Genetics

Question 1

Monohybrid cross

Answer 1

• Tt x Tt
• phenotype 3:1
• genotype 1:2:1

Question 2

Dihybrid cross

Answer 2

• TtYy x TtYy

- phenotype 9:3:3:1

Question 3

Sex-influenced trait

Answer 3

Inheritance is influenced by the sex of the individual

- ex/ baldness

Question 4

A karyotype uses chromosomes during?

Answer 4

Metaphase of mitosis

Question 5

Human chromosomes??

Answer 5

44 autosomes 2 sex chromosomes

Question 6

Gene mutation

Answer 6

Caused by a change in the DNA sequence

Question 7

Chromosome mutations

Answer 7

• can be observed under a light microscope
  1. Deletion
  2. Inversion - Order is changed
  3. Translocation crossing over between non-homologous chromosomes (ex/ #5 and #2)
  4. Polyploidy
  5. Nondisjunction
  6. Duplication

Question 8

Nondisjunction

Answer 8

Occurs in meioisis when homologous chromomes fail to separate

Question 9

PKU

Answer 9

• recessive

- Can’t break down amino acid phenylalanine(can’t eat it) or mental retardation

Question 10

Cystic fibrosis

Answer 10

• recessive
• most common lethal genetic disease in US
• buildup of extracellular fluid in the lungs, etc

Question 11

Tay-sachs disease

Answer 11

• Recessive

- lack of enzyme needed to break down lipids for brain function

Question 12

Huntington’s disease

Answer 12

• dominant

- Degenerate disease of the nervous system

Question 13

Griffith

Answer 13

• Bacterial transformation(bacteria can alter their genetic makeup by absorbing foreign DNA molecules from other cells)
• mice

Question 14

Avery, MacLeod, Mccarty

Answer 14

-proved DNA is the genetic material

Question 15

Hershey and Chase

Answer 15

• Proved that DNA, not proteins, is the molecule of inheritance
• bacteriophages

Question 16

Wilkins and Franklin

Answer 16

used X-Ray crystallography to show DNA is a double helix

Question 17

Watson and Crick

Answer 17

-Won Nobel PRize for building the first model of DNA

Question 18

P.A. Levine

Answer 18

DNA is made of nucleotides

Question 19

Chargaff

Answer 19

• Base pairing

- purines and pyrimidines

Question 20

Meselson and Stahl

Answer 20

DNA replication is seemiconservative

Question 21

Telomeres

Answer 21

• Special nonsense nucleotide sequences at the ends of chromosomes that repeat
• Protect the ends to prevent loss of genes

Question 22

Introns

Answer 22

• Intervening sequences

- Removed

Question 23

Exons

Answer 23

• Expressed sequences

- coding regions

Question 24

operon

Answer 24

-A cluster of functional genes and the switches that turn them on and off
ex/ promoter and operator
1. Lac; inducible operon
2. repressible operon

Question 25

Lac

Answer 25

• Inducible operon

- turned off unless it’s actively induced or triggered to turn on

Question 26

repressible operon

Answer 26

-Turned on unless it’s actively turned off because it’s not needed

Question 27

Promoter

Answer 27

• Binding site of RNA polymerase on DNA before transcription

- on switch

Question 28

Operator

Answer 28

-Binding site for the repressor, which turns off the Lac operon

Question 29

TATA box

Answer 29

Helps RNA polymerase bind to the promoter

Question 30

point mutation

Answer 30

-Gene mutation
-Base-pair substitution
-1 nucleotide converts to another
DOG –> HOG
ex/ sickle cell anemia

Question 31

Insertion; deletion

Answer 31

gene mutation

Frameshift

Question 32

Aneuploidy

Answer 32

Having abnormal number of chromosomes

Question 33

Polyploidy

Answer 33

Having extra sets of chromosomes 3n, 4n

Question 34

Junk

Answer 34

Noncoding regions of DNA

97% of human genome