Midterm 2 - Chapter 8

Question 1

Lagging strand

Answer 1

the end with the hydroxyl attached to 3 prime carbon

Question 2

Leading strand

Answer 2

The end with the phosphate attached to 5 prime carbon.

Question 3

DNA strands are always synthesized from:

Answer 3

five prime to 3 prime

Question 4

Gene

Answer 4

Segments of DNA that code for a functional products. Products are usually mRNA.

Question 5

mRNA

Answer 5

Carries coded information for for making proteins from DNA to ribosomes, where proteins are synthesized.

Question 6

transcription

Answer 6

The synthesis of a complementary RNA from a DNA template. A transfer of genetic info.

Question 7

What does RNA use instead of thymine?

Answer 7

Uracil.

Question 8

Transcription in prokaryotes takes place in the:

Answer 8

Cytoplasm.

Question 9

RNA splicing:

Answer 9

SnRNPs remove interons and splice the exons together

Question 10

What is the start codone?

Answer 10

AUG

Question 11

What are the stop codons?

Answer 11

UAA, UGA and UAG

Question 12

In bacteria, AUG forms:

Answer 12

formylmethionine

Question 13

DNA Gyrase

Answer 13

relaxes supercoiling ahead of replication fork.

Question 14

DNA Ligase

Answer 14

Makes covalent bonds to join DNA strands, Okazaki fragments and new segments in excision repair.

Question 15

DNA polymerase

Answer 15

Synthesizes DNA and proofreads and repairs DNA

Question 16

Helicase

Answer 16

Unwinds double stranded DNA

Question 17

RNA polymerase

Answer 17

Copies RNA from a DNA template

Question 18

1st step of DNA replication:

Answer 18

DNA helicase unwinds the parental double helix.

Question 19

2nd step of DNA replication:

Answer 19

DNA gurase stabilizes the DNA and prevents recoiling.

Question 20

3rd step in DNA replication:

Answer 20

The leading strand is synthesized continuously by DNA polymerase. DNA polymerase also proofreads strand.

Question 21

4th step in DNA replication:

Answer 21

the lagging strand is synthesized discontinuously. An RNA polymerase synthesizes a short RNA primer, which is then extended by DNA polymerase.

Question 22

5th step in DNA replication:

Answer 22

DNA polymerase adds new nucleotides and eats the RNA primer to replace it with DNA (exonuclease activity).

Question 23

6th step in DNA replication:

Answer 23

Gaps will be left so DNA ligase joins by covalent bonds.

Question 24

How many different combinations of codons is there?

Answer 24

64

Question 25

Degeneracy of genetic code means?

Answer 25

There is more than 1 codon per amino acid.

Question 26

Why is RNA always one stranded?

Answer 26

Because the other strand would be useless.