Biology Unit 3
The microtubules of the cytoskeleton are made of tubulin. The microtubules
?
Which of the following refers to a type of asexual reproduction?
budding
Crossing over
creates new combinations of alleles in populations
Removing growth factors from the environment around dividing cells is most likely going to
decrease the rate of cell division
In Mendelian genetics a capital letter is used to represent the __________ allele, which shows up in the phenotype even if there is only one copy of that allele
dominant
Which of the following has to happen last during mitosis?
the sister chromatids move to opposite poles of the cell
By definition, the number of types of chromosomes is n. For a given cell, n = 12. How many double helices of DNA are there during G2 of the mitotic cell cycle?
48
One duplicated chromosome has two sister chromatids. In prophase of mitosis you see 12 duplicated chromosomes in a cell. This cell type has n of One duplicated chromosome has two sister chromatids. In prophase of mitosis you see 18 duplicated chromosomes in a cell. This cell type has n of
6 9
By definition, the number of types of chromosomes is n. For a given cell, n = 16. How many double helices of DNA are there during G2 of the mitotic cell cycle?
64
Sister chromatids separate from each other during
anaphase II
Sister chromatids are made by
DNA synthesis during S phase
You would see tetrads during
metaphase I of meiosis
In a man, the sperm leave the testicle and would next be found in the
vas deferens
When in the life cycle are there meiotic cell divisions?
when gametes are made in the gonads
Consider the human life cycle. Which of the following is a diploid stage of the life cycle?
zygotes
How many double helices of DNA are in a tetrad?
4
Snails are hermaphrodites, reproduce sexually, are diploid, and have 24 chromosomes (n=12). Where do the chromosomes in a snail zygote come from?
12 from a sperm cell, 12 from an egg
Cats reproduce sexually, are diploid and have 38 chromosomes (n=19). Where do the chromosomes in a cat zygote come from?
19 from a sperm cell, 19 from an egg
The purpose of the meiosis is
to get exactly one copy of each type of chromosome into each daughter cell
Which of the following lists includes things that happen to the chromosomes during the mitotic cell cycle in the correct order?
DNA is duplicated, DNA condenses, chromosomes align on the metaphase plate, sister chromatids separate
In the mitotic cell cycle, which of the following would most immediately come after the S phase?
G2 phase
Of the following, which would happen most immediately before the separation of the sister chromatids during the mitotic cell cycle?
G2 phase
Starting at the G1 phase of the mitotic cell cycle, which of the following would come next?
G2 phase
You find unduplicated chromosomes in G1 of the cell cycle. You find duplicated chromosomes in G2 of the cell cycle. How many double helices of DNA are in one chromosome during G1 phase?
NOT 2 NOT 4
Imagine you are working in a lab and want cells in a Petri dish to divide. What would you do?
NOT REMOVE GROWTH FACTORS
Which of the following is LEAST critical for a cell to successfully undergo mitosis?
NOT alignment of the chromosomes on the metaphase plate NOT changes in the arrangement of the chromosomes
Centrosomes
NOT are where microtubules attach to chromosomes
Which of the following is LEAST likely to lead to cancer?
NOT avoiding exercise NOT skipping medical cancer screening, especially if you have a family history of cancer
During prophase I and metaphase I the cells are _________, and during prophase II and metaphase II they are ____________
NOT haploid, diploid NOT diploid, diploid
If a cell is stopped at the M checkpoint, it will not enter the next phase of mitosis, which is
NOT interphase
If a cell is stopped at the M checkpoint, it will not enter the next phase of mitosis, which is
NOT interphase NOT prophase
You are studying cells where the number of types of chromosomes (n) is equal to four. You look down the microscope and see one cell with four duplicated chromosomes lined up on the metaphase plate. This cell is in
NOT metaphase I of meiosis
Which of the following is a way sexual reproduction leads to new combinations of alleles?
NOT new combinations of maternal and paternal chromosomes in gametes generated by mitosis
During the mitotic cell cycle the cytoskeleton does NOT
NOT pull on duplicated chromosomes, so that they line up on the metaphase plate
Which of the following describes a cell with n = 15?
