Heredity

Question 1

Genotype

Answer 1

Genetic component of inheritance. Includes one copy from each parent

Question 2

Phenotype

Answer 2

Physical trait displayed, arising from genotype

Question 3

Gene

Answer 3

Basic unit or sequence of genetic material that encodes a trait

Question 4

Locus

Answer 4

A gene’s location within a genome

Question 5

Allele

Answer 5

variant form of a gene

Question 6

Homologous chromosomes

Answer 6

Pair of chromosomes that contain the same genes in the same locations

Question 7

Hemizygous

Answer 7

Having only one copy of a gene instead of two

Question 8

Heterozygous

Answer 8

Carrying a copy of the recessive allele on one of the homologous chromosomes and a copy of the dominant allele on the other chromosome

Question 9

Homozygous

Answer 9

Carrying the same alleles on each homologous chromosome

Question 10

Homozygous dominant

Answer 10

Carries two copies of the dominant allele (BB)

Question 11

Homozygous recessive

Answer 11

Carries two copies of the recessive allele (bb)

Question 12

Law of Segregation

Answer 12

During Anaphase 1, homologous chromosomes segregate resulting in haploid gametes that contain only one allele per gene

Question 13

Law of independent assortment

Answer 13

Lining up and seperation of one pair of homologous chromosomes does not influence that of a different pair of homologous chromosomes

Question 14

Law of dominance

Answer 14

Dominant allele masks the expression of a recessive allele

Question 15

Test cross

Answer 15

Genetic cross between homozygous recessive person and person in question to determine genetype of given trait

Question 16

P1 generation

Answer 16

Parental generation

Question 17

F1 generation

Answer 17

1st generation (offpsring)

Question 18

F2 generation

Answer 18

2nd generation

Question 19

Punnett squares

Answer 19

Diagram to observe probabilities of offspring genotypes using the parent genotypes

Question 20

Epistasis

Answer 20

One gene’s expression masks the phenotypic expression of another

Question 21

Epistasis example

Answer 21

Baldness gene over hair color gene

Question 22

Pleiotropy

Answer 22

Single gene affects multiple phenotypic traits

Question 23

Pleiotropy example

Answer 23

Single gene controls a plants height, color, texture

Question 24

Multiple alleles

Answer 24

More than two possible alleles for a gene

Question 25

multiple allele example

Answer 25

blood type, eye color

Question 26

Polygenic Inheritance

Answer 26

Many genes determine one phenotyptic outcome

Question 27

Polygenic inheritance example

Answer 27

Height, skin color

Question 28

Incomplete dominance

Answer 28

More than one dominant allele. Heterozygote with two dominant alleles shows a blended phenotype

Question 29

Codominance

Answer 29

Both inherited dominant allels are completely expressed. Heterozygote with two dominant alleles shows both phenotypes simultaneously

Question 30

Sex linked genes

Answer 30

Reside on sex chromosome

Question 31

Sex influenced genes

Answer 31

Expression is influenced by the sex of the individual

Question 32

X- inactivation

Answer 32

Female phenomemnon in which one of the two X chromosomes (random) condenses down into an inactivated Barr body. Expressed gene come from the remaining X chromosome

Question 33

# Phenotype Variability Penetrance

Answer 33

Probability that an organism with a specific genotype will express the corresponding phenotype

Question 34

# Phenotype Variability Expressivity

Answer 34

Level of expression of a phenotype for a specific genotype

Question 35

# Human genetic defects Aneuploidy

Answer 35

Organism or cell has an abnormal number of chromosomes

Question 36

Monosomy

Answer 36

One copy of chromosome

Question 37

Trisomy

Answer 37

Three copies of chormosome (Down syndrome)

Question 38

Nondisjunction

Answer 38

Failure of chromosomes or chromatids to seperate during mitosis-meisosis. Reults in gametes with too many/few chromosomes

Question 39

Autosomal dominant

Answer 39

Single copy of mutated gene is enough to express condition

Question 40

Autosomal recessive

Answer 40

Two copies of mutated gene must be present to express the condition

Question 41

X -linked dominant

Answer 41

Single copy of the mutation of a gene on the X chromosome is enough to cause the condition in both males and females

Question 42

X-linked dominant fact

Answer 42

Affected fathers always have affected daughters

Question 43

X-linked recessive

Answer 43

Two copies of mutated gene on the X chromosomes causes the condition in females; one copy will cause condition in males

Question 44

X-linked recessive facts

Answer 44

Affected mothers always have affected sons Common in males than females Normal fathers never have affected daughters

Question 45

# Chromosomal aberrations Inversions

Answer 45

Chromosome segement is rearranged in the reverse of its original orientation

Question 46

Deletions

Answer 46

Chromosome segment is missing or deleted

Question 47

Translocation

Answer 47

Chromosome segment is moved to another

Question 48

Duplication

Answer 48

Chromosome segment is repeated on the same chromosome