Flashcards
Meiosis and Genetic Variation
Cards in this deck (11)
- 1What is a: 1) gene? 2) locus? 3) allele?1) section of DNA that codes for a polypeptide
2) the position of a gene on a chromosome or DNA molecule
3) different forms of a particular gene - 2What does meiosis produce?Four daughter nuclei with half the genetic material (chromosomes) as the parent cell. Also known as haploid cells.
- 3When haploid cells fuse at fertilisation, what occurs?The diploid number of chromosomes is restored.
- 4How many nuclear divisions does meiosis have and when do they occur?Two nuclear divisions which normally occur one after the other.
- 5What happens during: 1) meiosis one? 2) meiosis two?1- The parent cell separates into two homologous chromosomes in different cells.
2- The chromatids move apart so four cells are formed. - 6In which two ways does meiosis bring about genetic variation between offspring?1- recombination of homologous chromosomes by crossing over
2- independent segregation of homologous chromosomes - 7Describe the independent segregation of chromosomes.Each chromosome lines up next to its homologous partner (randomly arranged. One chromatid from each chromosome then will pass into the daughter cell.
- 8What is the same in each member of a pair of homologous chromosomes?They have the exact same genes and therefore determine the same characteristics.
- 9How does variation occur in genetic combinations?The haploid gametes fuse in fertilisation to become the diploid state. Each gamete has a different genetic make up and the random fusion therefore produces variety in offspring.
- 10What happens in genetic recombination by crossing over?The chromatids of each pair become twisted round one another, tensions are created and portions of the chromatid breaks off, they rejoin with the chromatids of its homologous partner
- 11What is produced from crossing over?new genetic combinations
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- AS Biology2 (DNA and Meiosis) Flashcards on Meiosis and Genetic Variation, created by sammi_taylor01 on 29/05/2013.
- Created by
- sammi_taylor01 · May 2013
- Updated
- Feb 19, 2016
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