A1.2 (Nucleic Acids)

Question 1

Nucleic Acid

Answer 1

Polymers of nucleotides such as DNA and RNA

Question 2

DNA

Answer 2

Deoxyribonucleic acid: Molecule that carries genetic information for development and functioning of an organism

Question 3

RNA

Answer 3

Ribonucleic acid: A type of nucleic acid that has riobose sugar in its structure and is used by viruses to replicate

Question 4

How was DNA discovered

Answer 4

Friedrich Miescher performed experiments with white bloodcells which led to DNA extraction as the membrane had to be disintegrated first. this was based on the solubility of DNA in certain substances

Question 5

Components of as nucleotide

Answer 5

pentose sugar, nitrogenous base, phosphate group

Question 6

How does sugar phosphate bonding work

Answer 6

nucleotides link together through a covalent bond to form the single strands of DNA/RNA
1. Bond betwen phosphate group and hydroxylgroup attached to 3C
2. releases one molecule of water
3. continuous chain
4. forms strong sugar phosphate backbone
5. forms 2 ends: 3C hydroxyl group and 5C phosphate group

Question 7

Pure As Gold

Answer 7

Purines: Adenine, Guanine
Nitrogenous bases with two rings

Question 7

Cut The Pie

Answer 7

Pyrimidines: Cytosine, Thymine, Uracil
Nitrogenous bases with only one ring

Question 8

features of RNA

Answer 8

• single stranded
  *has uracil instead of thymine
• has AGUC as nitrogenous bases
• 2C has an OH

Question 8

Features of DNA

Answer 8

• double stranded
• strands are connected by hydrogen bonds
• has AGTC as nitrogenous bases
• 2C has an H

Question 9

structure of DNA explained

Answer 9

two polynucleotide chains aree coiled around the same axis in which the bases inside are supported by the sugar phosphate backbone

Question 10

role of complementary base pairing

Answer 10

• cell division
• gene expression

Question 11

how does complemetary base pairing affect cell division

Question 12

how does complementary base pairing affect gene expression

Answer 12

Complemetary base pairing ensures that the same protein is produced as the same bases = same code = same protein

Question 13

Genetic Code

Answer 13

Instructions in a gene in the form of a base sequence that become translated into a functional protein

Question 14

replication

Answer 14

Copying of DNA to make a new DNA molecule

Question 15

Translation

Answer 15

Process in which the transcribed DNA is translataed by the ribosomes to produce proteins

Question 15

Transcription

Answer 15

process in which DNA is used as a template to produce RNA

Question 16

DNA Base sequences

Processes that happen in the 5’ to 3’ direction

Answer 16

Replication, Translation, Transcription

Question 17

Example of specific enzyme which replicates DNA in the 5’ to 3’ direction

Answer 17

DNA Polymerase

Question 18

How does pairing purines and pyrimidines enable DNA stabilisation

Answer 18

As the length stays consistent (around 2nm diameter) the bond specificy is higher resulting in a more stable & strong bond

Question 19

Eukaryotic

Answer 19

A group of organisms whose cells typically contain a nucleus & membrane bound organelles

Question 20

Prokaryotic

Answer 20

A group of organisms whose cells do not contain a nucleus or membrane bound orgnisms

Question 21

Histones

Answer 21

Proteins around which DNA strands are wrapped

Question 22

nucleosomes

Answer 22

structural unit of eukaryotic chromatin in which DNA is wrapped around 8 histone and H1proteins

Question 22

Relationship between nucleosomes and chromosomes

Answer 22

Chromosome>chromatin fibre>Nucleosome>double helix

Question 22

Hershey Chase Experiment

Answer 22

proved that DNA, not protein, makes up the genetic material

Question 23

How does the Hershey Chase Experiment work

Answer 23

• used a T2 bacteriophage which injects DNA into a bacterial cell while its protein stays on the outside
• used radioactove phosphorus and sulfur to label the DNA and the protein viruses
• as the DNA was transferred the next generation all contained radioactive phosphor, proving that uit was DNA that was being transferred

Question 24

Chargaffs Data

Answer 24

proved that DNA is double stranded helix

Question 25

How was chargaffs data collected

Answer 25

he analysed samples of DNA using paper chromotography and discovered that the relative concentrations of the bases were equal