First Semester Review Flashcards
Meiosis Purpose
to produce gamete/sex cells that combine parental DNA
Meiosis I Processes
PMAT; takes a diploid cell, copies the DNA from egg and sperm, separates the homologous chromosome pairs
Cell Division Processes Order Mnemonic
P on the MAT: Prophase, Metaphase, Anaphase, Telophase
homologous chromosomes
each diploid cell has two sets of chromosomes, homologous chromosomes are a pair of the same chromosome number
Meiosis II Processes
PMAT; take a diploid cell and separates the two chromatids of one of the homologous chromosome pairs that was already separated in M1; creates four haploid cells from two diploid cells
haploid
only has one chromosome from a homologous chromosome pair
diploid
has both chromosomes from a homologous chromosome pair
asexual reproduction
uses mitosis to create exact copy of itself; still diploid; no genetic variation through gamete fusion
sexual reproduction
requires fertilization of two gametes to produce a zygote that then grows from mitosis and has variant combinations of parent DNA
fertilization
the fusion of an egg and a sperm that creates a diploid cell that then goes under meiosis to produce gametes for that organism; that zygote then grows using mitosis
chromosomal crossing over in meiosis
during M1: prophase 1 has homologous chromosomes physically attach and then detach and exchange genes so every chromosome is partially egg and partially sperm DNA; contributes to genetic variation
Mitosis vs Meiosis
Meiosis: creates 4 genetically variable, haploid cells; produces more gamete cells; Mitosis: creates diploid cells, exact copy of parent, 2 daughter cells
Meiosis 1 vs Meiosis 2
M1: splits a homologous chromosome pair to two chromosomes per cell; M2: splits a chromosome into two chromatids
Prophase
spindle fibers/microtubules first form and centrioles separate, chromosomes condense
Metaphase
nuclear envelope fragments, kinetochore forms on chromosomes, chromosomes align on metaphase plate, microtubules attach to kinetochore
Anaphase
cell elongates as mircotubules pull two chromatids (M2 and mitosis)/chromsomes (M1) apart
Telophase
fragmented nuclear envelopes reform around new DNA sets, chromosomes uncondense
independent assortment in meiosis
random orientation of homologous chromosomes so that during Anaphase 1 a different combination of chromosomes are pulled apart to contribute to genetic variation
random fertilization
two gametes meeting to fertilize each other makes infinite possibilities of diploid cells to contribute to genetic variation
chiasma
location of chromosomal crossing over where genes swap in homologous chromosomes
autosomes
non-sex chromosomes
sex determination
if the chromosome set that the sperm contributes has a Y chromosome for the sex chromosome, the organism is male, otherwise it’s female
Mitosis purpose
create a new clone cell to renew and repair cells, thus organisms often develop from a single cell
prokaryotic genetic material
usually one DNA molecule, circular DNA, floats around in cytoplasm
eukaryotic genetic material
packaged into chromosomes, sister chromatids are exact copies, sister chromatids form a homologous chromosome
Mitotic interphase
G1: cell grows producing proteins and organelles, S: copies chromosomes, G2: cell grows more, M: cytoplasm and DNA divide
cytokenesis: animals vs plants
cytokenesis divides two cells; in animals it creates a cleavage furrow that divides the cytoplasm; in plants, extra vesicles are aligned by microtubules and a new cell wall is created between the cells
cell cycle control system
uses checkpoints between each interphase phase (G1, S, G2) to regulate growth, cellular checkpoints are inside and outside of the cell,
G0 phase
phase that most cells are in, during interphase where no mitosis is occuring because growth/reproduction is not necessary at the moment
cell control system regulators
regulated by proteins and protein complexes: kinase enzymes and cyclin proteins that activate/deactivate proteins; growth factors are proteins that stimulate mitosis
cell control system external factors
density-dependent inhibition where crowded cells stop dividing; anchorage dependence: cells need to be attached to something to divide
cancerous cells
ignore lack of growth factors, by ignoring growth factors or making own; randomly stop mitosis cycle; can divide forever with nutrients; ignore cell signals to force cell death
