Genetics2017.18

A cell has 12 chromosomes. After meiosis, how many chromosomes will each daughter cell have?

• 4

• 6

• 12

• 24

Which of the following best describes meiosis?

• It is carried out in all tissues that require cell replacement.

• It occurs only in germ cells located in the reproductive structures of an organism.

• It happens in all tissues except the brain and spinal chord.

• It is the first stage of mitosis.

Crossing over results in a _____.

• female genotype

• male genotype

• genetic recombination

• phenotype replication

The diagram above shows homologous chromosomes during prophase I of meiosis. Which of the following correctly describes the process being illustrated?

• mutation in which the DNA content of the gene is altered

• segregation of sister chromatids

• condensation and segregation of alleles

• alleles are exchanged

The exchange of segments of DNA between homologous chromosomes

• ensures that variation within a species never occurs.

• acts as a source of variations within a species.

• always produces genetic disorders.

• is called crossing.

A haploid cell is one that

• has two homologues of each chromosome.

• is designated by the symbol n.

• has chromosomes found in pairs.

• does not exist

The numbers in Figure 10-1 represent the chromosome number found in each of the dog cells shown. The processes that are occurring at A and B are _____.

• mitosis and fertilization

• meiosis and fertilization

• mitosis and pollination

• meiosis and pollination

The sex of an offspring is determined by

• the mother.

• the father.

• both parents.

• the offspring.

The X and Y chromosomes are called the

• extra chromosomes

• phenotypes

• sex chromosomes

• reproductive chromosomes

A couple has two children, both of whom are boys. What is the chance that the parents' next child will be a boy?

• 0%

• 50%

• 25%

• 75%