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Cell Bio Exam 2 ch 14 and 15
N/A
224
Biology
Undergraduate 3
03/22/2014
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Term
True or False? • Organisms that could carry out fermentation evolved before those that could carry out aerobic respiration
 Definition
TRUE
Term
T/F • Organisms that could carry out oxygen producing photosynthesis evolved before those that could carry fermentation reactions
 Definition
FALSE
Term
True or False: Eukaryotic organisms were the first to evolve mechanism of chemiosmotic coupling
 Definition
FALSE
Term
True or False: Both photosynthesis and aerobic respiration first evolved in prokaryotes
 Definition
TRUE
Term
True or False: Aerobic respiration arose as an adaptation to increasing levels of oxygen in the atmosphere that had been produced by photosynthesis
 Definition
TRUE
Term
The link between bond-forming reactions and membrane transport processes in the mitochondria is called __________________.
 Definition
(a) chemiosmotic coupling
Term
Modern eucaryotes depend on mitochondria to generate most of the cell’s ATP. How many molecules of ATP can a single molecule of glucose generate?
 Definition
(b) 2
Term
TRUE OR FALSE: The number and location of mitochondria within a cell can change, depending on the both the cell type and the amount of energy required.
 Definition
TRUE
Term
TRUE OR FALSE: The inner mitochondrial membrane contains porins, which allow pyruvate to enter for use in the citric acid cycle.
 Definition
TRUE
Term
TRUE OR FALSE: The inner mitochondrial membrane is actually a series of discrete flattened membrane-enclosed compartments called cristae, similar to what is seen in the Golgi apparatus.
 Definition
TRUE
Term
TRUE OR FALSE:The intermembrane space of the mitochondria is chemically equivalent to the cytosol with respect to pH and the small molecules present.
 Definition
FALSE
Term
In which of the four compartments of a mitochondrion are each of the following located: Porin
 Definition
outer membrane
Term
In which of the four compartments of a mitochondrion are each of the following located: mitochondrial genome
 Definition
matrix
Term
In which of the four compartments of a mitochondrion are each of the following located: citric acid cycle enzymes
 Definition
matrix
Term
In which of the four compartments of a mitochondrion are each of the following located: proteins of the electron transport chain
 Definition
inner membrane
Term
In which of the four compartments of a mitochondrion are each of the following located: ATP synthase
 Definition
inner membrane
Term
In which of the four compartments of a mitochondrion are each of the following located: membrane transport protein for pyruvate
 Definition
inner membrane
Term
NADH contains a high-energy bond that, when cleaved, donates a pair of electrons to the electron-transport chain. What are the immediate products of this bond cleavage?
 Definition
(b) NAD+ + H-
Term
Electron transport is coupled to ATP synthesis in mitochondria, in chloroplasts, and in the thermophilic bacterium Methanococcus. Which of the following is likely to affect the coupling of electron transport to ATP synthesis in all of these systems?
 Definition
(d) an ADP analogue that inhibits ATP synthase
(e) dinitrophenol (permeabilizes membranes to protons)
Term
Stage 1 of oxidative phosphorylation requires the movement of electrons along the electron-transport chain coupled to the pumping of protons into the intermembrane space. What is the final result of these electron transfers?
 Definition
(c) O2 is reduced to H2O.
Term
Which component of the electron-transport chain is required to combine the pair of electrons with molecular oxygen?
 Definition
cytochrome c oxidase
Term
In oxidative phosphorylation, ATP production is coupled to the events in the electron-transport chain. What is accomplished in the final electron transfer event in the electron-transport chain?
 Definition
(c) O2 is reduced to H2O.
Term
TRUE OR FALSE: The pH in the mitochondrial matrix is higher than the pH in the intermembrane space.
 Definition
TRUE
Term
Which of the following types of ion movement might be expected to require co-transport of protons from the intermembrane space to the matrix, inasmuch as it could not be driven by the membrane potential across the inner membrane? (Assume that each ion being moved is moving against its concentration gradient.)
 Definition
(b) import of acetate ions into the matrix from the intermembrane space
Term
Bongkrekic acid is an antibiotic that inhibits the ATP/ADP transport protein in the inner mitochondrial membrane. Which of the following will allow electron transport to occur in mitochondria treated with bongkrekic acid?
 Definition
(c) making the inner membrane permeable to protons
Term
The relationship of free-energy change (δG) to the concentrations of reactants and products is important because it predicts the direction of spontaneous chemical reactions. In the hydrolysis of ATP to ADP and inorganic phosphate (Pi), the standard free-energy change (δG°) is -7.3 kcal/mole. The free-energy change depends on concentrations according to the following equation:

δG = δG° + 1.42 log10 ([ADP] [Pi]/[ATP])

