Meiosis and genetic variation

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  • Created by: lozzac
  • Created on: 02-02-15 10:00
What is the structure of a nucleotide?
Phosphate, Deoxyribose sugar, base (with nitrogen)
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What are the complementary base pairs and how are the linked?
A=T with 2 hydrogen bonds and C≡G with 3 hydrogen bonds
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What are the adaptations of DNA?
Stable (can pass without change), H Bonds (allows separation during DNA replication), large (holds increased amounts of genetic information), base pairs are complementary (protected from corruption), Double helix (sugar phosphate backbone)
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What is a triplet code?
3 bases that code for an amino acid (gene= amino acids= polypeptide)
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What is a gene?
A section of DNA that codes for a polypeptide
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What is a locus?
Portion of a gene on a chromosome or DNA molecule
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What is an allele?
One of the different forms of a particular gene
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What is the structure of a chromosome?
Chromatid (single thread) and centromere
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What is the difference in DNA between a prokaryotic and eukaryotic cell?
Prokaryotic= smaller, forms circle, no proteins= no chromosomes Eukaryotic= larger, forms line, proteins form chromosomes
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How is DNA packed into a chromosome?
DNA molecule > Combined with proteins (histones) > DNA- protein complex coiled > coils fold to form loops > loops coil and pack together to form chromosome
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What is Meiosis and why is it important?
The production of 4 unique haploid daughter cells. It maintains a constant number of chromosomes and causes variation
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Give a summary of meiosis.
parent cell= homologous chromosomes > homologous chromosomes separated into separate cells > chromatids separated by further cell division
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What is independent segregation?
when homologous chromosomes line up randomly. The chromosomes in daughter cells are random
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What is the process of crossing over?
chromatids of homologous chromosomes twist around each other > broken off portions of chromatids recombine with another chromatid (recombination)
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Describe genetic variation as a result of recombination by crossing over.
parent cells= homologous chromosomes after cross over/recombination > homologous chromosomes separated into separate cells > further cell division= 4 daughter cells with different genetic composition
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Other cards in this set

Card 2

Front

What are the complementary base pairs and how are the linked?

Back

A=T with 2 hydrogen bonds and C≡G with 3 hydrogen bonds

Card 3

Front

What are the adaptations of DNA?

Back

Preview of the front of card 3

Card 4

Front

What is a triplet code?

Back

Preview of the front of card 4

Card 5

Front

What is a gene?

Back

Preview of the front of card 5
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