DNA and Proteinsynthesis

Question 1

what is a genome?

Answer 1

complete set of genes in a cell

Question 2

what is a proteome?

Answer 2

full range of proteins that a cell is able to produce

Question 3

what is transcription?

Answer 3

production of mRNA from DNA

Question 4

what is the role of RNA polymerase?

Answer 4

joining mRNA nucleotides

Question 5

what does transcription in prokaryotes result in??s

Answer 5

results in directly the production of mRNA from DNA

Question 6

what does transcription in eukaryotes result in?

Answer 6

results in the production of pre-mRNA and this is spliced to form mRNA

Question 7

what is translation?

Answer 7

production of polypeptides from the sequence of codons carried by mRNA

Question 8

what is mRNA?

Answer 8

• made during transcription
• carries genetic code from DNA to ribosomes, where it is used to make a protein during translation

Question 9

what is the structure of mRNA?

Answer 9

• single polynucleotide strand
• groups of 3 adjacent bases = codons

Question 10

what is tRNA?

Answer 10

• involved in translation
• carries amino acids that are used to make proteins to the ribosomes

Question 11

what is the structure of tRNA?

Answer 11

• single polynucleotide chain
• clover shape
• hydrogen bonds between specific base pairs give clover shape
• have sequence of 3 bases at the end = anticodon
• amino acid binding site on other end

Question 12

where does transcription take place?

Answer 12

• eukaryotic cells = nucleus
• prokaryotic cells = cytoplasm

Question 13

what happens during the first stage of transpiration?

Answer 13

• RNA polymerase attaches to DNA
• eukaryotes = hydrogen bonds between 2 DNA strands are unwinded by DNA helicase attached to RNA polymerase
• separates stands and DNA molecule uncoils, exposing some bases
• one is the strands is used as a template to make mRNA copy

Question 14

what is the second stage of transcription?

Answer 14

• RNA polymerase lines up free RNA nucleotides alongside exposed bases on template strand (free bases attracted to exposed bases)
• specific complementary base pairing, mRNA strand = complementary copy of DNA template strand (U instead of T)
• once RNA nucleotides have paired up with specific bases on DNA strand, they are joined by RNA polymerase forming an mRNA strand

Question 15

what is the third stage of transcription?

Answer 15

• RNA polymerase moves along DNA assembling mRNA strand
• hydrogen bonds between uncoiled strands of DNA are form one RNA polymerase has passed by, forming double helix

Question 16

what is the final stage of transcription?

Answer 16

• when RNA polymerase reaches a stop signal it stops making mRNA and detaches from DNA
• eukaryotes = mRNA moves out of nucleus through nucleus pore and attaches to ribosome in cytoplasm