In a resting muscle, the concentrations of ATP, ADP, and Pi are approximately 0.005 M, 0.001 M, and 0.010 M, respectively. What is the δG for ATP hydrolysis in resting muscle?
 Definition
(a) -11.1 kcal/mole
Term
NADH and FADH2 carry high-energy electrons that are used to power the production of ATP in the mitochondria. These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle. Which molecuale below can produce the most ATP? Explain your answer.
 Definition
Term
donate high-energy electrons for synthesis of ATP.
 Definition
NADH
Term
Modern eucaryotes depend on mitochondria to generate most of the cell’s ATP. A single molecule of glucose can generate molecules of ATP.
 Definition
30
Term
gradient serves as an energy store and is used to drive the synthesis of ATP by the ATP
synthase.
 Definition
Proton
Term
The chemiosmotic mechanism of ATP synthesis in mitochondria is called .
 Definition
oxidative phosphorylation
Term
The cytochrome oxidase is a protein complex that receive electron from .
 Definition
cytochrome c
Term
Nuclear proteins for their nuclear import through nuclear pore complexes.
 Definition
do not need to be unfolded
Term
receives proteins and lipids from the ER, modifies them, and then and dispatched them to other destinations in the cells.
 Definition
Golgi apparatus
Term
. Nuclear localization signal is the signal sequence that directs a protein from the cytosol into the nucleus and typically consists of a short amino acid sequence as shown in .
 Definition
-proline-proline-lysine-lysine-lysine-arginine-lysine-valine-
Term
Vesicular transport between membrane-enclosed compartments of endomembrane system is highly organized. The endomembrane system includes nuclear, ER, Golgi apparatus, endosomes and
.
 Definition
lysosomes
Term
The supplies the plasma membrane with newly synthesized lipids and proteins.
 Definition
constitutive secretory pathway
Term
singals can act over a long range.
 Definition
endocrine
Term
Steroid hormones, which can diffuse directly across the plasma membrane, are all
.
 Definition
hydrophobic
Term
GPCRs activate a class of G proteins that can transmit signal and then switch themselves off by hydrolyzing their bound GTP to GDP.
 Definition
trimeric
Term
PKA, PKC, and CaM-kinases phosphorylate selected target proteins on , thereby altering protein activity.
 Definition
serines and threonines
Term
Ras activate a MAP-kinase signaling module by first activating .
 Definition
MAP kinase kinase kinase
Term
The end of a double stranded DNA is characterized by a phosphate group.
 Definition
5'
Term
A nucleosome contains molecule(s) each of histones H2A, H2B, H3 and H4.
 Definition
two
Term
Hershey and Chase showed that genes are made of DNA. The DNA in one batch of viruses is radioactively labeled with .
 Definition
32p
Term
Each human chromosome has origin(s) of replication, one centromere, and two telomeres.
 Definition
multiple
Term
Heterochromatin and euchromatin each represent a set of different chromatin structure with different degrees of extension or condensation. Overall, heterochromatin is condensed than euchromatin
 Definition
more
Term
Stage 1 of oxidative phosphorylation requires the movement of electrons along the electron- transport chain coupled to the pumping of protons into the intermembrane space. What is the final result of these electron transfers?
 Definition
o2 is reduced to H2O
Term
Which component of the electron-transport chain is required to combine the pair of electrons with molecular oxygen?
 Definition
cytochrome c oxidase
Term
Which of the following types of ion movement might be expected to require co-transport of protons from the intermembrane space to the matrix, inasmuch as it could not be driven by the membrane potential across the inner membrane? (Assume that each ion being moved is moving against its concentration gradient.)
 Definition
import of acetate ions (CH3COO-)into the matix from the intermembrane space
Term
NADH and FADH2 carry high-energy electrons that are used to power the production of ATP in the mitochondria. These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle. Which molecuale below can produce the most ATP?
 Definition
NADH from the citric acid cycle
Term
Experimental evidence supporting the chemiosmotic hypothesis was gathered by using artificial vesicles containing a protein that can pump protons in one direction across the vesicle membrane to create a proton gradient. Which protein was used to generate the gradient in a highly controlled manner in response to light?
 Definition
bacteriorhodopsin
Term
Which of the following is not an electron carrier that participates in the electron-transport chain?
 Definition
rhodopsin
Term
Oxidative phosphorylation, as it occurs in modern eucaryotes, is a complex process that probably arose in simple stages in primitive bacteria. Which mechanism is proposed to have arisen first as this complex system evolved?
 Definition
ATP-driven proton pumps
Term
The drug dinitrophenol (DNP) makes the inner mitochondrial membrane permeable to H+ ions. Therefore, when added to mitochondria, DNP
 Definition
will decrease both the production of ATP and the pH gradient across the membrane
Term
Bongkrekic acid is an antibiotic that inhibits the ATP/ADP transport protein in the inner mitochondrial membrane. Which of the following will allow electron transport to occur in mitochondria treated with bongkrekic acid?
 Definition
making the inner membrane permeable to protons
Term
Which of the following statements about the endoplasmic reticulum (ER) is false?
