Bio test 4 Flashcards


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1

How is photosynthesis similar in C4 and CAM plants?

A. in both cases, thylakoids are not involved in photosynthesis

B. types of plants make most of their sugar in the dark

C. types of plants make sugar without the Calvin cycle

D. in both cases, only photosystem I is used.

E. In both cases, rubisco is not used to fix carbon initially

Answer E

2

Which of the following does not occur during the Calvin cycle?

A. regeneration of the CO2 acceptor, RuBP

B. carbon fixation

C. consumption of ATP

D. oxidation of NADPH

E. release of oxygen

Answer E

3

What is the primary function of the Calvin cycle?

A. split water and release oxygen

B. use ATP to release carbon dioxide

C. synthesize simple sugars from carbon dioxide

D. use NADPH to release carbon dioxide

E. transport RuBP out of the chloroplast

Answer C

4

Why are C4 plants able to photosynthesize with no apparent photorespiration?

A. They conserve water more efficiently

B. They do not participate in the Calvin Cycle

C. They exclude oxygen from they tissues

D. They use PEP carboxylase to initially fix CO2 in mesophyll cells.

E. They are adapted to cold, wet climates

Answer D

5

In the process of carbon fixation, RuBP attaches a CO2 to produce a 6 carbon molecule, which is then split in two. After carbon fixation and reduction, what more needs to happen in the Calvin Cycle?

A. regeneration of RuBP

B. inactivation of RuBP carboxylase enzyme

C. a gain of NADPH

D. addition of a pair of electrons from NADPH

E. regeneration of ATP from ADP

Answer A

6

The centromere is a region in which

A. chromosomes are grouped during telophase

B. new spindle microtubules form at either end

C. .....

D. chromatids remain attached to one another until anaphase

E. the nucleus is located prior to mitosis

Answer D

7

During which phase of mitosis are chromosomes composed of two chromatids?

A. from G1 of interphase through metaphase

B. from interphase through anaphase

C. from G2 of interphase through metaphase

D. from anaphase through telophase

E. from metaphase through telophase

Answer C

8

Regarding mitosis and cytokinesis, one difference between higher plants and animals is that in plants

A. sister chromatids are identical, but they differ from one another in animals.

B. the spindles contain microfibrils in addition to microtubules, whereas animal spindles do not contain microfibrils

C. a cell plate begins to form at telophase, whereas in animals a cleavage furrow is initiated at that stage

D. chromosomes become attached to the spindle at prophase, whereas in animals chromosomes do not become attached until anaphase

Answer C

9

Where do microtubules of the sprinkle originate during mitosis in both plant and animal cells?

A. centriole

B. kinetochore

C. centrosome

D.chromatid

E. centromere

Answer C

10

Which term describes the centromeres uncoupling, sister chromatids separating, and the two new chromosomes moving to opposite poles of the cell?

A. telophase

B. anaphase

C. metaphase

D. prophase

E.prometaphase

Answer B

11

How do daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle?

A. The daughter cells have had the number of chromosomes and had the amount of DNA

B. The daughter cells have the same number of chromosomes and the same amount of DNA

C. The daughter cells have the same number of chromosomes and twice the amount of DNA

D.The daughter cells have half the amount of cytoplasm and half the amount of DNA

E. The daughter cells have the same number of chromosomes and half the amount of DNA

Answer B

12

A group .... assayed for DNA content immediately following mitosis and is found to have an average of 8 picograms of DNA per nucleus. Those cells would have _____ pictograms of DNA at the end of the S phase and ____ pictograms of DNA at the end of G2 phase.

A. 8;8

B. 16;8

C. 8;16

D. 12;16

E. 16;16

Answer E

13

Imagine looking through a microscope at a squashed onion root tip. The chromosomes of may of the calls are plainly visible. In one cell, replicated chromosomes are aligned along the center (equator) of the cell. This cell is at which stage of mitosis?

A. telophase

B. metaphase

C. prophase

D. prometaphase

E. anaphase

Answer B

14

If mammalian cells receive a go-ahead signal at the G1 checkpoint, they will

A. exit the cycle and switch to a non dividing state.

B. show a drop in MPF concentration

C. complete cytokines and form new cell walls.

D. move directly into telophase

E. replicate DNA, divide and complete the cell cycle

Answer E

15

The cyclin component of MPF is destroyed toward the end of this phase:

A. M

B. G0

C. S

D. G2

E. G1

Answer A

16

Which of the following describes cyclin-dependent kinase (CdK)?

A. CdK is inactive, or "turned off" in the presence of cyclin

B. CdK is present throughout the cell cycle

C. CdK is an enzyme that attaches phosphate groups to other proteins

D. Both A and B are true

E. Both B and C are true

Answer E

17

How many different combinations of maternal and paternal chromosomes can be packaged in gametes produced by an organism with a diploid number of 8 (2n-8)?

A. 32

B. 2

C. 16

D. 8

E. 4

Answer C

18

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

A. It must be an animal

B. It must be a primate

C. It must be human

D. Its gametes must have 23 chromosomes

E. It must be sexually reproducing

Answer D

19

After telophase I of mitosis, the chromosomal makeup of each daughter cell is

A. haploid, and the chromosomes are each composed of two chromatids

B. diploid, and the chromosomes are each composed of a single chromatid

C. diploid, and the chromosomes are each composed of two chromatids

D. haploid, and the chromosomes are each composed of a single chromatid

E. tetraploid, and the chromosomes are each composed of two chromatids

Answer A

20

How do cells at the completion of meiosis compare with cells that are at G1 phase?