NOT the cell has 15 duplicated chromosomes on the metaphase plate during metaphase of mitosis
Which of the following happens FIRST during the mitotic cell cycle?
NOT the cleavage furrow forms
Sister chromatids are made during
S phase of the mitotic and meiotic cell cycles
Which of the following situations is most likely if a eukaryotic cell is stuck at the G2 checkpoint?
There are errors in the replication of the DNA
Imagine you work in a lab and prepared two Petri dishes with plenty of nutrients and exactly the same density of cultured skin cells. The density starts at 1000 cells per dish. The cells are low enough density that they are not touching each other. The professor you work with asked you to test substance X to see if it is a growth factor. Which experiment and result would most strongly support the hypothesis that substance X is a growth factor?
You add X to one dish; when you count later the dish with X has 2000 cells and the dish without X has 1000 cells
Which of the following organisms is using asexual reproduction?
a budding hydra
During cytokinesis
actin microfilaments divide the cell into two cells
Unlike during mitosis, during meiosis homologous chromosomes
align with each other as tetrads on the metaphase plate
An ________ is a variation of a gene. Two of them make the same protein, but the protein may function differently because of the variations in the nucleotides of the gene and resulting amino acids of the proteins. Homologous chromosomes have different ones. In sister chromatids they are the same
allele
Homologous chromosomes separate from each other during meiosis. This happens during
anaphase I -chromatids are during anaphase II
Homologous chromosomes are two chromosomes of the same type. Homologous chromosomes
are similar, but not exactly the same because one came from mom and the other from dad
The actin microfilaments of the cytoskeleton
are small in diameter and divide the cell during cytokinesis
Prokaryotic cells divide by
binary fission
Which of the following lists includes things that happen to the cytoskeleton during the mitotic cell cycle in the correct order?
centrosomes duplicate, mitotic spindles form, microtubules pull sister chromatids apart, cytokinesis
For this question assume that the cells do NOT have density-dependent inhibition. If a cell had a mutation that caused a growth factor receptor to be stuck in the shape it normally had when growth factors were bound, then you would expect cells with this mutation to
divide more frequently than usual
If a cell had a mutation that caused a growth factor receptor to be stuck in the shape it normally had when growth factors were bound, then you would expect cells with this mutation to
divide more frequently than usual
If a mutation that caused a relay protein for a growth factor receptor to be stuck in the shape it normally had when growth factors were bound, then you would expect cells with this mutation to
divide more frequently than usual
You have a cell line that does not have density-dependent inhibition. You mutate a receptor for brain-derived growth factor in the cell line. The mutation makes the receptor take the shape it would be in if the growth factor were bound to the receptor. In other words, the receptor becomes an oncogene. Compared to cells of this line without the mutation, the cells with the oncogene would
divide more frequently than usual
The cytoskeleton plays a big role in the mitotic cell cycle. Actin microfilaments are used in the mitotic cell cycle for
dividing the cell in two during cytokinesis
In a cell that will undergo meiosis to make sperm cells, one copy of each type of chromosome came from the mother and the other copy came from the father of the organism. During meiosis
each daughter cell usually has alleles from each parent
Consider the human life cycle. Which of the following type of cell is haploid?
eggs
When in the life cycle do cells go from being haploid to being diploid?
fertilization
Which of the following refers to a type of sexual reproduction?
fertilization of an egg
Which of the following is a way sexual reproduction leads to new combinations of alleles?
fertilization of haploid eggs by haploid sperm
For each pair of homologous chromosomes in your somatic cells, one homolog came from your mom and one from your dad. Because humans produce gametes for sexual reproduction by the process of meiosis
for one pair of homologous chromosomes, each of your children has a 50% chance of inheriting the homolog from your mom and a 50% chance of inheriting the homolog from your dad
Each tetrad of duplicated homologous chromosomes
forms during prophase I of meiosis
You start with one cell where the # of types of chromosomes(n) is equal to ten, and watch it undergo meiosis. At the end of telophase II and cytokinesis II you would see
four cells, each with ten chromosomes
You start with one cell where the number of types of chromosomes (n) is equal to twelve, and watch it undergo meiosis. At the end of telophase II and cytokinesis II you would see
four cells, each with twelve chromosomes
For each pair of homologous chromosomes the zygote get one allele from the egg and one from the sperm cell. They may be the same or different alleles. All of the alleles on all of the chromosomes of one organism are its ____________
genotype
Assuming there are no mutations, sister chromatids
have identical DNA sequences to each other
Homologous chromosomes do NOT
have the same alleles
Sister chromatids
have the same lengths NOT HAVE THE SAME GENES, BUT IN DIFFERENT ORDERS FROM EACH OTHER
Assuming no mutations or crossing over events, homologous chromosomes
have the same lengths as each other
Assuming no mutations or crossing over events, sister chromatids
have the same lengths as each other
An individual is ____________ for a characteristic if they have two different alleles for one gene
heterozygous
Which of the following happens FIRST of the steps of meiosis listed below?
