LEC 16

Question 1

Genetics Def

Answer 1

Study of genes and their transmission from one generation to the next

Question 2

Inheritance

Answer 2

Something received from an ancestor or another person

Question 3

In terms of genes, we each inherit:

Answer 3

One complete set of genes from mom
One complete set of genes from dad

Question 4

Each set of genes has slight ___________ that vary from person to person, which accounts for our _________.

Answer 4

1. differences
2. diversity

Question 5

DNA Organization

Answer 5

23 pairs of chromosomes
Autosomes pairs - 22
Sex chromosome pairs - 1

Question 6

Autosomes Def(2)

Answer 6

1. Are identical in length & shape
2. May have slight differences in the DNA sequence

Question 7

Sex chromosomes

Answer 7

1. X & Y chromosomes are different length and shape
2. Y chromosome is smaller and shorter

Question 8

Homologous Chromosomes Def

Answer 8

1. Chromosomes that look alike
2. Have copies of the same gene at the same locus (plural: loci)

Question 9

Homologous Chromosomes Examples (2)

Answer 9

autosomes and female sex chromosomes

Question 10

Locus (plural: loci)

Answer 10

the physical location of a specific pair of genes on a chromosome

Question 11

Alleles characteristics (4)

Answer 11

1. When the gene pairs are not exactly alike
2. One or more base pair combinations differ in DNA
3. Resulting protein is slightly different structure & function
4. Changes in protein structure changes its function therefore we get different traits being expressed

Question 12

Types of Alleles (2)

Answer 12

1. Homozygous
2. Heterozygous

Question 13

Homozygous Allelle

Answer 13

two identical alleles for a particular gene

Question 14

Heterozygous Allele

Answer 14

two different alleles for a particular gene

Question 15

Case where more than two alleles for a particular gene exist: Blood Types

Answer 15

1. Blood types – A, B, O
2. Can only inherit two genes
3. Results in many combos - AA, AB, AO, BB, BO, OO

Question 16

_________ alleles arise from _________ that were not corrected in cells destined to become ___________

Answer 16

1. Different
2. mutations
3. gametes

Question 17

Genotype (3)

Answer 17

1. Your complete set of genes and alleles (also called the genome) ()
2. What you inherit from your parents
3. Without testing, it is not possible to determine exact genotype

Question 18

Phenotype def

Answer 18

Observable physical and functional traits that characterize us

Question 19

Dominant alleles def (2)

Answer 19

1. An allele that produces the same phenotype whether its paired allele is identical or different
2. Can be either: Homozygous (AA) or Heterozygous (Aa)

Question 20

Recessive alleles def (2)

Answer 20

1. An allele that produces its 2. characteristic phenotype only when its paired allele is identical
2. Can only be homozygous (aa)

Question 21

Polydactylism

Answer 21

having extra fingers & toes is a dominant trait (PP or Pp) but is rarely seen in the population

Question 22

Recessive alleles characteristics (2)

Answer 22

1. Started as mutations at some point in our evolutionary history but stayed in gene pool because they typically don’t cause any harm
2. Some can be harmful and are kept in check by either miscarriage of the fetus or premature death (before reproductive age)
3. Some harmful ones persist in a heterozygous state because they are “masked” by the dominant allele

Question 23

Father of Genetics

Answer 23

Gregor Mendel: Austrian monk

Question 24

Mendelian Genetics

Answer 24

1. Experimented with pea plants:
   Monohybrid cross
   Able to predict which trait will be visible

Question 25

Mendel tested for: (4)

Answer 25

Shape – seeds, pods
Color – seeds, pods, flowers
Flower position
Stem length

Question 26

Mendel results

Answer 26

Always resulted in a 3:1 ratio of dominant vs. recessive phenotype expressions

Question 27

Law of Segregation

Answer 27

When gametes are formed in parents, the alleles separate from each other so that each gamete only gets one allele of each gene

Question 28

Punnett Squares (2)

Answer 28

simple method used to predict:
1. Patterns of inheritance
2. The probability that a particular genotype will be inherited

Question 29

Punnett Squares Probability expressed as:

Answer 29

1. A ratio – ie. 3: 1 (dominant:recessive)
2. A fraction – ie. ¾ dominant and ¼ recessive
3. A percent – ie. 75% dominant, 25% recessive