AP Bio Midterm
- 1.
Which of the following statements regarding events in the functioning of photosystem II is false?
- A.
The splitting of water yields molecular oxygen as a by-product.
- B.
The P680 chlorophyll donates a pair protons to NADPH, which is thus converted to NADP+
- C.
Light energy excites electrons in an antenna pigment in a photosynthetic unit.
- D.
The electron vacancies in P680 are filled by electrons derived from water.
- E.
The excitation is passed along to a molecule of P680 chlorophyll in the photsynthetic unit.
Correct Answer
B. The P680 chloropHyll donates a pair protons to NADpH, which is thus converted to NADP+Explanation
The statement that is false is "The P680 chlorophyll donates a pair protons to NADPH, which is thus converted to NADP+". In photosystem II, the P680 chlorophyll does not donate protons to NADPH. Instead, it donates electrons to the electron transport chain, which eventually leads to the production of NADPH. NADP+ is reduced to NADPH by accepting electrons, not protons.Rate this question:
-
- 2.
Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?
- A.
Dehydration
- B.
Metabolism
- C.
Catabolism
- D.
Catalysis
- E.
Anabolism
Correct Answer
C. CatabolismExplanation
Catabolism is the correct answer because it specifically refers to the cellular process of breaking down large molecules into smaller ones. Dehydration, metabolism, catalysis, and anabolism are not as precise in describing this process. Dehydration refers to the removal of water, metabolism is a broad term encompassing all chemical reactions in the body, catalysis refers to the acceleration of chemical reactions, and anabolism refers to the building up of larger molecules from smaller ones. Catabolism, on the other hand, focuses specifically on the breakdown of large molecules into smaller ones.Rate this question:
-
- 3.
The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is:
- A.
The final transfer of electrons to oxygen
- B.
Oxidation of glucose to CO2 and water
- C.
The thermodynamically favorable transfer to phosphate from glycolysis and the citric acid cycle intermediate molecules of ADP
- D.
The difference in H+ concentrations on opposite sides of the inner mitochondrial membrane.
- E.
The thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers
Correct Answer
D. The difference in H+ concentrations on opposite sides of the inner mitochondrial membrane.Explanation
The correct answer is the difference in H+ concentrations on opposite sides of the inner mitochondrial membrane. This is because during respiratory oxidative phosphorylation, electrons from NADH are transferred through the mitochondrial electron transport chain, creating a proton gradient across the inner mitochondrial membrane. This proton gradient drives the synthesis of ATP by ATP synthase, as the flow of protons back into the mitochondrial matrix powers the phosphorylation of ADP to ATP.Rate this question:
-
- 4.
Which of the following is most likely to have a small protein called ubiquitin attached to it?
- A.
A cell surface protein that requires transport from the ER
- B.
An mRNA produced by an egg cell that will be retained until after fertilization
- C.
An mRNA that is leaving the nucleus to be translated
- D.
A regulatory protein that requires sugar residues to be attached
- E.
A cyclin that usually acts in G1, now that the cell is in G2
Correct Answer
A. A cell surface protein that requires transport from the ERExplanation
A cell surface protein that requires transport from the ER is most likely to have a small protein called ubiquitin attached to it. This is because ubiquitin is often attached to proteins that need to be transported or degraded by the cell. The attachment of ubiquitin marks the protein for degradation or for transport to specific cellular compartments. In this case, the cell surface protein needs to be transported from the ER, so it is likely that ubiquitin will be attached to it to facilitate its transport.Rate this question:
-
- 5.
Yeast cells are frequently used as hosts for cloning because
- A.
They are easy to grow.
- B.
They have multiple restriction sites.
- C.
They have plasmids.
- D.
A and B are correct.
- E.
A and C are correct.
