CH 23 SG

Question 1

genetics

Answer 1

the study of heredity and the variation of inherited characteristics

Question 2

true-breeding organisms

Answer 2

(pure-bred) self-fertilized or bred w/ another these organisms for the same traits, consistently produces offspring with the same traits

Question 3

What’s the genetic relationship between homologous chromosomes?

Answer 3

(pair of chromosomes) one from each parent, that contain the same genes in the same order, but may have different alleles (versions of the same gene).

Question 4

How does Mendel’s law of segregation apply to genetic crosses?

Answer 4

In gamete formation, the 2 alleles for a trait segregate (separate) from each other, so that each gamete contains only one allele for each trait

Question 5

How does Mendel’s law of independent assortment apply to a dihybrid cross?

Answer 5

alleles for different traits (genes) sort into gametes independently of each other (inheritance of one trait does not influence the inheritance of another)

Question 6

How can the rule of multiplication (product rule) and the rule of addition (sum rule) be used to determine the probability of an event?

Answer 6

Pro - calculates probability of 2/more independent events happening by multiplying individual probabilities
Sum - calculates probability of one of 2/more mutual events happening adding individual probabilities

Question 7

How can familial pedigrees help determine the inheritance of many human traits?

Answer 7

By analyzing the pattern of a trait’s appearance within a family, pedigrees can reveal whether a trait is inherited in a dominant, recessive, or sex-linked manner

Question 8

How are recessive and dominant disorders inherited?

Answer 8

Dom - inherited when a single copy of a mutated gene is enough to cause the condition
Rec - require two copies of the mutated gene, one from each parent, to manifest

Question 9

What are some examples on how we can detect genetic disorders during pregnancy?

Answer 9

– Amniocentesis
– Chorionic villus sampling (CVS)
– Noninvasive prenatal testing (NIPT)

Question 10

What are Mendel’s Laws?

Answer 10

-law of dominance
-law of segregation
-law of independent assortment

Question 11

How is the sickle-cell allele adaptive?

Answer 11

it provides protection against malaria, even in carriers who only have one copy of the allele (in areas where malaria is prevalent)

Question 12

ABO blood group

Answer 12

A,B, AB, O
Rh (+ is dominant/- is recessive)
A (ia) and B (ib) are codominant/O (i) is recessive
*codominant/multiple alleles

Question 13

Why are many traits complex and not able to be predicted by simple Mendelian inheritance?

Answer 13

They’re complex and don’t follow simple Mendelian inheritance due to various factors like incomplete dominance, co-dominance, multiple alleles, and environmental influences

Question 14

How does the sex chromosomes determine sex?

Answer 14

Females typically have two X chromosomes (XX), while males typically have one X and one Y chromosome (XY) (the Y carries the SRY gene it triggers the development of male characteristics)

Question 15

What role did Gregor Mendel play in the history of genetics?

Answer 15

considered the “father of genetics” for his pioneering work on heredity, specifically his experiments with pea plants (discovered the fundamental laws of inheritance, shows that traits are passed down in patterns based on unique units (genes))

Question 16

Why are serious dominant disorders less common than recessive disorders?

Answer 16

(Huntington’s disease (later)) individuals carrying a dominant allele for a harmful condition are more likely to be eliminated by natural selection /recessive disorders can be hidden by carriers ( tend it skip generations)

Question 17

What factors can affect genes?

Answer 17

Chemicals, nutrition, sunlight, and other internal and external environmental factors (location w/ high risk of malaria—are more likely to have higher #s of Sickle cell disease) (location w/ equator most likely determines one’s skin coloration)

Question 18

universal donor

Answer 18

O- (have nothing to attack)

Question 19

universal recipients

Answer 19

AB+ (has all the blood types can’t attack anything)

Question 20

Different sex chromosome systems in different animals

Answer 20

Crickets - M:22+X/F:22+XX
Chickens - M:76+ZZ/F:76+ZW
Bees - M:16(n)/F:32(2n)

Question 21

***Non-chromosomal sex determination mechanisms

Answer 21

components of chromosomes can be chemically modified by adding or removing chemical groups on the DNA and/or protein components of chromosomes (epigenetic inheritance) - an alligators environmental temperature can determine the sex

Question 22

Allele

Answer 22

Alternative form of a gene; alleles occur at the same locus on homologous chromosome

Question 23

Locus

Answer 23

Physical location of a trait/gene on a chromosome

Question 24

Phenotype

Answer 24

(Physical) visible expression of a genotype e.g. brown eyes or attached earlobes

Question 25

Genotype

Answer 25

Genes of an organism for a particular trait(s); often designated by letters - BB or Aa

Question 26

Dominant allele

Answer 26

Allele that exerts its phenotypic effect in the heterozygote; it masks, the expression of the recessive allele

