DNA, RNA and Protein Synthesis

Question 1

DNA

Answer 1

holds/stores genetic information and contains information needed for the growth + development of organisms
polymer as is made up of repeating subunits
dna is made up of deoxyribose sugar, nitrogen containing base and phosphate group
phosphodiester bonds join phosphate and deoxyribose
AT and GC base pairing

Question 2

RNA

Answer 2

transfers genetic code from DNA out of nucleus to the ribosomes
rna contains ribose sugar
single stranded
AU and GC base pairing- T is replaced with U

Question 3

RNA vs DNA

Answer 3

RNA has sugar ribose DNA has deoxyribose
RNA has uracil rather than thymine
RNA is single stranded but can fold into 3D structures
RNA is shorter than DNA

Question 4

DNA replication

Answer 4

occurs in preparation for mitosis
DNA helicase unwinds the double helix and breaks h bonds
each original strand acts as a template for a new strand
free nucleotides are attracted to exposed complementary bases, join by h bonds
DNA polymerase catalyses condenstaion reactions, creating phosphodiester bonds, joining sugar phosphate backbone
half of original DNA is now part of each fragment- semi conservative
ensures DNA strands are accurate

Question 5

genome

Answer 5

complete set of genes in a cell

Question 6

proteome

Answer 6

full range of proteins that a cell can produce

Question 7

mRNA structure

Answer 7

single stranded sugar phosphate backbone
short, can only carry one gene
short lifetime and is degraded after it is used

Question 8

tRNA structure

Answer 8

single stranded, folded into clover leaf shape by complementary base pairing
has an amino acid binding site
specific anticodon is complementary to codon on mRNA

Question 9

transcription

Answer 9

produces mRNA from DNA ( in nucleus)
RNA polymerase binds to promoter region of gene being transcribed
DNA helicase unwinds double helix and breaks h bonds
exposes nucleotide bases
exposed sense strand is used as a template for mRNA production
free RNA nucleotides line up to complementary bases
uracil replaces thymine and adenine binds
RNA polymerase joins nucleotides forming phosphodiester bonds, forming pre mRNA strand
pre mRNA is spliced to remove introns forming mRNA
prokaryotes- no splicing

Question 10

translation

Answer 10

one of mRNA attaches to a ribosome and the codon of mRNA binds to the anticodon of tRNA
tRNA brings a specific amino acid
amino acids join by condensation reaction forming a peptide bond
ATP is used to join
next codon becomes available to bind a tRNA with next amino acid

Question 11

DNA structure- function

Answer 11

hydrogen bonds weak to allow unwinding for replication
lots of hydrogen bonds are strong meaning two strands are held together
double helix so is compact
SPB provides strength and stability
large molecule so contains lots of information
base sequences allow info to be stored