Correct Answer
E. A and C are correct.Explanation
Yeast cells are frequently used as hosts for cloning because they are easy to grow and they have plasmids. Yeast cells are single-celled organisms that can be easily cultured in the laboratory, making them a convenient choice for cloning experiments. Additionally, yeast cells naturally contain plasmids, which are small, circular pieces of DNA that can be easily manipulated and used for cloning purposes. Therefore, both options A and C are correct.Rate this question:
-
- 6.
Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?
- A.
The absorption of light energy by chlorophyll
- B.
The synthesis of ATP
- C.
The flow of electrons from photosystem II to photosystem I
- D.
The reduction of NADP+
- E.
The splitting of water
Correct Answer
B. The synthesis of ATPExplanation
If a thylakoid is punctured and the interior of the thylakoid is no longer separated from the stroma, it will directly affect the synthesis of ATP. This is because the thylakoid membrane is where the electron transport chain and ATP synthase are located, which are responsible for the production of ATP during photosynthesis. Without the intact thylakoid membrane, the proper functioning of these processes would be disrupted, leading to a decrease in ATP synthesis.Rate this question:
-
- 7.
Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?
- A.
Insufficient cofactors
- B.
Saturation of the enzyme activity
- C.
Denaturization of the enzyme
- D.
Competitive inhibition
- E.
The activation energy of the reaction
Correct Answer
D. Competitive inhibitionExplanation
Increasing the substrate concentration in an enzymatic reaction could overcome competitive inhibition. Competitive inhibition occurs when a molecule similar in structure to the substrate binds to the active site of the enzyme, preventing the substrate from binding and inhibiting the reaction. By increasing the concentration of the substrate, the chances of the substrate binding to the active site of the enzyme increase, reducing the impact of the competitive inhibitor and allowing the reaction to proceed.Rate this question:
-
- 8.
What is proton-motive force?
- A.
The addition of hydrogen to NAD+
- B.
The force required to remove an electron from hydrogen
- C.
The transmembrane proton concentration gradient
- D.
Movement of hydrogen into the mitochondrion
- E.
Movement of hydrogen into the intermembrane space
Correct Answer
C. The transmembrane proton concentration gradientExplanation
Proton-motive force refers to the transmembrane proton concentration gradient. This gradient is created by the movement of protons across a membrane, such as the inner mitochondrial membrane, and is essential for various cellular processes, including ATP synthesis. The proton-motive force drives the movement of protons back across the membrane through ATP synthase, which generates ATP. Therefore, the correct answer is the transmembrane proton concentration gradient.Rate this question:
-
- 9.
Transcription factors in eukaryotes usually have DNA binding domains as well as other domains also specific for binding. In general, which of the following would you expect many of them to be able to bind?
- A.
Other transcription factors
- B.
ATP
- C.
TRNA
- D.
Repressors
- E.
Protein-based hormones
Correct Answer
A. Other transcription factorsExplanation
Many transcription factors in eukaryotes are known to have DNA binding domains, which allow them to bind to specific DNA sequences. Additionally, transcription factors often have other domains that are specific for binding to various molecules. Therefore, it would be expected that many transcription factors would be able to bind to other transcription factors, as they interact with each other to regulate gene expression.Rate this question:
-
- 10.
Which enzyme is used to make complementary DNA (cDNA) from RNA?
- A.
Restriction enzyme
- B.
DNA ligase
- C.
Reverse transcriptase
- D.
RNA polymerase
- E.
DNA polymerase
Correct Answer
C. Reverse transcriptaseExplanation
Reverse transcriptase is the enzyme used to make complementary DNA (cDNA) from RNA. This enzyme is capable of synthesizing a DNA strand using an RNA template. It catalyzes the reverse transcription process, where RNA is used as a template to produce a complementary DNA strand. This technique is commonly used in molecular biology research to study gene expression and analyze RNA molecules.Rate this question:
-
- 11.
Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.What did he conclude about the congregation of bacteria in the red and blue areas?
- A.
Bacteria congregated in these areas due to an increase in the temperature of the red and blue light.
- B.
Bacteria released excess carbon dioxide in these areas.
- C.
