Genetics 1 : Mitosis/ Meiosis Flashcards
Differentiate between the processes of replication and reproduction : parent, contribution of genes and genetic variation of offspring
Asexual: one parent contributes all the genes- replication
Offspring: clones
Sexual: two parents contribute half their genes- reproduction
Offspring: vary genetically
Compare concepts of hereditary and variation
Hereditary : sameness and Variation : differences.
What is Gene loci
The location of the allele on the chromosome. On diploid organisms, the allele at is at the same location on the chromosome.
What is difference between replicated chromosome and normal chromosome
Replicated chromosomes consist or 2 sister chromatids-> two identical strands of DNA, looks Like X.
Normally each chromosome from the each parent is just one chromatid -> 1 strand of DNA
What is a karyotype
A visual representation of a species chromosomes arranged in pairs at mitotic metaphase
Compare asexual and sexual reproduction: parents, output,
Asexual: One parent which contributes all genes, producing clones.
Sexual: Two parents, contributes half of their genes, therefore producing genetic variation.
What are the phases of the cell cycle
Interphase: (90% of cell activity)
G1, S (replication of chromosomes), G2
Mitotic (M) phase: Mitosis (division of genetic material) Cytokinesis
Compare terms Haploid vs Diploid. What are humans and therefore what is n.
Haploid is a single set of chromosomes (n)
Diploid is where the autosome is represented twice (1 from mum and 1 from dad) = 2n
Humans n= 23
What is Independent assortment - when and how much variation
At metaphase 1 of meiosis, homologous pairs align in a random orientation on the metaphase plate. Therefore each maternal and paternal homologue assorts independently of each other pair.
Number of possible gametes = 2^n
What is Crossing over - when and frequency
At Prophase 1 non sister chromatids exchange of genetic material, producing recombinant chromosomes.
This shuffles genes within the chromosome.
Frequency: This is obligative and happens 1-3x per chromosome pair.
What is a chiasma
The point of crossing over of non sister chromatids where they break and exchange parts.
How does random fertlisation increase genetic variation
The random nature of fertilization adds to genetic variation.
This is because each gamete already has 8 million possible combinations and this is combined with another gamete will produce 64 trillion possible diploid combinations.
What are the 3 ways sexual reproduction produces variation
Crossing over, independent assortment and random fertilisation
