Topic 2 - Nucleotides and nucleic acid

Question 1

DNA and RNA are both (1)

Answer 1

1 - polynucleotides

Question 2

What is the basic structure of a nucleotide

Answer 2

Phosphate group (circle) bonded to pentose sugar (pentagon) bonded to organic base (rectangle)

Question 3

DNA vs RNA
Number of strands

Answer 3

DNA - two antiparallel strands
RNA - one strand

Question 4

DNA vs RNA
Length

Answer 4

DNA - Very long
RNA - Relatively short

Question 5

DNA vs RNA
Pentose sugar

Answer 5

DNA - Deoxyribose
RNA - Ribos

Question 6

DNA vs RNA
Nitrogenous bases

Answer 6

DNA - Adenine, Cytosine, Guanine and thymine
RNA - Adenine, Cytosine, Guanine and Uracil

Question 7

DNA vs RNA
Function

Answer 7

DNA - Store genetic information
RNA - Transfer genetic information and forms ribosomes with proteins

Question 8

What are polynucleotides made up of, what reactions are involved and what bonds

Answer 8

Polynucleotides are polymers made up of many nucleotide monomers joined together by a series of condensation reactions, forming phosphodiester bonds.

Question 9

What is the DNA double helix head together by

Answer 9

Hydrogen bonds between complementary base pairs

Question 10

How many hydrogen bonds are there between complementary base pairs

Answer 10

2 hydrogen bonds between A & T
3 hydrogen bonds between C & G

Question 11

What is semi conservative replication

Answer 11

Semi conservative replication is the method in which DNA replicates, creating two molecules of DNA that consist of one original DNA strand and one newly synthesised DNA strand

Question 12

Describe the process of semi conservative replication

Answer 12

DNA helicase breaks H bonds between the two strands

Free nucleotides complementary base pair to the exposed strands

​DNA polymerase catalyses condensation reactions to join adjacent nucleotides, forming phosphodiester bonds.

Question 13

Draw the structure of ATP

Answer 13

3 phosphate groups (circle) bonded to a ribose sugar (pentagon) bonded to an adenine (rectangle)

Question 14

ATP -> ADP vs ADP -> ATP
Reaction type

Answer 14

ATP -> ADP - Hydrolysis
ADP -> ATP - Condensation

Question 15

ATP -> ADP vs ADP -> ATP
Enzyme involved

Answer 15

ATP -> ADP - ATP hydrolase
ADP -> ATP - ATP synthase

Question 16

ATP -> ADP vs ADP -> ATP
Energy profile of reaction

Answer 16

ATP -> ADP - release energy
ADP -> ATP - requires energy

Question 17

During which processes can the condensation of ADP to form ATP occur

Answer 17

Respiration and photosynthesis

Question 18

Describe DNA molecules in prokaryotes and their association with proteins

Answer 18

In prokaryotic cells, DNA molecules are short, circular and not associated with proteins.

Question 19

Describe DNA in eukaryotes

Answer 19

In eukaryotes, the nucleus contains very long, linear DNA molecules associated with proteins, called histones. Together a DNA molecule and its associated proteins form a chromosome.

Question 20

Which organelles in eukaryotic cells also contain DNA

Answer 20

The mitochondria and chloroplasts of eukaryotic cells also contain DNA which, like the DNA of prokaryotes, is short, circular and not associated with protein.

Question 21

What is the genome

Answer 21

The genome is the full set of DNA found in an organism.

Question 22

What is the proteasome

Answer 22

The proteasome is the full range of proteins that can be synthesised from the genome.

Question 23

What is a gene

Answer 23

A gene is a section of DNA that code for polypeptides and functional RNA and are located at a fixed locus on a DNA molecule.

Question 24

What is a sequence of 3 DNA bases

Answer 24

A sequence of three DNA bases, called a codon, codes for a specific amino acid. The genetic code is universal, non-overlapping and degenerate.

Question 25

What is a section of DNA that codes for polypeptides called

Answer 25

Introns

Question 26

What is a section of DNA that codes for amino acid sequences called

Answer 26

Exons

Question 27

What is transcription

Answer 27

Transcription is the process of making messenger RNA from a DNA template.

Question 28

Describe the process of transcription

Answer 28

DNA helicase breaks the hydrogen bonds between the DNA helix, free RNA nucleotides base pair with the exposed DNA template strand,

Question 29

In prokaryotes, transcription results directly in the production of (1) from DNA.

Answer 29

1 - mRNA

Question 30

In eukaryotes, transcription results in the production of (1)

Answer 30

1 - pre-mRNA; this is then spliced to form mRNA

Question 31

What is translation

Answer 31

Translation is the process of making proteins by forming a specific sequence of amino acids based on coded instructions in mRNA

Question 32

Describe the process of translation

Answer 32

RNA polymerase catalyses phosphodiester bonds between adjacent RNA nucleotides and the mRNA strand detaches, allowing the DNA helix to reform.
​mRNA attaches to a ribosome on the rough endoplasmic reticulum, tRNA carries the corresponding amino acid to each codon on the mRNA one at a time, with an enzyme catalysing the formation of a peptide bond between amino acids using ATP, until a stop codon is reached and the peptide is released, folding into its tertiary structure.