Cell Cycle Mitosis Flashcards
functions of cell division
Growth (usually multicellular organism), Asexual reproduction,Repair
Chromosome-
eukaryotic DNA molecule with proteins attached to it
Histones
chromosomal proteins that act as a spool for the DNA (DNA wounds twice around each histone)
Nucleosome
one unit of histone–DNA spool
pros and cons of tightly compact
benefit of tightly compact–no tangled, organized drawback–sometimes we need enzymes to access the DNA to copy it
Genome
cell’s total amount of DNA
gene
section of DNA codes for a protein that governs or controls a specific trait
how long is the DNA in a typical human cell?
3 meters DNA
how many genes do humans have
20k
Somatic cells amount of chromosomes
46
Gametes amount of chromosomes
23
chromatin
When not in cell division, chromosomes takes a granular appearance-contains one long linear DNA molecule associated with proteins
granular
grainy
each chromosome after duplication
consists of 2 sister chromatids-which are identical copies of one another
centromere
found in the middle of each chromatid and holds the chromatid together
mitosis (technical definition)
division of the nucleus
during process of mitosis-what happens to sister chromatids?
Sister chromatids are pulled apart and function as chromosomes
cytokinesis
division of the cell
what is mitosis followed by?
cytokinesis
fertilization–chromosomes
23 chromosomes from mother’s egg join with23 chromosomes from a father’s sperm to form 46 in a fertilized egg
karyotype
chromosomal constitution of 46 chromosomes that humans have. 2 copies of 23 (1-22 and xx or xy)
xx
female
xy
male
down syndrome
3 copies of chromosome 21
meiosis
Gametes in person are produced by meiosis (takes place in germ cells), which halves # of chromosomes and only occurs in gonads
M phase
Mitosis and cytokinesis. When cell divides. Stages—prophase, prometaphase, metaphase, anaphase, telophase
Interphase
Rest of cell cycle. Living its life. Phases—G1, S, G2
G1 phase
First gap/growth. Growth of cell.
G0
Permanent G1–many cells. Include neurons after certain age.
S phase
Synthesizing/copying DNA. Only cells destined to divide get here.