Eukaryotic cell division part 1 Flashcards
3 principles of the cell theory
All organisms are composed of one or more cells
Cells are the smallest living things
Cells arise only by division of a previously existing cell
Basic structural and functional units of every organism
cell
What are the steps of the eukaryotic cell cycle?
Interphase 3 parts G1 (G0 is in here) S G2 then M (cytokinesis)
What is metabolism
Cellular Respiration, Fermentation, Photosynthesis (Make ATP)
what is heredity
Genetics and DNA replication, Transcription, Translation
Cell division
what is same for prokaryotes and eukaryotes
Replicate DNA
Segregate (separate) DNA into daughter cells
Division of cellular components
what only happens in eukaryotes cell division
mitosis + cytokinesis
Reproduction (cell division)
Growth and development
Tissue renewal
3 eukaryotic cell types
somatic
germ cell (2N)
gamete (1N)
what is a somatic cell
Body cells
Not specialized for reproduction
Function of somatic cells
Each contains homologous pairs of chromosomes with corresponding genes
Diploid (2n) in mammals
Each parent contributes one homolog
Special about somatic cells
Each contains homologous pairs of chromosomes with corresponding genes
Diploid (2n) in mammals
Each parent contributes one homolog
what is germ cell
Specialized cells for reproduction
Found in testes and ovaries
2N
function of germ cells
produces gametes (1N)
Gametes
1N or haploid
2 meet together is fertilization
example of 2 gametes fusing
1N sperm cell and 1N egg cell for 2N zygote
what does 2N and 1N stand for
2N=diploid
1N=haploid (half)
number of chromosomes
Homologous chromosomes
Maternal and paternal copies of same chromosome before/after DNA replication
tell about Homologous chromosomes
same length & centromere position
it is the whole one side of chromosome but one from each parent
sister chromatids
see slide 5
they are from the same parent and part of the paired homologous chromosome
tell about sister chromatids
Arms of the chromosome linked by sister-chromatid cohesion
Exact copies
Exact same nucleotide sequence*
after DNA replication
Eukaryotic nuclear division 2 processes
mitosis
meiosis
Mitosis
Occurs in somatic cells
Results in two identical diploid (2n) daughter cells identical to the parent cell
meiosis
Occurs in germ cells
Produces four haploid (n) daughter cells genetically different from each other and from the parent cell
how many division of meosis are ther
2 nuclear divisions, to go 2N to N
Eukaryotic Chromosomes review
have centromere, 2 telomeres, and replication origins
centromere
Where sister chromatids are attached after DNA replication (mitosis and meiosis)
two telomeres
Repeated nucleotide sequences at each end of chromosome
replication origins see slide 7
Where DNA replication begins
Nucleosome
DNA wrapped around histone proteins
histone proteins
Small, positively charged
Chromatin packing
beads on a string
Nucleosome packs into compact chromatin fiber
Chromatin fiber folded into loops resulting in typical mitotic chromosome
First part of cell cycle
interphase
3 stages of interphase
G1 S G2
When a cell stays in G1 what happens
G0
what happens during interphase
cell increases in mass and size; doubles # of components in cytoplasm; replicates DNA (S (synthesis) phase)
What happens in G1 of interphase
cell growth and function
what happens during S of interphase
DNA replication or synthesis
What happens during G2 of interphase
Cell prepares for division
Organelles replicate
How long does interphase take
about 23 hours half in S
What comes after interphase or its last stage G2
M phase
What is m phase
Mitosis
what is mitosis
nuclear division
what are the stages to the cycle
see slide 9
IPPMAT (PMAT less than 1 hour) interphase preprophase prophase metaphase anaphase telophase
what happens after m phase
cytokinesis
what is cytokinesis
cytoplasmic division
What stage are most of our cells in
G0
not part of cell cycle
cells functioning but not dividing
Transient withdrawal
Cell types withdraw from cell cycle occasionally
Retain ability to reassemble cell-cycle control system and re-enter cell cycle
Ex: liver cells, fibroblasts, lymphocytes (some)
Consider two mammalian cells, one in G1 and the other in G0 (stationary) phase. If they are stimulated to pass the restriction point by the addition of an extracellular proliferation signal, but the signal is then immediately removed, what would you expect to happen?
A. Both cells will replicate their DNA.
B. Only the G1 cell will replicate its DNA.
C. Only the G0 cell will replicate its DNA.
D. Only the G1 cell will start to replicate its DNA, but will stop halfway through the replication and will not reach G2.
E. Neither of the cells will replicate their DNA.
A) both will replicate DNA
once passed the restriction point will replicate
