Chapter 11

What process do zygotes develop by in plants and animals?

Mitosis.

How many copies of each chromosome does a zygote have?

Two copies.

_________ is a process of nuclear division that reduces the number of chromosomes from 2 sets to 1 set.

Meiosis.

What is the cell produced by the fusion of an egg and sperm called?

Zygote.

The fusion of a male gamete with a female gamete is called what?

Syngamy.

What is the pairing of homologous chromosomes called?

Synapsis.

What process is essential for crossing over during meiosis?

Synapsis.

If you are studying an organism where 2n = 24, how many chromosomes will each nucleus have after meiosis II is complete?

12. 
    

The term for one of a pair of chromosomes with similar genetic information from different sources is called __________.

Homologue.

If you do not observe any chiasmata in meiosis I, what is the best conclusion?

There is no crossing over between non-sister chromatids.

Which statement about the reductive division of meiosis is false?

Sister chromatids migrate to opposite poles of the cell.

A cell in G2 before meiosis begins has __________ compared to cells produced at the end of meiosis II.

Four times as much DNA and twice as many chromosomes.

What event occurs first during meiosis?

Synapsis of homologous chromosomes.

In gene therapy for preventing defective genes from being passed on, aim to insert normal copies into __________.

Germ-line cells.

What is nondisjunction?

The failure of homologous chromosomes or sister chromatids to separate during meiosis or mitosis.

If 18 pairs of sister chromatids segregate normally during meiosis II in cats (n=19) but 1 pair undergoes non-disjunction, what will be the results?

2 cells with 19 chromosomes, 1 with 20, and 1 with 18.

The point of connection between two sister chromatids before anaphase II is called the __________.

Centromere.

Which statement about crossing over is false?

Crossing over takes place between sister chromatids.

What does a mutation in Rec8 protein that prevents its degradation affect?

Normal segregation during meiosis II.

What happens if cyclin B does not associate with its cyclin-dependent kinase near the end of meiosis I?

Activation of DNA replication.

At the end of meiosis II, each of the four resulting cells contains __________.

One full set of chromosomes, each with 1 molecule of DNA.