Genetics: Quiz 2

Question 1

Define gene

Answer 1

A segment/band on a chromosome that determines a particular characteristic

Question 2

Define alleles

Answer 2

Each genes possible different forms.
Ex. Gene = hair colour
Allele = brown, blond etc

Question 3

Define dominant allele

Answer 3

Always represented in the physical characteristics of an individual if present

Question 4

Define recessive allele

Answer 4

Only represented in the physical characteristics of an individual if dominant allele is absent

Question 5

An individual where both alleles are the same is…

Answer 5

Homozygous dominant OR recessive

Question 6

An individual in which both alleles are different is…

Answer 6

Heterozygous

Question 7

Define genotype

Answer 7

Genetic makeup of the individual

Question 8

Define phenotype

Answer 8

Physical appearance of the individual

Question 9

Who was the father of modern genetics? (In terms of inheritance)

Answer 9

Gregor Mendel

• Austrian monk
• examined garden peas
• each trait in the peas had only two possible variations
• first person to propose principle of dominance, law of segregation, law of independent assortment

Question 10

Define principle of dominance

Answer 10

When individuals with different alleles reproduce, offspring only express the dominant trait

Question 11

Define Law of segregation

Answer 11

Each gene separates from the other so that the offspring get only one gene from each parent

Question 12

State generation terms

Answer 12

P - parental
F1 - children
F2 - children’s children

Question 13

Define complete dominance

Answer 13

One allele is dominant and masks the presence of the other allele

Question 14

Define incomplete dominance

Answer 14

Neither allele is dominant. A blend of the 2 is expressed in the phenotype

Question 15

Define codominance

Answer 15

Both alleles are dominant traits. Both expressed in phenotype

Question 16

List the blood alleles

Answer 16

A B and O

Question 17

List the 4 blood types and their genotypes

Answer 17

A = IAIA OR IAi
B = IBIB OR IBi
AB = IAIB
O = ii

Question 18

What is a pedigree?

Answer 18

Diagrams that illustrate the genetic relationship among a group of related individuals

Question 19

Define Autosomal inheritance

Answer 19

Males and females affected EQUALLY Since there’s no difference between autosomes it males and females

Question 20

Define sex-linked inheritance

Answer 20

Alleles causing genetic disorders found on X and Y chromosomes (sex chromosomes)

Question 21

Describe X-linked disorders

Answer 21

• phenotypic expression on an allele that is found only on X chromosome
• recessive X disorder is more likely to express itself in males than females because males only have 1 X

Question 22

Describe Y linked disorders

Answer 22

• passed only from father to son

- fewer y disorders than x because Y chromosome is small and doesn’t carry as much genetic info as x

Question 23

What does DNA stand for?

Answer 23

Deoxyribonucleic acid

Question 24

What are the 3 main components of DNA

Answer 24

• a pentose sugar
• a phosphate sugar
• a nitrogenous base

Question 25

What is a nucleotide and what are the 4 possible bases?

Answer 25

NUCLEOTIDE - the repeating unit in DNA. Made of a phosphate Group, pentose sugar and a nitrogenous bade.

4 possible bases:
Adenine
Cytosine
Guanine
Thymine

Question 26

Describe complementary base pairing

Answer 26

Pairing of the nitrogenous base of one strand of DNA with the nitrogenous base of another: A+T G+C

Question 27

Describe the human genome project

Answer 27

• goal was to determine the complete 3 BILLION nitrogenous base sequences of human DNA
• worldwide project

Question 28

Difference between coding and non coding DNA

Answer 28

CODING - region of DNA that contains a sequence of nucleotides that will be expressed (a gene)

NON CODING - region of DNA that DOES NOT contain a sequence of nucleotides that will be expressed

Question 29

Describe DNA fingerprinting

Answer 29

A pattern of bands on gel that is characteristic to humans, but unique to each individual