lecture 11

Question 1

Mutation

Answer 1

• change in the DNA
• once the change has occurred the mutant DNA is treated like any other
  strand of DNA
• all current DNA was “mutant” DNA at some time in the past

Question 2

Several types of Mutation

Answer 2

substitution, deletion, insertion, and translocation.

Question 3

Substitution

Answer 3

substitution: one base is substituted for another
1. in some cases, the substitution doesn’t affect the nucleotide, therefore doesn’t affect the structure of the protein and has no effect on the phenotype of the organism

Question 4

Substitution

Answer 4

substitution: one base is substituted for another
1. in some cases, the substitution doesn’t affect the nucleotide, therefore doesn’t affect the structure of the protein and has no effect on the phenotype of the organism

Question 5

Insertion

Answer 5

Insertion: one or more nucleotides are inserted into the DNA

Question 6

Deletion

Answer 6

one or more nucleotides deleted from the DNA

Question 7

Inserting/deleting nucleotides causes

Answer 7

1.Inserting/deleting nucleotides causes a shift that will affect every subsequent amino acid (since the nucleotides are read in pairs of 3 – codon)
2. Possible to have insertion/deletion of a whole triplet

Question 8

Inserting/deleting nucleotides causes

Answer 8

1.Inserting/deleting nucleotides causes a shift that will affect every subsequent amino acid (since the nucleotides are read in pairs of 3 – codon)
2. Possible to have insertion/deletion of a whole triplet

Question 9

Why do mutations happen?

Answer 9

Why do mutations happen?
- Presence of mutagens
1. Something that causes mutation
o E.g. high energy radiation (gamma rays)
o Certain chemicals (cigarette smoke)
- DNA replication
1. Not a perfect process, mistakes can occur
2. About 1 error per 1-10 billion bases Mutation rates vary based on
- Presence/absence of mutagens
- Environmental effects on DNA
1. When cells are put under stress their replication delity tends to break down
- Different parts of the DNA have higher mutation rates than others

Question 10

Most mutations have

Answer 10

Most of mutations will have little or no effect

Question 11

Gene regulation

Answer 11

Gene Regulation
- The expression of genes is regulated
- Genes are expressed only under certain conditions
- Some genes only expressed at certain times
-some are expressed more than others
- Some only expressed in certain cells

Question 12

Gene regulation

Answer 12

Gene Regulation
- The expression of genes is regulated
- Genes are expressed only under certain conditions
- Some genes only expressed at certain times
-some are expressed more than others
- Some only expressed in certain cells

Question 13

Most important mechanism in the control of gene transcription

Answer 13

Control of transcription is the most important mechanism in the
control of gene transcription 1. Negative control

Question 14

Most important mechanism in the control of gene transcription

Answer 14

Control of transcription is the most important mechanism in the
control of gene transcription 1. Negative control

Question 15

Negative control

Answer 15

Something must be removed in order to allow transcription to happen

Question 16

Positive control

Answer 16

Something must be added to allow transcription to occur
Using Sickle Cell Anemia as an example
- Some individuals have the allele for sickle cell hemoglobin

Question 17

What are inherited diseases caused by?

Answer 17

Inherited diseases that prevent reproduction are generally cause by recessive alleles

Question 18

Why are Inherited diseases that prevent reproduction are generally cause by recessive alleles?

Answer 18

Why?
o If a disease that prevented reproduction is caused by a
dominant allele, it will never be inherited