Genes and Protein synthesis

Question 1

Genes

Answer 1

• Gene is a sequence of DNA nucleotides that codes for polypeptide.
• The sequence of amino acids in polypeptide forms the primary structure of a protein.
• Order of nucleotide bases determine order of a.a which determines what protein is made.
• Each a.a is coded by triplets.

Question 2

Messenger RNA

Answer 2

• mRNA is a single polynucleotide strand.
• Made in nucleus during transcription.
• mRNA carries genetic code from DNA to cytoplasm where it’s used to make a protein during translation.
• Groups of 3 adjacent bases are called codons.

Question 3

Transfer RNA

Answer 3

• tRNA is a single polynucleotide strand that is folded into a clover shape.
• H-bonds between specific base pairs make this shape.
• Every tRNA molecule has a specific sequence of 3 bases at one end called an ANTICODON.
• tRNA is found in cytoplasm where it’s involved in translation: it carries amino acids that are used to make proteins in ribosomes.

Question 4

Ribosomal RNA

Answer 4

• rRNA forms 2 subunits in ribosome, along with proteins.
• Ribosome moves along mRNA during protein synth.
• rRNA in ribosome helps catalyse the formation of peptide bonds between amino acids.