Meiosis & Sexual Reproduction - Ch 11

Alteration Generations

life-cycle type in which the diploid and haploid stages alternate

Chiasmata (singular, Chiasma)

the structure that forms at the crossover points after genetic material is exchanged

Cohesin

proteins that form a complex that seals sister chromatids together at their centromeres until anaphase II of meiosis

Crossover

exchange of genetic material between non-sister chromatids resulting in chromosomes that incorporate genes from both parents of the organism 

fertilization

union of two haploid cells from two individual organisms

gametophyte

a multicellular haploid life-cycle stage that produces gametes

germ cells

specialized cell line that produces gametes, such as eggs or sperm

interkinesis

(also, interphase II) brief period of rest between meiosis I and meiosis II

life cycle

the sequence of events in the development of an organism and the production of cells that produce offspring

meiosis

a nuclear division process that results in four haploid cells

meiosis I

first round of meiotic cell division; referred to as reduction division because the ploidy level is reduced from diploid to haploid

meiosis II

second round of meiotic cell division following meiosis I; sister chromatids are separated into individual chromosomes, and the result is four unique haploid cells

recombination nodules

protein assemblies formed on the synaptonemal complex that mark the points of crossover events and mediate the multistep process of genetic recombination between non-sister chromatids of a homologous pair

reduction division

nuclear division that produces daughter nuclei each having one-half as many chromosome sets as the parental nucleus; meiosis I is a reduction division

somatic cell

all the cells of a multicellular organism except the gametes or reproductive cells

spore

haploid cell that can produce a haploid multicellular organism or can fuse with another spore to form a diploid cell

sporophyte

a multicellular diploid life-cycle stage that produces haploid spores by meiosis

synapsis

formation of a close association between homologous chromosomes during prophase I

synaptonemal complex

protein lattice that forms between homologous chromosomes during prophase I, supporting crossover

tetrad

two duplicated homologous chromosomes (four chromatids) bound together by chiasmata during prophase

Meiosis usually produces ________ daughter cells.

a. two haploid

b. two diploid

c. four haploid

d. four diploid

c. four haploid

What structure is most important in forming the tetrads?

a. centromere

b. synaptonemal complex

c. chiasma

d. kinetochore

b. synaptonemal complex

At which stage of meiosis are sister chromatids separated from each other?

a. prophase I

b. prophase II

c. anaphase I

d. anaphase II

d. anaphase II

At metaphase I, homologous chromosomes are connected only at what structures?

a. chiasmata

b. recombination nodules

c. microtubules

d. kinetochores

a. chiasmata

Which of the following is not true in regard to crossover?

a. Spindle microtubules guide the transfer of DNA across the synaptonemal complex.

b. Non-sister chromatids exchange genetic material.

c. Chiasmata are formed.

d. Recombination nodules mark the crossover point.

a. Spindle microtubules guide the transfer of DNA across the synaptonemal complex.

What phase of mitotic interphase is missing from meiotic interkinesis?

a. G0phase

b. G1phase

c. S phase

d. G2phase

c. S phase

The part of meiosis that is similar to mitosis is ________.

a. meiosis I

b. anaphase I

c. meiosis II

d. interkinesis

c. meiosis II

If a muscle cell of a typical organism has 32 chromosomes, how many chromosomes will be in a gamete of that same organism?

a. 8

b. 16

c. 32

d. 64

b. 16

Which statement best describes the genetic content of the two daughter cells in prophase II of meiosis?

a. haploid with one copy of each gene

b. haploid with two copies of each gene

c. diploid with two copies of each gene

d. diploid with four copies of each gene

b. haploid with two copies of each gene

The pea plants used in Mendel’s genetic inheritance studies were diploid, with 14 chromosomes in somatic cells. Assuming no crossing over events occur, how many unique gametes could one pea plant produce?

a. 28

b. 128

c. 196

d. 16,384

b. 128

How do telophase I and telophase II differ during meiosis in animal cells?

a. Cells remain diploid at the end of telophase I, but are haploid at the end of telophase II.

b. Daughter cells form a cell plate to divide during telophase I, but divide by cytokinesis during telophase II.

c. Cells enter interphase after telophase I, but not after telophase II.

d. Chromosomes can remain condensed at the end of telophase I, but decondense after telophase II.

a. Cells remain diploid at the end of telophase I, but are haploid at the end of telophase II.

What is a likely evolutionary advantage of sexual reproduction over asexual reproduction?

a. Sexual reproduction involves fewer steps.

b. There is a lower chance of using up the resources in a given environment.

c. Sexual reproduction results in variation in the offspring.

d. Sexual reproduction is more cost effective.

c. Sexual reproduction results in variation in the offspring.

Which type of life cycle has both a haploid and diploid multicellular stage?

a. asexual life cycles

b. most animal life cycles

c. most fungal life cycles

d. alternation of generations

d. alternation of generations

What is the ploidy of the most conspicuous form of most fungi?

a. diploid

b. haploid

c. alternation of generations

d. asexual

b. haploid

A diploid, multicellular life-cycle stage that gives rise to haploid cells by meiosis is called a ________.

a. sporophyte

b. gametophyte

c. spore

d. gamete

a. sporophyte

Hydras and jellyfish both live in a freshwater lake that is slowly being acidified by the runoff from a chemical plant built upstream. Which population is predicted to be better able to cope with the changing environment?

a. jellyfish

b. hydra

c. The populations will be equally able to cope.

d. Both populations will die.

b. hydra

Many farmers are worried about the decreasing genetic diversity of plants associated with generations of artificial selection and inbreeding. Why is limiting random sexual reproduction of food crops concerning?

a. Mutations during asexual reproduction decrease plant fitness.

b. Consumers do not trust identical appearing produce.

c. Larger portions of the plant populations are susceptible to the same diseases.

d. Spores are not viable in an agricultural setting.

c. Larger portions of the plant populations are susceptible to the same diseases.