Genetics: Chromosomes Part 2 Flashcards
(38 cards)
Why is it important to study the processes controlling cell division?
So we can try and fix or manipulate these processes for our own benefits. For example, we could try and improve regenerative mechanisms
What is apoptosis? When does it occur
Programmed cell death. It occurs when it fails a checkpoint and has damaged chromosomes
How are telomeres extended in the germ cells?
There’s a complex called telomerase which adds telomeres to the chromosomes
Meiosis produces _ gametes while mitosis produces _ daughter cells
4, 2
What is the cell cycle?
The sequence of events from a cell’s formation until its own division into two daughter cells.
What phases are part of the cell cycle?
Interphase and the cell division phase (mitosis and cytokinesis)
What is the general process for mitosis? What are the 6 official phases?
Duplicate chromosomes and separate the duplicated chromosomes so that each cell receives one copy.
Interphase, prophase, prometaphase, metaphase, anaphase, telophase/cytokinesis
What phases does interphase consist of?
Growth 0/1, S phase (chromosome duplication), Growth 2 (check for damaged or unduplicated DNA)
The cell cycle is under tight ________ in eukaryotes. This causes several __________ in the cycle that send stop or go signals
regulation, checkpoints
What sort of checkpoints exist to stop the cell cycle?
- Check for favourable environmental conditions
- Check for DNA damage or stalled replication forks
- Check for damaged or unduplicated DNA
- Check for chromosome attachment to mitotic spindle
What helps the cell actually split in animal and plant cells?
Animal: Contractile ring (which makes the cleavage furrow)
Plant: Golgi Vesicles and cell plates
Some organisms like _________ can regenerate amputated limbs via activation of _____ _______ to supply new cells in the growing limb
salamanders, cell division
How do hydras reproduce?
A mass of cells divide by mitosis to form a bud, which developers into a small hydra that detaches from the parent
What is asexual reproduction?
Reproduction from oneself
What is cancer often caused by?
A series of mutations in chromosomes DNA
Why do cancer cells reproduce uncontrollably?
Cancer cells do not respond normally to the cell cycle control system
What are telomeres? What are they used for?
Sequences of DNA capping off chromosome ends. They are essential for DNA replication, is the enzyme attaches to them.
What happens to telomeres as cells divide? What are the implications of this?
Telomeres get shorter each time a cell divides. Once they are short enough, the prevent cell division, which leads to senescence and possibly oncogenic transformation of cells
Learning how plants clone themselves via mitosis can enable plant breeders to _______ these plant propagation techniques
optimise
What did Thomas Hunt Morgan’s work with fruit flies uncover in relation to genetic diversity?
It showed recombination, and how genes on the same chromosome could recombine during meiosis to produce novel phenotypes
Describe Thomas Hunt Morgan’s work that allowed him to discover recombination
He noticed that certain traits were linked and always inherited together: Grey/Long vs Black/Short
Both these traits are carried on the X-chromosome. Since the fly inherits one whole chromosome from mother and father, one would expect that the traits are inherited together.
However, he noticed some flies with Grey/Short and Black/Long
What does sexual reproduction depend on?
Meiosis and fertilization
What is meiosis?
The process in which haploid gametes are created from diploid cells
Describe the human life cycle for the gametes.
- Meiosis occurs to produce haploid gametes
- Fertilisation combines the haploid paternal and maternal genomes to produce a diploid zygote
- The diploid zygote undergoes mitosis to produce identical diploid cells