 Definition
proteins to be delivered to the ER lumen are sunthesized on the smooth ER
Term
Where are proteins in the mitochondria synthesized?
 Definition
in both the cytosol and the mitochondria
Term
Your friend works in a biotechnology company and has discovered a drug that blocks the ability of
Ran to exchange GDP for GTP. What is the most likely effect of this drug on nuclear transport?
 Definition
Nuclear transport receptors would be unable to release their cargo in the nucleus
Term
You are interested in Fuzzy, a soluble protein that functions within the ER lumen. Given that information, which of the following statement must be true?
 Definition
Once the signal sequence from Fuzzy has been cleaved, the signal peptide will be ejected into the ER membrane and degraded.
Term
The following figure shows the organization of a protein that normally resides in the plasma membrane. The boxes labeled 1 and 2 represent membrane-spanning sequences and the arrow represents a site of action of signal peptidase. Given this diagram, which of the following statements must be true?
 Definition
The C-terminus of this protein is cytoplasmic.
Term
Which of the following choices reflects the appropriate order through which a protein destined for the plasma membrane travels?
 Definition
ER → Golgi → plasma membrane
Term
TRUE OR FALSE: Clathrin molecules are important for binding to and selecting cargos for transport.
 Definition
FALSE
Term
Your friend has just joined a lab that studies vesicle budding from the Golgi and has been given a cell line that does not form mature vesicles. He wants to start designing some experiments but wasn’t listening carefully when he was told about the molecular defect of this cell line. He’s too embarrassed to ask and comes to you for help. He does recall that this cell line forms coated pits but vesicle budding and the removal of coat proteins don’t happen. Which of the following proteins might be lacking in this cell line?
 Definition
dynamin
Term
TRUE OR FALSE: Activation of the UPR occurs when receptors in the cytoplasm sense misfolded proteins.
 Definition
FALSE
Term
All members of the steroid hormone receptor family .
 Definition
interact with signal molecules that diffuse through the plasma membrane
Term
Acetylcholine is a signaling molecule that elicits responses from heart muscle cells, salivary gland cells, and skeletal muscle cells. TRUE OR FALSE:Heart muscle cells, salivary gland cells, and skeletal muscle cells all express an acetylcholine receptor that belongs to the transmitter-gated ion channel family.
 Definition
FALSE
Term
The following figure shows the pathway through which nitric oxide (NO) triggers smooth muscle relaxation in a blood-vessel wall. Which of the following situations would lead to relaxation of the smooth muscle cells in the absence of acetylcholine?
 Definition
B) a muscle cell that has a defect in guanylyl cyclase such that it constitutively converts GTP to cyclic GMP
Term
Acetylcholine binds to a GPCR on heart muscle, making the heart beat more slowly. The activated receptor stimulates a G protein, which opens a K+ channel in the plasma membrane, as shown in the following figure. Which of the following would enhance this effect of the acetylcholine?
 Definition
addition of a high concentration of a non-hydrolyzable analog of GTP
Term
What produces diacylgycerol and IP3?
 Definition
Phospholipase C
Term
Which of the following accurately describes a receptor tyrosine kinase?
 Definition
It can lead to the activation of Ras.
Term
The growth factor Superchick stimulates the proliferation of cultured chicken cells. The receptor that binds Superchick is a receptor tyrosine kinase (RTK), and many chicken tumor cell lines have
mutations in the gene that encodes this receptor. Which of the following types of mutation would be expected to promote uncontrolled cell proliferation?
 Definition
a mutation that inactivates the protein tyrosine phosphatase that normally removes the phosphates from tyrosines on the activated receptor
Term
TRUE OR FALSE: PI 3-kinase phosphorylates a lipid in the plasma membrane.
 Definition
TRUE
Term
Akt promotes the survival of many cells. It is activated by an intracellular signaling pathway that is triggered by an RTK that activates PI 3-kinase, as diagrammed in the following figure. TRUE OR FALSE:In the absence of survival signal, Bad is phosphorylated.
 Definition
FALSE
Term
In human females,
 Definition
D) inactivation of an X-chromosome leads to a 50/50 chance that a father's or mother's X- associated gene will be expressed in at least part of every tissue.
Term
In a DNA double helix, .
 Definition
the two DNA strands run antiparallel
Term
The human genome has enough DNA to stretch more than 2 m. However, this DNA is not contained in a single molecule; it is divided into linear segments and packaged into structures called chromosomes. What is the total number of chromosomes found in each of the somatic cells in your body?
 Definition
46
Term
Stepwise condensation of linear DNA happens in five different packing processes. Which of the following four processes has a direct requirement for histone H1?
 Definition
formation of the 30 nm fiber
Term
TRUE OR FALSE:The δE′0 of a redox pair does not depend on the concentration of each member of the pair.
 Definition
TRUE
Term
Which of the following reactions have a large enough free-energy change to enable it to be used, in principle, to provide the energy needed to synthesize one molecule of ATP from ADP and Pi under standard conditions? See Table 14-23. Recall that

