chapter 9 biology

which is the smallest unit containing the entire human genome

1 human somatic cell

which of the following best describes the frequency of crossing over in mammals

1-2 per chromosome pair

If there are 20 chromatids in a cell, how many centromeres are there? If there are 20 chromatids in a cell, how many centromeres are there? 10 20 80 30 40

10

if there are 20 centromeres in a cell at anaphase, how many chromosomes are there in each daughter cell following cytokinesis

10

a group is assayed for DNA...

16;16

Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells? Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells? 32 4 8 64 16

32

How many chromosomes are in human somatic cells

46, 23 pairs (23 from mom, 23 from dad)

29) Which of the following is released by platelets in the vicinity of an injury? A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk

A

35) The MPF protein complex turns itself off by A) activating a process that destroys cyclin components. B) activating an enzyme that stimulates cyclin. C) binding to chromatin. D) exiting the cell. E) activating the anaphase-promoting complex.

A

motor proteins require what

ATP

15) A triploid cell contains three sets of chromosomes. If a cell of a usually diploid species with 42 chromosomes per cell is triploid, this cell would be expected to have which of the following? A) 63 chromosomes in 31 1/2 pairs B) 63 chromosomes in 21 sets of 3 C) 63 chromosomes, each with three chromatids D) 21 chromosome pairs and 21 unique chromosomes

B

37) Density-dependent inhibition is explained by which of the following? A) As cells become more numerous, they begin to squeeze against each other, restricting their size and ability to produce control factors. B) As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing. C) As cells become more numerous, the protein kinases they produce begin to compete with each other, such that the proteins produced by one cell essentially cancel those produced by its neighbor. D) As cells become more numerous, more and more of them enter the S phase of the cell cycle. E) As cells become more numerous, the level of waste products increases, eventually slowing down metabolism

B

In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common? In a human karyotype, chromosomes are arranged in 23 pairs. If we choose one of these pairs, such as pair 14, which of the following do the two chromosomes of the pair have in common? a) They have nothing in common except they are X-shaped. B) length, centromere position, staining pattern, and traits coded for by their genes C) length, centromere position, staining pattern, and DNA sequences length, centromere position, and staining pattern only length and position of the centromere only

B

1) If a horticulturist breeding gardenias succeeds in having a single plant with a particularly desirable set of traits, which of the following would be her most probable and efficient route to establishing a line of such plants? A) Backtrack through her previous experiments to obtain another plant with the same traits. B) Breed this plant with another plant with much weaker traits. C) Clone the plant asexually to produce an identical one. D) Force the plant to self-pollinate to obtain an identical one. E) Add nitrogen to the soil of the offspring of this plant so the desired traits continue.

C

27) A plant-derived protein known as colchicine can be used to poison cells by blocking the formation of the spindle. Which of the following would result if colchicine is added to a sample of cells in G₂? A) The cells would immediately die. B) The cells would be unable to begin M and stay in G₂. C) The chromosomes would coil and shorten but have no spindle to which to attach. D) The chromosomes would segregate but in a disorderly pattern. E) Each resultant daughter cell would also be unable to form a spindle.

C

41) Cells from an advanced malignant tumor most often have very abnormal chromosomes, and often an abnormal total number of chromosomes. Why might this occur? A) Cancer cells are no longer density dependent. B) Cancer cells are no longer anchorage dependent. C) Chromosomally abnormal cells can still go through cell cycle checkpoints. D) Chromosomally abnormal cells still have normal metabolism. E) Transformation introduces new chromosomes into cells.

C

Which of the following describes cyclin dependent kinase (Cdk)

Cdk is present throughout the CC and is an enzyme that attaches phosphate groups to other proteins

14) Measurements of the amount of DNA per nucleus were taken on a large number of cells from a growing fungus. The measured DNA levels ranged from 3 to 6 picograms per nucleus. In which stage of the cell cycle did the nucleus contain 6 picograms of DNA? A) G₀ B) G₁ C) S D) G₂ E) M

D

30) Which of the following is a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex? A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk

D

31) Which of the following is a protein maintained at constant levels throughout the cell cycle that requires cyclin to become catalytically active? A) PDGF B) MPF C) protein kinase D) cyclin E) Cdk

E

38) Which of the following is true concerning cancer cells? A) They do not exhibit density-dependent inhibition when growing in culture. B) When they stop dividing, they do so at random points in the cell cycle. C) They are not subject to cell cycle controls. D) When they stop dividing, they do so at random points in the cell cycle, and they are not subject to cell cycle controls. E) When they stop dividing, they do so at random points in the cell cycle; they are not subject to cell cycle controls; and they do not exhibit density-dependent inhibition when growing in culture.

