Gene Expression

Question 1

What does gene expression involve?

Answer 1

The transcription and translation of DNA sequences.

Question 2

How many genes in a cell are expressed?

Answer 2

Only a fraction of genes in a cell are expressed.

Question 3

State the three types of RNA, transcription and translation involve.

Answer 3

mRNA, tRNA & rRNA

Question 4

describe what is RNA

Answer 4

RNA is single-stranded and is composed of
nucleotides containing ribose sugar,
phosphate and one of four bases: cytosine,
guanine, adenine and uracil.

Question 5

describe mRNA

Answer 5

• Messenger RNA (mRNA) carries a copy of
  the DNA code from the nucleus to the ribosome.
• mRNA is transcribed from DNA in the
  nucleus and translated into proteins by
  ribosomes in the cytoplasm. Each triplet of
  bases on the mRNA molecule is called a
  codon and codes for a specific amino acid.

Question 6

describe tRNA

Answer 6

• Transfer RNA (tRNA) folds due to
  complementary base pairing. Each tRNA
  molecule carries its specific amino acid to
  the ribosome.
• A tRNA molecule has an anticodon (an
  exposed triplet of bases) at one end and
  an attachment site for a specific amino acid
  at the other end.

Question 7

what is rRNA

Answer 7

Ribosomal RNA (rRNA) and
proteins form the ribosome.