δG° = -n (0.023) δE′0 and δE′0 = E′0 (acceptor) - E′0 (donor).
 Definition
the reduction of a molecule of cytochrome b by NADH
Term
TRUE OR FALSE: Mitochondrial electron carriers with the highest redox potential generally contain copper ions and/or heme groups.
 Definition
TRUE
Term
Photosynthesis is a process that takes place in chloroplasts and uses light energy to generate high-energy electrons, which are passed along an electron-transport chain. Where are the proteins of the electron-transport chain located in chloroplasts?
 Definition
thylakoid membrane
Term
In stage 1 of photosynthesis, a proton gradient is generated and ATP is synthesized. Where do protons become concentrated in the chloroplast?
 Definition
thylakoid space
Term
Which of the following is not an electron carrier that participates in the electron-transport chain?
 Definition
rhodopsin
Term
Stage 2 of photosynthesis, sometimes referred to as the dark reactions, involves the reduction of CO2 to produce organic compounds such as sucrose. What cofactor is the electron donor for carbon fixation?
 Definition
NADPH
Term
If you shine light on chloroplasts and measure the rate of photosynthesis as a function of light intensity, you get a curve that reaches a plateau at a fixed rate of photosynthesis, x, as shown in Figure Q14-45.Which of the following conditions will increase the value of x?
 Definition
increasing the number of reaction centers
Term
The enzyme ribulose bisphosphate carboxylase (rubisco) normally adds carbon dioxide to ribulose 1,5-bisphosphate. However, it will also catalyze a competing reaction in which O2 is added to ribulose 1,5-bisphosphate to form 3-phosphoglycerate and phosphoglycolate. Assume that phosphoglycolate is a compound that cannot be used in any further reactions. If O2 and CO2 have the same affinity for rubisco, which of the following is the lowest ratio of CO2 to O2 at which a net synthesis of sugar can occur?
 Definition
3:1
Term
If you add a compound to illuminated chloroplasts that inhibits the NADP+ reductase, NADPH generation ceases, as expected. However, ferredoxin does not accumulate in the reduced form because it is able to donate its electrons not only to NADP+ (via NADP+ reductase) but also back to the cytochrome b6-f complex. Thus, in the presence of the compound, a “cyclic” form of photosynthesis occurs in which electrons flow in a circle from ferredoxin, to the cytochrome b6-f complex, to plastocyanin, to photosystem I, to ferredoxin. What will happen if you now also inhibit photosystem II?
 Definition
Plastoquinone will accumulate in the oxidized form.
Term
In 1925, David Keilin used a simple spectroscope to observe the characteristic absorption bands of the cytochromes that participate in the electron-transport chain in mitochondria. A spectroscope passes a very bright light through the sample of interest and then through a prism to display the spectrum from red to blue. If molecules in the sample absorb light of particular wavelengths, dark bands will interrupt the colors of the rainbow. His key discovery was that the absorption bands disappeared when oxygen was introduced and then reappeared when the samples became anoxic. Subsequent findings demonstrated that different cytochromes absorb light of different frequencies. When light of a characteristic wavelength shines on a mitochondrial sample, the amount of light absorbed is proportional to the amount of a particular cytochrome present in its reduced form. Thus, spectrophotometric methods can be used to measure how the amounts of reduced cytochromes change over time in response to various treatments. If isolated mitochondria are incubated with a source of electrons such as succinate, but without oxygen, electrons enter the respiratory chain, reducing each of the electron carriers almost completely. When oxygen is then introduced, the carriers oxidize at different rates, as can be seen from the decline in the amount of reduced cytochrome (see Figure Q14-49). Note that cytochromes a and a3 cannot be distinguished and thus are listed as cytochrome (a + a3). How does this result allow you to order the electron carriers in the respiratory chain? What is their order?
 Definition
b,c1,c, (a + a3)
Term
chloroplasts are closely related to
 Definition
cyanobacteria
Term
mitochondria is closely related to
 Definition
bascillus
Term
TRUE OR FALSE:The ER is the major site for new membrane synthesis in the cell.
 Definition
TRUE
Term
TRUE OR FALSE:Proteins to be delivered to the ER lumen are synthesized on smooth ER.
 Definition
FALSE
Term
TRUE OR FALSE:Steroid hormones are synthesized on the smooth ER.
 Definition
TRUE
Term
TRUE OR FALSE:The ER membrane is contiguous with the outer nuclear membrane.
 Definition
TRUE
Term
Which of the following organelles are not part of the endomembrane system?
 Definition
mitochondria
Term
You discover a fungus that contains a strange star-shaped organelle not found in any other eucaryotic cell you have seen. On further investigation you find the following.
1. The organelle possesses a small genome in its interior.
2. The organelle is surrounded by two membranes.
3. Vesicles do not pinch off from the organelle membrane.
4. The interior of the organelle contains proteins similar to those of many bacteria.
5. The interior of the organelle contains ribosomes.

