8.3 -> 8.5

Question 1

genome

Answer 1

complete set of genes in a cell, including those in mitochondria and chloroplasts

Question 2

preteome

Answer 2

full range of proteins produced by genome

Question 3

RNA nucleotide structure

Answer 3

pentose sugar base
one of organic base adenine, guanine, cytosine and uracil
phosphate group

Question 4

messanger rna

Answer 4

1. consists of thosuands of mononucleotides - long strand
2. single heix
3. posseses info in codons

Question 5

codon

Answer 5

3 bases that are complementary to triplet in DNA

Question 6

trasnfer RNA

Answer 6

1. small molecules made up of 80 nucleotides
2. single-stranded chain folded into clover-leaf shape
3. contains binding site for amino acid
4. contains anticodon that is specific to amino acid

Question 7

transcription

Answer 7

1. enzyme acts on specific region of DNA, causing two strands to separate and expose nucleotide bases
2. nucleotide bases acts as template and pair with complementary nucleotides from the pool
3. Enzyme RNA polymerase moves along strand and joins nucleotides together to form pre MRNA molecules(stops when reaches terminator sequence)
4. DNA strands rejoin behind rna polymerase

Question 8

splicing

Answer 8

base sequences corresponding to introns are removed from pre mRNA and functional exons are joined together to from mRNA

Question 9

stage between transcription and translation

Answer 9

leave nucleus via nuclear pore(too large to diffuse out)

mRNA is attracted to ribosomes to which it becomes attached

Question 10

intron

Answer 10

a section of DNA that doesn’t code for proteins and interrupts the sequence of genes

Question 11

exon

Answer 11

Triplet sequence that codes for sequence of amino acids

Question 12

synthesising a polypeptide(translation)

Answer 12

1. ribosome becomes attached to starting codon at one end of mRNA molecule
2. tRNA molecule with complementary anticodon sequence(and specific amino acid) moves to ribosome and pairs with codon on mRNA. another tRNA molecules with complementary anticodon pairs with codon on next mRNA
3. ribosome moves along mRNA, bringing together two tRNA molecules at any time
4. the amino acids on the tRNA are joined by peptide bonds using an enzyme and ATP(hydrolysed)
5. tRNA is released from amino acid and is free to collect another specific amino acid
6. this process continues until ribosome reaches a stop codon, so mRNA and last tRNA separate and polypeptide chain is complete.