E

4) Proteins that are involved in the regulation of the cell cycle, and that show fluctuations in concentration during the cell cycle, are called A) ATPases. B) kinetochores. C) kinases. D) proton pumps. E) cyclins.

E

A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following? A) It must be human. B) It must be a primate. C) It must be an animal. D) It must be sexually reproducing. E) Its gametes must have 23 chromosomes.

E

Eukaryotic sexual life cycles show tremendous variation. Of the following elements, which do all sexual life cycles have in common? I. Alternation of generations II. Meiosis III. Fertilization IV. Gametes V. Spores

II, III, IV

The cyclin component of MPF is destroyed toward the end of which phase

M

which of the following triggers the cell's passage past the G2 checkpoint and into mitosis

MPF

I. Prophase I V. Prophase II II. Metaphase I VI. Metaphase II III. Anaphase I VII. Anaphase II IV. Telophase I VIII. Telophase II Centromeres of sister chromatids disjoin and chromatids separate.

VII

when a cell is in late anaphase of mitosis, what might we see

a clear area in the middle of the cell

which of the following best describes a karyotype

a display of each of the chromosomes of a single cell

for a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes

about 8 million

Which of the following most accurately describes a cyclin

activated a Cdk molecule when it is in sufficient concentration

which of the following might result in a human zygote of 45 chromosomes

an error in either egg or sprem meiotic anaphase

during which phase do chromatids become chromosomes

anaphase

f an organism is diploid and a certain gene found in the organism has 18 known alleles (variants), then any given organism of that species can/must have which of the following?

at most 2 alleles

which of these statements is false

at sexual maturity, the ovaries and testies produce diploid gametes by meiosis

wnere do the microtubules of the spindle originate during mitosis in animal cells

centrosome

the beginning of anaphase is indicated by which of the following

cohesin is cleaved enzymatically

experiments with cohesins have found that

cohesins are protected from chromosomes at the centromere before anaphase I

Which of the following is true of a species that has a chromosome number of 2n = 16?

each cell has 8 homologous pairs

The karyotype of one species of primate has 48 chromosomes. In a particular female, cell division goes awry and she produces one of her eggs with an extra chromosome (25). The most probable source of this error would be a mistake in which of the following?

either anaphase I or II

referring to a plant's sexual life cycle, which of the following terms describes the process that leads directly to the formation of gametes

gametophyte mitosis

the somatic cells of a privet shrub each contain 46 chromosomes. to be as different as they are from human cells, which have the same number of chromosomes, which of the following must be true

genes of privet chromosomes are significantly different than those in humans

which of the following are primarily responsible for cytokinesis in plant cells but not animal cells

gogli derived vesicles

Mitosis is commonly found in all of the following except

haploid animal cell

after telophase I of meiosis, the chromosomal makeup of each daughter cell is

haploid, and the chromosomes are each composed of 2 chromatids

f a cell has completed the first meiotic division and is just beginning meiosis II, which of the following is an appropriate description of its contents?

has half the amount of DNA

compared to most prokaryotic cells, eukaryotic cells usually

have more dna and larger genomes

when does the synaptonemal complex disappear

late prophase of meiosis I

at which stage of mitosis are chromosomes photographed in preparation for a karyotype

metaphase

Which of these is a karyotype?

organized images of a cell's chromosomes

at which phase are cnetrioles moving apart in animal cells

prophase

Using which of the following techniques would enable your lab group to distinguish cells in G2 and cells in G1

radioactive labeled nucelotides

Why do nuerons and some other specialized cells divide infrequently

they dont receive a go ahead signal in the G1 checkpoint

how do cells at the completion of meiosis compare with cells that have replicated their DNA and are just about to begin meiosis

they have half the # of chromosomes and one fourth the amount of DNA

whether during mitiosis or meiosis, sister chromatids are held together by proteins referred to as cohesins. such molecules must have which of the following properties

they must be removed before anaphase can occur

independent assortment of chromosomes occurs.

this is true only for meiosis I

Humans produce skin cells by mitosis and gametes by meiosis. The nuclei of skin cells produced by mitosis will have

twice as much DNA

a pair of homologoys chromosomes includes which of the following sets of DNA strands

two sister chromatids that have synapsed