dee - enn - ayyyy

Question 1

DNA

Answer 1

deoxyribonucleic acid

Question 2

define dna

Answer 2

a chemical found in the nucleus of each of our body cells - a code that your body uses as its instructions

Question 3

genes, chromosomes, amino acids, protiens, etc

Answer 3

Genes are segments of DNA that contain the code for a specific protein that functions in one or more types of cells in the body. Chromosomes are structures within cells that contain a person’s genes (protein [row of amino acids] and a DNA molecule). Genes are contained in chromosomes in the cell nucleus.

Question 4

Structure of DNA: watson and crick model

Answer 4

• common ratio of bases
• G (triple) C
• A = T
• set distance between strands
• antiparallel (5’, 3’)
• sugar phosphate backbone
• nucleotide made of a phosphate root, attached to deoxyribose sugar and nitrogenous base (adenine, thymine, guanine, cytosine)

Question 5

DNA vs RNA (name and structure)

Answer 5

DNA = deoxyribonucleic acid --> double stranded molecule (helix shape) 
RNA = ribonucleic acid --> single stranded

Question 6

DNA vs RNA (location, role)

Answer 6

DNA:

• main chemical in the nucleus, small amount found in mitochondria and chloroplast
• chemical code used in protein synthesis and responsible for transmitting inherited traits from one cell to another

RNA:

• small amount in nucleus, large amount in cytoplasm (associated with ribosomes)
• Role: used in the process of protein synthesis - includes (messenger - mRNA, transfer - tRNA, ribosomal - rRNA)

Question 7

Structures of DNA

Answer 7

• each chromosome is made up of chromatin fibres
• each chromatin fibre is a tight wound supercoil
• each supercoil is made up of coils (aka a chain of beadlike structures)
• each nucleosome consists of DNA wound around histones

Question 8

role of topoisomerase

Answer 8

topoisomerase relaxes DNA from supercoiled state

Question 9

role of helicase

Answer 9

unwinds the double helix, uses ATP to catalyse the breakage of weak hydrogen bonds between nitrogenous bases

Question 10

role of single stranded binding proteins (SSBs)

Answer 10

bind to newly separated single stranded DNA to stabilise it

Question 11

primase

Answer 11

for synthesis to be started, a short strand of RNA (RNA primer) needs to be made and attached to the DNA by primase

Question 12

role of polymerase

Answer 12

polymerase III adds nucleotides to unzipped DNA to synthesise new strands

polymerase I and II will backtrack and edit any mistakes (a missed mistake = a mutation)

Question 13

role of ligase

Answer 13

DNA ligase seals the two new strands back together

Question 14

the cell cycle: G1

Answer 14

cell growth - metabolic changes prepare the cell for division

Question 15

S phase

Answer 15

synthesis: each of the 46 chromosomes is duplicated

Question 16

G2 phase

Answer 16

enzymes in the cell check the duplicated chromosomes and cytoplasmic materials prep for division

Question 17

DNA replication full

Answer 17

• topoisomerase relaxes dna from supercoiled state
• helicase unwinds the double helix and uses atp to catalyse the breakage of weak hydrogen bonds between nitrogenous bases
• single stranded binding proteins bind to newly separated single stranded DNA to stabilise it
• a short strand of RNA (RNA primer) needs to be made and attached to the DNA by primase
• DNA polymerase III adds nucleotides to unzipped DNA to synthesise new strands
• polymerase I and II backtracks to edit any mistakes
• DNA ligase seal the two together