Chapter 8&9 Bio

Question 1

Purine

Answer 1

Adenine and Guanine.
They have DOUBLE carbon rings.

Question 2

Pyrimidine

Answer 2

Thymine and cytosine
They have SINGLE carbon rings.

Question 3

What 2 bases have 2 hydrogen bonds?

Answer 3

Adenine and thymine

Question 4

What 2 bases have 3 hydrogen bonds?

Answer 4

Guanine and cytosine

Question 5

Adenine will always pair with?

Answer 5

Thymine

Question 6

Guanine will always pair with?

Answer 6

Cytosine

Question 7

Topoisomerase function

Answer 7

This is the first step in DNA replication.
This enzyme untwists the double helix of DNA, relives the supercooling ahead of the helicase.

Question 8

DNA helicase function

Answer 8

This is the second step in DNA replication.
This enzyme breaks hydrogen bonds between the DNA strands.

Question 9

Primase function

Answer 9

This is the third step in DNA replication.
This enzyme makes primers.

Question 10

Primer function

Answer 10

This is the fourth step in DNA replication.
A primer is a single strand of DNA or RNA that’s complementary to a targeted sequence [DNA polymerase needs primers]
A primer serves to prime and lay a foundation for DNA synthesis.

Question 11

DNA polymerase function

Answer 11

This is the fifth step in DNA replication.
This enzyme joins free nucleotides into a new strand of DNA, synthesize DNA in the 5’—>3’ prime direction of the new DNA.
Carries out DNA replication. Uses a DNA template to assemble a complementary strand of DNA.

Question 12

What is the leading strand?

Answer 12

6) The new CONTINUOUS complementary DNA strand synthesized along the template in the 5’—>3’ direction, moving toward the replication fork.

Question 13

What is the lagging strand?

Answer 13

6) A DISCONTINUOUSLY synthesized DNA strand that is created in fragments/segments called Okazaki fragments. Runs in the 5’—>3’ direction AWAY from the replication fork.

Question 14

Okazaki fragments

Answer 14

6) Segments/fragments of the lagging strand.

Question 15

DNA ligase

Answer 15

7) This enzyme connects the sugar phosphate backbone of the okazaki fragments.

Question 16

What is the initial substrate of DNA replication?

Answer 16

DNA

Question 17

What is the final product of DNA replication

Answer 17

2 DNA

Question 18

Where in the cell does DNA replication occur?

Answer 18

Nucleus

Question 19

What is the initial substrate of transcription

Answer 19

DNA

Question 20

What is the final product of transcription?

Answer 20

MRNA

Question 21

Where in the cell does transcription occur?

Answer 21

Nucleus

Question 22

What is the function of RNA polymerase?

Answer 22

First step in transcription
Acts as a helicase, unwinding the DNA and also copies the DNA [carries out transcription] once it attaches to a promoter.

Question 23

What is the function of a promoter?

Answer 23

Second step in transcription
The promoter tells the RNA polymerase where to “sit down” on the DNA and begin transcribing.

Question 24

What is the third step in transcription?

Answer 24

RNA polymerase attaches to the start codon [after attaching to the promoter].

Question 25

What is the start codons nucleotide bases? What is the chemical name?

Answer 25

“AUG” Methionine

Question 26

Where is the start codon located?

Answer 26

MRNA

Question 27

What is the fourth step in transcription?

Answer 27

RNA polymerase reaches TERMINATION [which means it has finished making the copy of mRNA]

Question 28

What kind of nucleic acid is TERMINATION?

Answer 28

DNA nucleic acid Think of it like this, RNA polymerase is copying DNA off of a DNA strand to make mRNA. When RNA polymerase reaches the end [done copying off the DNA strand] it stops. It was copying off of a DNA strand, which means TERMINATION is a DNA nucleic acid.

Question 29

What is RNA processing? What is another name for RNA processing?

Answer 29

This is the fifth step in transcription Removing introns Keeping exons ALTERNATIVE SPLICING

Question 30

What is the sixth step in transcription?

Answer 30

1. A modified GUANINE nucleotide is added at the beginning of the mRNA as a “cap”. 2. Extra adenine [poly-A] nucleotides are added to the end of the mRNA strand, forming a “tail”.

Question 31

What is the eighth step in transcription?

Answer 31

After the mRNA has been matured, it can leave the nucleus through a nuclear pore and move on to TRANSLATION.

Question 32

Where in the cell does translation occur?

Answer 32

Ribosomes/cytoplasm

Question 33

What is the initial substrate for translation?

Answer 33

MRNA

Question 34

What is the final product of translation?

Answer 34

Protein

Question 35

What is the first step in translation?

Answer 35

mRNA binds to a ribosome.

Question 36

What happens in initiation in translation?

Answer 36

A tRNA show up with the anticodon [UAC] complementary to the start codon of mRNA [AUG, methionine] This is called INITIATION

Question 37

What is the second step in translation?

Answer 37

Elongation This is where the process repeats. A tRNA will come deliver amino acids/anticodons mRNA the codon, the amino acids will be linked by peptide bonds. Remember that it takes energy to create peptide bonds between amino acids.

Question 38

What kind of reaction would translation be?

Answer 38

Endergonic [positive change of G, not spontaneous].

Question 39

What is the final step in translation?

Answer 39

Termination. This means that tRNA as reached mRNAs STOP CODON which means end of translation. A tRNA does not have an anticodon complementary to the mRNAs stop codon.

Question 40

What kind of reaction would DNA replication be?

Answer 40

Endergonic [positive change of G, not spontaneous]

Question 41

What kind of reaction would transcription be?

Answer 41

Endergonic [positive change of G, not spontaneous]