DNA, genes and chromosomes

Question 1

how is DNA stored in eukaryotic vs prokaryotic

Answer 1

eukaryotic - long, linear, associated with proteins called histones, tightly coiled into chromosomes

prokaryotic - short, circular, not associated with proteins

Question 2

what is the DNA in mitochondria and chloroplasts like

Answer 2

short, circular, not associated with proteins

Question 3

what is a gene

Answer 3

sequence of DNA bases that codes for an amino acid sequence of a polypeptide or a functional RNA and tRNA
a gene occupies a fixed position called a locus in a particular DNA molecule

Question 4

what is the nature of the genetic code

Answer 4

sequence of DNA triplets codes for sequence of amino acids

it is
- universal: the same specific DNA triplets code for the same amino acids in all living organism
- non overlapping: discrete, each base can only be used once and in only one triplet
- degenerate: the same amino acid can be coded for by more than one base triplet

Question 5

what does a lot of DNA in eukaryotes not code for polypeptides

Answer 5

between genes there are non coding multiple repeats
within genes only exons code for amino acids which are separated by one or more no coding sequences called introns