Gene Expression

• The main components of a ribosome are

  rRNA and protein
• what is the site and molecule synthesised in TRANSLATION

  cytoplasm, protein
• what is the site and molecule synthesised in TRANSCRIPTION

  nucleus, mRNA
• Which of the following processes occurs

  during RNA splicing?

  Introns are removed
• A primary transcript is a strand of

  RNA comprising introns and exons
• Exons in the primary transcript of mRNA are

  Coding regions and are joined together to

  form a mature transcript
• in RNA does the strand contain thymine or uracil

  uracil
• RNA is single stranded and contains ribose sugar
• Name the type of bond that joins amino acids

  into a chain.

  peptide
• A mature transcript is made up of

  RNA composed of exons only
• tRNA contains uracil
• A mature mRNA transcript is produced from

  a primary mRNA transcript by

  removing introns
• exons are coding regions and introns and non coding regions
• the sequence of bases in the primary mRNA transcript contain URACIL
• State the term used to describe the coding regions of a primary mRNA transcript.

  exons
• Name the process by which the coding regions of a primary mRNA transcript are joined together to produce a mature mRNA transcript.

  alternative RNA splicing
• State the location for the translation of a mature mRNA transcript into a polypeptide.

  ribosome
• 1. State what non-coding regions of a gene are called.

  introns
• Explain why it is important that non-coding regions

  are removed from the primary transcript of this gene before translation.

  So that the correct functional protein is formed.
• Describe two ways in which the structure of a molecule of mRNA differs from that of DNA.

  RNA single stranded and DNA double stranded

  RNA contains ribose and DNA contains deoxyribose

  RNA contains uracil and DNA contains thymine
• The diagram represents part of a molecule of DNA on which a molecule of mRNA is being synthesised.

  1. Name this process.

  Transcription.
• State the location in the cell in which this transcription occurs.

  nucleus
• both DNA and mRNA are made in the nucleus
• DNA forms genes
• mRNA attaches to the ribosomes
• Name the molecule which transport the

  amino acids to the mRNA.

  tRNA.
• during the formation of a protein molecule, amino acids are joined together by peptide bonds
• the synthesis of mRNA takes place in the nucleus
• mRNA consists of many nucleotides, each consisting of a base, ribose and phosphate
• mRNA creates a copy of DNA and is located in the cytoplasm and nucleus
• tRNA transfers amino acids to the ribosome and is located in the cytoplasm
• transcription occurs in the nucleus
• State one other

  difference between RNA and DNA.

  RNA is single stranded whereas DNA is double stranded/RNA has a ribose sugar whereas DNA has

  deoxyribose sugar.
• The primary transcript of RNA can then undergo a

  process. State the name of this process and give an

  account of it.

  RNA splicing
• RNA synthesis takes place in the nucleus
• Describe the function of this enzyme.

  Unwinds DNA and separates strands.
• RNA splicing is when introns are removed and exons are spliced
• What is the name given to triplets of bases in an mRNA

  molecule?

  codon
• What is the name given to triplets of bases in an tRNA molecule?

  anticodon
• Name the sugar present in mRNA.

  ribose