Chapter 12

Question 1

Genetics

Answer 1

Study of heredity (and all things relating to DNA)

Question 2

Heredity

Answer 2

Is the transmission of biological traits from parent to offspring

Question 3

What genetic principles account for the transmission of traits from parents to offspring?

Answer 3

“Blending” hypothesis : genetic material mix together like paint colors
“Particulate” hypothesis of inheritance : parents pass on discrete heritable units called genes that code for a particular trait

Question 4

Gregor Mendel

Answer 4

Founded the science of genetics and discovered the basic principles of heredity
-documented inheritance through his experiments with garden peas

Question 5

Character

Answer 5

A heritable feature, such as flower color

Question 6

Trait

Answer 6

A variant of a character, such as purple or white flowers

Question 7

True-breeding plants

Answer 7

-Self pollination yields offspring with the same traits as parent
-Mendel chose true-breeders to begin tracking inheritance

Question 8

Monohybrid cross

Answer 8

Track single trait

Question 9

P generation

Answer 9

Parent generation, Mendel crossed parents with different traits for a given character
Ex: plant with purple flowers mates with plant with white flowers

Question 10

F1 generation

Answer 10

The hybrid offspring of the cross pollination of P generation

Question 11

F2 generation

Answer 11

Produced when F1 individuals self-pollinate or crossed (F1xF1)

Question 12

Hybrid

Answer 12

Parent generation was two different traits

Question 13

Medel had no knowledge of chromosome or genes or the phases of meiosis

Question 14

Alleles

Answer 14

Are alternative versions of genes account for variations of inherited traits

Question 15

Dominant

Answer 15

Allele determines the organisms appearance
-designated by UPPERCASE letter ( ex: P for purple)

Question 16

Recessive

Answer 16

Allele has no noticeable effect on the organisms appearance
-designated by lowercase letter (ex: p for white)

Question 17

Homozygous

Answer 17

Organism for a particular gene if it has a pair of identical alleles for a trait (both dominant or both recessive -PP or pp)- it will exhibit true breeding

Question 18

Heterozygous

Answer 18

Organism for a particular gene if the pair of alleles are different for that trait (one dominant and one recessive (Pp) - only the dominant gene will ‘show’)

Question 19

Phenotype

Answer 19

Organisms physical appearance (ex:tall, purple)

Question 20

Genotype

Answer 20

Genetic make up (homozygous/heterozygous)

Question 21

Probability

Answer 21

Likelihood of an event occurring

Question 22

Punnet square

Answer 22

Used to determine all possible outcomes of known genotypes

Question 23

Testcross

Answer 23

In pea plants with purple flowers the genotype is not immediately obvious

A dominant phenotype may result from either genotype (homozygous dominant (PP) or heterozygous (Pp)

Allows us to determine the unknown genotype of an organisms with the dominant phenotype

Question 24

Dihybrids

Answer 24

Heterozygous for both characters

Question 25

Law of segregation

Answer 25

Meiosis separates homologous pairs of chromosome so that a gamete receives only one (during metaphase 1)

Question 26

Law of independent assortment

Answer 26

Homologue a zygote (offspring) receives is random based on the alignment of tetrads (during metaphase 1)

Question 27

Law of independent assortment

Answer 27

A dihybrid cross illustrates the inheritance of two characters ; the destination of one allele (on a chromosome) into a gamete is completely unrelated to the destination of any other allele.

Question 28

Complete dominance

Answer 28

Occurs when the phenotypes of the heterozygous and dominant homozygote are identical , one allele completely dominates

Question 29

Co-dominance

Answer 29

Two dominant alleles affect the phenotype in separate distinguishable ways

Question 30

Incomplete Dominance

Answer 30

Phenotype of f1 hybrids is somewhere between the phenotypes of the two parental varieties

Question 31

Pleiotropy

Answer 31

Gene has multiple phenotypic effects

Question 32

Epistasis

Answer 32

Gene at one locus alters the phenotypic expression of a gene at a second locus

Question 33

Cystic fibrosis

Answer 33

Abnormal chloride transport protein Thick mucus builds up in some internal organs (digestive tract, lungs) Abnormal absorption of nutrients, chronic bronchitis, infections

Question 34

Sickle cell disease

Answer 34

Malformed RBC clump and clog vessels Insufficient oxygen exchange to tissues Incomplete and codominance

Question 35

Consanguineous

Answer 35

Mating with the same blood line

Question 36

Huntingtons disease

Answer 36

Degenerative disease of the nervous system (victim of reproductive age passes the disorder to offspring)

Question 37

Multi factorial disorders

Answer 37

Many human diseases have both genetic and environment components - any character influenced by both genetic and environmental factors

Question 38

Thomas hunt Morgan

Answer 38

First geneticist to associate a specific gene with a specific chromosome

Question 39

Chromosome theory of inheritance

Answer 39

Chromosomes are the vehicles of genetic heredity

Question 40

Sex linked gene

Answer 40

Gene locates on either sex chromosome

Question 41

Nondisjunction

Answer 41

Pairs of homologous chromosome or sister chromatids (do not separate normally during meiosis)