DNA and the genetic code W3

Question 1

DNA is a polymer of

Answer 1

nucleotides

Question 2

each nucleotide that composes DNA has three components:

Answer 2

phosphate sugar base

Question 3

what are the four bases

Answer 3

A C T G

Question 4

what the name of the sugar in DNA

Answer 4

doxyribose

Question 5

what are the two purine bases

Answer 5

A - adenine G - guanine

Question 6

what are the two pyrimidine bases

Answer 6

C - cytosine T - thymine

Question 7

each polynucleotide strand has a direction, explain

Answer 7

5’ prime end (top) 3’ prime end (bottom)

Question 8

what is the DNA base sequence

Answer 8

5’ ACTG 3’

Question 9

structure o f bases and double helix only allows pairing of…. and …. and ….. and ….

Answer 9

A:T C:G

Question 10

what bonds are present in A:T

Answer 10

2H-bonds

Question 11

what bonds are present in C:G

Answer 11

3H-bonds

Question 12

base pairings only possible if the DNA strands run….

Answer 12

antiparallel

Question 13

3 base pairing rules

Answer 13

1. automated and self directed 2. reversible 3.is exact

Question 14

how is DNA (genetic information) replicated

Answer 14

one strand can act as template and through base pairing another ‘complementary strand can be made this requires the involvement of DNA polymerase

Question 15

what are genes

Answer 15

the sections of DNA that encode specific functional gene products

Question 16

what are exons

Answer 16

stretches of DNA that code for amino acid sequences

Question 17

what are introns

Answer 17

parts of DNA that dont code for amino acid sequences

Question 18

what is a codon

Answer 18

a series of three nucleotides which code fro a specific amino acid

Question 19

what is the start codon

Answer 19

ATG

Question 20

what are the stop codons (3)

Answer 20

TAG

TGA

TAA

Question 21

what do muttions in proteins arise from

Answer 21

changes in DNA sequence

Question 22

types of changes in DNA sequence (base mutations) (4)

Answer 22

mid-sense substitution

silent substitution

missense deletion

nonsense insertion

Question 23

explain mis-sense substitution

Answer 23

one of the bases in a protein is changed to a different one, resulting in the formation of a completely different amino acid. no subsequent codons are affected.

Question 24

explain silent substitution

Answer 24

a base in a codon is replaced with a different base, but this results in no change to the amino acid produced. subsequent codons are not affected.

Question 25

explain missense deletion

Answer 25

a base in a codon is deleted, resulting a change in all subsequent codons but only a change in the amino acid produced from that codon

Question 26

explain nonsense insertion

Answer 26

a base is inserted into a codon sequence, resulting in a change of all subsequent codons, and therfore all subsequent amino acids produced

Question 27

base mutations can potentially change ….

Answer 27

protein structure and function