Ap Bio Chapter 13

Front 1

heredity

Back 1

the passing of traits from parents to offspring

Front 2

genetics

Back 2

The scientific study of heredity

Front 3

variation

Back 3

an organism that has characteristics resulting from chromosomal alteration

Front 4

gene

Back 4

sequence of DNA that codes for a protein and thus determines a trait

Front 5

chromosome

Back 5

condensed threads of genetic material formed from chromatin as a cell prepares to divide

Front 6

life cycle

Back 6

the entire span in the life of an organism from one generation to the next

Front 7

somatic cell

Back 7

Any cell in a multicellular organism except a sperm or egg cell.

Front 8

asexual reproduction

Back 8

reproduction that does not involve the union of gametes and in which a single parent produces offspring that are genetically identical to the parent

Front 9

sexual reproduction

Back 9

process in which genetic material from two parents combines and produces offspring that differ genetically from either parent

Front 10

karyotype

Back 10

the appearance of the chromosomal makeup of a somatic cell in an individual or species (including the number and arrangement and size and structure of the chromosomes)

Front 11

homologous chromosome

Back 11

chromosomes that have the same sequence of genes, that have the same structure, and that pair during meiosis

Front 12

locus

Back 12

the position of a gene on a chromosome

Front 13

sex chromosome

Back 13

a chromosome that determines the sex of an individual

Front 14

autosome

Back 14

any chromosome other than a sex chromosome

Front 15

diploid

Back 15

an organism or cell having two sets of chromosomes or twice the haploid number

Front 16

haploid

Back 16

an organism or cell having only one complete set of chromosomes

Front 17

gamete

Back 17

a mature sexual reproductive cell having a single set of unpaired chromosomes

Front 18

fertilization

Back 18

process in sexual reproduction in which male and female reproductive cells join to form a new cell

Front 19

zygote

Back 19

diploid cell formed when the nucleus of a haploid sperm cell fuses with the nucleus of a haploid egg cell

Front 20

meiosis

Back 20

a process in cell division during which the number of chromosomes decreases to half the original number by two divisions of the nucleus, which results in the production of sex cells

Front 21

meiosis 2

Back 21

the function of M2 is to seperate the sister chromatids. each daughter cell ends up with single stranded chromosomes

Front 22

synapsis

Back 22

the pairing of homologous chromosomes during meiosis

Front 23

sister chromatid

Back 23

one of the two identical parts of a duplicated chromosome in a eukaryotic cell

Front 24

tetrad

Back 24

A paired set of homologous chromosomes, each composed of two sister chromatids. Tetrads form during prophase I of meiosis.

Front 25

crossing over

Back 25

the interchange of sections between pairing homologous chromosomes during the prophase of meiosis

Front 26

chiasmata

Back 26

The X-shaped, microscopically visible region representing homologous chromatids that have exchanged genetic material through crossing over during meiosis.

Front 27

synaptomal complex

Back 27

proteins that hold tetrad together untill cross over occurs

Front 28

independent assortment

Back 28

the random distribution of the pairs of genes on different chromosomes to the gametes

Front 29

alternation of generation

Back 29

An organism that has this pattern alternates between a haploid and a diploid generation

Front 30

sporophyte

Back 30

diploid, or spore-producing, phase of an organism

Front 31

gametophyte

Back 31

Haploid, or gamete-producing, phase of an organism