GI: DNA, Genes and Chromosomes

Question 1

What type of DNA do eukaryotic cells contain?

Answer 1

Long, linear DNA molecules that exist as chromosomes, wound around proteins called histones.

DNA and histone is coiled very tightly to make a compact chromosome.

Question 2

Within eukaryotic cells, what else have their own DNA?

What is this similar to?

Answer 2

Mitochondria and chloroplasts.

Similar to prokaryotic DNA - circular and shorter than molecules in nucleus. Not associated with histones.

Question 3

What is DNA wound around in eukaryotic cells?

What does this do?

Answer 3

Histones.

Histone proteins helo support the DNA.

Question 4

Describe DNA within prokaryotes:

Answer 4

DNA as single circular strand.

Molecules are shorter than eukaryotes and circular.

Not wound around histones - condenses to fit in cell by supercoiling.

Question 5

How does prokaryotic DNA fit into the cell:

Answer 5

By supercoiling

Question 6

Gene

Answer 6

Sequence of DNA bases that codes for either a polypeptide or functional RNA.

Question 7

Genome

Answer 7

Complete set of genes in the cell.

Question 8

Proteome

Answer 8

Full range of proteins that the cell is able to produce.

Question 9

Sequence of DNA bases that codes for either a polypeptide or functional RNA.

Answer 9

Gene

Question 10

Complete set of genes in the cell.

Answer 10

Genome

Question 11

Full range of proteins that the cell is able to produce.

Answer 11

Proteome

Question 12

What forms the primary sturcture of a protein?

Answer 12

The sequence of amino acids in a polypeptide.

Question 13

What determines the order of amino acids in a polypeptide?

Answer 13

The order of bases in a gene.

Question 14

What is each amino acid coded by?

Answer 14

Sequence of three bases in a gene called a triplet.

Question 15

If genes don’t code for a polypeptide, what do they code for instead?

Answer 15

A functional RNA

Question 16

Functional RNA

Answer 16

RNA molecules other than mRNA, which perform special tasks during protein synthesis, eg. tRNA and ribosmal rRNA.

Question 17

RNA molecules other than mRNA, which perform special tasks during protein synthesis, eg. tRNA and ribosmal rRNA.

Answer 17

Functional RNA

Question 18

Does most DNA in eukaryotic cells code for polypeptides of functional RNA?

Answer 18

Functional RNA

Question 19

Introns

Answer 19

Sections of DNA that don’t code for amino acids.

Question 20

Exons

Answer 20

Sections of DNA that do code for amino acids.

Question 21

Sections of DNA that don’t code for amino acids.

Answer 21

Introns

Question 22

Sections of DNA that do code for amino acids.

Answer 22

Exons

Question 23

Does prokaryotic DNA have introns?

Answer 23

No

Question 24

What happens to introns in DNA?

Answer 24

They are removed during protein synthesis - so don’t affect amino acid order.

Question 25

Do introns affect amino acid order?

Answer 25

No as they are removed during protein synthesis.

Question 26

Apart from introns and exons, what else does eukaryotic DNA also contain?

Answer 26

Multiple repeats that are outside of genes - don't determine amino acid sequence.

Question 27

What are multiple repeats?

Answer 27

DNA sequences that repeat over and over. Don't code for amino acids and so are non-coding repeats.

Question 28

Allele

Answer 28

Alternate form of a gene.

Question 29

What differs between alleles of the same gene?

Answer 29

The order of bases is slightly different, so they code for slightly different versions of the same polypeptide.

Question 30

Homologous pairs

Answer 30

Pairs of matching chromosomes