A. They have had the number of chromosomes and one-fourth the amount of DNA.

B. They have had the number of chromosomes and had the amount of DNA

C. They have twice the amount of cytoplasm and had the amount of DNA

D. They have the same number of chromosomes and had the amount of DNA

E. They have haled the amount of cytoplasm and twice the amount of DNA

Answer B

21

Tetrads of chromosomes are aligned at the equator of the spine; alignment determines

A. I

B. II

C. IV

D. VII

E. VIII

Answer B

22

Synapsis of homologous pairs occurs; crossing over may occur.

A. I

B. II

C. IV

D. VII

E. VIII

Answer A

23

Controllers of sister chromatids disjoin and chromatids separate.

A. I

B. II

C. IV

D. VII

E. VIII

Answer E

24

1. Formation of four new nuclei, each with half the chromosomes present in the parental nucleus

2. Alignment of tetrads at the metaphase plate

3. Seperation of siste chromatids

4. Separation of the homologues; no uncoupling of the centromere

5. Synapsis; chromosomes moving to the middle of the cell in pairs

From the descriptions above, which of the following is the order that most logically illustrates a sequence of meiosis?

A. 5,2,4,3,1

B. 1,2,3,4,5

C. .....

D. 5,4,2,1,3

E. 4,5,2,1,3

Answer A

25

Independent assortment of chromosomes is a result of

A. the relatively small degree of homology shared by the X and Y chromosomes.

B. the random and independent what in which each pair of homologous chromosomes lines up

C. the random nature of the fertilization of ova by sperm

D. the random distribution of the sister chromatids to the two daughter cells during anaphase II.

E. All of the above

Answer B

26

Chiasmata are what we see under a microscope that let us know which of the following has occurred?

A. Separation of homologs

B. Meiosis II

C. Asexual reproduction

D. Crossing over

E. Anaphase II

Answer D

27

A cross between homozygous purple-flowered and homozygous white-flowered pea plants results in offsprings with purple flowers. This demonstrates

A. true-breeding

B. the mistakes made by Mendel.

C. dominance

D. a dihybrid cross

E. the blending model of genetics

Answer C

28

Two plants are crossed, resulting in offspring with a 3:1 ratio for a particular trait. This suggests

A. that the parents were true-breeding for contrasting traits.

B. incomplete dominance

C. that each offspring has the same alleles

D. that a blending of traits has occurred

E. that the parents were both heterozygous

Answer E

29

Two characters that appear in a 9:3:3:1 ratio in the F2 generation should have which of the following properties?

A. Each of the genes controlling the characters has two alleles

B. each of the traits is controlled by single genes

C. Sixteen different phenotypes are possible

D. Four genes are involved

E. The genes controlling the characters obey the law of independent assortment

Answer E

30

Mendel's second law of independent assortment has its basis in which of the following events of meiosis I?

A. Synapsis of homologous chromosomes

B. Separation of cells at telophase

C. Crossing over

D. Alignment of tetrads at the equator

E. Separation of homologs at anaphase

Answer D

31

Which of the following about the law of segregation is false?

A. It can account for the 3:1 ratio seen in the F2 generation of Mendel's crosses.

B. It is a method that can be used to determine the number of chromosomes in a plant

C. It can be used to predict the likelihood of transmission of certain genetic diseases within families

D. It can be explained by the segregation of homologous chromosomes during meiosis.

E. It states that each of two alleles for a given trait segregate into different gametes

Answer B

32

Huntingtons disease is a dominant condition with late age of onset in humans. If one parent has the disease, what is the probability that his or her child will have the disease?

A. 3/4

B. 1/4

C. 1/2

D. 1

E. 0

Answer C

33

Cystic Fibrosis is a Mendelian disorder in the human population that is inherited as a recessive. Two normal parents have two children with CF. The probability of their next child being normal for this characteristic is which of the following?

A. 1/4

B. 3/4

C. 1/2

D. 1/8

E. 0

Answer A

34

When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both re- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?

A. Other male-specific factors influence eye color in flies

B. The gene involved is on the X chromosome

C. The gene involved i on an autosome

D. Other female-specific factors influence eye color in flies.

E. The gene involved is on the Y chromosome

Answer B

35

Males are more often affected by sex-linked traits than females because.

A. X chromosomes in males generally have more mutations than X chromosomes in females.

B. females hormones such as estrogen often compensate for the effects of X-linked mutations

C. male hormones such as testosterone often alter the effects of mutations on the X chromosome

D. males are homozygous for the X chromosome

E. mutations on the Y chromosome often worsen the effects of X-linked mutations

Answer D

36

Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents? (XC is the normal allele, Xc is the disease allele)

A. XcXc and XCY

B. XcXc and XcY

C. XCXC and XcY

D. XCXc and XCY

E. XCXC and XCY

Answer D

37

What is the reason that linked genes are inherited together?

A. Genes align that way during metaphase I of meiosis

B. They are located close together on the same chromosome

C. The number of genes in a cell is greater than the number of chromosomes

D. Alleles are paired together during meiosis

E. Chromosomes are unbreakable

Answer B

38

What is the mechanism for the production of genetic recombinants?

A. Separation of sister chromatids

B. Mutation in DNA sequence

C. DNA deletions and duplications during meiosis

D. X inactivation

E. Crossing over and independent assortment

Answer E

39

A sexually reproducing animal has two unlinked genes, one for head shape (H) and one for tail length (T). Its genotype is HhTt. Which of the following genotypes is possible in a gamete from this organism?

A. T

B. HT

C. tt

D. Hh

E. HhTt

Answer B

40

In cats, black fur color is caused by an X-linked allele (XB); the other allele at this locus causes orange color (XO). The heterozygote (XBXO) is tortoiseshell(calico cat). What kinds of offspring would you expect from the cross of a black female and an orange male?

A. Orange females; black males

B. Orange females; orange males

C. Black females; orange males

D. Calico females;black males

E. Calico females; Calico males

Answer D