DNA, genes and chromosomes

Question 1

DNA in prokaryotes?

Answer 1

DNA in prokaryotes is short, circular, and not associated with histones

Question 2

How does prokaryote DNA fit in a cell?

Answer 2

• Condesnses to fit in a cell by supercoiling

- the DNA isn’t wound around histones

Question 3

DNA in eukaryotes?

Answer 3

• DNA is wound around proteins called histones
• DNA and protein coils to form a chromosome
• DNA molecule is long, linear and associated with histones

Question 4

DNA in mitochondria and chloroplast?

Answer 4

The mitochondria and chloroplasts of eukaryotic cells also contain DNA which, like the DNA of prokaryotes, is short, circular, and not associated with proteins

Question 5

What is a gene?

Answer 5

A gene is a section of DNA that codes for the amino acid sequence of a polypeptide and functional RNA ( tRNA and ribosomal RNA)

Question 6

What is the locus?

Answer 6

a fixed position that a gene occupies on a DNA molecule

Question 7

What codes for an amino acid?

Answer 7

A sequence of three DNA bases, called a triplet, codes for a specific amino acid.

Question 8

3 features of the genetic code?

Answer 8

1. degenerate
2. non-overlapping
3. universal

Question 9

What does degenerate mean?

Answer 9

• Some amino acids are coded for by more than one base triplet

Question 10

What does non-overlapping mean?

Answer 10

• each base is read only once

Question 11

What does universal mean?

Answer 11

• the same specific base triplets code for the same amino acids in all living things

Question 12

What is non-coding DNA called?

Answer 12

intron

doesn’t code for an amino acid

Question 13

What are the sections of DNA that code for an amino acid called?

Answer 13

exons

Question 14

What is an intron?

Answer 14

section of DNA which doesn’t code for an amino acid

Question 15

What is an exon?

Answer 15

section of DNA that codes for an amino acid

Question 16

Do prokaryotes contain introns?

Answer 16

NO!!!!