2.7 DNA Replication, Transcription and Translation

Question 1

What does the replication of DNA depend on?

Answer 1

Complementary base pairing

Question 2

What does helicase do to DNA?

Answer 2

Helicase unwinds the double helix and separates the two strands

Question 3

How does helicase unwind the double helix?

Answer 3

By breaking hydrogen bonds

Question 4

What does DNA polymerase do?

Answer 4

Links nucleotides together to form a new strand, using the pre-existing strand as a template

Question 5

What is an Okazaki fragment?

Answer 5

DNA fragments that are formed on the lagging template strand during DNA replication

Question 6

What keeps an unwound DNA strand apart?

Answer 6

Single-strand binding proteins

Question 7

What are RNA primers?

Answer 7

Short segments of RNA (10 nucleotides long) formed by primase

Question 8

What is the purpose of RNA primers?

Answer 8

Must bind to DNA segments to begin replication

Question 9

What does primase do?

Answer 9

Primase forms the short segments of RNA needed by RNA primer

Question 10

In which directions do DNA strands grow?

Answer 10

5’ to 3’

Question 11

What does the 3’ end of DNA contain?

Answer 11

Hydroxyl

Question 12

What does the 5’ end of DNA contain?

Answer 12

Phosphate

Question 13

What binds to unzipped DNA?

Answer 13

Free nucleotides (Nucleoside triphosphates)

Question 14

What catalyzes the nucleotide binding process?

Answer 14

DNA Polymerase

Question 15

Where does DNA polymerase elongate?

Answer 15

The 3’ end

Question 16

What is DNA polymerase?

Answer 16

The catalyse of free nucleotides binding to DNA

Question 17

What are the two strands during DNA nucleotide-binding?

Answer 17

The leading strand and the lagging strand

Question 18

What is Polymerase Chain Reaction?

Answer 18

Produces large quantities of DNA

Question 19

What are the three steps of Polymerase Chain Reaction?

Answer 19

Occurs in a thermal cycler through:

Denaturation, annealing, and elongation

Question 20

What does mRNA do?

Answer 20

Takes a message from DNA in nucleus to ribosomes in cytoplasm

Question 21

What does rRNA do?

Answer 21

rRNA and proteins make up ribosomes where proteins are synthesized

Question 22

What does tRNA do?

Answer 22

tRNA transfers a particular amino acid to a ribosome

Question 23

What is transcription?

Answer 23

Transcription is the synthesis of mRNA copied from the DNA base sequences by RNA polymerase

Question 24

Where does transcription take place?

Answer 24

In the nucleus

Question 25

What are the steps of transcription? (1-3)

Answer 25

1. RNA polymerase attaches to a promoter on DNA 2. Transcription factor is needed for polymerase to bind to DNA 3. Complementary RNA nucleotides pair with DNA nucleotides of the strand

Question 26

What are the steps of transcription? (4-5)

Answer 26

4. RNA polymerase covalently bonds RNA nucleotides | 5. Terminator sequence causes RNA polymerase to stop transcribing DNA, and to release mRNA

Question 27

What do spliceosomes do?

Answer 27

Remove introns from DNA

Question 28

What is an exon?

Answer 28

The part of DNA that will be expressed

Question 29

What is a codon?

Answer 29

Three sequential bases on mRNA that correspond to one amino acid

Question 30

What is genetic code made of?

Answer 30

mRNA triplets(codons)

Question 31

How many codons are there?

Answer 31

64

Question 32

How many amino acids are there?

Answer 32

20

Question 33

How many start codons are there? Stop codons?

Answer 33

One start, three stop

Question 34

What is translation?

Answer 34

The synthesis of polypeptides on ribosomes

Question 35

Where does translation take place?

Answer 35

Takes place in cytoplasm

Question 36

What is a polypeptide?

Answer 36

A chain of amino acids

Question 37

What does translation depend on?

Answer 37

The complementary base pairing between codons on mRNA and anticodons on tRNA

Question 38

What is translated during translation?

Answer 38

Nucleic acids are translated to proteins

Question 39

What are the steps of translation?

Answer 39

1. Chain Initiation 2. Chain Elongation 3. Chain Termination

Question 40

What is Chain initiation?

Answer 40

1. A small ribosomal subunit attaches to mRNA start codon | 2. First tRNA pairs with this codon and large ribosome subunit attaches to smaller ribosome subunit

Question 41

What is required to bring together necessary components during translation?

Answer 41

Initiation proteins

Question 42

What is Chain Elongation?

Answer 42

1. New tRNA arrives at A site | 2. Amino acid at P site is attached by a peptide bond to the newly arrived amino acid

Question 43

What catalyzes Chain Elongation?

Answer 43

Larger ribosome's ribozyme

Question 44

What is translocation?

Answer 44

When tRNA moves from site A to P in translation

Question 45

What is Chain Termination?

Answer 45

1. Occurs at stop codon that does not code for amino acid | 2. Release factor protein binds to stop codon

Question 46

What are polyribosomes?

Answer 46

Clusters of several ribosomes synthesizing the same protein

Question 47

In what way is DNA replicated?

Answer 47

Semi-conservative

Question 48

What does conservative replication look like?

Answer 48

One old DNA, and one new DNA

Question 49

What does dispersive DNA look like?

Answer 49

Chunks of new and old DNA for each new strand