Gene Expression - Learning outcomes/ questions

Question 1

How much of the genes in a cell are expressed?

Answer 1

Only a fraction of the genes in a cell are expressed.

Question 2

Transcription and translation involves three types of RNA. Name them.

Answer 2

Transcription and translation involves three types of RNA (mRNA, tRNA and rRNA).

Question 3

Structure of RNA and base names.

Answer 3

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

Question 4

Messenger RNA (mRNA) job is what?

Answer 4

Messenger RNA (mRNA) carries a copy of the DNA code from the nucleus to the ribosome.

Question 5

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

Answer 5

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

Question 6

Each triplet of bases on the mRNA molecule is called a what and what does it code for?

Answer 6

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

Question 7

What happens due to due to complementary base pairing. (tRNA)

Answer 7

Transfer RNA (tRNA) folds due to complementary base pairing.

Question 8

What does each tRNA molecule carry?

Answer 8

Each tRNA molecule carries its specific amino acid to the ribosome.

Question 9

A tRNA molecule has a what at one end and a what type of site for a specific amino acid at the other end?

Answer 9

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 10

Ribosomal RNA (rRNA) and proteins form what?

Answer 10

Ribosomal RNA (rRNA) and proteins form the ribosome.

Question 11

What does RNA polymerase do along the DNA?

Answer 11

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

Question 12

RNA polymerase synthesises what?

Answer 12

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

Question 13

In DNA, adenine is complementary to thymine, what is it complementary too in RNA?

Answer 13

Uracil in RNA is complementary to adenine.

Question 14

RNA splicing forms a mature what?

Answer 14

RNA splicing forms a mature mRNA transcript.

Question 15

The introns of the primary transcript are what type of region and do they stay?

Answer 15

The introns of the primary transcript are non-coding regions and are removed.

Question 16

The exons are what type of region and are joined together to form what?

Answer 16

The exons are coding regions and are joined together to form the mature transcript.

Question 17

Does the order of exons change splicing or not?

Answer 17

The order of the exons is unchanged during splicing.

Question 18

Translation begins and ends with what?

Answer 18

Translation begins at a start codon and ends at a stop codon.

Question 19

Anticodons bond to codons by what type of base pairing, and what does the genetic code become?

Answer 19

Anticodons bond to codons by complementary base pairing, translating the genetic code into a sequence of amino acids.

Question 20

What type of bonds join the amino acids together?

Answer 20

Peptide bonds join the amino acids together.

Question 21

Each tRNA then leaves what?

Answer 21

Each tRNA then leaves the ribosome as the polypeptide is formed.

Question 22

Different mature mRNA transcripts are produced from the same what?

Answer 22

Different mature mRNA transcripts are produced from the same primary transcript depending on which exons are retained.

Question 23

Polypeptide chains fold to form a what type of shape of a protein, and how is it held together?

Answer 23

Polypeptide chains fold to form the three-dimensional shape of a protein, held together by hydrogen bonds and other interactions between individual amino acids.

Question 24

Proteins have a large what of shapes which determines what?

Answer 24

Proteins have a large variety of shapes which determines their functions.

Question 25

Phenotype is determined by the proteins produced as what?

Answer 25

Phenotype is determined by the proteins produced as the result of gene expression.

Question 26

Phenotype is also influenced by what factors?

Answer 26

Environmental factors also influence phenotype.