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