How might this organelle have arisen?
 Definition
A genome, a double membrane, ribosomes, and proteins similar to those found in bacteria
are evidence for an organelle having evolved from an engulfed bacterium.
Term
TRUE OR FALSE: The signal sequences on mitochondrial proteins are usually C-terminal.
 Definition
FALSE
Term
TRUE OR FALSE: Most mitochondrial proteins are not imported from the cytosol but are synthesized inside the mitochondria.
 Definition
FALSE
Term
TRUE OR FALSE:Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes.
 Definition
FALSE
Term
TRUE OR FALSE: Mitochondrial proteins cross the membrane in their native, folded state.
 Definition
TRUE
Term
Most proteins destined to enter the endoplasmic reticulum
 Definition
begin to cross the membrane while still being synthesized.
Term
After isolating the rough endoplasmic reticulum from the rest of the cytoplasm, you
purify the RNAs attached to it. Which of the following proteins do you expect the RNA
from the rough endoplasmic reticulum to encode?
 Definition
ALL OF THE ABOVE ( SOLUBLE SECRETED PROTEINS; ER PROTEINS; PLASMA MEMBRANE PROTEINS)
Term
In which cellular location would you expect to find ribosomes translating mRNAs that encode ribosomal proteins?
 Definition
in the cytosol
Term
What is the role of the nuclear localization sequence in a nuclear protein?
 Definition
It is bound by cytoplasmic proteins that direct the nuclear protein to the nuclear
pore.
Term
Your friend works in a biotechnology company and has discovered a drug that blocks the ability of Ran to exchange GDP for GTP. What is the most likely effect of this drug on nuclear transport?
 Definition
Nuclear transport receptors would be unable to release their cargo in the nucleus.
Term
You are interested in Fuzzy, a soluble protein that functions within the ER lumen. Given that information, which of the following statement must be true?
 Definition
Once the signal sequence from Fuzzy has been cleaved, the signal peptide will be ejected into the ER membrane and degraded.
Term
An individual transport vesicle
 Definition
will fuse with only one type of membrane.
Term
N-linked oligosaccharides on secreted glycoproteins are attached to
 Definition
the asparagine in the sequence Asn-X-Ser/Thr.
Term
The three main classes of proteins that must be sorted before they leave the trans Golgi
network in a cell capable of regulated secretion are
 Definition
(1) those destined for lysosomes, (2)
those destined for secretory vesicles, and (3) those destined for immediate delivery to the
cell surface.
Term
You are working in a biotech company that has discovered a small-molecule drug called H5434. H5434 binds to LDL receptors when they are bound to cholesterol. H5434 binding does not alter the conformation of the LDL receptor’s intracellular domain. Interestingly, in vitro experiments demonstrate that addition of H5434 increases the affinity of LDL for cholesterol and prevents cholesterol from dissociating from the LDL receptor even in acidic conditions. Which of the following is a reasonable prediction of what may happen when you add H5434 to cells?
 Definition
Cytosolic cholesterol levels will decrease relative to normal cells.
Term
Name three possible fates for an endocytosed molecule that has reached the endosome.
 Definition
1. recycled to the original membrane
2. destroyed in the lysosome
3. transcytosed across the cell to a different membrane.
Term
Cells have oligosaccharides displayed on their cell surface that are important for cell–cell recognition. Your friend discovered a transmembrane glycoprotein, GP1, on a pathogenic yeast cell that is recognized by human immune cells. He decides to purify large amounts of GP1 by expressing it in bacteria. To his purified protein he then adds a branched 14-sugar oligosaccharide to the asparagine of the only Asn-X-Ser sequence found on GP1 (Figure Q15-33). Unfortunately, immune cells do not seem to recognize this synthesized glycoprotein. Which of the following statements is a likely explanation for this problem?
 Definition
(c). Oligosaccharides are usually further modified by enzymes in the ER and the Golgi before the glycoprotein is inserted into the plasma membrane.
Term
Which of the following statements about disulfide bond formation is false?
 Definition
Disulfide bonds form spontaneously within the ER because the lumen of the ER is oxidizing
Term
Which of the following statements about the unfolded protein response (UPR) is false?
 Definition
Activation of the UPR occurs when receptors in the cytoplasm sense misfolded proteins.
Term
TRUE OR FALSE: In a typical cell, the area of the endoplasmic reticulum membrane far exceeds the area of plasma membrane.
 Definition
TRUE
Term
TRUE OR FALSE: The nucleus is the only organelle that is surrounded by a double membrane.
 Definition
FALSE
Term
TRUE OR FALSE: Other than the nucleus, most organelles are small and thus, in a typical cell, only about 10% of a cell’s volume is occupied by membrane-enclosed organelles; the other 90% of the cell volume is the cytosol.
 Definition
FALSE
Term
TRUE OR FALSE: The nucleus is the only organelle that contains DNA.
 Definition
FALSE
Term
Plasma membrane proteins are inserted into the membrane in the
 Definition
ER
Term
the address information fro protein sorting in a Eukaryotic cell is contain in the
 Definition
amino acid sequence of the proteins
Term
proteins enter the nucleus in their ____ state
 Definition
folded
Term
Proteins that remain in the cytosol do not contain a
 Definition
sorting signal
Term
proteins are transported into the golgi apparatus via
 Definition
transport vesicle
Term
the proteins transported into the ER by
 Definition
Protein translocation are in their unfolded form
Term
Where are proteins in the chloroplast synthesized?
 Definition
in both the cytosol and the chloroplast
Term
What would happen in each of the following cases? Assume in each case that the protein involved is a soluble protein, not a membrane protein.

