1.3

Question 1

translation

Answer 1

mrna attaches to the ribosome
codons in the mrna code for a specific amino acid
transfer of amino acids to the ribosome by trna
anticodon on the trna matches codons on the mrna strand
amino acids are linked to form polypeptides by peptite bonds

Question 2

transcription

Answer 2

sections of dna carying the gene to be transcribed unwinds
dna strands separate
antisense strand used as a template
rna polymerase binds to the non coding DNA located infront of the gene
rna polymerase produces a complimentary strand of the mrna from coding dna of a gene by complimentary base pairing
a-t
g-c
mrna leaves nucleus through nuclear pore

Question 3

atp

Answer 3

energy supply for cells
nucleotide with three phosphate groups
when energy is needed the third phosphate group is broken in a hydrolysis reaction by the enzyme ATPase the product is adp
reaction releases energy

Question 4

dna replication

Answer 4

two strands of DNA unzip and unravel
-dna helicase breaks hydrogen bonds
the strands act as templates
free nucleotide bases attract
phosphodiester bonds synthesised
-dna polymerase
complimentary nucleotides bind
hydrogen bonds form between AT GC
-dna ligase to join fragments

Question 5

chromosomal mutations

Answer 5

changes in the position of genes within the chromasomes

Question 6

whole chromasome mutation

Answer 6

an entire chromosome is lost during meiosis

Question 7

dna bases

Answer 7

hydrgogen bonds between bases
at- 2 bonds
gc- 3 bonds

Question 8

nucleotides

Answer 8

pentose sugar
nitrogen containing base
phosphate group
provides energy in the form atp
formed in a condensation reaction with the elimination of two water molecules

Question 9

nucleic acid

Answer 9

polynucleotides
information needed to form new cells
found in dna then copied into mrna
direct the production of proteins
made in a condensation reaction
joined in a phosphodiester bond

Question 10

gene mutation

Answer 10

one or a small number of nucleotides are miscopied

Question 11

substituiton

Answer 11

one base substitutes for another

Question 12

deletions

Answer 12

base completly lost

Question 13

addition

Answer 13

extra base added

Question 14

nucleotide bases

Answer 14

purine
2 nitrogen containing rings
a+g
pyrimidines
1 nitrogen containing ring
c+t+u

Question 15

deoxyribose

Answer 15

Question 16

sugar phosphate backbone

Answer 16

both dna and rna have one
dna has two polynucleotide strands and rna has one

Question 17

conservative

Answer 17

origional double helix stays intact
and instructs the formation of a new identical double helix

Question 18

semi conservative

Answer 18

dna is unzipped and new nucleotides line along each strand
each double helix consists of one origional and one new

Question 19

degenerate

Answer 19

more than one triplet for each amino acid

Question 20

non overlapping

Answer 20

each base is only part of one triplet (codon)

Question 21

phosphodiester bonds

Answer 21

between nucleotides
-pentose sugar and phosphate

Question 22

enzymes in dna replication

Answer 22

helicase
-unzips and unwinds breaking the hydrogen bonds
ligase
-lines up and catalyses the phosphodiester bonds joining fragments of DNA between phosphate and sugar
polymerase
-forms phosphodiester bonds joining the sugar-phosphate backbone

Question 23

why are dna bases more variable than the amino acid sequences

Answer 23

more triplet codes than amino acids
so code is degenerate
some amino acids may have a different code
maintaining structure of a protein

Question 24

modified molecule

Answer 24

5’ 3’ ends - dna code
inside molecule - mrna code

Question 25

hydrogen bond

Answer 25

between bases 5’ and 3’
hold two strands of DNA together in a double helix

Question 26

how are monomers bonded to a polypeptite chain

Answer 26

peptite bond between amino acid and carboxyl group
condensation reaction