Exam #8: Genetics Flashcards
(88 cards)
1
Q
Mendel’s Law of Segregation
A
Genes occur in pairs, separate into gametes (each gamete received 1 copy of the gene)
2
Q
Who is known as the father of genetics?
A
Gregor Mendel
Mendel conducted experiments in 1866 using garden pea plants.
3
Q
What type of plants did Mendel use for his experiments?
A
Garden pea plants
They were chosen for their distinctive traits and ease of care.
4
Q
What is the procedure Mendel used for his genetic experiments?
A
Cross-pollinate parental pea plants with true-breeding traits
He rubbed pollen from one plant onto the stigma of another.
5
Q
What does the ‘Q’ represent in Mendel’s flower color example?
A
The dominant gene for the purple trait.
6
Q
What does the ‘q’ represent in Mendel’s flower color example?
A
The recessive gene for the white trait.
7
Q
What are genes located on?
A
Chromosomes.
8
Q
What is a purebred?
A
Plants that produce offspring of the same variety when they self-pollinate.
9
Q
What is the phenotype?
A
Appearance of the trait
Examples include purple flowers and white flowers.
10
Q
What is the genotype?
A
Actual genes inherited
For example, purple flower can be QQ or Qq, while white flower is qq.
11
Q
Define homozygous.
A
2 inherited genes are the same.
12
Q
What is homozygous dominant?
A
QQ.
13
Q
What is homozygous recessive?
A
qq.
14
Q
Define heterozygous.
A
2 inherited gene copies are different
Example: Qq (hybrid, carrier).
15
Q
What is an allele?
A
Alternative forms of a gene.
16
Q
What does locus refer to in genetics?
A
Position or location of a gene on the chromosome.
17
Q
What does the P generation represent?
A
Parental generation; cross between purebreds.
18
Q
What does F1 stand for?
A
1st initial generation; offspring of parental cross.
19
Q
What is a monohybrid cross?
A
A cross between heterozygotes.
20
Q
What does F2 represent?
A
2nd filial generation; offspring of F1 parents.
21
Q
Mendel’s Law of Independent Assortment
A
Different traits are inherited independently of each other.
22
Q
Test Cross
A
Done to determine the genotype of an individual having a dominant trait but of unknown parentage.
23
Q
Dihybrid Cross
A
Inheritance of 2 traits; gene pairs are on 2 different sets of homologous chromosomes.
24
Q
Incomplete Dominance
A
In heterozygous, intermediate form, blending of traits (in between)
25
Codominance
In heterozygotes, both gene alleles completely express their traits.
26
ABO blood typing
Multiple alleles, 2 genes are possible in a population.
It classifies blood based on the presence or absence of A and B antigens on the surface of red blood cells.
27
Blood type A can donate blood to?
A and AB
28
Blood type A can receive blood from?
A and O
29
Blood type B can donate blood to?
B and AB
30
Blood type B can receive blood from?
B and O
31
Blood type O can donate blood to?
Anyone
32
Blood type O can receive blood from?
O
33
Blood type AB can donate blood to? and receive from?
Donate to AB
Receive from anyone
34
Epistasis
1 gene affects the expression of a second pair of genes.
35
Example of Epistasis
1 gene pair codes for melanin (B for brown, b for pigment)
2nd gene pair codes for whether melanin will be made or not.
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What is pleiotropy?
One gene affects more than 1 trait
## Footnote
Examples include sickle cell anemia and the albino gene affecting visual development.
38
What is polygenic inheritance?
Traits result from the effects of 2 or more genes
## Footnote
Examples include height, weight, intelligence, and personality.
39
What is the formula for calculating the number of phenotypes in polygenic inheritance?
2n + 1, where n = number of genes
40
What is hybrid vigor?
Traits expressed in offspring in excess of either parent
## Footnote
Example: short parents having a tall child.
41
What does variable expressivity mean?
The same gene expresses itself differently at different times
## Footnote
Example: polydactylism, where a person may have an extra finger or toe.
42
How can environmental effects impact gene expression?
Gene expression is affected by the environment
## Footnote
Examples include Siamese cats and water buttercups.
43
What is chromosomal mapping?
Determining the location of genes on a chromosome
## Footnote
Linkage maps estimate gene locations.
44
What was the Human Genome Project?
A scientific effort to map and sequence the entire human genome, completed in 2003.
45
What is nondisjunction?
The failure of chromosomes to separate properly during cell division.
46
What is Down Syndrome?
Trisomy 21; 47 chromosomes with an extra #21
## Footnote
Symptoms include short stature, eyelid fold, and high risk of leukemia.
47
What characterizes Turner Syndrome?
XO; 45 chromosomes; lacking a sex chromosome
## Footnote
Symptoms include short stature and sterility.
48
What is Klinefelter's Syndrome?
XXY or XXXY; 47 chromosomes with extra sex chromosomes, occurs in males. Extra X chromosome
## Footnote
Characterized by sterile males with small testes and possible learning disabilities.
49
What is Trisomy (XXX) also known as?
Metafemale; 47 chromosomes with potential menstrual irregularities.
50
What defines Jacob Syndrome (XYY)?
47 chromosomes; normal male, very tall, possibly aggressive
## Footnote
Once thought to be associated with criminal behavior.
