Chapter 2 Study Guide Flashcards
1
Q
Which statement is characteristic of the bacteria and makes them different from both the archaea and the eukaryotes?
A
Bacteria have no histones associated with their chromosomes and the other two groups do.
2
Q
In which stage of the cell cycle does the cell duplicate its DNA?
A
S
3
Q
Eukaryotic cells that contain more than two sets of genetic information are referred to as:
- homologous
- polyploid
- diploid
- haploid
A
polyploid.
4
Q
What is the function of the telomere?
- to help keep plasmid DNA circular
- to protect the end of a DNA molecule
- to hold together sister chromatids
- to act as the site for the start of replication
A
to protect the end of a DNA molecule
5
Q
What is the constricted region of the chromosome where the kinetochore forms?
- checkpoint
- centromere
- telomere
- plasmid
- origin of replication
A
centromere
6
Q
The products of mitosis normally are genetically ________ to the parent cell.
- identical
- different
- twice as many DNA molecules
A
identical
7
Q
Which stage of mitosis involves sister chromatids separating and moving toward opposite poles?
A
anaphase
8
Q
In order to pass the G2/M checkpoint the cell must:
- have its DNA completely replicated and undamaged.
- have all the enzymes needed for DNA replication available.
- have sister chromatids already separated from each other.
A
have its DNA completely replicated and undamaged.
9
Q
Assume that a cell has six chromosomes while it is in the G1 stage of the cell cycle.
How many chromosomes and how many DNA molecules will it have in the G2 stage?
- 3 chromosomes and 6 DNA molecules
- 6 chromosomes and 12 DNA molecules
- 6 chromosomes and 6 DNA molecules
- 12 chromosomes and 12 DNA molecules
A
6 chromosomes and 12 DNA molecules
10
Q
In which stage of meiosis does the separation of homologous chromosomes occur?
- anaphase II
- telophase II
- anaphase I
- metaphase II
- prophase I
A
anaphase I
11
Q
Meiosis results in genetic variation among its product cells.
One source of this genetic variation is the random distribution of maternal and paternal chromosomes, and the other source of genetic variation is:
- the arrival of chromosomes at the spindle poles in telophase I.
- chromosomes condensing at prophase II.
- crossing over occurring at prophase I.
- the division of the cytoplasm at cytokinesis.
A
crossing over occurring at prophase I.
12
Q
Which of the statements is not a difference between mitosis and meiosis?
- The products of mitosis are usually genetically identical but the products of meiosis are genetically different.
- In mitosis, there is one cell division while in meiosis there are two cell divisions.
- Mitosis usually produces two daughter cells while meiosis usually produces four cells.
- Sister chromatids separate during mitosis but not during meiosis.
A
Sister chromatids separate during mitosis but not during meiosis.
13
Q
Which molecule holds sister chromatids together during mitosis and meiosis?
- cohesin
- chromatin
- histone
- shugoshin
- separase
A
cohesin
14
Q
How many ova, plural for ovum, can be produced from two primary oocytes through meiosis?
- 1
- 2
- 4
- 8
- 16
A
2
15
Q
In flowering plants, meiosis in the male portion of the flower produces:
- four microspores that will divide mitotically to form male gametophytes.
- four haploid sperm that are able to fertilize the egg produced by the female portion of the flower.
- one haploid sperm and three polar bodies that fail to function.
- two diploid sperm that will divide mitotically to form the functional male gametophyte.
- four megaspores, but only one survives and functions.
A
four microspores that will divide mitotically to form male gametophytes.
16
Q
Viruses are:
- archaea
- prokaryotic
- neither
- eukaryotes
A
neither.
Viruses are neither prokaryotic nor eukaryotic because they do not possess the structure of a cell.
17
Q
Telomeres are the:
- points at which spindle fibers attach to a chromosome.
- newly replicated, sister chromosomes.
- natural ends of a chromosome.
- the central portions of chromosomes.
A
natural ends of a chromosome.
Telomeres are at the ends of each chromosome and protect the rest of the chromosome from degeneration.
18
Q
Which of these are diploid cells? -secondary spermatocytes -sperm -ovum spermatogonium
A
spermatogonium
As a precursor to the gamete, spermatogonium still has a full set of chromosomes and is thus diploid.
19
Q
All of these are distinguishing factors of a eukaryotic cell EXCEPT:
- multiple linear DNA molecules.
