Lecture 3 (Mutations, mitosis, meiosis)

Question 1

gene

Answer 1

a region of DNA that had enough instructions to make a polypeptide or RNA

Question 2

mutation

Answer 2

there HAS to be a change in the sequence of DNA for it to be a mutation

Question 3

a point mutation

Answer 3

a change in just one base pair of the gene

Question 4

wild type

Answer 4

the normal or healthy version of the sequence

Question 5

What could cause a mutation?

Answer 5

1. In the S phase of the cell cycle, replication occurs. Sometimes DNA pol will make a mistake and it’ll not be corrected
2. Exposure to radiation, x-ray, sun, and any harmful chemicals

Question 6

Mistakes to DNA

Answer 6

Substitution - substitute one base for another

Insertion- insertion of an extra base

Deletion - deletion of a base

Question 7

What is the most harmful mistake to DNA?

Answer 7

insertion or deletion because it can cause a frameshift

Question 8

frameshift

Answer 8

caused by an insertion or deletion and it changes the way you read the sequence

Question 9

silent

Answer 9

if the substitute doesn’t change the amino acid

Question 10

missense

Answer 10

if the substitution changes the amino acid

Question 11

nonsense

Answer 11

if the substitution changes the amino acid to a STOP

Question 12

where are mutations are most dangerous?

Answer 12

polypeptide- N terminus
RNA- 5’
DNA- 3’

Question 13

Which is the MOST dangerous effect?

Answer 13

nonsense

Question 14

what are homologous pairs?

Answer 14

they are a pair of chromosomes. they are the same length and possess the same genes for the same characteristics at corresponding loci. you get one from mom and dad

Question 15

where can you find homologous pairs?

Answer 15

diploid cells

Question 16

autosomes

Answer 16

chromosomes numbered 1-22

Question 17

sex chromosomes

Answer 17

X and Y

Question 18

what is the human haploid number (1n)?

Answer 18

23

Question 19

what is the human diploid number (2n)?

Answer 19

46

Question 20

somatic cells

Answer 20

• all body cells except for reproductive
• they’re diploid
• they only do mitosis
• a mutation at a regular body cell won’t get passed down

Question 21

germ cells

Answer 21

• diploid cells involved in reproduction
• found in testes and ovaries
• can do both mitosis and meiosis
• mutation at a germ cell could get passed down

Question 22

gametes

Answer 22

• finished product of meiosis

- they’re diploid

Question 23

recombiant chromosomes

Answer 23

crossing over results in recombination. offspring can have a different combination of genes than their parents

Question 24

how does meiosis contribute to genetic variation?

Answer 24

independent assortment
crossing over
random fertilization