DNA and Chromosomes

Question 1

What are the key differences between DNA in prokaryotic cells and the DNA in eukaryotic cells?

Answer 1

-PROKARYOTIC CELLS-
=DNA molecules are shorter
-DNA molecules are circular
-DNA molecules are not associated with protein molecules

-EUKARYOTIC CELLS-
-DNA molecules are longer
-DNA molecules are linear
-DNA molecules are associated with proteins called ‘histones’ to form structures called chromosomes

Question 2

What is the structure of the chromosome?

Answer 2

-Made up of two chromatids
-Held together by a central ‘centromere’
-Chromatids are highly coiled polypeptides

Question 3

What is a locus?

Answer 3

The physical location of a gene on a chromosome.

Question 4

What is the nature of homologous chromosomes?

Answer 4

Homologous pairs refers to the combining of maternal and paternal chromosomes. They carry the same genes, but not necessarily the same alleles for those genes.

Question 5

What is an allele?

Answer 5

An allele is one of a number of alternative forms of a gene.