Question 27

Recessive allele

Answer 27

Allele that exerts its phenotypic effect only in the homozygote; its expression is masked by the dominant allele

Question 28

Homozygous

Answer 28

Possessing two identical alleles for a particular trait (AA)

Question 29

Heterozygous

Answer 29

Possessing unlike alleles for a particular trait (AB)

Question 30

Monohybrid cross

Answer 30

Cross between parents that defer in only one trait

Question 31

Punnett Square

Answer 31

Visual representation developed by Reginald Punnett that is used to calculate the expected results of simple, genetic crosses

Question 32

Testcross

Answer 32

Cross between an individual with a dominant phenotype to determine whether the dominant individual is heterozygous or homozygous

Question 33

Dihybrid cross

Answer 33

Cross between parents that differ in two traits

Question 34

Pedigree

Answer 34

Chart of genetic relationship of family individuals across generations (family tree)

Question 35

Tay-Sach disease

Answer 35

Autosomal recessive genetic disorder that results in a deficiency in the enzyme hexosaminidase A; causes a accumulation of glycolipids in the lysosomes, resulting in a progressive loss of psychomotor function

Question 36

Cystic fibrosis

Answer 36

Genetic disease caused by a defect in the CFTR gene, which is responsible for the transformation of a transmembrane chloride ion transporter causes the mucus of the body to be vicious/thick/over abundant

Question 37

Phenylketonuria (PKU)

Answer 37

Autosomal recessive, genetic disorder that causes a lack of the enzyme that metabolizes phenylalanine; the accumulation of this causes problems with nervous system development and function

Question 38

Sickle cell disease

Answer 38

Autosomal recessive, genetic disorder that causes a malformation of hemoglobin molecules, causing red blood cells to form a sickle shape; also sometimes s-c anemia due to the symptoms of the disease

Question 39

Marfan syndrome

Answer 39

Autosomal dominant genetic disorder of the connective tissue, specifically the fibrillin protein

Question 40

Huntington’s disease

Answer 40

Autosomal dominant, genetic disorder that affects the nervous system; results in a progressive loss of neurons in the brain

Question 41

Osteogenesis imperfecta

Answer 41

Dominant genetic disorder of humans that is characterized by a weakened bone structure

Question 42

Incomplete dominance

Answer 42

Inheritance pattern in which an offspring has an intermediate phenotype (red flower plant and a white flower plant produce a pink flower offspring)

Question 43

Familial hypercholesterolemia

Answer 43

Dominant genetic disorder that causes an accumulation of cholesterol in the blood due to defects in the LDL receptors on the cell surface

Question 44

Multiple alleles

Answer 44

the situation where a gene has more than two allelic forms (variations) within a population (different fur colors in a rabbit (ex. effects an organism’s phenotype))

Question 45

Codominance

Answer 45

Inheritance pattern in which both alleles of a gene are equally expressed as a heterozygote

Question 46

Polygenic inheritance

Answer 46

Pattern of inheritance where a trait is controlled by a several allelic pairs (many genes = one trait) (ex. height, skin, color, body size, diabetes, heart, disease, cancer, etc.)

Question 47

Hybrid

Answer 47

The offspring of two different purebred varieties

Question 48

The different generations

Answer 48

P generation - parental plants F1 generation - their hybrid offspring F2 generation - across of the F1 plants forms

Question 49

Wild-type

Answer 49

Traits those seen most often in nature are not necessarily specified by dominant alleles

Question 50

Carriers

Answer 50

Individuals who have the recessive allele of a disorder, but appear normal

Question 51

Pleiotropy

Answer 51

When one gene influences several characteristics (sickle cell disease – result in abnormal, hemoglobin protein)

Question 52

Chromosome Theory of Inheritance

Answer 52

Humans have an estimated 21,000 genes located on 23 pairs of chromosomes

Question 53

Linked genes

Answer 53

Located near each other on the same chromosome and tend to travel together during meiosis and fertilization (do not follow Mendel‘s law of independent assortment)

Question 54

Gene

Answer 54

The basic unit of genetic information each it consists of a stretch of DNA that is part of a chromosome, and it affects at least one genetic trait

Question 55

Law of Dominance

Answer 55

one trait (dom) will mask the other (rec) in the 1st generation (F1) of offspring. In 2nd generation (F2), both traits will reappear, but the dominant trait will be more prevalent

Question 56

Law of Segregation

Answer 56

(a parent gives just one allele for a gene to each give me they produce) Mendelian principle that explains how an a diploid organism allele separate during the formation of the gametes

Question 57

P generation

Answer 57

parental generation

Question 58

F1 generation

Answer 58

the first generation of offspring produced by a set of parents

Question 59

F2 generation

Answer 59

second generation of offspring resulting from cross-breeding

Question 60

Trait

Answer 60

Any inherited feature of an organism that can be observed or detected (size, color and length of fur)