Chapter 19 of human biology by Sylvia S. Mader and Windelspecht. Cell division

chromosones

made up of DNA

Autosomes

Any chromosome that is not a sex chromosome

Chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

sex chromosomes

Chromosomes that determine the sex of an individual

Karyotypes

A picture of all the chromosomes in a cell arranged in pairs

Mitosis

part of eukaryotic cell division during which the cell nucleus divides

sister chromatids

joined copies of the original chromosome

centromere

Area where the chromatids of a chromosome are attached

2 parts of cell cycle

interphase and mitosis (cell division)

interphase 3 stages

G1, S, G2

what does g1 phase do

Cell growth

S stage of interphase

DNA replication

G2 stage of interphase

Occurs after DNA has been copied; all cell structures needed for division are made (e.g. centrioles); both organelles & proteins are synthesized

G0 stage of interphase

-Cells become nondividing remain viable and metabolically active but are not proliferative

-can be stimulated to return to G1

duplication division

mitosis, another name

Cytokinesis

division of the cytoplasm

apoptosis

programmed cell death

interphase checkpoints

The checkpoints occur at the end of G1, G2, & M

This happens to make sure that the cell is the right size and that the cell has duplicated the DNA fully

What is the G1 checkpoint

integrity of DNA is checked

what is the G2 checkpoint

no DNA damage, chromosome set complete, enough cell components

what is the mitotic checkpoint

a control point in the cell cycle where "STOP" signals are overridden by "GO" signals

External control

stimulate a cell to divide

parent cell

original cell before cell division

daughter cell

the two new cells that result from mitosis and cytokinesis

centromere

Region of a chromosome where the two sister chromatids attach

Diploid (2n)

two copies of each chromosome

mitotic spindle

An assemblage of microtubules and associated proteins that is involved in the movements of chromosomes during mitosis.

Aster

an array of microtubules

Mitosis phases

prophase, metaphase, anaphase, telophase

prophase purpose

centrosomes duplicate and chromosomes condense, nuclear envelope fragments, and nucleolus disappears.

Prometaphase purpose

spindles attach to centromeres, and chromosomes are placed in the nucleus

Metaphase

The chromosomes line up at the metaphase plate.

Anaphase purpose

centromeres divide, and sister chromatids are now called chromosomes.

Telophase purpose

chromosomes arrive t poles and become chromatin, spindle disappears, nuclear envelope and nucleolus reappears, 2 daughter nuclei.

nucleolus

Makes ribosomes

Cleavage furrow

The first sign of cleavage in an animal cell; a shallow groove in the cell surface near the old metaphase plate.

actin filaments

protein fibers that play a role in cell division and shape

Meiosis

reduction division process, occurring only in reproductive cells, in which one diploid (2n) cell produces four haploid (n) cells that are not genetically identical

homologous chromosomes

Chromosomes that have the same sequence of genes and the same structure

interkenesis

Period of time between meiosis I and meiosis II during which no DNA replication takes place.

Prophase I

synapsis and crossing over

Spermatogenesis

Formation of sperm

Oogenesis

The production of mature egg cells.

How many sperm are made per min?

300,000 sperm

How many sperm are made per day?

400 million

spermatids

four haploid cells that are formed when a diploid reproductive cell divides meiotically

Spermatozoa

a mature sperm cell

Polar body

holds discarded chromosomes.

Allele

Different forms of a gene

Nondisjunction

Error in meiosis in which homologous chromosomes fail to separate.

Trisomy

extra chromosome 2n + 1

Monosomy

missing a chromosome (2n-1)

Trisomy 21

Down syndrome

Are trisomy usually fatal

yes

Barr body

Inactivated X chromosome

Turner Syndrome

A chromosomal disorder in females in which either an X chromosome is missing, making the person XO instead of XX, or part of one X chromosome is deleted.

Jacob's Syndrome

XYY males, nondisjunction during meiosis II

who is likely to have a child with trisomy 21

women over 40.

down syndrome symptoms

- Intellectual Disability (#1 Cause)

- Epicanthal Folds (Eyes)

- Flat Facies

- Single Palmar Crease

- Gap Between 1st-2nd Toe

- Duodenal Atresia

- Hirschsprung Disease

- Heart Disease (Septal Defects)

syndrome

A group of symptoms typical of a particular disease or condition

SRY gene

sex determining region of the Y chromosome

Testis Determining Factor (TDF)

protein encoded by a gene in the SRY that triggers testes formation

Klinefelter syndrome

47, XXY

female poly x syndrome

more than 2 x chromosomes and extra Barr bodies

Deletion

part of a chromosome is missing

inversion

segment of a chromosome is inverted

duplication

the presence of a chromosomal segment more than once in the same chromosome

Translocation

movement of a segment from one chromosome to another nonhomologous chromosome

nonhomologous

nonmatching chromosomes

Williams syndrome

chromosome 7 loses a tiny end piece

Cri du chat syndrome

deletion on chromosome 5

tetralogy of fallot

congenital malformation involving four distinct heart defects

Clubbing

widening of the fingertips