Mitosis and Meiosis Flashcards
(29 cards)
What are the two main processes of cell division?
Mitosis and meiosis.
What occurs during the G1 phase of the cell cycle?
Cell growth and mRNA/protein synthesis before DNA replication.
What happens during the S phase of the cell cycle?
DNA replication occurs.
What occurs during the G2 phase of the cell cycle?
Cell growth and protein synthesis for mitosis.
What is the final stage of the cell cycle?
Cell division (M phase).
What is the restriction point in G1 phase?
A checkpoint to ensure the cell has received the signal to divide.
What checkpoints are present after G1 and G2 phases?
DNA damage checkpoints to ensure there are no errors.
What is the spindle assembly checkpoint?
A checkpoint during mitosis to ensure spindle fibres have formed.
How many chromosomes and DNA are present in the S phase?
46 chromosomes and 92 DNA as each chromosome consists of two sister chromatids.
What happens during prophase?
The nuclear envelope dissolves, chromosomes condense, and spindle fibres appear.
What occurs during prometaphase?
Kinetochore attaches to spindle fibres.
What happens during metaphase?
Chromosomes line up on the metaphase plate.
What occurs during anaphase?
Sister chromatids move to the poles.
What happens during telophase?
The nuclear envelope reforms, chromosomes decondense, and spindle fibres disappear.
What are the stages of prophase?
There are 5 stages in prophase where the synaptonemal complex forms and crossing over occurs.
What do centimorgans indicate?
Centimorgans show the frequency of recombination in an area of the chromosome.
What forms after crossing over at the chiasmata?
Recombinant chromosomes form after crossing over at the chiasmata, creating genetic diversity.
What does a spermatogonium produce in males?
A spermatogonium produces a primary spermatocyte which gives rise to 4 spermatids that form mature sperm.
What occurs during oogenesis?
An oogonium forms a primary oocyte, then polar bodies, then an ovum.
What is unique about the Y chromosome?
The Y chromosome is almost completely genetically inert apart from its male determining genes.
What happens to one X chromosome in females?
One X chromosome is silenced in females.
How do X and Y chromosomes find each other?
X and Y chromosomes find each other by using the PAR regions, which must crossover in meiosis.
What can occur due to non-disjunction?
An aneuploidy can occur due to non-disjunction.
What is a chromosome?
Made of a protein and a single molecule of DNA, contains the specific instructions that make each type of living creature unique
