Chapter 2 Mastering and Cat

Which of the following is true about sex-determining chromosomes

They act like homologous chromosomes during meiosis so each gamete will get one sex chromosome

A--- chromosome has its centromere located very close to, but not on, the end of the chromosome. .

acrocentric

Which chromosome has a telomere but the p arm is much shorter than the q arm

acrocentric

The centromere of a chromosome separates during

anaphase

During meiosis, chromosome number reduction takes place in

anaphase 1

When do sister chromatids separate during meiosis

anaphase 11

the stage at which "sister chromatids go to opposite poles" immediately follows which of the stages listed

mitotic metaphase and metaphase of meiosis 11

Meiosis allows

1. the generation of genetic variation among offspring 2. the generation of new combinations of alleles on the same chromosome 3. the transmission of equivalent amounts of genetic information from generation to generation 4. the genetic contribution of two individual parents to each offspring

The diploid chromosome number of an organism is usually represented as 2n. Humans have a diploid chromosome number of 46. What would be the expected haploid number in a human

23

The house fly, Musca domestica, has a haploid chromosome number of 6. How many chromatids should be present in a diploid, somatic, metaphase cell

24

A diploid somatic cell has 2n=20 chromosomes. At the end of mitosis, each daughter cell would have --- chromosomes. At the end of meiosis 1, each daughter cell would have --- chromosomes. At the end of meiosis 1, each daughter cell would have --- chromosomes. At the end of meiosis 11, each daughter cell would have

2n-20, 1n=10, 1n-10 In mitosis, ploidy is maintained from one generation to the next. So daughter cells will be 2n and have 20 chromosomes. Meiosis, ploidy are reduced by half. So by meiosis 1 would be 1n=10. Ploidy then is no longer reduced.

if a typical somatic cell has 64 chromosomes, how many chromosomes are expected in each gamete of that organism

32

What significant genetic function occurs in the S phase of the cell cycle

DNA synthesis

After meiosis 11--- would be formed

Monads

Which of the following is NOT a source of genetic variation in meiosis

Polar body formation

Which part of interphase does DNA duplication take place

S phase

what is the outcome of synapsis, a significant event in meiosis

Side-by-side alignment of homologous chromosomes.

2n=2 anaphase of meiosis 11

Single cromatids being pulled apart by spindle fibers to opposite sides of cell.

What is the arrangement of chromosomes during metaphase

Sister chromatids align along the equatorial plane of the cell

During which stage of prophase 1 does crossing over take place A tetrad is composed of one pair of homologous chromosomes at synapsis of prophase 1 When do sister chromatids separate during meiosis

Pachynema: when bivalents are closely paired True: Chromosomes are duplicated during interphase, at synapsis of prophase 1, one chromosome in a tetrad is paternallly inherited while the other is maternally inherited. Anaphase 11

The nucleolus organizer region (NOR) is responsible for production of what type of cell structure

Ribosome

Which of the following cell structures is directly involved in protein synthesis

Rough endoplasmic reticulum and ribosomes

Which of the following statements about meiosis is true

The chromosome number is reduced by one-half Meiosis produces gametes, which fuse to form zygote that have the original number of chromosomes present before meiosis. This can happen only if gametes contain one-half the number of chromosomes as the zygote.

In humans, what is a fundamental difference between the production of female gametes and male gametes

The production of female gametes but not male gametes involves an unequal division of cytoplasm.

Metaphase

chromosomes are fully condensed, and visible by microscopy.

A haploid cell

has one complete set of chromosomes. Ploidy (n)refers to sets of chromosomes; a haploid cell has one complete set (1n), a diploid cell has two sets (2n). Aneuploid cells have incomplete sets of chromosomes (2n+1, 3n-1). Most somatic (body) cells in humans are diploid, gametes are haploid.

A cell in the G0 stage

has withdrawn from the cell cycle Cell is performing normal metabolic activities, but is not replicating DNA. May remain permanently

Which term describes meiosis 1

reducational

which of the following is true about the second meiotic division

sister chromatids are pulling apart

During oogenesis in animals

there can be very long time gaps (years) between one stage and the next OOgenesis= creation of ova (egg cells)

The meiotic cell cycle involves---- number of cell divisions and ---- number of DNA replications

two one

Prophase 11

Crossing over occurs with no homologous pairs.

During meiosis 1,

Crossing over takes place Place during prophase

During interphase of the cell cycle,

DNA content essentially doubles

The parent cell that enters meiosis is diploid, wheras the four daughter cells that result are haploid Which statement correctly describes how cellular DNA content and ploidy levels change during meiosis 1 and meiosis 11

DNA content is halved in both meiosis 1 and meiosis 11. Ploidy level changes from diploid to haploid in meiosis 1, and remains haploid in meiosis 11

Living organisms are categorized into two major groups based on the presence or absence of a nucleus. What group is defined by the presence of a nucleus

Eukaryotic organism

Electron microscopy of metaphase chromosomes demonstrated various degrees of coiling. What was the name of the model that depicted this process

Folded-Fiber

When cells withdraw from the continous cell cycle and enter a "quiescent" phase, they are said to be in what stage

G0

Cells that are metabolically active, but not destined to proliferate are said to be in

G0 phase: Withdrawn from the cell cycle

During which stage can cells either exit the cell cycle or become committed to completing the cell cycle The longest stage of interphase is G2 Which condition is evaluated at the G2/M checkpoint

G1- cells can exit the cell cycle and enter G0 or initiate DNA Synthesis False- the longest stage of interphase is S: shortest stage is G2. Precise replication of DNA:

Checkpoints are points between phases of the cell cycle at which a cell determines whether all the requirements necessary for each phase of the cell cycle have been properly satisfied. For example, because a cell with damaged DNA can lead to cancer if it is allowed to divide, a cell with damaged DNA usually arrests the cell cycle until the damage can be repaired. At which phases of the cell cycle would a cell normally check for the integrity of its DNA.

G1/S: monitors cell size and checks for damaged DNA G2/M: monitors whether DNA replication and repair to any damaged DNA has been completed.

The picture depicts a cell that started out as 2n=4. What stage of mitosis or meiosis is it in

Metaphase Because chromosomes are lined up on the metaphase plate. Mitosis because the chromosomes are visible as four dyads and no synapsed as tetrads in metphase 1

2n=2

Metaphase 1 Single cell with 2 homologous pairs of chromosomes lined up in the middle, left-to-right

Which of the following could occur if a cell cycle checkpoint was missed

An unreplicated chromosome could be put through mitosis

In mitosis, sister chromatids are separated during----, while in meiosis sisters are separated in --

Anaphase anaphase 11 In meiosis, Homologous chromosomes are separated in anaphase 1

Which of the following are the areas where chromatids intertwine during meiosis

Chiasma

Name two cellular organelles, each containing genetic material, which are involved in either photosynthesis or respiration.

Chloroplasts and mitochondria