Ch 17.3: Gene Expression from Gene to Protein

Question 1

What are mutations?

Answer 1

they are changes in the genetic information of a cell

Question 2

What are point mutations?

Answer 2

they are changes in just one nucleotide pair of a gene

Question 3

What are the two types of point mutations?

Answer 3

single nucleotide-pair substitutions and nucleotide-pair insertions or deletions

Question 4

What is a nucleotide-pair substitution?

Answer 4

replaces one nucleotide and its partner with another pair of nulcoetides

Question 5

What are silent mutations?

Answer 5

mutations that have no effect on the amino acid produced by a codon because of redundancy in the genetic code

Question 6

What are missense mutations?

Answer 6

mutation that still codes for an amino acid, but not the correct amino acid

Question 7

What are nonsense mutations?

Answer 7

mutations that change an amino acid codon into a stop codon; most lead to a nonfunctional protein

Question 8

What are insertions and deletions?

Answer 8

they are additions or losses of nucleotide pairs in a gene

Question 9

What are frameshift mutations?

Answer 9

the insertion or deletion of nucleotides that alter the reading frame

Question 10

What are mutagens?

Answer 10

physical or chemical agents that can cause mutations

Question 11

What is gene editing?

Answer 11

the altering of genes in a specific way

Question 12

What is the CRISPR-Cas9 technique?

Answer 12

the Cas9 protein will cut any sequence to which it is targeted. Scientists can introduce a Cas9-guide RNA complex into a cell they wish to alter, the guide RNA is engineered to target a gene, Cas9 cuts both strands of the targeted gene. the broken ends trigger a DNA repair system which repair enzymes remove or add some random nucleotides while joining the broken ends