Biology Exam 3 mastering Biology
A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid cycle, but together these two processes yield only a few molecules of ATP. What happened to most of the energy that the cell obtains from the oxidation of glucose?
It is stored in NADH and FADH2
Which of the following events occurs in the light reactions of photosynthesis?
Light is absorbed and funneled to reaction-center chlorophyll a.
If photosynthesizing green algae are provided with CO2 containing heavy oxygen (18O), subsequent analysis will show that 18O is absent from which of the following molecules produced by the algae?
O2
Humans produce skin cells by mitosis and gametes by meiosis. Which of the following statements about the nuclei of skin cells is correct?
They contain twice as much DNA as the nuclei of gametes produced by meiosis.
Why are carbohydrates and fats considered high-energy foods?
They have a large number of electrons associated with hydrogen.
What is a cleavage furrow?
a groove in the plasma membrane between daughter nuclei
The oxygen atoms used to form water in the complete reactions of cellular respiration are derived from which of the following molecules?
molecular oxygen (O2)
The complete reactions of cellular respiration in the presence of oxygen (C6H12O6 + 6 O2 →→ 6 CO2 + 6 H2O + energy) result in which of the following?
oxidation of C6H12O6 and reduction of O2 Submit
Which of the following metabolic pathways occur(s) in mitochondria?
oxidation of pyruvate to acetyl CoA and the citric acid cycle
Reactions that consume CO2 take place in
the Calvin cycle only.
Approximately what percentage of the ATP formed by the electron transport chain is produced by substrate-level phosphorylation?
0%
Approximately what percentage of the ATP formed by the reactions of glycolysis is produced by substrate-level phosphorylation?
100%
Glycolysis results in a net production of which of the following molecules from each molecule of glucose?
2 NADH, 2 pyruvate, and 2 ATP
Somatic cells in elephants have 56 chromosomes. How many chromosomes would be carried by the gametes produced by elephants?
28
Beginning with a fertilized egg (zygote), how many cells would be present in an embryo following a series of five cell divisions?
32
In the complete oxidation of a molecule of glucose (C6H12O6) in aerobic cellular respiration, how many molecules of ATP are produced by substrate-level phosphorylation?
4
A human bone marrow cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain?
92
What are the products of linear electron flow?
ATP and NADPH
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
ATP and NADPH
Yeast cells grown anaerobically can obtain energy by fermentation, which results in the production of
ATP, CO2, and ethanol.
Which of the following components make(s) up eukaryotic chromatin?
DNA and proteins
Why is glycolysis described as having an energy investment phase and an energy payoff phase?
Early steps consume energy from ATP, and later steps store an increased amount of energy in ATP and NADH.
Which of the following molecules donates electrons directly to the electron transport chain at the lowest energy level?
FADH2
Cells will usually divide if they receive the proper signal at a checkpoint in which phase of the cell cycle?
G1
Which of the following molecules or structures are primarily responsible for cytokinesis in plant cells but not in animal cells?
Golgi-derived vesicles
As a result of an oxidation-reduction reaction, how is the oxidizing agent changed?
It gains electrons and gains potential energy. Submit
In an oxidation-reduction reaction, how is the reducing agent changed?
It loses electrons and loses potential energy. Submit
Which of the following statements about NAD+ is true?
NAD+ is reduced to NADH during glycolysis. Submit
Which of the following molecules donates electrons directly to the electron transport chain at the highest energy level?
NADH
What compound provides the reducing power for the Calvin cycle reactions?
NADPH
Which of the following statements about the chemiosmotic synthesis of ATP is correct?
The chemiosmotic synthesis of ATP requires that electron transport in the inner mitochondrial membrane be coupled to proton transport across the same membrane.
Which statement about the citric acid cycle is correct?
The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.
Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?
The light reactions provide ATP and NADPH to the Calvin cycle, and the Calvin cycle returns ADP, i, and NADP+ to the light reactions.