Bacteria congregated in these areas due to an increase in the temperature caused by an increase in photosynthesis.
- D.
Bacteria are attracted to red and blue light and thus these wavelengths are more reactive than other wavelengths.
- E.
Bacteria congregated in these areas because these areas had the most oxygen being released.
Correct Answer
E. Bacteria congregated in these areas because these areas had the most oxygen being released.Explanation
Engelmann concluded that the bacteria congregated in the areas illuminated by red and blue light because these areas had the most oxygen being released.Rate this question:
-
- 12.
The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is known as:
- A.
Noncooperative inhibition
- B.
Metabolic inhibition
- C.
Feedback inhibition
- D.
Allosteric inhibition
- E.
Reversible inhibition
Correct Answer
C. Feedback inhibitionExplanation
Feedback inhibition is the mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway. This is a regulatory mechanism that helps maintain homeostasis by preventing the overproduction of a particular molecule. When the concentration of the end product reaches a certain threshold, it binds to an enzyme involved in an earlier step of the pathway, causing a conformational change that inhibits the enzyme's activity. This feedback loop helps regulate the rate of the metabolic pathway and ensures that the production of the end product is balanced with the cell's needs.Rate this question:
-
- 13.
Which of the folllowing intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate?
- A.
Oxaloacetate
- B.
Citrate
- C.
Glyceraldehyde-3-phosphate
- D.
Acetyl CoA
- E.
Lactate
Correct Answer
D. Acetyl CoAExplanation
Acetyl CoA is the correct answer because it is the intermediary metabolite that enters the citric acid cycle and is formed by the removal of a carbon (CO2) from one molecule of pyruvate. Acetyl CoA is a crucial molecule in cellular respiration as it carries the acetyl group, derived from pyruvate, into the citric acid cycle where it can be further oxidized to produce energy.Rate this question:
-
- 14.
At the beginning of this century there was a general announcements regarding the sequencing of the human genome and the genomes of many other multicellular eukaryotes. There was surprise expressed by many that the number of protein-coding sequences is much smaller than they had expected, Which of the following accounts for most of the rest?
- A.
RRNA and tRNA coding sequences
- B.
Non-protein coding DNA that is transcribed into several kinds of small RNAs without biological function
- C.
DNA that is translated directly without being transcribed
- D.
"junk" DNA that serves no possible purpose
- E.
Non-protein coding DNA that is transcribed into several kinds of small RNAs with biological function
Correct Answer
E. Non-protein coding DNA that is transcribed into several kinds of small RNAs with biological functionExplanation
The correct answer is non-protein coding DNA that is transcribed into several kinds of small RNAs with biological function. This accounts for most of the rest of the sequences because it has been discovered that a significant portion of the genome is transcribed into non-coding RNAs, which play important regulatory roles in gene expression and other cellular processes. These small RNAs have been found to have various biological functions, such as regulating gene expression, silencing genes, and controlling protein production. This discovery has challenged the previous notion that non-coding DNA was "junk" DNA with no purpose.Rate this question:
-
- 15.
Which enzyme is used to produce RFLPs?
- A.
Restriction enzyme
- B.
DNA ligase
- C.
Reverse transcriptase
- D.
RNA polymerase
- E.
DNA polymerase
Correct Answer
A. Restriction enzymeExplanation
Restriction enzymes are used to produce RFLPs (Restriction Fragment Length Polymorphisms). These enzymes recognize specific DNA sequences and cleave the DNA at those sites. This results in the generation of DNA fragments of different lengths, which can be separated and analyzed to identify genetic variations or polymorphisms. DNA ligase is responsible for joining DNA fragments together, reverse transcriptase is used to synthesize DNA from RNA, RNA polymerase is responsible for synthesizing RNA from a DNA template, and DNA polymerase is involved in DNA replication and repair. However, none of these enzymes are directly involved in producing RFLPs.Rate this question:
-
- 16.