You add a signal sequence (for the ER) to the N-terminal end of a normally cytosolic protein.
 Definition
Protein to ER lumen
Term
What would happen in each of the following cases? Assume in each case that the protein involved is a soluble protein, not a membrane protein.

You change the hydrophobic amino acids in an ER signal sequence into charged amino acids.
 Definition
signal NOT recognized and protein remains in cytosol
Term
What would happen in each of the following cases? Assume in each case that the protein involved is a soluble protein, not a membrane protein.

You change the hydrophobic amino acids in an ER signal sequence into other, hydrophobic, amino acids.
 Definition
delivered to ER
Term
What would happen in each of the following cases? Assume in each case that the protein involved is a soluble protein, not a membrane protein.

You move the N-terminal ER signal sequence to the C-terminal end of the protein.
 Definition
Protein will not enter ER
Term
TRUE OR FALSE:The signal sequences on mitochondrial proteins are usually C-terminal.
 Definition
FALSE
Term
TRUE OR FALSE: Most mitochondrial proteins are not imported from the cytosol but are synthesized inside the mitochondria.
 Definition
FALSE
Term
TRUE OR FALSE: Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes.
 Definition
FALSE
Term
TRUE OR FALSE:Mitochondrial proteins cross the membrane in their native, folded state.
 Definition
TRUE
Term
Most proteins destined to enter the endoplasmic reticulum
 Definition
begin to cross the membrane while still being synthesized.
Term
After isolating the rough endoplasmic reticulum from the rest of the cytoplasm, you purify the RNAs attached to it. Which of the following proteins do you expect the RNA from the rough endoplasmic reticulum to encode?
 Definition
all of the above: soluble secreted proteins; ER membrane proteins; plasma membrane proteins;
Term
In which cellular location would you expect to find ribosomes translating mRNAs that encode ribosomal proteins?
 Definition
(c) in the cytosol
Term
What region of the thiolase protein contains the peroxisomal targeting sequence? Explain your answer.
 Definition
The peroxisomal targeting sequence lies between amino acids number 100 and number
125.
Term
TRUE OR FALSE: In a typical cell, the area of the endoplasmic reticulum membrane far exceeds the area of plasma membrane.
 Definition
TRUE
Term
TRUE OR FALSE: The nucleus is the only organelle that is surrounded by a double membrane.
 Definition
FALSE
Term
TRUE OR FALSE: Other than the nucleus, most organelles are small and thus, in a typical cell, only about 10% of a cell’s volume is occupied by membrane-enclosed organelles; the other 90% of the cell volume is the cytosol.
 Definition
FALSE
Term
TRUE OR FALSE: The nucleus is the only organelle that contains DNA.
 Definition
FALSE
Term
Plasma membrane proteins are inserted into the membrane in the
 Definition
ER
Term
the address information fro protein sorting in a Eukaryotic cell is contain in the
 Definition
amino acid sequence of the proteins
Term
proteins enter the nucleus in their ____ state
 Definition
folded
Term
Proteins that remain in the cytosol do not contain a
 Definition
sorting signal
Term
proteins are transported into the golgi apparatus via
 Definition
transport vesicle
Term
the proteins transported into the ER by
 Definition
Protein translocation are in their unfolded form
Term
Where are proteins in the chloroplast synthesized?
 Definition
in both the cytosol and the chloroplast
Term
What would happen in each of the following cases? Assume in each case that the protein involved is a soluble protein, not a membrane protein.

You add a signal sequence (for the ER) to the N-terminal end of a normally cytosolic protein.
 Definition
Protein to ER lumen
Term
What would happen in each of the following cases? Assume in each case that the protein involved is a soluble protein, not a membrane protein.

You change the hydrophobic amino acids in an ER signal sequence into charged amino acids.
 Definition
signal NOT recognized and protein remains in cytosol
Term
What would happen in each of the following cases? Assume in each case that the protein involved is a soluble protein, not a membrane protein.

You change the hydrophobic amino acids in an ER signal sequence into other, hydrophobic, amino acids.
 Definition
delivered to ER
Term
What would happen in each of the following cases? Assume in each case that the protein involved is a soluble protein, not a membrane protein.

You move the N-terminal ER signal sequence to the C-terminal end of the protein.
 Definition
Protein will not enter ER
Term
TRUE OR FALSE:The signal sequences on mitochondrial proteins are usually C-terminal.
 Definition
FALSE
Term
TRUE OR FALSE: Most mitochondrial proteins are not imported from the cytosol but are synthesized inside the mitochondria.
 Definition
FALSE
Term
TRUE OR FALSE: Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes.
 Definition
FALSE
Term
TRUE OR FALSE:Mitochondrial proteins cross the membrane in their native, folded state.
 Definition
TRUE
Term
Most proteins destined to enter the endoplasmic reticulum
 Definition
begin to cross the membrane while still being synthesized.
Term
After isolating the rough endoplasmic reticulum from the rest of the cytoplasm, you purify the RNAs attached to it. Which of the following proteins do you expect the RNA from the rough endoplasmic reticulum to encode?
 Definition
all of the above: soluble secreted proteins; ER membrane proteins; plasma membrane proteins;
Term
In which cellular location would you expect to find ribosomes translating mRNAs that encode ribosomal proteins?
 Definition
(c) in the cytosol
Term
What region of the thiolase protein contains the peroxisomal targeting sequence? Explain your answer.
 Definition
The peroxisomal targeting sequence lies between amino acids number 100 and number
125.
Term
What is the role of the nuclear localization sequence in a nuclear protein?
 Definition
It is bound by cytoplasmic proteins that direct the nuclear protein to the nuclear pore.
Term
Your friend works in a biotechnology company and has discovered a drug that blocks the ability of Ran to exchange GDP for GTP. What is the most likely effect of this drug on nuclear transport?
 Definition
Nuclear transport receptors would be unable to release their cargo in the nucleus.
Term
You are interested in Fuzzy, a soluble protein that functions within the ER lumen. Given that information, which of the following statement must be true?
 Definition
Once the signal sequence from Fuzzy has been cleaved, the signal peptide will be ejected into the ER membrane and degraded.
Term
Figure Q15-19 shows the organization of a protein that normally resides in the plasma membrane. The boxes labeled 1 and 2 represent membrane-spanning sequences and the arrow represents a site of action of signal peptidase. Given this diagram, which of the following statements must be true?
 Definition
The C-terminus of this protein is cytoplasmic.
Term
Briefly describe the mechanism by which an internal stop-transfer sequence in a protein causes the protein to become embedded in the lipid bilayer as a transmembrane protein with a single membrane-spanning region. Assume that the protein has an N-terminal signal sequence and just one internal hydrophobic stop-transfer sequence.
 Definition
The amino-terminal signal sequence initiates translocation and the protein chain starts to
thread through the translocation channel. When the stop-transfer sequence enters the
translocation channel, the channel discharges both the signal sequence and the stoptransfer
sequence sideways into the lipid bilayer. The signal sequence is then cleaved, so
that the protein remains held in the membrane by the hydrophobic stop-transfer sequence.
Term
Using genetic engineering techniques, you have created a set of proteins that contain two (and only two) conflicting signal sequences that specify different compartments. Predict which signal would win out for the following combinations. Explain your answers.

