KA3- Gene Expression

Question 1

Gene expression

Answer 1

Involves the transcription and translation of DNA sequences
Only a fraction of the genes in a cell are expressed

Question 2

mRNA

Answer 2

Carries a copy of the DNA code from the nucleus to the ribosome
Is transcribed from DNA in the nucleus and translated into proteins by ribosomes in the cytoplasm

Question 3

tRNA

Answer 3

Folds due to complementary base pairing. Each tRNA molecule carries its specific amino acid to the ribosome
A tRNA a 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 4

rRNA

Answer 4

Ribosomal RNA
And proteins form the ribosome

Question 5

Result of alternative RNA splicing

Answer 5

Different proteins can be expressed from one gene, as a result of alternative RNA splicing
Different mature mRNA transcripts are produced from the same primary transcript depending on which exons are retained

Question 6

Protein structure

Answer 6

Amino acids are linked by peptide bonds to form polypeptides
Polypeptide chains fold to form the three-dimensional shape of a protein, held together by hydrogen bonds and other interactions between individual amino acids
Proteins have a large variety of shapes which determines their functions

Question 7

Phenotype

Answer 7

Is determined by proteins produced as a result of gene expression
Environmental factors also influence phenotype