DNA and RNA

Question 1

what is a gene?

Answer 1

-its a sequence of DNA bases that codes for either a polypeptide or a functional RNA

Question 2

what is a triplet and what does it code for?-

Answer 2

-three bases in a gene
-its the order of the bases that determines the order of the amino acid in a particular polypeptide

Question 3

how is DNA arranged in a eukaryotic cell?

Answer 3

-linear DNA that exisits as chromosomes
-the DNA double helix is too long,
-so DNA is wound around histone proteins
-DNA is coiled up repeatedly to form a single chromosome

Question 4

how is DNA arranged in a prokaryotic cell?

Answer 4

-DNA molecules are shorter and circular
-circular chromosome is supercoiled to fit into the cell

Question 5

definition of a intron

Answer 5

-genes in eukaryotic DNA that code for polypeptides but dont code for amino acids

Question 6

definition of exons

Answer 6

a sequence of DNA that codes for an amino acid

Question 7

why are introns removed?

Answer 7

-so they dont affect the amnio acid order

Question 8

what are alleles?

Answer 8

• code for slightly different versions of the same polypeptide

Question 9

what is messenger RNA/mRNA?

Answer 9

-made during transcription
-carries the genetic code from the DNA to the ribosomes, to make a protein in translation
-contains codons