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Flashcards in Exam #6 Deck (52)
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1
Q

Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cell?

  • 32
  • 8
  • 60
  • 4
A

32

2
Q

If there are 20 chromatids in a cell, how many centromeres are there?

  • 100
  • 20
  • 85
  • 10
A

20

3
Q

In eukaryotic cells, chromosomes are composed of DNA and __.

  • and proteins
  • and RNA
  • only
  • and phospholipids
A

And proteins

4
Q

Which of the following defines a genome?

  • The complete set of an organism’s genes
  • A Karyotype
  • The complete set of an organism’s polypeptides
  • The complete set of a species’ polypeptides
A

The complete set of an organism’s genes.

5
Q

Which is the smallest unit containing the entire human genome?

  • All of the DNA of one human
  • One human chromosome
  • One human somatic cell
  • The entire human population
A

One human somatic cell

6
Q

Which of the following is a true statement about sexual vs. asexual reproduction?

  • In sexual repro, individuals transmit 50% of their genes to each offspring
  • Sexual repro requires that parents be diploid
  • Asexual repro, but not sexual repro, is characteristic of plants and fungi
  • Asexual repro produces only haploid offspring
A

In sexual reproduction, individuals transmit 50 % of their genes to each of their offspring.

7
Q

What do we mean where we use the terms mono hybrid cross and dihybrid cross?

  • mono- single parent dihybrid - two parents
  • mono- 9:3:3:1 dihybrid 3:1
  • dihybrid - heterozygous for 2 characters ; mono involves one
  • mono - progeny dihybrid - two progeny
A

A dihybrid cross involved organisms that are heterozygous for two characters, and a mono hybrid cross involves only one.

8
Q

What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?

  • there is considerable genetic variation in garden peas
  • genes are composed of DNA
  • traits are inherited in discrete units, and are not the results of “blending d”
  • recessive genes occur more frequently in the F1 generation than do dominate ones
A

Traits are inherited in discrete units, and are not the results of “blending” .

9
Q

Which of the following differentiates between independent assortment and segregation ?

  • the law of segregation is accounted for by anaphase of mitosis
  • the law of segregation requires describing two or more genes relative to one another
  • the law of segregation requires having two or more generations to describes
  • the law of independent assortments requires describing two or more genes relative to one another
A

The law of independent assortment requires describing two or more genes relative to one another.

10
Q

What is the produced if a cell divides by mitosis but does not undergo cytokinesis?

  • one cell with two nuclei, each identical to the nucleus of the parent cell
  • two cells, with half of genetic material of the parent cell
  • two cells, one of cell containing two nuclei and a second cell with out a nucleus
  • one cell with one nucleus containing half of the genetic material of the parent cell
A

One cell with two nuclei, each identical to the nucleus of the parent cell

11
Q

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

  • 4 times as much DNA as the nuclei of gametes produced by meiosis
  • same amount of DNA as the nuclei of gametes “
  • twice as much DNA as the “
  • half as much DNA “
A

Twice as much DNA as the nuclei of gametes produced by meiosis.

12
Q

Compared to most prokaryotic cells, eukaryotic cells typically have

  • the same number of DNA molecules and similarly sized genomes
  • fewer DNA molecules and smaller genomes
  • more DNA molecules and larger genomes
  • the same number of DNA molecules but larger genomes
A

More DNA molecules and larger genomes.

13
Q

At which phase are centrioles beginning to move apart in animal cells?
PMAT

A

Prophase

14
Q

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

  • 50
  • 10
  • 35
  • 200
A

10

15
Q

At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype?
PMAT

A

Metaphase

16
Q

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

A

Each cell has eight homologous pairs.

17
Q

Which of these statements is false?

  • at sexual maturity, ovaries and testes produced diploid gametes by meiosis
  • in humans, the 23rd pair, the sex chromosomes determine gender
  • sexual life cycles differ with respect to the relative timing of meiosis and fertilization
  • single, haploid sets of chromosomes … Single called zygote
A

At sexual maturity, ovaries and testies produce diploid gemetes by meiosis .
- it’s haploid

18
Q

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
  • sporophyte meiosis
  • alternation of generations
  • sporophyte mitosis
A

Gametophyte mitosis

19
Q

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

A

Gametophytes mitosis

20
Q

Which of the following is an example of alternation of generation?