Signals for import into the nucleus and import into the ER.
 Definition
protein enter the ER
Term
Using genetic engineering techniques, you have created a set of proteins that contain two (and only two) conflicting signal sequences that specify different compartments. Predict which signal would win out for the following combinations. Explain your answers.

Signals for export from the nucleus and import into the mitochondria.
 Definition
protein enter mitochondria
Term
Using genetic engineering techniques, you have created a set of proteins that contain two (and only two) conflicting signal sequences that specify different compartments. Predict which signal would win out for the following combinations. Explain your answers.

Signals for import into mitochondria and retention in the ER.
 Definition
protein enters mitochondria
Term
Proteins are transported out of a cell via the __________________ or __________________ pathway.
 Definition
secretory; exocytic
Term
Which of the following choices reflects the appropriate order through which a protein destined for the plasma membrane travels?
 Definition
ER → Golgi → plasma membrane
Term
Fluids and macromolecules are transported into the cell via the __________________ pathway
 Definition
endocytic
Term
All proteins being transported out of the cell pass through the __________________ and the __________________.
 Definition
ER; Golgi Apparatus
Term
Transport vesicles link organelles of the __________________ system.
 Definition
endomembrane
Term
The formation of __________________ in the endoplasmic reticulum stabilizes protein structure.
 Definition
disulfide bonds
Term
TRUE OR FALSE: Clathrin molecules are important for binding to and selecting cargos for transport.
 Definition
false
Term
TRUE OR FALSE: Adaptins interact with clathrin.
 Definition
true
Term
TRUE OR FALSE: Once vesicle budding occurs, clathrin molecules are released from the vesicle.
 Definition
true
Term
TRUE OR FALSE: Clathrin molecules act at the cytosolic surface of the Golgi membrane.
 Definition
true
Term
Your friend has just joined a lab that studies vesicle budding from the Golgi and has been given a cell line that does not form mature vesicles. He wants to start designing some experiments but wasn’t listening carefully when he was told about the molecular defect of this cell line. He’s too embarrassed to ask and comes to you for help. He does recall that this cell line forms coated pits but vesicle budding and the removal of coat proteins don’t happen. Which of the following proteins might be lacking in this cell line?
 Definition
dynamin
Term
Which of the following protein families are not involved in directing transport vesicles to the target membrane?
 Definition
adaptins
Term
N-linked oligosaccharides on secreted glycoproteins are attached to
 Definition
the asparagine in the sequence Asn-X-Ser/Thr.
Term
Name two types of protein modification that can occur in the ER but not in the cytosol.
 Definition
glycosylation and disulfide bond formation
Term
If you remove the ER-retention signal from a protein that normally resides in the ER lumen, where do you predict the protein will ultimately end up?
 Definition
The protein would end up in the extracellular space.
Term
TRUE OR FALSE: The membrane of a secretory vesicle will fuse with the plasma membrane when it discharges its contents to the cell’s exterior.
 Definition
TRUE
Term
TRUE OR FALSE: Vesicles for regulated exocytosis will not bud off the trans Golgi network until the appropriate signal has been received from the cell.
 Definition
FALSE
Term
TRUE OR FALSE: The signal sequences of proteins destined for constitutive exocytosis ensure their packaging into the correct vesicles.
 Definition
FALSE
Term
TRUE OR FALSE: Proteins destined for constitutive exocytosis aggregate as a result of the acidic pH of the trans Golgi network.
 Definition
FALSE
Term
If a lysosome breaks, what protects the rest of the cell from lysosomal enzymes?
 Definition
low pH
Term
NADH and FADH2 carry high-energy electrons that are used to power the production of ATP in the mitochondria. These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle. Which molecuale below can produce the most ATP? Explain your answer.
 Definition
NADH from the citric acid cycle
Term
Which ratio of NADH to NAD+ in solution will generate the largest, positive redox potential?
 Definition
Term
N-linked oligosaccharides on secreted glycoproteins are attached to
 Definition
the asparagine in the sequence Asn-X-Ser/Thr.
Term
Name two types of protein modification that can occur in the ER but not in the cytosol.
 Definition
glycosylation and disulfide bond formation
Term
If you remove the ER-retention signal from a protein that normally resides in the ER lumen, where do you predict the protein will ultimately end up?
 Definition
The protein would end up in the extracellular space.
Term
TRUE OR FALSE: The membrane of a secretory vesicle will fuse with the plasma membrane when it discharges its contents to the cell’s exterior.
 Definition
TRUE
Term