Which one of the following statements about the redox reactions of the electron transport chain is correct?
The redox reactions of the electron transport chain are directly coupled to the movement of protons across a membrane.
What is the relationship between wavelength of light and the quantity of energy per photon?
They are inversely related.
Which of the following is true of kinetochores?
They are sites at which microtubules attach to chromosomes.
What is true of all cancers?
They have escaped normal cell cycle controls.
Why do most cells in the human body divide infrequently?
They have exited the cell cycle and entered G0.
Which of the following is true of benign tumors but not malignant tumors?
They remain confined to their original site.
A reduction in the amount of NADP+ available in plant cells in the light will ultimately result in
a decrease in the rate of linear electron flow.
At which phase of mitosis do the sister chromatids become daughter chromosomes?
anaphase
A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are being absorbed by this pigment?
blue and violet
Reduction of oxygen to form water occurs during
cellular respiration only.
Inside an active mitochondrion, most electrons follow which of the following pathways?
citric acid cycle →→ NADH →→ electron transport chain →→ oxygen
Where does glycolysis occur in animal cells?
cytosol
In chemiosmosis, what is the most direct source of energy that is used to convert ADP + Pi to ATP?
energy released from movement of protons down their electrochemical gradient through ATP synthase Submit
The beginning of anaphase is indicated by which of the following events?
enzymatic cleavage of cohesin
Under anaerobic conditions, what carbon sources can be metabolized by yeast cells to produce ATP from ADP?
glucose
Which of the following sequences represents the correct order in which metabolic reactions occur during the complete oxidation of glucose through aerobic respiration?
glucose →→ glycolysis →→ pyruvate oxidation →→ citric acid cycle →→ electron transport chain
Which of the following metabolic pathways is common to both aerobic cellular respiration and anaerobic fermentation?
glycolysis
Which of the following metabolic pathways occur(s) in the cytosol of eukaryotic cells?
glycolysis and fermentation
Where in mitochondria is the enzyme ATP synthase localized?
inner membrane
Where are the proteins of the electron transport chain located in a eukaryotic cell?
inner mitochondrial membrane
The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during
neither photosynthesis nor respiration.
Where are the motor proteins that move chromosomes toward the poles of the mitotic spindle located?
on the kinetochores and at the centrosomes Submit
What will be the result if a eukaryotic cell completes mitosis but does not undergo cytokinesis?
one cell with two nuclei, each identical to the nucleus of the parent cell
What is the primary function of the Calvin cycle?
produce simple sugars from carbon dioxide
The NADPH required for the Calvin cycle comes from
reactions initiated in photosystem I. Submit
Which of the following is directly associated with photosystem I?
receiving electrons from the thylakoid membrane electron transport chain
What is the source of the energy used to generate the proton gradient across the inner mitochondrial membrane?
redox reactions in the electron transport chain Submit
When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the NAD+ molecule becomes
reduced
Movement of the chromosomes during anaphase would be most affected by a drug that prevents which of the following processes?
shortening of microtubules
Following DNA replication, each eukaryotic chromosome consists of two identical DNA molecules known as
sister chromatids
When oxygen is released as a result of photosynthesis, it is a direct by-product of
splitting water molecules. Submit
Where do the enzymatic reactions of the Calvin cycle take place?
stroma of the chloroplast
Where does the Calvin cycle take place?
stroma of the chloroplast
Which chemical process generates the ATP produced in the citric acid cycle?
substrate-level phosphorylation Submit
In mitochondria, the electron transport chain pumps protons from the matrix into the intermembrane space, whereas in chloroplasts, the electron transport chain pumps protons from
the stroma to the thylakoid space.
In a plant cell, where are ATP synthase complexes located?
thylakoid membrane and inner mitochondrial membranes
What is the primary role of oxygen in cellular respiration?
to serve as an acceptor for electrons and protons, forming water
The electrons stripped from glucose in cellular respiration end up in which compound?
water
