DNA and Chromosomes

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Flashcards by , created about 6 years ago

AS Biology2 (DNA and Meiosis) Flashcards on DNA and Chromosomes, created by sammi_taylor01 on 05/29/2013.

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Created by sammi_taylor01 about 6 years ago
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Question Answer
What is the DNA like in prokaryotic cells, such as bacteria? -much smaller -forms circles -do not associate with protein molecules -do not have chromosomes
What is the DNA like in eukaryotic cells? -associates with proteins -has chromosomes -molecules are larger and linear
What are the two assets of a chromosome? -two chromatids -one centromere in the centre holding the chromosome together
When are chromosomes visible? When cells are dividing (prophase)
How is the DNA in the chromosomes held in position? proteins
How is the length of the DNA found? Highly coiled and folded.
How many chromosomes do humans have? 46
Chromosomes occur in pairs called.. homologous pairs.
Homologous chromosomes are made up of.. one chromatid from the mother and one from the father, it is diploid.
A homologous pair is always.. two chromosomes that determine the same genetic characteristics, however determining the same characteristics is not the same as being identical.
What is an allele? variation of a gene
What does each allele code for? It's own polypeptide
What happens as a consequent of a difference in the base sequence of an allele of a single gene occurs? May result in a different sequence of amino acids being coded for, therefore different polypeptides- different primary therefore tertiary structure, substrate may not fit enzyme's active site etc.