Nucleic acids.

Question 1

Structure of a nucleotide.

Answer 1

-Phosphate group
-Nitrogenous base
-Pentose sugar.

Question 2

ATP structure.

Answer 2

-3 phosphate groups
-Ribose
-adenine.

Question 3

ATP condensation and hydrolysis.

Answer 3

Condensation:
-Gains a Phosphate–>tri
-Stores energy(endergonic)
-ATPSynthesase
+30.6KJ/mol
Hydrolysis:
-Release energy
-Loses a phosphate group–>di
-ATPase
-30.6kj/mol
-exogonic.

Question 4

ATP uses.

Answer 4

-‘universal energy currency’
-stores and transfers energy
-To enable all life processes
-Released from respiration
-Hydrolysis breaks a phosphate bond which releases energy used by the cell.
-relaesed in small,usable amounts
-Travels to where it is needed easily.

Question 5

Purine bases.

Answer 5

adenine and guanine

Question 6

pyrimidine bases.

Answer 6

thymine,cytosine,uracil.

Question 7

Purine structure

Answer 7

2 fused c-n rings.

Question 8

Pyrimidine structure

Answer 8

Single carbon-nitrogen ring.

Question 9

DNA structure

Answer 9

-double helix
h bonds between complementary bases
antiparallel strands(read in diff directions)(one 3 prime to 5 prime and vice versa.
-sugar phosphate backbone with phosphodiester bonds
a,g,c,t

Question 10

RNA structure

Answer 10

-1 strand
-ribose sugar
-a,c,g,u
used in protein synthesis

Question 11

tRNA structure

Answer 11

-single stranded
-anticodon at bottom
-h bonds between bases
-delivers specific amino acids to ribosomes.
-amino acid binding site

Question 12

mRNA structure

Answer 12

-single stranded
-long
-synthesised in nucleus
-carries genetic code from nucelus to ribosomes in cytoplasm.

Question 13

rRNA structure

Answer 13

-large, complex
-made in nucleolus
-added to proteins=ribosomes.

Question 14

DNA functions

Answer 14

-protein synthesis
-DNA replication

Question 15

DNA replication process

Answer 15

-DNA helicase unwinds DNA and breaks h bonds between bases
-free nucleotides attach to template strands by comp bases pairing
-DNA polymerase joins free nucleotides together in 5–>3 prime direction by phosphodiester bonds.
-the 2 DNA molecules refold into double helix.

Question 16

Meselsons and stahls experiment

Answer 16

-bacteria in sol
-contains N15
-sample in centrifuge
-heavy 15 at bottom
-then allowed to replicate once with lighter n14
-15 and 14 in middle mixed
-allowed to replicate again
-14 at top bottom 15 and 14
-proves semi-conservative replication of DNA

Question 17

Genetic code definition

Answer 17

The genetic code is a linear, triplet, non-overlapping,
degenerate, unambiguous, universal code for the
production of polypeptides

Question 18

The triplet code

Answer 18

-amino acids coded for by base triplets in DNA
-transcribed to make codons in mRNA
-then sequence of a acids

Question 19

Exons and introns

Answer 19

exons=nucelotide sequence in dna and pre-mrna-coding
introns=non-coding nucleotide sequence in dna and removed from pre-mrna–.mature mrna

Question 20

Transcription

Answer 20

-Dna helicase breaks h bonds between bases and unwinds dna
-comp rna nucleotides align
-rna polymerase forms sugar-phosphate backbone
-forms pre-mrna
-premrna that has introns removed via splicing to make mature mrna.

Question 21

Translation

Answer 21

-each trna brings specific amino acid
-ribosome binds to start codon on mrna
-2 amino acids form peptide bonds
-ribosome moves along mrna one codon at time untilstop codon reached.

Question 22

Further peptide chain modifictaion

Answer 22

-polypeptide chain folded to become proteins
-can be 1,2,3
-carbs,lipids or phosphates can be added as well as other polypeptides to make complete protein.

Question 23

codon definition

Answer 23

-3 bases on mrna

Question 24

anticodon definition

Answer 24

-3 bases of trna