TRUE OR FALSE: Vesicles for regulated exocytosis will not bud off the trans Golgi network until the appropriate signal has been received from the cell.
 Definition
FALSE
Term
TRUE OR FALSE: The signal sequences of proteins destined for constitutive exocytosis ensure their packaging into the correct vesicles.
 Definition
FALSE
Term
TRUE OR FALSE: Proteins destined for constitutive exocytosis aggregate as a result of the acidic pH of the trans Golgi network.
 Definition
FALSE
Term
If a lysosome breaks, what protects the rest of the cell from lysosomal enzymes?
 Definition
low pH
Term
NADH and FADH2 carry high-energy electrons that are used to power the production of ATP in the mitochondria. These cofactors are generated during glycolysis, the citric acid cycle, and the fatty acid oxidation cycle. Which molecuale below can produce the most ATP? Explain your answer.
 Definition
NADH from the citric acid cycle
Term
Which ratio of NADH to NAD+ in solution will generate the largest, positive redox potential?
 Definition
Term
Cytochrome oxidase is an enzyme complex that uses metal ions to help coordinate the transfer of four electrons to O2. Which metal atoms are found in the active site of this complex?
 Definition
b) one iron atom and one copper atom
Term
Which ratio of NADH to NAD+ in solution will generate the largest, positive redox potential?
 Definition
1:10
Term
TRUE OR FALSE:Only compounds with negative redox potentials can donate electrons to other compounds under standard conditions.
 Definition
FALSE
Term
TRUE OR FALSE:Compounds that donate one electron have higher redox potentials than those of compounds that donate two electrons.
 Definition
FALSE
Term
TRUE OR FALSE:The δE′0 of a redox pair does not depend on the concentration of each member of the pair.
 Definition
TRUE
Term
TRUE OR FALSE:The free-energy change, δG, for an electron transfer reaction does not depend on the concentration of each member of a redox pair.
 Definition
FALSE
Term
TRUE OR FALSE: Ubiquinone is associated with the inner mitochondrial membrane as a protein-bound electron carrier molecule.
 Definition
FALSE
Term
TRUE OR FALSE: Ubiquinone can transfer only one electron in each cycle.
 Definition
FALSE
Term
TRUE OR FALSE: The iron–sulfur centers in NADH dehydrogenase are relatively poor electron acceptors.
 Definition
TRUE
Term
TRUE OR FALSE: Cytochrome oxidase binds O2 using an iron–heme group, where four electrons are shuttled one at a time.
 Definition
TRUE
Term
The photosystems in chloroplasts contain hundreds of chlorophyll molecules, most of which are part of
 Definition
THE ANTENNA COMPLEX
Term
In the electron-transport chain in chloroplasts, ________-energy electrons are taken from __________.
 Definition
LOW; H20
Term
TRUE OR FALSE: The dark reactions of photosynthesis occur only in the absence of light.
 Definition
false
Term
TRUE OR FALSE: Much of the glyceraldehyde 3-phosphate made in the chloroplast ends up producing the molecules needed by the mitochondria to produce ATP.
 Definition
true
Term
TRUE OR FALSE: Ribulose 1,5-bisphosphate is similar to oxaloacetate in the Krebs cycle in that they are both regenerated at the end of their respective cycles.
 Definition
true
Term
TRUE OR FALSE: Each round of the Calvin cycle uses five molecules of CO2 to produce one molecule of glyceraldehyde 3-phosphate and one of pyruvate.
 Definition
false
Term
The F1 portion of the mitochondrial ATP synthase comprises several different protein subunits. Which subunit binds to ADP + Pi and catalyzes the synthesis of ATP as a result of a conformational change
 Definition
β
Term
TRUE OR FALSE: The driving force that pulls protons into the matrix is called the proton-motive force, which is a combination of the large force due to the pH gradient and the smaller force that results from the voltage gradient across the inner mitochondrial membrane.
 Definition
TRUE
Term
TRUE OR FALSE: Under anaerobic conditions, the ATP synthase can hydrolyze ATP instead of synthesizing it.
 Definition
TRUE
Term
TRUE OR FALSE: ATP is moved out of the matrix, across the inner mitochondrial membrane, in a co-transporter that also brings ADP into the matrix.
 Definition
TRUE
Term
TRUE OR FALSE: Brown fat cells make less ATP because they have an inefficient ATP synthase.
 Definition
TRUE
Term
Oxidative phosphorylation, as it occurs in modern eucaryotes, is a complex process that probably arose in simple stages in primitive bacteria. Which mechanism is proposed to have arisen first as this complex system evolved?
 Definition
ATP-driven proton pumps
Term
Below is a list of breakthroughs in energy metabolism in living systems. Which is the correct order in which they are thought to have evolved?

A. H2O-splitting enzyme activity
B. light-dependent transfer of electrons from H2S to NADPH
C. the consumption of fermentable organic acids
D. oxygen-dependent ATP synthesis
 Definition
C (the consumption of fermentable organic acids), B (light-dependent transfer of electrons from H2S to NADPH), A (H2O-splitting enzyme activity), D (oxygen-dependent ATP synthesis)
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