  • a diploid plant ( sporophyte ) produces, by meiosis, a spore that gives rise to a mutlicellular, haploid pollen grain ( gametophyte)
  • a diploid cell divides by mitosis to produce two diploid daughter cells, which then fuse to produce a tetrapods cell
  • a diploid animal produces gametes by meiosis, and the gametes undergo fertilization to produce a diploid zygote
  • a grandparent and grandchild each have dark hair, but the parent has blond hair
A

A diploid plant ( sporophyte) produces, by meiosis, a spore that gives rise to a multicellular, haploid pollen grain ( gametophyte).

21
Q

Mendel accounted for the observation that traits that had disappeared in the F1 generation reappeared in the F2 generation by proposing that

  • new mutations were frequently generated in the F2 progeny, “reinventing” traits that had been lost in the F1
  • the traits were lost in the F1 due to dominance of the parental traits
  • traits can be dominate or recessive, and the recessive traits were obscured by the dominant one in the F1
A

Traits can be dominated or recessive, and the recessive traits were observed by the dominate ones in the F1

22
Q

Why did the F1 offspring of Mendel’s Classic pea cross always look like one of the two parental varieties ?

  • each allele affected phenotypic expression
  • no gene integrated to produce the parental phenotype
  • one allele was dominate
  • the traits blended together during fertilization
A

One allele was dominant.

23
Q

Which of the following describes the ability of a single gene to have multiple phenotypic effects?

  • epistasis
  • pleiotropy
  • incomplete dominance
  • multiple alleles
A

Pleiotopy

24
Q

Which of the following is an example of polygenic inheritance ?

  • pink flowers
  • skin pigmentation in humans
  • the ABO blood group in humans
  • white and purple flower color in peas
A

Skin pigmentation in Humans.

25
Q

Where do the microtubules of the spindle originate during mitosis in animal cells?

  • centromere
  • centrosome
  • centriole
  • chromatid
A

Centrosome

26
Q

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

  • dynein
  • kinetochores
  • Golgi- derived vesicles
  • centrioles and centromeres
A

Golgi- derived vesicles

27
Q

The beginning of anaphase is indicated by which of the following ?

  • kinetochores attach to the metaphase plate
  • cohesin attaches the sister chromatids to each other
  • chromatids lose their kinetochores
  • cohesin is cleaved enzymatically
A

Cohesion is cleaved enzymatically.

28
Q

During which phase of mitosis do the chromatids become chromosomes ?
PMAT

A

Anaphase

29
Q

What is the cleavage furrow?

  • a groove in the plasma membrane between daughter nuclei
  • a ring of vesicles forming a cell plate
  • the separation of dividend prokaryotes
  • the metaphase plate where chromosomes attach to the spindle
A

A groove in the plasma membrane between daughter nuclei

30
Q

The human X and Y chromosomes

  • are called autos omens
  • included genes that determine an individual’s sex
  • are both present in every somatic cell of males and females alike
  • are about the same size and have approximately the same number of genes
A

Include genes that determine an individual’s sex.

31
Q

Which of these is a karyotype?

  • organized images of a cell’s chromosomes
  • a display of all the cell types in an organism
  • a natural cellular arrangement of chromosomes in the nucleus
  • a display of a cell’s mitotic stages
A

Organized images of a cell’s chromosomes

32
Q

Mitosis is commonly found in all of the following except

  • a diploid bacteria cell
  • a haploid animal cell
  • a diploid animal cell
  • a diploid plant cell
A

A haploid animal cell

33
Q

Which of these is a way that the sexual life cycle increases genetic variation in a species?

  • by allowing an increase in cell number
  • by conserving chromosomal gene order
  • by allowing crossing over
  • by increasing gene stability
A

By allowing crossing over

34
Q

Motor proteins require which of the following to function in the movement of chromosomes toward the poles of the mitotic spindle ?

  • ATP as an energy source
  • intact centromeres
  • synthesis of cohesin
  • a kinetochore attached to the metaphase plate
A

ATP as an energy source

35
Q

When a cell is in late anaphase of mitosis, which of the following will we see?

  • breaking down of the nuclear envelope
  • chromosomes clustered at the poles
  • individuals chromatids beginning to separate from one another
  • clear area in the centers of the cell
A

A clear area in he center of he cell

36
Q

Which is the first checkpoint in the cell cycle where a cell will be caused to exit the cycle if this point is not passed?

