EXAM 4 study guide Flashcards
In photosynthesis, plants use carbon from __________ to make sugar and other organic molecules.
carbon dioxide
How does carbon dioxide enter the leaf?
Through the stomata
In a rosebush, chlorophyll is located in __________.
thylakoids, which are in chloroplasts in the mesophyll cells of a leaf
Chlorophyll molecules are in which part of the chloroplast?
Thylakoid membranes
The source of the oxygen produced by photosynthesis has been identified through experiments using radioactive tracers. The oxygen comes from __________.
water
In photosynthesis, what is the fate of the oxygen atoms present in CO2? They end up __________.
in sugar molecules and in water
Molecular oxygen is produced during __________.
linear electron flow during the light reactions
The reactions of the Calvin cycle are not directly dependent on light, but they usually do not occur at night. Why?
The Calvin cycle requires products only produced when the photosystems are illuminated.
The Calvin cycle occurs in the __________.
Stroma
What is the role of NADP+ in photosynthesis?
It forms NADPH to be used in the Calvin cycle.
A photon of which of these colors would carry the most energy?
Blue
The most important role of pigments in photosynthesis is to __________.
capture light energy
What is the range of wavelengths of light that are absorbed by the pigments in the thylakoid membranes?
Violet-blue and red
Based on the work of Engelmann, a plot of photosynthetic activity versus wavelength of light is referred to as __________.
an action spectrum
When chloroplast pigments absorb light, __________.
the pigments’ electrons become excited
What structure is formed by the reaction center, light-harvesting complexes, and primary electron acceptors that cluster in the thylakoid membrane?
The photosystem
Where do the electrons entering photosystem II come from?
Water
During photosynthesis in chloroplasts, O2 is produced from __________ via a series of reactions associated with __________.
H2O; photosystem II
Which of the following is cycled in the cyclic variation of the light reactions?
Electrons
Both mitochondria and chloroplasts __________.
use chemiosmosis to produce ATP
You could distinguish a thylakoid membrane from an inner mitochondrial membrane because the thylakoid membrane would __________.
have photosynthetic pigments
During photosynthesis in a eukaryotic cell, an electrochemical gradient is formed across the __________.
thylakoid membrane
The light reactions of photosynthesis generate high-energy electrons, which end up in __________ through linear electron flow. The light reactions also produce __________ and __________.
NADPH; ATP; oxygen
The energy used to produce ATP in the light reactions of photosynthesis comes from __________.
movement of H+ through a membrane
What is the role of NADP+ in photosynthesis?
It is reduced and then carries electrons to the Calvin cycle.
CO2 is reduced.
Which of the following occurs during the Calvin cycle?
ATP is hydrolyzed, and NADPH is oxidized.
Rubisco is __________.
the enzyme in plants that captures CO2 to begin the Calvin cycle
In the Calvin cycle, CO2 is combined with __________.
a five-carbon compound to form an unstable six-carbon compound, which decomposes into two three-carbon compounds
Glyceraldehyde-3-phosphate (G3P) is produced in the stroma of chloroplasts. Which of the following statements is most accurate regarding this compound?
All of the listed responses are correct.
Which of the following statements correctly describes the relationship between the light reactions and the Calvin cycle?
The light reactions produce ATP and NADPH, both of which are used in the Calvin cycle.
The use of non-C3 and non-CAM plants as crops may be limited in some regions because on hot, dry days, they close their stomata. What happens as a result of closing their stomata?
All of the listed responses are correct.
Why are C4 plants more suited to hot climates than C3 plants?
Unlike C3 plants, they keep fixing carbon dioxide even when the concentration of carbon dioxide in the leaf is low.
You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark?
While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation.
The function of the mitotic cell cycle is to produce daughter cells that __________.
are genetically identical to the parent cell (assuming no mutation has occurred)
Which of the following is false regarding sister chromatids?
Both of the sister chromatids end up in the same daughter cell after cytokinesis has occurred.
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called __________.
chromatin
The region of a chromosome in which the two double strands of replicated DNA are held together is called __________.
a centromere
The centromere is a region in which __________.
sister chromatids are attached to one another in prophase
How many maternal chromosomes are present in a somatic human cell when it is not engaged in cell division?
23
A cell entering the cell cycle with 32 chromosomes will produce two daughter cells, each with __________.
none of the listed numbers of chromosomes
“Cytokinesis” refers to __________.
the division of the cytoplasm
Chromatids are __________.
identical copies of each other if they are part of the same duplicated chromosome
If a cell contains 60 chromatids at the start of mitosis, how many chromosomes will be found in each daughter cell at the completion of the cell cycle?
30
A biochemist measured the amount of DNA in cells growing in the laboratory and found that the quantity of DNA in the cells doubled __________.
between the G1 and G2 phases
A cell biologist carefully measured the quantity of DNA in grasshopper cells growing in cell culture. Cells examined during the G2 phase of the cell cycle contained 200 units of DNA. What would be the amount of DNA at G1 of the cell cycle in one of the grasshopper daughter cells?
100 units
During interphase, the genetic material of a typical eukaryotic cell is __________.
dispersed in the nucleus as long strands of chromatin
DNA replication occurs in __________.
the S phase of interphase
If a human somatic cell is just about to divide, it has __________ chromatids.
92
Down syndrome is characterized by cells having three copies of chromosome 21. As a cell in an individual with Down syndrome prepares to enter mitosis, how many chromatids would be present?
94
Which of the following does not occur during mitosis?
replication of chromosomes
During what phase in the cell cycle would you find the most DNA per cell?
G2
In telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in __________.
prophase
Which of the following phases of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?
Telophase
Assume that you are dealing with a species in which the number of chromosomes in each somatic cell is 14. How many sister chromatids are present in the early telophase of mitosis?
0
In a human skin cell that is going through the cell cycle, when do the centrosomes separate?
Prophase
Following cytokinesis in an animal cell, how many centrioles does each new daughter cell possess?
Two
The phase of mitosis during which the chromosomes move toward separate poles of the cell is __________.
anaphase
One event occurring during prophase is __________.
the beginning of the formation of a spindle apparatus
Which event or events occur during anaphase?
All of the listed responses are correct.
Which of the following represents a mismatch or incorrect description?
Metaphase: the nuclear envelope disappears
At what point do sister chromatids separate?
Anaphase
In animal cell mitosis, the cleavage furrow forms during which stage of the cell cycle?
Cytokinesis
At which stage of mitosis are chromosomes lined up in one plane in preparation for their separation to opposite poles of the cell?
Metaphase