Meiosis

Question 1

Somatic Cells

Answer 1

Any cell in a multicellular organism except a sperm or egg cell or a cell that develops into a sperm or egg

Question 2

Homologous chromosomes

Answer 2

The two chromosomes that make up a matched pair in a diploid cell. Homologous chromosomes are of the same length, centromere position, and staining pattern, and possess genes for the same characters at corresponding loci. One homologous chromosome is inherited from the organism’s father, the other from the mother

Question 3

Locus

Answer 3

the particular site where a gene is found on a chromosome homologous chromosomes have corresponding gene loci

Question 4

Sex Chromosome

Answer 4

A chromosome that determines whether an individual is male or female

Question 5

Autosome

Answer 5

A chromosome not directly involved in determining the sex of an organism in mammals, for example, any chromosome other than x or y

Question 6

Life cycle

Answer 6

the entire sequence of stages in the life of an organism, from the adults of one generation to the adults of the next

Question 7

Diploid

Answer 7

in an organism that reproduces sexually, a cell containing two homologous sets of chromosomes, one set inherited from each parent; 2n cell

Question 8

gamete

Answer 8

a sex cell; a haploid egg or sperm. the union of two gametes of opposite sex(fertilization)–> a zygote

Question 9

Haploid

Answer 9

In the life cycle of an organism that reproduces sexually, a cell containing a single set of chromosomes; an n cell

Question 10

fertilization

Answer 10

the union of the nucleus of a sperm cell with the nucleus of an egg cell, producing a zygote

Question 11

zygote

Answer 11

the diploid fertilized egg, which results from the union of a sperm cell nucleus and an egg cell nucleus

Question 12

meiosis

Answer 12

In a sexually reproducing organism, the division of a single diploid nucleus into four haploid daughter nuclei. Meiosis and cytokinesis produce haploid gametes from diploid cells in the reproductive organs of the parents

Question 13

Crossing over

Answer 13

The exchange of segments between chromatids of homologous chromosomes during synapsis in prophase 1 of meiosis, also, the exchange of segments between DNA molecules in prokaryotes

Question 14

Chiasma

Answer 14

the microscopically visible site where crossing over has occurred between chromatids of homologous chromosomes during prophase 1 of meiosis

Question 15

Recombinant chromosome

Answer 15

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

Question 16

Nondisjunction

Answer 16

an accident of meiosis or mitosis in which a pair of homologous chromosomes or a pair of sister chromatids fail to separate at anaphase

Question 17

Karyotype

Answer 17

A display of micrographs of the metaphase chromosomes of a cell, arranged by size and centromere position. Karyotypes may be used to identify certain chromosomal abnormalities

Question 18

trisomy 21

Answer 18

a human genetic disorder resulting from the presence of an extra chromosome 21; characterized by heart and respiratory defects and varying degrees of mental retardation

Question 19

Deletion

Answer 19

the loss of one or more nucleotides from a gene by mutation the loss of a fragment of a chromosome

Question 20

Duplication

Answer 20

repetition of part of a chromosome resulting from fusion with a fragment from a homologous chromosome; can result from an error in meiosis or from mutagenesis

Question 21

Inversion

Answer 21

a change in a chromosome resulting from reattachment of a chromosome fragment to the original chromosome, but in the reverse direction. Mutagens and errors during meiosis can cause inversions

Question 22

Translocation

Answer 22

A change in a chromosome resulting from a chromosomal fragment attaching to a nonhomologous chromosome; can occur as a result of an error in meiosis or from mutagenesis