _____.
two molecules of ATP are used and four molecules of ATP are produced
Which of the following is the correct form of the Michaelis-Menton equation?
v0 = Vmax[S] / Km + [S]
Which organelle often takes up much of the volume of a plant cell?
vacuole
Chemiosmotic theory was originally termed ______ by its proposer.
vectorial metabolism
In the Week 5 Action Set you plotted the equation y = (ax)/(x+k) where a and k are constants. What is the simplest form of the equation when x=k?
y = a/2