Meiosis and Mitosis Flashcards
somatic cell?
any body cell that doesnt produce gametes
germ cell?
a diploid reproductive cell that gives rise to gamete
diploid
cell with 2 sets of chromosomes
haploid
cell with 1 set of chromosomes
Q: Define: Homologous chromosomes and non-homologous chromosomes
A:
Homologous chromosomes: A matching pair (same genes, different alleles) — one from each parent
Non-homologous chromosomes: Chromosomes that do not share gene content or structure
Q: What is the structural relationship between DNA, chromatids, and chromosomes?
A:
DNA wraps around proteins to form chromatin, which condenses into chromosomes
A chromosome consists of two sister chromatids joined at a centromere after replication
Q: What happens to chromosomes and alleles during mitosis?
A:
Each chromosome duplicates to form sister chromatids
During mitosis, chromatids separate so each daughter cell gets an identical set of alleles
Q: What happens to chromosomes and alleles during meiosis?
A:
In Meiosis I: Homologous chromosomes (with different alleles) separate
In Meiosis II: Sister chromatids separate
Final result: 4 haploid gametes, each with one allele per locus
Q: Why are mitosis and meiosis different processes?
A:
Mitosis: Growth and repair; identical diploid cells
Meiosis: Gamete formation; genetic diversity; haploid cells
Q: What happens in Prophase I of meiosis?
A:
Chromosomes condense
Homologous chromosomes pair up (synapsis)
Crossing over occurs between chromatids
Nuclear envelope breaks down
Spindle begins to form
Q: What happens in Metaphase I of meiosis?
A:
Homologous pairs (tetrads) align at the metaphase plate
Spindle fibers attach to centromeres
Independent assortment occurs
Q: What happens in Anaphase I of meiosis?
A:
Homologous chromosomes are pulled to opposite poles
Sister chromatids remain attached
Q: What happens in Telophase I and Cytokinesis?
A:
Nuclear envelope may reform
Chromosomes may decondense
Cell divides into 2 haploid cells
Q: What happens in Prophase II of meiosis?
A:
Chromosomes condense again in the two haploid cells
New spindle fibers form
Nuclear envelope dissolves (if reformed)
Q: What happens in Metaphase II of meiosis?
A:
Chromosomes align at the metaphase plate
Spindle fibers attach to centromeres of sister chromatids
Q: What happens in Anaphase II of meiosis?
A:
Sister chromatids finally separate and move to opposite poles
Q: What happens in Telophase II and Cytokinesis?
A:
Chromosomes decondense
Nuclear envelopes reform
Cells divide → 4 genetically unique haploid gametes
what is unique about meiosis?
hom chromosomes seperate instead sister chromatids, crossing over exchanging genetic info
