Genetics (Lect2)

Question 1

What is genetic variation?

Answer 1

The differences in DNA sequences among individuals within a population

Question 2

What is evolution?

Answer 2

Changes happen to inherited characteristics within a population over time as a result of natural selection

Question 3

What are the 3 things genetic variation can result from?

Answer 3

-Mutations
-Sexual reproduction: meiosis= new combo of genes
-gene flow= transfer of genes between populations through migration=new genetic material introduced

Question 4

What is inheritance?

Answer 4

process by which genetic info is passed from parents to offspring

Question 5

What is gene-environemnt interaction?

Answer 5

-the impact of an environmental exposure of disease risk is different for people with different genotypes OR
-the impact of a genotype on disease risk is different in people with different environmental exposures

Question 6

What is DNA composed of?

Answer 6

-2 strands that coil around each other= double helix
-each strand= nucleotides made up of sugar, phosphate + nitrogenous base

Question 7

What are genes?

Answer 7

-segments of DNA that contain instruction for building proteins
-varies in length

Question 8

What is a trait?

Answer 8

any observable feature/characteristic of an organism

Question 9

What is an inherited character?

Answer 9

produced by genes transmitted from parent to offspring

Question 10

What is an oligogenic/qualitative character?

Answer 10

-a character controlled by only a few genes
-discontinuous variation e.g. blood type
-not influenced by environment

Question 11

What is a polygenic/quantitative character ?

Answer 11

-a character controlled by many genes
-continuous variation e.g. weight
-influences by environment

Question 12

What is a genotype?

Answer 12

the total genetic makeup of an organism

Question 13

What is a phenotype?

Answer 13

all observable traits of an organism that results from the interaction of its genotype with its environment

Question 14

What is an allele?

Answer 14

different versions of the same gene that can result in different traits

Question 15

What is a mutation?

Answer 15

-a change in the DNA sequence of an organism
-can be beneficial, harmful or neutral

Question 16

What can mutations result from?

Answer 16

-errors in DNA replication during cell division
-exposure to mutagens
-viral infection

Question 17

What are the types of mutations?

Answer 17

-substitution
-inversion
-insertion
-deletion (causes large no. of genetic diseases)

Question 18

What is an oncogene?

Answer 18

a mutated gene that has the potential to cause cancer

Question 19

How does cancer arise from a oncogene?

Answer 19

-before oncogene becomes mutated= proto-oncogene
-mutates causing cell to divide and multiply uncontrollably

Question 20

What is an exon?

Answer 20

-region of genome that ends up within an mRNA molecule
-some are coding (info for making a protein) others= non-coding

Question 21

What does Mendelian inheritance refer to?

Answer 21

-how traits are passed
-focuses on traits controlled by single gene with 2 alleles

Question 22

What does the pattern of inheritance of Mendelian traits depend on?

Answer 22

whether traits are controlled by genes on autosomes or by genes on sex chromosomes.

Question 23

Representations of inheritance