homologous chromosomes separate
Meiosis I, meiosis II and mitosis have similarities and differences. A major difference between meiosis I and mitosis is that during meiosis I
homologous non-sister chromatids exchange alleles by crossing over tetrads form NOT the cytoskeleton forms a spindle that separates chromatids
An individual is ___________ for a characteristic if they have two of the same alleles for that gene
homozygous
There is one gene for protein H. It is called gene H. Gene H has alleles G and g in the population you are studying. Which one of the following is always true?
if allele for gene H is on chromosome 4 then an allele for gene H is at the same locus on the other copy of chromosome 4
There is one gene for protein H. It is called gene H. Gene H has alleles G and g in the population you are studying. Which of the following is always true?
if one allele for gene H is on chromosome 4, then an allele for gene H is at the same locus on the other copy of chromosome 4
There is one gene for protein R. It is called gene R. Gene R has alleles G and g in the population you are studying. Which of the following is always true?
if one allele for gene R is on chromosomes 20, then an allele for gene R is at the same locus on the other copy of chromosome 20
Plant cells and animal cells both undergo mitosis and cytokinesis. New cell wall material is deposited from vesicles
in plant cells during cytokinesis
What is an advantage of sexual reproduction compared to asexual reproduction?
it generates genetic diversity
You look at a cell and see 14 tetrads on the metaphase plate. From this information you would know that
it is a non-human cell in metaphase 1
You look at a cell and see 19 tetrads on the metaphase plate. From this information you would know that
it is a non-human cell in metaphase I
What is an advantage of asexual reproduction over sexual reproduction?
it is more effective than sexual reproduction when population density is low
The purpose of the mitotic cell cycle (not just mitosis) is to
make more identical cells
Exactly one copy of each type of chromosome is in each daughter cell after
meiosis
You are studying cells where the number of types of chromosomes (n) is equal to seven. You look down the microscope and see one cell with seven duplicated chromosomes lined up on the metaphase plate. This cell is in
metaphase II of meiosis
You are studying cells where the # of types of chromosomes(n) is equal to seven. You look down in the microscope and see one cell with fourteen duplicated chromosomes line up individually on the metaphase plate. This cell is in
metaphase of mitosis
You are studying cells where the number of types of chromosomes (n) is equal to four. You look down the microscope and see one cell with eight duplicated chromosomes lined up on the metaphase plate. This cell is in
metaphase of mitosis
You are studying cells where the number of types of chromosomes (n) is equal to seven. You look down the microscope and see one cell with fourteen duplicated chromosomes lined up individually on the metaphase plate. This cell is in
metaphase of mitosis
Which of the following is most likely to stop a cell at the G2 checkpoint?
