Storing and Using Genetic Information

Question 1

DNA

Answer 1

A chain of nucleotide monomers with a double helical structure. There is a sugar-phosphate backbone and each nucleotide is joined by hydrogen bonds. Adenine pairs with thymine (uracil in RNA), cytosine with guanine.

Question 2

DNA replication

Answer 2

Replication occurs in the nucleus. DNA is packaged into chromosomes, special proteins then unzip the double helix by breaking H bonds, new nucleotide monomers are the paired with the two DNA strands. It is replicated in a 5’ to 3’ direction. It is a semi-conservative process as one half of each molecule is old and one new.

Question 3

Transcription of DNA to RNA

Answer 3

Role of RNA is in protein synthesis. DNA has introns (non-coding regions) and exons (coding regions). During transcription introns are removed and exons are spliced.

Question 4

Post-transcriptional processing of RNA

Answer 4

The pre-mRNA strand undergoes alternative splicing to create mRNA and then proteins. mRNA then transports the RNA out of the nucleus.

Question 5

Translation of mRNA

Answer 5

Occurs in the cytoplasm attached to ribosomes. mRNA is converted to tRNA (anticodons). tRNA translates mRNA into an amino acid sequence. It acts as an adaptor molecule between mRNA and the amino acid sequence coded for. tRNA then becomes rRNA which is part of the ribosome and responsible for reading the order of amino acids and linking them together to make a ribosome.