DNA and Chromosomes

Question 1

whats a gene

Answer 1

a short section of DNA that codes for a polypeptide and functional RNA

Question 2

whats the locus

Answer 2

the location of a particular gene on a chromosome

Question 3

whats an allele

Answer 3

alternative forms of a gene

Question 4

whats a chromosome

Answer 4

what DNA is stored as in a cell nucleus

Question 5

how many chromosomes do human have

Answer 5

23 pairs of chromosomes = 46 in total

Question 6

what are homologous pairs

Answer 6

pairs of matching chromosomes
- same size and same genes BUT could have different alleles

Question 7

how is DNA stored as a chromosome in a eukaryotic cell

Answer 7

• the chromatids are tightly coiled strands of DNA
• the DNA is wrapped around a histone (a protein)

Question 8

what is a nucleosome

Answer 8

the structure of DNA being tightly wrapped around a histone

Question 9

how is DNA stored in a prokaryotic cell

Answer 9

• DNA in chromosomes
• shorter and circular structure
• chromosomes supercoil to fit inside of the cell

Question 10

whats the difference between the way DNA is stored as chromosomes in a eukaryotic and prokaryotic cell

Answer 10

eukaryote:
- chromosomes are longer and tightly coiled around a protein called histones - this is called a nucleosome
prokaryote:
- shorter and circular DNA
- chromosomes arent coiled around histone protein
- chromosome supercoils to fit inside of the cell

Question 11

in what way is the DNA found in the mitochondria and chloroplast, similar to the prokaryote DNA

Answer 11

• shorter and circular
• not coiled around a histone