DNA and protein synthesis

name the type of bond between complementary base pairs

hydrogen bonds

name the type of bond between adjacent nucleotides in a DNA strand

phosphodiester bonds

describe differences between the structure of a tRNA molecule and the structure of an mRNA molecule

1. tRNA is ‘clover leaf shaped’, mRNA is linear

2. tRNA has hydrogen bonds, mRNA does not

3. tRNA has an amino acid binding site, mRNA does not

4. tRNA has anticodon, mRNA has codon

describe and explain a difference in the structure of pre-mRNA and mRNA molecules

1. mRNA fewer nucleotides
2. because of splicing

describe how one amino acid is added to a polypeptide that is being formed at a ribosome during translation

1. tRNA brings specific amino acid to ribosome

2. anticodon on tRNA binds to codon on mRNA

3. amino acids join to form a peptide bond using ATP

describe how mRNA is produced from an exposed template strand of DNA. do not include DNA helicase or splicing in your answer.

1. free RNA nucleotides form complementary base pairs

2. phosphodiester bonds form

3. by action of RNA polymerase

describe how mRNA is formed by transcription in eukaryotes

1. hydrogen bonds between DNA bases break separating the DNA strands
2. only one DNA strand acts as a template
3. free RNA nucleotides align by complementary base pairing
4. adenine pairs with uracil, thymine pairs with adenine, cytosine pairs with guanine, guanine pairs with cytosine
5. RNA polymerase joins adjacent RNA nucleotides
6. by phosphodiester bonds between adjacent nucleotides forming pre-mRNA
7. pre-mRNA is spliced to form mRNA

describe how a polypeptide is formed by translation of mRNA

1. mRNA attaches to ribosomes
2. ribosome moves to the start codon
3. tRNA anticodons bind to complementary mRNA codons
4. tRNA brings a specific amino acid
5. amino acids join by peptide bonds
6. amino acids join together with the use of ATP
7. tRNA released after amino acid joined to polypeptide
8. the ribosome moves along the mRNA to form the polypeptide

what is the proteome of a cell?

the full range of different proteins that a cell is able to produce at a given time

what are the structural differences between mRNA and tRNA?

1. mRNA does not have hydrogen bonds, tRNA does
2. mRNA does not have an amino acid binding site, tRNA does
3. mRNA has more nucleotides
4. different mRNAs have different lengths, all tRNAs are same length
5. mRNA has codons, tRNA has an anticodon
6. mRNA is linear, tRNA is ‘clover leaf shaped’

the genetic code is described as degenerate. what is meant by this?

more than one codon codes for a single amino acid

give the two types of molecule from which a ribosome is made

rRNA and proteins

describe the role of a ribosome in the production of a polypeptide. do not include transcription in your answer.

1. mRNA binds to ribosome
2. two codons
3. allows tRNA with anticodons to bind
4. catalyses formation of peptide bond between amino acids held by tRNA molecules
5. moves along mRNA to the next codon

in a eukaryotic cell, the base sequence of the mRNA might be different from the sequence of the pre-mRNA. explain why.

1. introns in pre-mRNA
2. splicing - removal of sections of pre-mRNA