Chapter 14

Question 1

Ancient theory: Homunculus

Answer 1

A supposed microscopic but fully formed human being from which a fetus was formerly believed to develop.

Question 2

Ancient theory: Blending

Answer 2

Colors of the parents mix just like colors. Hypothesis- eventually everyone will be uniform.

Question 3

Mendel- “particulate inheritance” theory

Answer 3

Hereditary elements are passed on in discrete units rather than “blended” together at each new generation.

Question 4

Character

Answer 4

A heritable feature that varies among individuals. Color is a character, the specific color is a trait.

Question 5

Traits

Answer 5

Variants for a character. Color is a character, the specific color is a trait.

Question 6

“True Breeding”

Answer 6

Always produces identical offspring with regard to character under study.

Example: a plant with purple flowers is true-breeding if the seeds produced by self-pollination in successive generations all give rise to plants that also have purple flowers.

Question 7

Self-pollinating

Answer 7

Plant which produces pollen to fertilize itself.

Question 8

Hybridization

Answer 8

Mating or crossing of 2 true/pure-breeding varieties

Question 9

Law of Independent Assortment

Answer 9

The alleles of two (or more) different genes get sorted into gametes independently of one another. In other words, the allele a gamete receives for one gene does not influence the allele received for another gene.

Happens in metaphase 1.

Mendel’s second law

Question 10

Law of Segregation

Answer 10

2 alleles for a heritable character segregate (separate from each other) during gamete formation and end up in different gametes. Depending on tetrad formation, can happen during anaphase I or anaphase II.
One gamete = just G, not Gg or gg or GG.

Question 11

Codominance

Answer 11

Red flower + White flower = Red/white flower.

A type of inheritance in which two versions (alleles) of the same gene are expressed separately to yield different traits in an individual.

Question 12

Incomplete Dominance

Answer 12

Red flower + White flower = Pink flower

A form of Gene interaction in which both alleles of a gene at a locus are partially expressed, often resulting in an intermediate or different phenotype

Question 13

Monohybrids

Answer 13

The offspring of two individuals that differ in respect of a single gene. Need to be different at at least one locus.

Question 14

Dihybrid Cross

Answer 14

A hybrid that is heterozygous for alleles of two different genes. 2 different characters.

Question 15

Multiple Alleles

Answer 15

Cases where more than two different alleles of the same gene are present in a population, such as blood type.

Question 16

Pleiotropy

Answer 16

Where a single gene controls/influences multiple phenotypic results. Unrelated results.

Question 17

Polygenic inheritance

Answer 17

Where a single trait is controlled by more than 2 genes. A bellshape curve distribution of phenotypes. An ABC genotype, vs multiple alleles, which is an I_ai, I_bi, or ii.

Question 18

Nature vs. Nurture

Answer 18

Environment vs Genetic coding.

I.e. soil ph affecting hydrangea flower colors.

Question 19

Human Inheritance Patterns

Answer 19

identify genotypes and predict future inheritance patterns of human traits.

Question 20

Multifactorial

Answer 20

Many factors affect phenotype - genetics and environment.

Question 21

Dominantly Inherited Disorders

Answer 21

Don’t need to be homozygous to be expressed. Huntington’s disease can be Hh or HH. Achondroplasic dwarfism.

Question 22

Achondroplasic Dwarfism

Answer 22

Extremely rare. Dominantly inherited disorder.

Question 23

Fetal Testing.

Answer 23

Also known as prenatal testing. Can identify whether your baby is more or less likely to have certain birth defects

Question 24

Newborn Screening

Answer 24

A PKU (phenylketonuria) screening test is a blood test given to newborns one to three days after birth. The test measures the amount of phenylalanine (Phe) in the baby’s blood. A normal level is less than 2 milligrams per deciliter (mg/dL)

Question 25

Epistasis

Answer 25

alleles of 1 gene totally mask allele expression of a totally seperate (another locus) gene.

Question 26

Amniocentesis

Answer 26

Amniocentesis (also called amnio) is a prenatal test that takes amniotic fluid from around your baby in the uterus (also called womb). The fluid is tested to see if your baby has certain health conditions.

16-20 weeks.

Question 27

Chorionic Villus Sampling

Answer 27

(CVS) Is a prenatal test that involves taking a sample of tissue from the placenta. The test is used to diagnose certain birth defects and genetic abnormalities in a baby.

Uses ultrasound to make sure they control needle.

Question 28

Heterozygote superiority

Answer 28

Sickle-cell anemia - ss
Sickle-cell trait - Ss
Normal cell - SS

Ss has ‘heterozygote superiority’, because the deformed cells (due to mal-formed cell) provide some resistance to the malarial protozoan.

Question 29

Carriers

Answer 29

Phenotype = normal
Genotype = contains recessive disorder allele