Chapter 6- Nucleic Acid

Question 1

What are the names of the monomers that form DNA

Answer 1

Nucleotides

Question 2

Nucleotides are made up of 3 smaller components:

Answer 2

-A phosphate head
-Nitrogenous base
-A pentose sugar

Question 3

what’s the difference between deoxyribose and ribose

Answer 3

Deoxyribose is short one oxygen

Question 4

state the bases found in DNA and RNA

Answer 4

DNA- adenine , thymine, guanine, cytosine
RNA-adenine, uracil, guanine, cytosine

Question 5

what is the structure of ATP made up of

Answer 5

-3 phosphate groups
-a ribose
-Adenine

Question 6

Describe the structure of DNA

Answer 6

• made up of 2 polynucleotide strands with a double helix
• contains complementary bases
• The chains run in opposite directions (antiparallel) 5’-3’ and vice versa
• the complementary bases have hydrogen bonds
• Phosphodiester bonds that form between the sugarn and phosphate to form the backbone of nucleic acids

Question 7

How many hydrogen bonds are between A-T and G-C

Answer 7

A-T= 2
G-C=3

Question 8

What’s the difference between purines and pyrimidine

Answer 8

Purine- 2 ringed structures (A & G)
Pyrimidine- 1 ringed structure (T&C)

Question 9

How many phosphate groups does ADP, AMP and ATP have

Answer 9

AMP- 1
ADP- 2
ATP- 3

Question 10

How does ATP release energy

Answer 10

This occurs when one phosphate group is broken down through hydrolysis. energy is released and ATP becomes ADP

Question 11

What are the 2 key abilities of DNA

Answer 11

-the ability to accurately replicate
-the ability to store information through their bases

Question 12

which bonds form the sugar phosphate backbone

Answer 12

phosphodiester bonds

Question 13

Which enzymes are involved in DNA replication

Answer 13

-DNA polymerase
-DNA- helicase
-DNA ligase

Question 14

The break down of hydrogen bonds is carried by the enzyme

Answer 14

DNA helicase

Question 15

What is the function of the DNA polymerase

Answer 15

it joins and aligns the free nucleotides to each other by phosphodiester bonds

Question 16

what are the lagging and leading strands

Answer 16

Leading- when its 3’-5’, the strand copied runs in the same direction as the helicase enzyme
Lagging- 5’-3’, strand runs the opposite direction as the helicase enzyme

Question 17

what results to Okazaki fragments

Answer 17

• the discontinuous copying of the DNA strand by DNA polymerase which leads to fragments left out

Question 18

what is the role of DNA ligase

Answer 18

Helps to join Okazaki fragments to form proper phosphodiester bonds

Question 19

What is semi conservative replication

Answer 19

This is when the DNA molecule is copied to form 2 identical molecules with one new strand forming and the original strand joining

Question 20

what are the 3 types of RNA

Answer 20

mRNA
tRNA
rRNA

Question 21

mention any three differences between the structure of RNA and DNA

Answer 21

RNA
»short and is a single strand
»do not have the base thymine but instead uracil
»contains the pentose sugar ribose and not deoxyribose

Question 22

what is a gene

Answer 22

a sequence of nucleotides that forms part of DNA That codes for a specific amino acid that in turn, creates a polypeptide chain

Question 23

what is a codon

Answer 23

This a triplet base e.g ACG

Question 24

What are the features of the genetic code

Answer 24

> triplet code
> it is universal
> code has punctuations
>it is degenerate

Question 25

what does it mean when the genetic code is universal

Answer 25

-Almost all living organisms have the same codon code meaning that genes are transferable

Question 26

what does it mean when the genetic code is degenerate

Answer 26

Multiple codons can code for the same type of amino acid

Question 27

Protein synthesis occurs in 2 main processes:

Answer 27

-Transcription -Translation

Question 28

what are the 8 key terms when describing protein synthesis

Answer 28

>mRNA >>tRNA >>Anti codon >>codon >>ribosome >>amino acid >> peptide bond >>polypeptide

Question 29

what is transcription

Answer 29

It is the copying of the information of the DNA into mRNA in the nucleus

Question 30

describe the steps taken for transcription

Answer 30

1-In the nucleus, the enzyme helicase breaks down the hydrogen bonds between the 2 DNA strands 2-RNA polymerase attaches to the beginning of the gene. one strand will act as a template (transcribed strand) 3-Free RNA nucleotides line up against their complementary bases with the help of RNA polymerase 4- once a STOP codon arrives transcription is completed. the strand of RNA is released by polymerase which goes to the ribosomes

Question 31

what is RNA splicing

Answer 31

When the non coding sections (introns) of RNA are removed to join the coding sections(exons)

Question 32

What is an anticodon

Answer 32

A triplet of unpaired bases in the tRNA

Question 33

Describe Translation

Answer 33

1-RNA splicing occurs 2-mRNA attaches to the ribosomes in the cytoplasm. 3- Each tRNA has the complementary anticodon to the codon in the mRNA 4-The first tRNA forms a hydrogen bond to the START codon and the next anticodon forms another hydrogen bond. This results into a peptide bond forming 5-the ribosome moves in the 5'-3' direction and translates the next codon 6-This continues until a polypeptide chain forms. Once a STOP codon reaches then the chain is complete

Question 34

what is a gene mutation

Answer 34

The random change in the base sequence within the gene

Question 35

Describe substitution in mutation

Answer 35

This occurs when a random base in the sequence is replaced with another different nitrogenous base it can take 3 forms: - silent substitution- the mutation does not alter the amino acid sequence - Missense substitution- the mutation alters one amino acid. - Nonsense substitution- This is a mutation that involves substituting a STOP codon resulting in the polypeptide being incomplete

Question 36

what is insertion and deletion mutation

Answer 36

when one of the nucleotides is permanently removed from the DNA strand or one of the nucleotide is added to the DNA strand

Question 37

what is a frameshift

Answer 37

This a complete change in the base sequence