Deck 7

Question 1

Semi Conservative

Answer 1

Half old DNA
Half new DNA

Question 2

Where do new nucleotides go in DNA

Answer 2

Add to the 3’ end with the free OH

Question 3

Where does the energy come from for replication

Answer 3

The breakdown of the triphosphate on the deoxyribonucleoside

Question 4

Sliding DNA

Answer 4

Protein that encircles DNA and sits in the back of the dna polymerase

• tethers DNA polymerase to the strand to make it more efficient
• without it, enzyme will detach after a couple dozen polymerization

Question 5

DNA polymerase

Answer 5

Used in DNA replication
Enzyme that moves from 5’ to 3’ direction

Question 6

Origin of replication

Answer 6

Where the unwise occurs
- proteins bind to the ori and promote binding of DNA helicase

Question 7

What unwinds the DNA

Answer 7

Helicase that bonds to the proteins on the ori

Question 8

Topoisomerase

Answer 8

Prevents twisting of DNA during replication
- cuts DNA ahead of replication fork and turns one side opposite to twisting force and reattaches sides

Question 9

Leading strand

Answer 9

Strand replicated continuously
5’ to 3’ direction

Question 10

Lagging strand

Answer 10

Strand replicated discontinuously
3’ to 5’ direction

Question 11

Okazaki fragments

Answer 11

short segments of replicated DNA in lagging strand

Question 12

DNA ligase

Answer 12

Covalently bonds neighbouring nucleotides of Okazaki fragments

Question 13

RNA primer

Answer 13

Synthesized by RNA primase
- acts as starting point for DNA polymerase to synthesize new dna strands

Question 14

Gene

Answer 14

Discrete unit of hereditary information consisting of specific sequences of nucleotides in DNA

Question 15

Gene expression

Answer 15

Process by which DNA directs the synthesis of products

Question 16

Transcription

Answer 16

Occurs in the nucleus
RNA polymerase creates mRNA to be transferred for protein synthesis

Question 17

Promoter

Answer 17

Specific start point

Question 18

Terminator

Answer 18

Stop point

Question 19

Types of RNA

Answer 19

mRNA- messenger RNA

rRNA- ribosomal RNA

tRNA- transport RNA

Question 20

How is mRNA built

Answer 20

RNA polymerase begins at promoter and creates the complimentary nucleotide sequence based on DNA template
- stops at terminator and detaches

Question 21

What is added to the mRNA before leaving the nucleus

Answer 21

5’ modified g cap

Poly A tail

Question 22

What is a 5’ modified G Cap

Answer 22

5’ to 5’

Protects mRNA from degrarion from cytoplasmic enzymes
- helps ribosomes to bind
- orientates upstream/downstream UTR

Question 23

What is a poly a tail

Answer 23

Repeated adenine bases that prevent degradation and aid in the export from nucleus

Question 24

Pre mRNA

Answer 24

mRNA that is made of both introns and exons before splicing

Question 25

mRNA splicing

Answer 25

Occurs in the spliceosome where introns are cut out and only exons are left

Question 26

What is a spliceosome

Answer 26

Complex formed between pre mRNA and a handful of small ribonucleoprotein particles

Question 27

Alternative splicing

Answer 27

Removal of different sections of introns to produce different sequences and thus different proteins without increasing the size of the genome

Question 28

Exon shuffling

Answer 28

Existing protein regions for domains are mixed into novel combinations to create new proteins

Question 29

Translation

Answer 29

Assembly of amino acids into polypeptides on ribosomes

Question 30

Orientation of polypeptide during translation

Answer 30

From N-terminus to C- terminus because the codons are read from 5’ to 3’ end

Question 31

tRNA

Answer 31

Transfer RNA Being amino acids to the ribosomes for addition to the polypeptide chain

Question 32

Anticodon

Answer 32

At the tip of the tRNA, three nucleotide sequence that has pairs with the codon in mRNA

Question 33

Aminoscylation(charging)

Answer 33

Process of adding an acid to tRNA Finished product is called aminoacyl-tRNA

Question 34

Ribosome

Answer 34

Made of two parts- small subunit and the large subunit Contains APE sites

Question 35

APE sites

Answer 35

A- where the charged tRNA is added P- where the tRNA carrying the growing polypeptide is bound E site- where the exiting tRNA binds as it leaves the ribosome

Question 36

3 steps to translation

Answer 36

Initiation Elongation Termination

Question 37

Initiation

Answer 37

Starts at AUG codon then begins reading subsequent codons

Question 38

Peptidyl- tRNA

Answer 38

A tRNA linked to a growing polypeptide chain containing 2 or more AA - binds only to P site - one exception is the initiator tRNA

Question 39

Initiator tRNA

Answer 39

First tRNA with the anticodon for AUG that carries a methionine

Question 40

Peptidyl Tranferase

Answer 40

Catalyzes the reaction between the peptide bonds in P site and A site

Question 41

Termination

Answer 41

Stop codon arrives in the A site - release factor binds to the A site and causes the ribosome to disassemble into its subunits

Question 42

Polysome

Answer 42

Multiple ribosomes synthesizes polypeptides from the same mRNA strand

Question 43

GTP

Answer 43

Gaunasine triphosphate It’s hydrolysis powers translation