Gene Expression

Question 1

what is a mutation?

Answer 1

change in the genetic sequence of DNA

Question 2

are mutations always harmful?

Answer 2

NO in some cases mutations do not harm the natural processes in the body

for example, mutation allows humans to digest LACTOSE as adults –> lactose persistence

Question 3

how do you know whether a mutation will be transferred to offspring?

Answer 3

if the mutation is located on a gamete (reproductive cells) –> mutation has a chance to be inherited by the offspring

if the mutation is located on a body cell (for ex hair cell, eye cell, skin cell, stomach cell) –> the offspring will not inherit that mutation

Question 4

what are the two categories of mutations and what are they?

Answer 4

1. chromosomal mutation – which is when the shape or part of an entire chromosome is altered –> since a chromosome is made up of large strand of DNA, alot of genes are affected in this mutation type
2. genetic mutation – when the DNA sequence of only a specific gene is altered –> only that single gene is affected in the mutation

Question 5

what are the 3 types of genetic mutations?

Answer 5

1. substitution – mutation substitutes one base for another
   original: AATGT –> mutated: AATCT therefore the C is the cause of the mutation
2. addition – mutation adds in an extra base
   original: AATGT –> mutated: AATGTC therefore the C is the cause of the mutation
3. deletion – mutation deletes one of the bases
   original: AATGT –> mutated: AATG therefore the missing T is the cause of the mutation

Question 6

how do mutations occur?

Answer 6

they can occur naturally, or via mutagenic agents, or by the environment

Question 7

what is a mutagenic agent? give examples

Answer 7

something that makes it easier for DNA to become mutated

for ex, x-rays, radiation, UV light, radioactive susbtances

Question 8

how does the environment affect genes?

Answer 8

through “selective pressure” the environment can change the EFFECTS of the gene and how they present themselves

Question 9

how do the himalayan white rabbits show how environment affects gene expression

Answer 9

himalayan rabbits live in the snow. their fur production is dependent on the temperature of the environment. cooler temperature results in dark fur whereas hotter temperature results in white fut. the rabbits tail, paws, nose, and ears are usually touching cold air or snow so they are brown. the rest of the rabbit is white because it is not exposed to cold areas as much as the tail, paws, nose, and ear