Topic D: Mitosis and Meiosis Flashcards
Every species has a characteristic number of _________ and ______________. The number of ____________describes the ploidy of chromosomes
Every species has a characteristic number of chromosomes and chromosome sets . The number of sets of chromosomes describes the ploidy of chromosomes
What are homologous chromosomes?
In a diploid (2n) cell, every chromosome has a homologue.
Homologous chromosomes have the same genes in the same order, but may have different alleles for a given gene.
Homologous chromosomes are highly _________, but not __________.
Homologous chromosomes are highly SIMILAR, but not IDENTICAL.
the same genes may be in the same order, but it may not be the same alleles! (Abc VS. ABc)
3 features used to differentiate chromosomes?
- size
- centromere position
- other features (like banding)
Bacteria reproduces asexually by
Binary fission, where the chromosome is fully replicated, and then the cell divides in two, allowing a bacterial to make an identical copy of itself.
Why do cells need to divide in multicellular eukaryotes?
Mitosis: replenishes old, damaged cells, repairs cells, and divides for growth. Cells must divide to make more copies of itself
Meiosis: to produce gametes/reproductive cells.
DNA replications always precedes ____ _______
cell division
DNA replication occurs in the ____ phase, before cell _________
DNA replication occurs in the S phase, before cell division
Cell division occurs in 3 different ways:
- Binary fission (bacteria)
- Mitosis
- Meiosis
While Mitosis occurs for Eukaryotes both _____ and ______, Meiosis occurs for Eukaryotes only _________
While Mitosis occurs for Eukaryotes both DIPLOID and HAPLOID, Meiosis occurs for Eukaryotes only DIPLOID
While mitosis is an _________ _______, Meiosis is a ___________ ___________.
While mitosis is an EQUATIONAL DIVISION Meiosis is a REDUCTION DIVISION.
DNA must be fully replicated before Mitosis or meiosis, this occurs during the :
Synthesis (S) phase
What occurs during the S phase?
- DNA content (C) is doubled (DNA is replicated)
- Ploidy remains unchanged
- chromosome number remains unchanged
Mitosis is an equational division, where …..
- ploidy does NOT change
- two daughter cells are produced that are identical
- both haploid and diploid cells can undergo mitosis
Meiosis is a reduction division, where….
- Ploidy is reduced from 2n to n
- 4 meiotic products are produced
- typically, only diploid cells can undergo meiosis
Cell division changes the _____ ______ in a diploid cell
DNA CONTENT
By the end of Meiosis DNA content is C= ___. DNA content is halved in meiosis 1 from C=____ to C=____. DNA content is halved once more in meiosis 2 from C=____ to C=____.
By the end of Meiosis DNA content is C= 1. DNA content is halved in meiosis 1 from C=4 to C=2. DNA content is halved once more in meiosis 2 from C=2 to C=1.
During Mitosis, a cell divides to produce;
two daughter cells with the same ploidy and chromosome number