3.8-3.9 nucleic acids and DNA

Question 1

What is a codon/ triplet code?

Answer 1

3 bases that code for an amino acid

Question 2

How many combos of bases are there?

Answer 2

64

Question 3

What is a degenerate code?

Answer 3

When there is more than one codon for an amino acid

Question 4

What is an advantage of a degenerate code?

Answer 4

If a mutation were to occur it wouldn’t affect the amino acids that have more than one codon

Question 5

What is a gene?

Answer 5

A section of DNA that codes for a polypeptide or length of RNA

Question 6

what is an advantage of the triplet code?

Answer 6

it is universal

Question 7

what is the nature of the genetic code?

Answer 7

nearly universal
degenerate
non-overlapping

Question 8

what is semi-conservative replication?

Answer 8

when new DNA is formed one new strand is made and one old strand is conserved

Question 9

what is the role of DNA polymerase?

Answer 9

catalyses the addition of free nucleotides by reading the template strand and bringing the free nucleotide.

builds a new strand from the 5’ to 3’ end but moves along the template strand from the 3’ to 5’ end (strands run anti-parallel)

Question 10

what end does the leading strand start from?

Answer 10

the 3’ end

Question 11

what end does the lagging strand start from?

Answer 11

the 5’ end

Question 12

what is the role of helicase in DNA replication?

Answer 12

unzips the DNA by breaking the hydrogen bonds

Question 13

how does the DNA strand stay apart in DNA replication?

Answer 13

using single-stranded binding proteins

Question 14

what is the role of topoisomerase?

Answer 14

prevents the DNA from supercoiling

Question 15

what is the role of primase?

Answer 15

adds RNA primers to the 3’ end to show DNA polymerase where ro start working

Question 16

What are okazaki fragments?

Answer 16

on the lagging strand primate and DNA polymerase have to constantly rush to the 3’ end as this strand unzips 5’ to 3’. this creates fragments known as okazaki fragments

Question 17

what is the role of ligase?

Answer 17

seals the gaps between okazaki fragments

Question 18

what strand undergoes continuous replication?

Answer 18

the leading strand

Question 19

what strand undergoes discontinuous replication ?

Answer 19

the lagging strand

Question 20

what does the continuous chain of pentose sugars and phosphates make?

Answer 20

sugar-phosphate backbone with phosphodiester bonds

Question 21

what are nucleotides?

Answer 21

the building blocks for DNA containing a phosphate group (PO4 2- ), a pentose sugar and a nitrogenous base

Question 22

what are the two types of bases?

Answer 22

purine and pyramidine

Question 23

compare purine and pyramidine bases

Answer 23

purine:
-has a double ring of carbon and nitrogen
-Adenine and Guanine
pyramidine:
-has a single ring of carbon and nitrogen
-thymine/Uracil and cystonine

Question 24

what is complementary base pairing?

Answer 24

a purine base will always pair with a pyramidine base.
A+T= 2 hydrogen bonds
C+G= 3 hydrogen bonds

Question 25

compare DNA and RNA

Answer 25

-DNA has thymine whereas RNA has uracil -DNA has hydrogen bonds and RNA doesnt -DNA has complementary base pairing, RNA doesn't -both have phosphodiester bonds -both formed by a condensation reaction -both have guanine, adenine and cystonine

Question 26

how many hydrogen bonds do A+T form ?

Answer 26

2

Question 27

how many hydrogen bonds does C+G form?

Answer 27

3

Question 28

describe the process of DNA extraction

Answer 28

1. grind the sample with a motor and pestle to break down the cell walls 2. mix the sample with detergent to break down the cell membrane and nuclear envelope 3. add salt to break the hydrogen bonds between DNA 4. add protease to break down any proteins 5. add alcohol to precipitate DNA out of the solution 6. spool it out