1.3 Gene Expression

Question 1

What is RNA?

Answer 1

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

Question 2

How is mRNA transcribed?

Answer 2

mRNA is transcribed from DNA in the nucleus and translated into proteins by ribosomes in the cytoplasm

Question 3

What is a codon?

Answer 3

Each triplet of bases on the mRNA molecule is called a codon and codes fro a specific amino acid

Question 4

What is an anticodon?

Answer 4

tRNA molecules have anticodons (an exposed triplet of bases) and an attachment site for a specific amino acid at the other end

Question 5

What base is uracil complementary to?

Answer 5

Uracil is complementary to adenine in RNA

Question 6

Are all genes in a cell expressed?

Answer 6

No, only a fraction of genes in a cell are expressed

Question 7

What is the function of RNA polymerase?

Answer 7

RNA polymerase synthesises a primary transcript of mRNA from RNA nucleotides by complementary base pairing

Question 8

What happens to the order of exons during splicing?

Answer 8

The order of exons remains unchanged during splicing

Question 9

How is RNA polymerase involved in the transcription of DNA?

Answer 9

RNA polymerase moves along DNA unwinding the double helix and breaking the hydrogen bonds between bases

Question 10

What factor can influence a phenotype?

Answer 10

Environmental factors can also influence phenotype