A

A clear area in the center of the cell

37
Q

Which is the first checkpoint in the cell cycle where a cell will be caused to exit the cycle if this point is not passed?

  • G1
  • G2
  • G0
  • S
A

G1

38
Q

Which of the following is released by platelets in the vicinity of an injury ?

  • protein kinase
  • cyclin
  • MPF
  • PDGF
A

PDGF

39
Q

Which of the following triggers the cell’s passage past the G2 checkpoint into mitosis?

  • cyclin
  • MPF
  • Protein kinase
  • PDGF
A

MPF

40
Q

Which of the following provides an example of epistastsis ?

  • recessive genotype for each genes ( aabb) result in an albino corn snake
  • in rabbits and many other mammals, one genotype ( ee) prevents any fur color from developing.
  • In Drosophila (fruit flies), white eyes can be due to an X-linked gene or to a combo of other genes
A

In rabbits and many other mammals, one genotype ( ee) prevents any fur color from developing.

41
Q

A given organism has 46 chromosomes in its karyotype. We can therefore conclude which of the following ?

  • it gametes must have 23 chromosomes
  • it must be an animal
  • it must be sexually reproducing
  • it must be a primate
A

It’s gametes must have 23 chromosomes

42
Q

Which of the following can utilize both mitosis and meiosis in the correct circumstance?

  • a diploid cell from a plant stem
  • any diploid animal cell
  • a plantlike protist
  • a haploid animal cell
A

A plantlike protist

43
Q

To view and analyze human chromosomes in a dividing cell, which of the following is (are ) required?

  • a stain particular to human cells
  • a scanning electron microscope
  • DNA staining and a light microscope
  • fluorescent staining and a transmission electron microscope
A

DNA staining and a light microscope

44
Q

After telophase 1 of meiosis, the chromosomal makeup of each daughter cell is

  • diploid and the chromosomes are each composed of two chromatids
  • tetraploid and the chromosomes are each composed of two chromosomes
  • haploid and the chromosomes are each composed of two chromatids
A

Haploid, and the chromosomes are each composed of two chromatids.

45
Q

When does the synaptonemal complex disappear?

  • late metaphase of meiosis II
  • late prophase of meiosis I
  • during fertilization or fusion of gametes
  • early anaphase of meiosis I
A

Late prophase of meiosis 1

46
Q

Density- dependent inhibition is explained by which of the following ?

  • As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing.
  • 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.
  • As cells become more numerous, the level of waste products increases, eventually slowing down metabolism.
A

As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing

47
Q

Which of the following is true concerning cancer cells?

  • When they stop dividing, they do so at random points in the cell cycle
  • When they stop dividing, they do so at random in the cell cycle; they are not subject to cell cycle controls; and they do no exhibit density-dependent inhibition when growing in culture.
  • They are not subject to cell cycle controls.
  • They do not exhibit density- dependent inhibition when growing in culture.
A

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.

48
Q

Why do neurons and come other specialized cells divided infrequently ?

  • They no longer carry receptors for signal molecules
  • They no longer have active nuclei
  • They have been shunted into G0
  • They show a drop in MPF concentration
A

They have been shunted in G0

49
Q

Which of the following most accurately described a cyclin ?

  • It is activated to phosphorylate by completing with a Cdk
  • It activates a Cdk molecule when it is in sufficient concentration
  • It is present in similar concentrations throughout the cell cycle.
  • It activates a Cdk when it’s concentration is decreased
A

It activates a Cdk molecule when it is in sufficient concentration.

50
Q

All cell cycle checkpoints are similar in which way?

  • They utilize same Cdks
  • They respond to the same cyclins
  • They give the go-ahead signal to progress to the next checkpoint
  • They activate or inactivate other proteins
A

They give the go - ahead to progress to the next checkpoint.

51
Q

Which of the following happens at the conclusion of meiosis 1?

  • Cohesions are cleaved at the centromeres
  • The chromosome number per cell is conserved
  • Homologous chromosomes of a pair are separated from each other
  • Sister chromatids are separated
A

Homologous chromosomes of a pair are separated from each other.

52
Q

Which of the following occurs in meiosis but not in mitosis?

  • production of daughter cells
  • condensation of chromatin
  • chromosome replication
A

Synapsis of chromosomes