B6G

The diagram above shows the process of meiosis. The segregation that occurs during meiosis results in a -

• decrease in the total number of cells per organism

• reduction in the number of chromosomes per cell

• single fertilized egg cell

• group of genetically identical cells

Crossing over between nonsister chromatids during meiosis is significant in heredity. This process most likely leads to an increase in which of the following?

• the expression of dominant traits

• number of gametes

• occurrence of polyploidy

• genetic variation

Sexual reproduction in animals depends on the production of gametes. Which of these processes produces gametes in animals?

• mitosis

• fertilization

• meiosis

• binary fission

Human body cells each have 46 chromosomes in their nuclei. Meiosis is necessary in order to ensure that each gamete produced in the human body has -

• 12 chromosomes

• 23 chromosomes

• 46 chromosomes

• 92 chromosomes

During meiosis, homologous chromosomes exchange genetic material. This exchange of genetic material -

• increases the genetic variation

• reduces the diploid number to the haploid number

• increases the haploid number to the diploid number

• reduces the probability of mutation

Which diagram demonstrates how crossing over contributes to genetic variety during meiosis?

• A

• B

• C

• D

In the early 1900's, Thomas Hunt Morgan was among the first scientists to contribute to the chromosomes theory of heredity. Morgan's investigations into heredity in fruit flies led him to propose that the event represented in the diagram sometimes occurs. Which statement about the event represented in the diagram is valid?

• the event represents RNA translation in the smooth endoplasmic reticulum

• the events takes place in bacterial cells

• the event produces genetically identical daughter cells

• the event produces genetic diversity in eukaryotic cells

Gametes produced by an organism contain a combination of genes from that organism. In every gamete, this combination is -

• the same because it is created with the same DNA

• the same because chromosomes are copied prior to meiosis

• different due to DNA replication prior to mitosis

• different due to independent assortment during meiosis