- membrane-bound organelles.
- a nucleus.
- a relatively small amount of DNA.
A
a relatively small amount of DNA.
Prokaryotes have a relatively small amount of DNA, but eukaryotes have a relatively large amount of DNA.
20
Q
What stage of the cell cycle lasts a variable period of time and is attributed to cells that are neither dividing nor preparing to divide?
- G0
- G1
- S
- G2
A
G0
G0 is a non-dividing phase.
21
Q
What is the major function of cohesin during mitosis?
- It degrades shugoshin just before anaphase.
- It holds sister chromatids together.
- It holds homologous chromosomes together.
- It attaches the spindle fibers to the centromere regions at prometaphase.
A
It holds sister chromatids together.
Cohesin holds sister chromatids together during mitosis.
22
Q
Which of these characteristics distinguishes eukaryotes from both archaea and eubacteria?
- the presence of plasmids among the eukaryotes
- the presence of a cell wall in eukaryotes
- the presence of a nuclear membrane in eukaryotes
- the presence of histones in eukaryotes
A
the presence of a nuclear membrane in eukaryotes
A major difference between prokaryotic and eukaryotic cells is that a eukaryotic cell has a nuclear membrane, which surrounds the genetic material to form a nucleus and separates the DNA from the other cellular contents.
23
Q
A cell has eight chromosomes in G1 of interphase. How many chromosomes will be found in the anaphase of mitosis?
- 0
- 4
- 16
- 8
A
16
The number of chromosomes increases in anaphase as the two chromatids separate and each now becomes a separate chromosome.
24
Q
Which of these relationships is true?
- Shugoshin protects cohesin from being degraded by separate.
- Separase protects cohesin from being degraded by shugoshin.
- Shugoshin protects separase from being degraded by cohesin.
- Cohesin protects shugoshin from being degraded by separase.
A
Shugoshin protects cohesin from being degraded by separase.
Shugoshin protects cohesin, the protein that holds sister chromatids together during mitosis and meiosis, from separase.
25
What is shugoshin?
The protein, Shugoshin, is actually Japanese for a guardian spirit. Just as its name suggests, the Shugoshin protein guides chromosome cohesion during cell division. It does this by preventing the cohesin complex which regulates chromatid separation from prematurely dissociating.
26
Which of these might be used as a means of fighting a bacterial infection instead of using antibiotics?
- bacteriophages
- vaccines
- eukaryotes
- plasmids
bacteriophages
Some viruses, called bacteriophages, can be used to fight bacteria.
27
What would be the consequence of a chromosome losing its centromere?
- The chromosome would not be drawn into a newly formed nucleus and would be lost.
- The chromosome would not replicate during S stage.
- The chromosome ends would be degraded.
- The chromosome would replicate in an uncontrolled manner.
The chromosome would not be drawn into a newly formed nucleus and would be lost.
Centromeres are the attachment sites for the spindle microtubules.
28
Assume that a drug is developed that prevents the prometaphase stage of mitosis from occurring, but does not prevent any stages of mitosis prior to prometaphase from occurring, nor does it interfere with any part of interphase. What will be the immediate consequence of this drug?
- Sister chromatids will not be present.
- Spindle microtubules will not be able to attach to chromatids.
- DNA replication will not happen so that each chromosome will contain a single DNA molecule
- The chromosomes will not be able to condense.
Spindle microtubules will not be able to attach to chromatids.
Sister chromatids are produced during the S phase prior to mitosis.
29
Termites live in a mutualistic relationship with protozoa (unicellular eukaryotes) and methanogenic archaea, both of which live in the termite's digestive tract, allowing it to digest cellulose (wood). Freja smears a slide with cells from the termite's digestive tract. Most likely some of the cells will be from the termite itself, but if the cells were from either the protozoa or the methanogenic archaea, how would she be able to distinguish the two?
- Each protozoa would have a nucleus, and each archaeal cell would lack a nucleus.
- The protozoans would have multiple cells, while the archaea would be unicellular.
- The protozoans would move while the archaea would remain stationary.
- The archaeal cells will be significantly larger than the protozoan cells.
Each protozoa would have a nucleus, and each archaeal cell would lack a nucleus.
Protozoans are eukaryotes, and therefore have nuclei, while archaea are prokaryotes, and therefore lack nuclei.
