Sexual Reproduction And Meiosis

Question 1

Aneuploidy

Answer 1

A chromosomal aberration in which one or more chromosomes are present in extra copies or are deficient in number

Question 2

Chiasma (plural chiasmata)

Answer 2

The X-shaped, microscopically visible region where crossing over has occurred earlier in prophase I between homologous nonsister chromatids. Chiasmata become visible after synapsis ends, with the two homologs remaining associated due to sister chromatid cohesion

Question 3

Fertilisation

Answer 3

The union of haploid gametes to produce a diploid zygote

Question 4

Homologous chromosomes

Answer 4

A pair of chromosomes of the same length, centromere position, and staining pattern that possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organisim’s father, the other from the mother. Also called homologs, or a homologous pair

Question 5

Sister chromatids

Answer 5

Two copies of a duplicated chromosome attached to each other by proteins at the centromere. When joined, two sister chromatids make up one chromosome. Chromatids are eventually separated during mitosis or meiosis II

Question 6

Homozygous

Answer 6

Having two identical alleles for a given gene

Question 7

Heterozygous

Answer 7

Having two different alleles for a given gene

Question 8

Haploid cell

Answer 8

A cell containing only one set of chromosomes (n)

Question 9

Gamete

Answer 9

A haploid reproductive cell, such as an egg or sperm. Gametes unite during sexual reproduction to produce a diploid zygote

Question 10

Diploid cell

Answer 10

A cell containing two sets of chromosomes (2n), one set inherited from each parent.

Question 11

Autosome

Answer 11

A chromosome that is not directly involved in determining sex; not a sex hormone

Question 12

Crossing over

Answer 12

The reciprocal exchange of genetic material between nonsister chromatids during prophase I of meiosis

Question 13

Nondisjunction

Answer 13

An error in meiosis or mitosis in which members of a pair of homologous chromosomes or a pair of sister chromatids fail to separate properly from each other

Question 14

Locus

Answer 14

A specific place along the length of a chromosome where a given gene is located

Question 15

Recombinant chromosome

Answer 15

A chromosome created when crossing over combines DNA from two parents into a single chromosome