Transmembrane Proteins Must Have

Question: A protein that is temporarily associated with a biological membrane is a(n):

Answer: peripheral membrane protein.

Question: What is the function of the contractile vacuole?

Answer: to help single-celled organisms maintain homeostasis in a hypotonic environment

Question: Where is the SRP receptor located in a cell?

Answer: in the membrane of the rough endoplasmic reticulum

Question: Which of the following statements is true regarding cytosol?

Answer: Cytosol is the "jelly" substance within cells and it excludes organelles.

Question: A proton pump is needed in the lysosomal membrane because:

Answer: -the interior of the lysosome needs to be acidic.-protons are being moved from low to high concentration.-protons cannot move across a membrane on their own.

Question: Transmembrane proteins must have:

Answer: both a signal sequence and a signal-anchor sequence.

Question: A researcher is using a modified version of FRAP. He has labeled all peripheral membrane proteins with a fluorescent tag, and has bleached a specific area of the cell membrane. After 24 hours, he notices that fluorescence has returned to the bleached area. What can he deduce from this experiment?

Answer: Peripheral membrane proteins may not be permanently associated with the cell membrane.

Question: During osmosis, water moves from a region of _________ solvent concentration to a region of _________ solvent concentration.

Answer: "high solvent concentration; low solvent concentration"

Question: During osmosis, water moves from a region of _________ solute concentration to a region of _________ solute concentration.

Answer: "low solute concentration; high solute concentration"

Question: If cells had monolayer membranes reminiscent of micelles, how would the structures of transmembrane proteins be affected?

Answer: Transmembrane proteins would possess a hydrophobic region in the cell interior and a hydrophilic region in the extracellular space.

Question: Which of the following cellular processes would tend to reduce entropy?

Answer: both transcription in the nucleus and translation in the endoplasmic reticulum

Question: What would be the outcome if the pump protein shown in Fig. 5.13a instead acted as a carrier that allowed protons to move from the extracellular fluid into the cytoplasm?

Answer: Two answer options are true: ATP could be synthesized from ADP + Pi AND the number of protons on either side of the membrane would equalize.

Question: The synthesis of ATP from ADP and Pi is a(n) _____ reaction with a ____ ΔG.

Answer: endergonic; positive

Question: Noncompetitive inhibitors of a reaction will bind _______.

Answer: somewhere on the enzyme that is not at the active site

Question: You have entered a 5K race. As you finish the last 50 yards you are breathing harder than at the start of the race and sweating profusely. This is an example of the _______________ law of thermodynamics because ______ is increasing.

Answer: second; entropy

Question: Which of the following organisms would be considered heterotrophs?

Answer: most bacteria and dogs

Question: Imagine that several atoms bond to form a carbohydrate, creating a more orderly system. Which of the following statements is true regarding the universe after this carbohydrate forms?

Answer: The entropy of the universe increases

Question: ATP is a nucleotide composed of adenine, ___________, and three phosphate groups.

Answer: ribose

Question: Escherichia coli bacteria in your colon are best categorized as _______________.

Answer: chemoheterotrophs

Question: True or False: Like glycolysis, acetyl-CoA synthesis produces both pyruvate and acetyl-CoA. These two products feed directly into the citric acid cycle and are the reactants for this process.

Answer: FALSE

Question: ATP is not generated directly in the citric acid cycle; instead, an intermediate is first generated by substrate-level phosphorylation. The intermediate is:

Answer: GTP

Question: For the potential energy of a proton gradient to be converted to the chemical energy of ATP, the movement of protons down their electrochemical gradient must be coupled with ATP synthesis. This coupling is made possible by:

Answer: ATP Synthase

Question: Which of the following statements is true regarding Earth's earliest organisms?

Answer: These organisms likely carried out fermentation and may have had rudimentary proton pumps.

Question: Which of the following would not be synthesized on the endoplasmic reticulum?

Answer: cytoskeletal proteins

Question: Cellular respiration is a series of _____ reactions.

Answer: catabolic

Question: The final electron acceptor of the electron transport chain is:

Answer: oxygen

Question: During acetyl-CoA synthesis, pyruvate is:

Answer: oxidized

Question: During fermentation, pyruvate is:

Answer: reduced

Question: Which of the following statements is true regarding triacylglycerols?

Answer: Triacylglycerols can be used to generate acetyl-CoA.

Question: Which of the following statements is true regarding a reducing agent?

Answer: it loses electrons

Question: Beta-oxidation of fatty acids does not produce:

Answer: ATP

Question: Which of the following statements is true regarding acetyl-CoA synthesis?

Answer: Acetyl-CoA synthesis forms the same number of NADH (per glucose molecule) as glycolysis.

Question: During the citric acid cycle:

Answer: ATP is synthesized by substrate level phosphorylation.

Question: Due to the pumping action of the electron transport chain, protons have a high concentration in the _____ and a low concentration in the _____.

Answer: intermembrane space; mitochondrial matrix

Question: The _____ forms of the electron carriers NAD+/NADH and FADH/FADH2 have high potential energy.

Answer: reduced

Question: In cellular respiration, glucose is _____ to CO2 and oxygen is _____ to water.

Answer: oxidized; reduced

Question: Which of the following statements is true regarding the equation C6H12O6 + 6O2 →6CO2+ 6H2O + energy?

Answer: The oxygen atoms in both CO2 and H2O are electronegative, and glucose could be considered a reducing agent.

Question: The inputs to glycolysis do not include

Answer: NADH

Question: The second phase of glycolysis:

Answer: cleaves a phosphorylated sugar molecule and rearranges the products.

Question: The majority of ATP produced during acetyl-CoA synthesis is the result of substrate-level phosphorylation.

Answer: FALSE

Question: In cellular respiration, oxygen:

Answer: gains electrons and is an oxidizing agent.

Question: Imagine that a eukaryotic cell carries a mutation impairing its ability to phosphorylate glucose during glycolysis. What is a likely result of this mutation?

Answer: glucose could move out of the cell; slowing cellular respiration

Question: Imagine that you discover a carnivorous deep-sea fish that cannot utilize the carbon in carbonic acid (or any other inorganic molecule) present in seawater to form glucose (or other organic molecules). Living so far beneath the water's surface, this fish is also incapable of harnessing energy from the sun. This fish would be considered a:

Answer: chemoheterotroph