Reproduction Flashcards
What characteristcs do all mammals share?
Mammary Glands
Three Bones in Middle Ear
One bone in Lower Jaw
Fur/Hair
Sebaceous (oil) and Sudoriferous (Sweat) Glands
Heterodont Dentification (different teeth)
Diploid (2n)
share 2 copies of each chromosomes
autosomal cells
Haploid (n)
one copy of each chromosome
germ cells
The Stages of Cell Cycle
G1 , S, G2, M
G1, S and G2 are known as…
interphase, the longest part of cell cycle
Cells that do NOT divide are in the…
G0 phase, they just perform a function and do not divide
During interphase, chromosomes are not visible, they are in the form of….because…
chromatin so the DNA is available for transcription
G1 Stage
cells create organelles for energy and protein production but also grow
To go from G1 to S phase…
must pass through restriction point where it checks from proper complement of DNA
S Stage
cell replicates its genetic material for each daughter cell
Each chromosome is now two identical chromatids
NUMBER OF CHROMOSOMES IS SAME, JUST CHROMATIDS IS DOUBLED
Chromatid
made during S phase with condensing and replication of DNA to be bound at centromere
G2 Phase
cell has twice as much DNA now than in G1
another checkpoint to make sure there are enough organelles/cytoplasm for division and that DNA has been properly replicated
M Phase
mitosis and cytokinesis
4 stages: prophase, metaphase, anaphase and telophase
cytokinesis is the splitting into two cells
If there has been any damage to the DNA the cell cycle goes into arrest until DNA is repaired, the main protein involved in this process is….
p53
Cyclins and Cyclin Dependent kinases (CDKs)
molecules responsible for cell cycle
CDK is activated by specific cyclins to activate and phosphorylate transcription factors to transcript genes for next stage of cell cycle
Most common mutation to cause cancer…
mutation of p53 gene, the TP53
Cancer
uncontrolled cell division caused by allowing DNA to not properly be replicated and produce cells growths known as tumors
Metastasis
invasion of cancerous cells to other parts of the body
Mitosis occurs in….
somatic cells, those not involved in sexual reproduction
Prophase
chromatin condenses to chromosomes
centriole pairs separate and move towards opposite poles of the cell to the centrosome
Nuclear membrane goes away
centrioles prepare spindle fibers which can either anchor the centriole to the cellular membrane or attach to centromere of chromosomes via kinetochores
Centriole
produce spindle fibers (made of microtubules) to attach to cell membrane or chromosomes
Centrosome
region where centrioles are kept
Spindle fibers
come from centrioles, made of microtubuleles
Asters
spindle fibers which anchor centrioles to the cell membrane
Kinetochores
protein structures on centromeres that are attatchment points for kinetochore fibers
Kinetochore Fibers
spindle fibers that bind to kinetochores of the centromeres of the chromosomes
Metaphase
kinetochore fibers interact with fibers of spindle apparatus to align the chromosomes at the metaphase plate
Anaphase
centromeres split so each chromatid has its own centromere
sister chromatids are now separated and pulled towards the opposite ends of the cell
Telophase
spindle apparatus disappears, nuclear membrane reforms around chromosomes and chromosomes uncondense
Cytokinesis
separation of cytoplasm and organelles so there is enough for each cell
Meiosis occurs in…and result in…
gametocytes (germ cells) , identical sex cells known as gametes
Meiosis 1 vs Meiosis 2
M1: results in homologous chromosomes being seperated resulting in haploid daughter cells
M2: similar to mitsosis where seperation of sister chromatids occurs
Reductional Division
Meiosis one, haploid daughter cells are created
Equational Division
Meiosis 2, similar to mitosis where sister chromatid are separated
Homologous Pairs
2 separate chromosomes paired together when lined up in meiosis, one chromosome from each parent
Prophase 1
chromatin condenses into chromosomes, spindle apparatus forms
homologous chromosomes come together and intertwine and from tetrads
crossing over may occur
Synapsis
the intertwining process of homologous chromosomes
Tetrad
formed when homologous chromosomes are paired, referes to the total of 4 chromatids
Synaptonemal Complex
How tetrads are bound together
Crossing Over
When chromosomes in tetrad break equivalent amounts of DNA at chiasmas and switch
can be single or double
OCCURS BETWEEN HOMOLOGOUS CHROMOSOMES NOT SISTER CHROMATID
Chiasma
point of contact for chromatids in tetrad
Linkage
tendency of genes to be inherited together; genes located further away are more likely to undergo crossing over when compared to one another
Mendels Second Law of Independent Assortment
inheritance of one allele has no effect on the likelihood of inheriting certain alleles for other genes
Metaphase 1
homologous pairs align at metaphase plate and each pair is attached to a separate spindle fiber
main difference is each homologous chromosome is across one another and attached to a spindle fiber where as in mitosis each chromosome is attached to 2 spindle fibers