Genetics Chapter 1 Pt. 1

nuclear DNA

linear chromosomes inside thenucleus

nuclear envelope

the distinguishingfeature of eukaryotes

organelle DNA

circular chromosomes in themitochondria and, in plants and algae, the chloroplasts

G-1 phase

cell growth

G-2 phase

cell growth

S-phase

DNA replication (synthesis)

M-phase

mitosis and cytokinesis; eukaryotic cell division

what does interphase consist of

G1, S, G2

G0

the cell may exit the division cycle during G1 to become a non-dividing cell (quiescience)

checkpoints

steps at which the progression through thecell division cycle is monitored and regulated

At the end of mitosis and during G1 or G0,

a chromosome consists of a single DNA molecule

After S-phase and during G2 each chromosome

consists of two DNA molecules (two identical sister chromatids)

telomeres

stable ends of linear chromosomes

centromere

region of the chromosome at which sister chromatids are joined. Also present before DNA replication

before DNA replication ____ DNA molecule

one

after DNA replication ____ DNA molecule

two

chromatin

condenses into visible chromosomes before cell division due to the tightening of interactions between DNA and chromatin proteins

histones

protein molecules around which DNA is tightly coiled in chromatin

sequence that encodes a trait

gene

p arm

short arm of chromosome

q arm

long arm of chromosome

chromatin

fibers of decondensed DNA chromosomes; occurs during the non-divisional phases of the cell cycle

submetacentric

near the center

metacentric

at the center

telocentric

at the telomere

acrocentric

near telomere

haploid (n)

one copy of genetic material subdivided into chromosomes

diploid (2n)

two copies of genetic material subdivided into chromosomes

alleles

alternative forms of a gene found at the sameposition (locus) of homologous chromosomes

locus

Location of a gene on a chromosome

homologous chromosome

chromosomes with the same length and centromere location; contain the same linear sequence of loci, but not necessarily identical DNA; NOT sister chromatids

gene (transmission genetics)

a unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring

gene (molecular genetics)

a region of a chromosome that codes for a functional product

all genes are loci but

not all loci contain genes

karyotype

visual representation of the complete set of chromosomes of an individual organism

autosomal

all the other genes in the body that are not sex-linked

normal human karyotype

22 pairs of autosomal chromosomes and 1 pair of sex chromosomes

polyploid

3n, 4n, 5n, etc.

aneuploid

Abnormal number of chromosomes (in humans, a number of

chromosomes that is not 46)

mitosis

division of the nucleus.

cytokinesis

the division of the cytoplasm and the cellmembrane

Chromosome (DNA) replication

the duplication of theDNA molecules in the nucleus; results in sisterchromatids

kinetochore

protein structure that is assembled on the centromer, spindle microtubules attach to it and mediate disjunction of sister chromatids

spindle microtubules

attach to the kinetochores of chromosomes and move the chromosomes to the metaphase plate

centrosome

a pair of centrioles. It is the microtubule-organizing center (MTOC) of animal cells

centrioles

Cell organelle that aids in cell division in animal cells only

prophase

the chromatin condenses into visible chromosomes. The centrosome is duplicated. The two centrosomes will become the poles (ends) of the mitotic spindle, made of microtubules.

prometaphase/metaphase

he nuclear envelope breaks down (except in fungi), the mitotic spindles attach to the centromeres of the chromatids, and the chromosomes lineup at the metaphase plate

anaphase

the chromatids are pulled apart by the mitoticspindles

telophase

the chromatids are segregated and their DNAdecondenses. The chromatids become the chromosomesof the daughter cells. The nuclear envelopes reassemble

when does the nuclear envelope disintegrate in mitosis?

prometaphase

are sister chromatids pulled to the metaphase plate in mitosis

no, they go there themselves and are not connected

what is the outcome of mitosis

2 identical diploid daughter cells

when does cytokinesis occur

simultaneously with or following telophase

each chromosome consists of how many DNA molecules

a single DNA molecule

during anaphase of mitosis, the chromosmes...

are disjoined and are segregated to daughter cells

do chromosomes pair in mitosis

homolgous chromosomes do not pair at any time