If you ran the same experiment without passing light through a prism, what would you predict?
- A.
The number of bacteria present would decrease due to an increase in the carbon dioxide concentration.
- B.
The number of bacteria present would increase due to an increase in the carbon dioxide concentration.
- C.
The number of bacteria would decrease due to a decrease in the temperature of the water.
- D.
The bacteria would be relatively evenly distributed along the algal filaments.
- E.
There would be no difference in results.
Correct Answer
D. The bacteria would be relatively evenly distributed along the algal filaments.Explanation
Without passing light through a prism, the bacteria would be relatively evenly distributed along the algal filaments. This is because passing light through a prism causes the light to separate into its different wavelengths, which can have different effects on the bacteria. Without this separation of light, the bacteria would not experience any specific changes in their distribution along the algal filaments.Rate this question:
-
- 17.
Which of the following is true for all exergonic reactions?
- A.
Some reactants will be converted to products.
- B.
The reaction proceeds with a net release of free energy.
- C.
The products have more total energy than the reactants.
- D.
A net input of energy from the surroundings is required for the reactions to proceed.
- E.
The reactions are nonspontaneous.
Correct Answer
B. The reaction proceeds with a net release of free energy.Explanation
Exergonic reactions are characterized by a net release of free energy. This means that the energy released during the reaction is greater than the energy required to initiate the reaction. In other words, the products have less total energy than the reactants, resulting in a release of energy. This is in contrast to endergonic reactions, which require an input of energy from the surroundings in order to proceed. Therefore, the statement "The reaction proceeds with a net release of free energy" is true for all exergonic reactions.Rate this question:
-
- 18.
A molecule that is phosphorylated:
- A.
Has been oxidized as a result of a redox reaction involving the gain of an inorganic phosphate.
- B.
Has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate.
- C.
How less energy than before its phosphorylation and therefore less energy for cellular work.
- D.
Has a decreased chemical reactivity; it is less likely to provide energy for cellular work.
- E.
Has an increased chemical reactivity; it is primed to do cellular work.
Correct Answer
E. Has an increased chemical reactivity; it is primed to do cellular work.Explanation
When a molecule is phosphorylated, it means that a phosphate group has been added to it. This addition of a phosphate group increases the chemical reactivity of the molecule, making it more likely to participate in chemical reactions. This increased reactivity allows the molecule to be involved in cellular work, such as energy transfer or signal transduction. Therefore, a phosphorylated molecule is considered to be "primed" and ready to perform cellular functions.Rate this question:
-
- 19.
One of the hopes for use of recent knowledge gained about non-coding RNAs lies with the possibilities for their use in medicine. Of the following scenarios for future research, which would you expect to gain most from RNAs?
- A.
Exploring a way to turn on the expression of pseudogenes.
- B.
Targeting siRNAs to disable the expression of an allele associated with autosomal recessive disease
- C.
Looking for a way to prevent viral DNA from causing infection in humans
- D.
Creating knock-out organisms that can be useful for pharmaceutical drug design
- E.
Targeting siRNAS to disable the expression of an allele associated with autosomal dominant disease
Correct Answer
E. Targeting siRNAS to disable the expression of an allele associated with autosomal dominant diseaseExplanation
Targeting siRNAs to disable the expression of an allele associated with autosomal dominant disease would likely gain the most from non-coding RNAs. Autosomal dominant diseases are caused by a mutation in a single copy of a gene, and targeting siRNAs can specifically inhibit the expression of the mutated allele, potentially reducing or eliminating the symptoms of the disease. This approach holds promise for developing targeted therapies for a wide range of genetic disorders.Rate this question:
-
Quiz Review Timeline +
Our quizzes are rigorously reviewed, monitored and continuously updated by our expert board to maintain accuracy, relevance, and timeliness.
-
Current Version
-
Aug 29, 2023Quiz Edited by
ProProfs Editorial Team -
Dec 12, 2010Quiz Created by
Lizpaschal
Back to top