30
Ted is looking through a light microscope. He observes a number of rod-shaped masses, none of which have a large dark spot. The diameter of the cell is between 1 and 10 micrometers. What type of cell has Ted discovered?
- archaeal cells
- viruses
- eukaryotic
- prokaryotic
prokaryotic cells
The absence of the dark spot (nucleus) eliminates eukaryotic cells, and the size of the cell and the fact that Ted could see it under a light microscope eliminates the virus (also viruses are not cells). With only a light microscope, Ted cannot differentiate between archaea and bacteria, but he can tell it is a prokaryote.
31
Which of these statements about homologous chromosomes is true?
- They pair with each other during prophase II of meiosis.
- One member of a homologous pair comes from the mother and one from the father.
- They separate from each other during anaphase II of meiosis.
- They are genetically identical.
One member of a homologous pair comes from the mother and one from the father.
One member does come from the mother and the other from the father of the organism producing the cell.
32
Successful cell reproduction requires:
- DNA replication, copy separation, and cell division.
- DNA replication, binary fission, and cytoplasmic replication.
- reduction in chromosome number, sister chromatid separation, and cytokinesis.
- DNA fission, cytoplasmic doubling, and cell division.
DNA replication, copy separation, and cell division.
DNA replication must take place so that each new cell has a full copy, and then the two copies must separate before cell division so that there is a full set of DNA in each new cell.
33
Ori is observing lactobacillus bacteria under a microscope. As he gazes through the lens, he notes that one of the rod-shaped cells has split in two. Ori has just observed:
- meiosis
- budding
- binary fission
- mitosis
binary fission.
Prokaryotic cells reproduce by binary fission, which involves the replication of its circular chromosome followed by cell division.
34
The first meiotic division in oogenesis results in which of these products?
- one ovum and one polar body
- two polar bodies
- one secondary oocyte and one polar body
- two ovum
one secondary oocyte and one polar body
The first meiotic division of oogenesis results in one secondary oocyte and one polar body.
35
In what stage of meiosis do homologous chromosomes line up?
- metaphase II
- anaphase I
- anaphase II
- metaphase I
metaphase I
Homologous chromosomes line up on the metaphase plate during metaphase I.
36
What would be the consequence of a chromosome losing both of its telomeres in an animal cell?
- Spindle fibers could not attach to the chromosome.
- The chromosome could not be replicated.
- The chromosome would lose its histone proteins.
- The chromosome ends would be degraded.
The chromosome ends would be degraded.
The loss of a telomere would cause the chromosome ends to be degraded.
37
In some bacteria, newly replicated chromosomes separate by:
- anchoring to opposite sides of the cell membrane.
- meiosis
- mitosis
- attachment to the spindle fibers
anchoring to opposite sides of the cell membrane.
As the prokaryotic chromosome replicates, the origins segregate to opposite sides.
38
A cell has 12 pairs of sister chromatids in G2 of the cell cycle. How many pairs of homologous chromosomes should be seen at metaphase II of meiosis?
- 24
- 12
- 6
- 8
6
After meiosis II, each cell should have half a set of genetic information, which in this case (12/2) is 6.
39
When do the sources of genetic variation in meiosis occur?
- meiosis II
- meiosis I
- prophase II
meiosis I
Crossing over occurs during meiosis I resulting in genetic variation.
40
The process of _____ produces cells with half the number of chromosomes.
- interkinesis
- cytokineses
- meiosis
- mitosis
meiosis
Meiosis produces sex cells that join to create a new organism. Each sex cell must have half a set of chromosomes in order to produce a single full set upon joining with a second sex cell.
41
In plants, meiosis produces haploid cells during which phase of development?
- megaspore
- endosperm
- gametophyte
- sporophyte
sporophyte
The sporophyte is a diploid cell that produces haploid spores through meiosis, and the gametophyte produces haploid gametes through mitosis.
42
Homologous chromosomes separate during _____ of meiosis.
- telophase II
- telophase I
- anaphase I
- anaphase II
anaphase I
Homologous chromosomes separate during anaphase I of meiosis and move toward opposite poles.
43
Imagine you are designing a research project at a lab. You need an organism that can grow in a petri dish, can replicate itself and has a simple genome. Which organism should you pick?
- eukaryotic
- viruses
- prokaryotes
- amoeba
prokaryote
Prokaryotes are unicellular, so they can be grown in a petri dish. They can replicate their own DNA, and they have a simple genome.
