Cell Division Flashcards
What are the different types of asexual reproduction?
1) binary fission
2) budding
3) spore production
4) vegetative reproduction (no seed - cut off piece of plant to grow another)
What are the advantages and disadvantages of asexual reproduction?
+ fast, easy, one parent, many offspring mature quickly
– lacks diversity, enviro changes kill entire pop
What are the advantages and disadvantages of sexual reproduction?
+ biodiversity, can cope with change in enviro
– slow, few offspring, two parents needed
What do cells do? How/why/what happens?
- grow : by proteins + organelles accumulated in cytoplasm
- divide : surface area of cell membrane becomes inadequate
- die : need to be replaced
- reproduce : passes on genetic material
What are chromosomes?
compressed strings of DNA, tightly wound chromatin
What is chromatin?
DNA that is unwound, found when cell is not dividing (DNA + Histones [protein] )
What are sister chromatids?
chromosome duplicates to make 2 identical copies (DNA replication)
What is a centromere?
where chromatids join together
What is a telomere?
region of repetitive nucleotide sequences at each end of a chromatid, protects end of chromosome
What are genes?
DNA sequences located on chromosomes and code for specific traits
What is a genotype? What is a phenotype?
genotype - exact code of DNA
phenotype - how DNA is expressed (looks/functions)
What are the two types of cell division?
asexual - mitosis, in somatic cells
sexual - meiosis, in gametes
What are the three parts of interphase?
G1 - growth phase
Synthesis - DNA replication (doubling)
G2 - growth / prep for div
What is interphase and what happens?
- where the cell spends 90% of its time
- preps cell for div; cell div and makes organelles
- DNA is in form of chromatin
- DNA replication occurs
What is mitosis?
- process by which the cell divides
- 10% of the cycle
- cell undergoes cell div
What are the stages of Mitosis? IPMAT
1) prophase - chromatin starts to condense into chromosomes
2) metaphase - chromosomes line up
3) anaphase - pulling apart
4) telophase - nucleus starts to appear
What is prophase?
- chromatin condenses
- nuclear membrane starts to disintegrate
- astral rays (microtubles) form around centrioles that move to opposite pole of the cell
What is metaphase?
- chromosomes line up at equatorial plate
- centromere attaches to spindle fibres and later, splits, separating sister chromatids
- nuclear membrane disappears
What is anaphase?
- spindle fibers contract
- chromosomes are pulled to opposite poles
- centromeres divide
What is telophase?
- chromatids reach opposite poles
- spindle and astral rays disappear
- chromosomes unwind back into chromatin
- nuclear membrane reforms
- cytokinesis takes place, cell divides in two
What’s the difference between plant and animal cells?
1) Plants have no centrioles, but have microtubules with many of the same proteins
2) Plants don’t undergo cytokinesis, instead a cell wall forms at the equator