mistakes in the replication of DNA
Mendel performed _________ crosses. In this breeding strategy the parents are both true-breeding for all of the key traits. The parents have different phenotypes for only one of the traits
monohybrid
During anaphase II of meiosis, the chromosomes
move to opposite poles of the cell
Plant cells and animal cells both undergo mitosis and cytokinesis. In plant cells, but not animal cells, during cytokinesis
new cell wall material is deposited from vesicles
During synapsis and crossing over
new combinations of alleles are created
There is exactly one double helix of DNA in
one non-duplicated chromosome
In woman, an egg is released from a follicle in the ________, then travels through the oviduct to the uterus
ovary
Assume no mutations for this question. You are studying a multicellular animal. All of the cells that are NOT dividing have
pairs of homologous chromosomes with one from the mom and one from the dad
Mendel did his experiments on ____ ________. This was a good idea because they have many offspring, are easy to grow, and reproduce many generations quickly. He also could control which individuals bred with which other individuals
pea plants
The proteins of the genotype are expressed differently depending on the history and environment in each cell. Together these differentiated cells, working together as tissues, organs and organ systems, determine the __________ of the organism, which also could be describes as the physical appearance and function of the organism
phenotype
During meiosis
plasma membranes undergo cytokinesis at the end of meiosis I and meiosis II
The purpose of _______________ is making more cells to repair wounds and replace dead cells, for asexual reproduction of single-celled eukaryotes, and for growth during development.
the mitotic cell cycle
When does the nuclear envelope dissolve?
prophase/prometaphase
The cytoskeleton plays a big role in the mitotic cell cycle. Microtubules are used in the mitotic cell cycle for
pulling the sister chromatids apart
In Mendelian genetics a lower case letter is used to represent the ________ allele, which is only apparent in the phenotype if both copies (one from mom and one from dad) are the same
recessive
Which of the following is LEAST likely to directly involve the cytoskeleton?
repairing mutations when the DNA is replicated incorrectly
Binary fission
results in two daughter cells, each with one copy of the circular chromosome is how prokaryotes reproduce
Exposing cells to growth factors is most likely going to
send the cells through the G1 checkpoint
Each tetrad of duplicated homologous chromosomes
separates during anaphase I of meiosis
Which of the following would raise your risk of dying from cancer?
smoking
In the mitotic cell cycle, if the sister chromatids of a duplicated chromosome have both of their kinetochores bound to the same pair of centrioles with microtubules, then the cell will most likely
stop at metaphase
During the human life cycle
the adults and zygotes are diploid
During the human life cycle
the adults are diploid and the gametes are haploid
Which of the following describes a cell with n = 9?
the cell has 9 tetrads on the metaphase plate during metaphase I
Which of the following happens LAST during the mitotic cell cycle?
the cleavage furrow forms
Asexual reproduction is more advantageous than sexual reproduction when
the environment is constant, because new combinations of alleles are not as important as when the environment is changing
During metaphase I of meiosis
the kinetochores of each homologous chromosome are attached to the same centrosome tetrads are aligned together in the middle of the cell
The purpose of ______ is making more cells to repair wounds and replace dead cells, for asexual reproduction of single-celled eukaryotes, and for growth during development
the mitotic cell cycle
Of the events below, which would happen NEXT in the mitotic cell cycle after the DNA was replicated?
the mitotic spindle would start to form
You are working with environmental contaminants, and have found chemical A in the water supply. You are concerned it is a growth factor, so you run experiments to test this hypothesis. You have two sets of identical flasks of cells, set 1 and set 2. You do not add chemical A to set 1, but you add chemical A to set 2. You wait a three days and measure the number of cells again. The data that is most convincing that chemical A is a growth factor would be
the number of cells in set 1 is smaller than the number in set 2 at the end of the experiment
Of the events below, which would happen LAST in the mitotic cell cycle after the DNA was replicated?
the plasma membrane would form a cleavage furrow and would divide the cell into two daughter cells
Which of the following situations is most likely if a eukaryotic cell is stuck at the M checkpoint?
there are errors in the replication of the DNA
The purpose of the mitotic cell cycle is
to generate a daughter cell that is identical to the cell that divides
The purpose of the meiotic cell cycle (not just meiosis) is
to generate haploid gametes for sexual reproduction
The purpose of the meiotic cell cycle is
to generate haploid gametes for sexual reproduction
The purpose of mitosis is
to get exactly one copy of each chromosome into each daughter cell
When do cells divide by going through the meiotic cell cycle?
to make sperm
When do cells divide by going through the mitotic cell cycle?
to replace dead cells
When a plant self-fertilizes generation after generation, and always shows the same phenotype for the characteristic being considered, then the plant is called ____________
true breeding
One sister chromatid has
two molecules of DNA as one double helix
Which of the following are identical?
two sister chromatids
During telophase of mitosis, the chromosomes
uncoil from their condensed state