51
What is an example of an autosomal dominant disorder?
Huntington’s Disease
## Footnote
Characterized by loss of voluntary muscle control and insanity onset usually after 30.
52
What is neurofibromatosis?
1 in 3,000; characterized by large tan spots on the skin and benign tumors.
53
What is albinism?
1 in 20,000; lack of pigmentation leading to increased skin cancer and blindness.
54
What is phenylketonuria (PKU)?
1 in 10,000 births; lack an enzyme to metabolize phenylalanine
## Footnote
Leads to mental disability and is treatable with diet.
55
What does cystic fibrosis cause?
Thick mucus in the respiratory and digestive passageways
## Footnote
Average life span = 25 years.
56
What is Tay-Sachs disease?
1 in 3,600 Jewish people; lack of lysosomal enzyme causing severe mental disability.
57
What is sickle cell anemia?
1 in 400 African Americans; abnormal hemoglobin causing severe pain and damage to organs.
58
What is red-green color blindness?
1 in 12 males and 1 in 250 females; lack of visual pigment in the retina.
59
What is royal hemophilia?
1 in 15,000 males; inability of blood to clot, leading to severe risk from minor injuries.
60
What is Duchenne muscular dystrophy?
1 in 3,500 boys; abnormal protein causing muscle deterioration and paralysis by age 12.
61
What are Barr bodies?
Normal inactivated X sex chromosomes in all mammalian females
## Footnote
Women are mosaics of X-linked traits.
62
What are Y-linked traits?
Traits determined by genes on the Y chromosome, passed from father to son
## Footnote
Example: hairy ears.
63
What is parental (genomic) imprinting?
Same gene expressed differently when inherited from different parents.
64
What condition is associated with a deletion from maternal chromosome 15?
Angelman’s Syndrome
## Footnote
Symptoms include intellectual disability and severe speech impairment.
65
What condition is associated with a deletion from paternal chromosome 15?
Prader-Willi Syndrome
## Footnote
Symptoms include weak muscle tone and feeding difficulty.
66
What is the Rh blood type?
Presence or absence of 'D' protein on red blood cell membrane.
67
Fill in the blank: Erythroblastosis fetalis occurs when an Rh- mom has an Rh+ _______.
fetus
68
Examples of nondisjunction?
Down syndrome, turner syndrome, Klinefelter's syndrome, trisomy, and jacob syndrome.
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Examples of autosomal Dominant
Huntington's disease and neurofibromatosis
70
Examples of autosomal recessive
Albinism, PKU, cystic fibrosis, and Tay-Sachs.
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What is an example of autosomal recessive AND/OR codominant?
Sickle cell anemia
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X-linked recessive
Red-green color blindness
Royal Hemophilia
Duchenne Muscular Dystrophy
73
How do you determine if there is a dominant trait in pedigree?
No carriers
Frequent
Does not skip generations
74
How do you determine if there is a recessive trait in pedigree?
Carriers
Infrequent
Skips generations
75
How do you determine autosomal inheritance in pedigree?
Afflicted males and females
Both males and females are carriers
76
How do you determine X-linked inheritance in a pedigree?
More males afflicted than females
Only females are carrier
If girl has it , dad has to have it
77
How do you determine Y-linked inheritance in a pedigree?
only men , ALL men
78
79
What is karyotyping?
A process involving blood sample analysis to photograph and examine chromosomes after isolating white blood cells and freezing during cell division.
## Footnote
Karyotyping helps in diagnosing genetic disorders by analyzing the chromosomal structure.
80
What is amniocentesis and when is it performed?
A procedure performed at 16-18 weeks to remove amniotic fluid and isolate fetal cells for testing.
## Footnote
Amniocentesis provides results in 2-4 weeks and can be used for karyotyping, enzyme tests, and DNA analysis.
81
What is the purpose of chorionic villi sampling (CVS)?
To remove chorion at 10-12 weeks for fetal testing, providing results in 1-2 weeks.
## Footnote
CVS allows for early diagnosis of genetic disorders by analyzing fetal cells.
82
What does biochemical analysis test for?
The presence of normal enzymes.
## Footnote
This analysis is crucial for diagnosing certain metabolic disorders.
83
What are gene markers?
Bits of DNA often inherited along with disease genes.
## Footnote
Gene markers can help track genetic disorders within families.
84
What are single nucleotide polymorphisms (SNPs)?
A single nucleotide substitution found near a disease gene.
## Footnote
SNPs can serve as markers for genetic disease susceptibility.
85
What dietary management is used for PKU and galactosemia?
Dietary restrictions to manage the conditions.
## Footnote
These genetic disorders require specific dietary modifications to avoid harmful substances.
86
What drug is used in the treatment of cystic fibrosis?
DNAse.
## Footnote
DNAse helps to break down the thick mucus in cystic fibrosis patients.
87
What is gene therapy?
Inserting a normal copy of a gene into cells of persons with a disorder.
## Footnote
Gene therapy is being researched for conditions like ADA deficiency and cystic fibrosis.
88
What does genetic engineering involve?
The direct manipulation of genes for practical purposes.
## Footnote
Genetic engineering is a key component of biotechnology and has applications in medicine, agriculture, and research.