44
Venla has a light microscope. Once an object is in the range of 10 micrometers or less, the image becomes blurry. Therefore, Venla's light microscope can be used to observe which of these?
- viruses
- bacterial cells
- eukaryotic cells
- archaeal cells
eukaryotic cells
Eukaryotic cells range from 10 to 100 micrometers in size, so Venla will be able to see some distinguishing characteristics. Many organelles will be too small to see, however.
45
Archaea are more similar to bacteria in _____, but more similar to eukaryotes in _____.
- shape/size
- size/shape
- cell structure; genetic processes
- genetic processes; cell structure
cell structure; genetic processes
Archaea are more similar to bacteria in cell structure but more similar to eukaryotes in genetic processes.
46
In flowering plants, which of these is true?
- Microsporocytes undergo mitosis and produce two microspores.
- Microsporocytes fuse with megasporocytes to produce the endosperm.
- Microsporocytes undergo meiosis and produce four microspores.
- Microsporocytes undergo mitosis and produce two sperm.
Microsporocytes undergo meiosis and produce four microspores.
Microsporocytes undergo meiosis to produce four haploid microspores.
47
What is a prokaryotic cell?
A prokaryote is a unicellular organism with a relatively simple cell structure.
48
What is a eukaryotic cell?
A eukaryote has a compartmentalized cell structure with components bounded by intracellular membranes; eukaryotes may be either unicellular or multicellular.
49
List the several characteristics that bacteria and archaea have in common and that distinguish them from eukaryotes.
Bacteria and archaea are prokaryotes. They differ from eukaryotic in possessing no nucleus, a genome that usually consists of a single circular chromosome, and a smaller amount of DNA.
50
What are the two major phases of the cell cycle?
- S phase and M phase
- mitosis and cytokinesis
- interphase and M phase
- G1 and G2
- prophase and telophase
interphase and M phase
51
Which phase of the cell cycle best describes a cell that has exited from active cell division and remains indefinitely with each chromosome consisting of a single chromatid?
- G0
- G1
- G2
- S
- Neither
G0
52
If a cell normally has 12 chromosomes, how many DNA molecules are present in the G1 phase of the cell cycle?
- 12
- more than 12 but fewer than 24
- 24
- 6
12
53
During which phase of the cell cycle would each cell be undergoing biochemical events required to prepare for cell division, and each chromosome consist of two identical chromatids?
- G2
- G1
- G0
- S
- neither
G2
54
In which portion of the cell cycle do chromosomes begin to condense and the spindle fibers begin to form from the centrosomes?
- prophase
- G2
- anaphase
- metaphase
- S
prophase
55
If a cell normally has 12 chromosomes, how many chromosomes are present in the G2 phase of the cell cycle?
- 6
- 12
- None
- 24
- more than 12 but fewer than 24
12
56
If a cell normally has 12 chromosomes, how many chromosomes are present in the anaphase of the cell cycle?
- 12
- 6
- 24
- more than 12 but lesser than 24
- None
24
57
If a cell normally has 12 chromosomes, how many DNA molecules are present in the metaphase of the cell cycle? Remember that DNA molecules are the same as chromatids.
- 6
- 24
- 12
- None
- Neither
24
58
A cell starts out in G2 phase with 12 chromosomes, but after mitosis, each of the daughter cells has only 11 chromosomes in G1 phase.
What event provides the most likely explanation for this scenario?
- During prometaphase in the original cell, one of the chromosomes failed to attach to a spindle fiber.
- The DNA in the original cell was not properly replicated in S phase.
- The original cell skipped metaphase during mitosis.
- This is not unexpected, as the chromosome number drops between G2 and G1 phases of the cell cycle.
- During anaphase in the original cell, one of the centromeres did not divide.
During prometaphase in the original cell, one of the chromosomes failed to attach to a spindle fiber.
59
If a cell starts out in G2 phase with 12 chromosomes, how many chromosomes would you expect in each of the daughter cells if one of the chromosomes failed to separate in anaphase? Remember that if two chromatids are still attached at the centromere (as they would be in this case), we count them as one chromosome.
- One daughter cell will have 11 chromosomes, and the other will have 12.
- Each daughter cell will have 11 chromosomes.
- One daughter cell will have 12 chromosomes, and the other will have 13.
One daughter cell will have 11 chromosomes, and the other will have 12.
