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Science - Living Earth > Ch11+14 - Genetics > Flashcards

Ch11+14 - Genetics Flashcards

1
Q

What is genetics?

A

the study of heredity

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2
Q

What is a gene?

A

A segment of DNA that controls traits

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3
Q

What is an allele?

A

A version of a gene

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4
Q

Who was Gregor Mendel? What was he known for?

A
  • Father of Genetics (1822)
  • Austrian monk who worked at a monastery garden
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5
Q

What are the parts and functions of a basic flower?

A
  • Sepal: bottom of flower, protects flower bud
  • Petals: attract pollinators whole protecting inner reproductive structures
  • Stamen: Male parts of flower, produces pollen
  • Carpel: Female parts of flower, produces eggs
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6
Q

Why did Gregor Mendel choose garden peas to perform his research?

A
  • Garden peas self pollinate - Sexual structures are enclosed with petals
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7
Q

Define pollination

A

Transferring pollen from anthers to stigma of flowers for fertilization

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8
Q

What is true-breeding? Example

A

Seeds produced will inherit the same qualities as parents due to self-pollination
- Ex. True-bred tall plants will only produce tall plants

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9
Q

How did Gregor Mendel prevent self pollination?

A

He cut away the stamen

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10
Q

What is cross pollination? How did Mendel cross-pollinate?

A

Cross-pollination: Pollen from 1 flower fertilizes egg of another flower
- Mendel dusted flower 1 with pollen from flower 2

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11
Q

When/how is a test cross used?

A

Crossing dominant phenotype with a pure organism to find its genotype

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12
Q

Monohybrid vs Dihybrid cross? Ratios?

A

Monohybrid: involving 1 trait (3:1)
Dihybrid: involving 2 traits (9:3:3:1)

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13
Q

What is a trait?

A

A specific characteristic determined by genes and varies in individuals

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14
Q

What are hybrids?

A

the offsprings of a cross involving parents with different traits

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15
Q

What is the principle of dominance?

A

Some alleles are dominant while others are recessive

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16
Q

What is the law of segregation?

A

A gene has 2 alleles which are equally separated during gamete formation

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17
Q

Define probability

A

the likelihood that an event will occur

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18
Q

When is a punnett square used?

A

Diagram that shows the offspring gene combinations from a genetic cross

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19
Q

Homozygous vs. Heterozygous

A

Homozygous: having 2 identical alleles
Heterozygous: having 2 different alleles

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20
Q

Phenotype vs Genotype

A

Phenotype: physical characteristics
Genotype: genetic makeup

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21
Q

What is the principle of independent assortment?

A

genes for different traits segregate independently of each other during gamete formation

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22
Q

What are the principles beyond Mendelian genetics?

A
  1. Some alleles are neither dominant nor recessive
  2. Many traits are controlled by multiple alleles/ genes
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23
Q

What is complete dominance?

A

When the dominant allele is always expressed

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24
Q

What is incomplete dominance? Example

A

One allele is not completely dominant over another
The heterozygous phenotype is a blend of both parents
Ex. homozygous red x homozygous white = heterozygous pink
- No recessive allele = shown using 2 different capital letters

25
What is codominance?
Both alleles contribute to the phenotype Ex. AB Blood type is codominant
26
What happens with multiple alleles? Ex
Having more than 2 alleles - Ex. 3 blood types
27
Define polygenic traits. Examples
Having traits controlled by 2+ genes Ex. height, skin color
28
What is a karyotype?
A visual of fully condensed, paired up chromosomes - used to analyze chromosomes
29
Define pedigree. When is it used?
Chart which shows the relationship within a family - Used to study how a trait is passed from 1 generation to the next - Infer genotypes of family members
30
Expand on the Rh Blood group
Determined by a single gene w/ 2 alleles - Positive (dominant): you have the antigen - Negative (recessive): you don't have the antigen
31
Expand on the ABO blood group
Consists of 3 alleles IA & IB are codominant --> AB i is recessive --> O
32
List the recessive allele disorders
Albinism Cystic Fibrosis Galactosemia Phenylketonuria (PKU) Tay-Sachs Disease
33
What are the effects of albinism?
Lack of pigment in skin, hair and eyes
34
What are the causes and effects of cystic fibrosis?
Causes: - Recessive allele in chromosome 7 - Deletion of 3 bases in the middle of a sequence - The protein allows chloride ions to pass across biological membranes - Deletion causes improper protein folding - cells do not transport protein to cell membrane Effects - Tissue starts malfunctioning - Excess mucus in lungs, digestive tract, liver - Increased susceptibility to infections - Death in infancy, unless treated
35
What are the effects of galactosemia?
- Inability to digest galactose - accumulation of galactose in tissues - Mental retardation - Eye and liver damage
36
What are the causes and effects of phenylketonuria?
Causes - Recessive allele in chromosome 12 - Lack enzyme needed to break down phenylalanine (amino acid in milk) Effects - Accumulation of phenylalanine in blood/ tissue - Abnormal skin pigment - Mental retardation
37
What are the effects of Tay-Sachs disease?
- Nervous system breaks down - Lipid accumulation in brain cells - Mental deficiency - Blindness - Death in childhood
38
List the dominant allele disorders?
Achondroplasia Huntingtons disease Hypercholesterolemia
39
What are the effects of achondroplasia?
Dwarfism
40
What are the causes and effects of Huntington's disease?
Causes - Dominant allele at end of chromosome 4 - Inheriting a single dominant allele Effects - mental deterioration - Uncontrollable movements
41
What are the effects of Hypercholesterolemia?
- Excess cholesterol in blood - Heart disease
42
List the codominant allele disorders?
Sickle cell disease
43
What are the causes and effects of sickle cell disease?
Causes - Allele codes for betaglobin --> insert of valine instead of glutamine results in hemoglobin sticking together - Forms sickle shape - Bent/ twist red blood cells get stuck in capillaries, blood stops moving - Heterozygous sickle cell allele allows resistance to malaria Effects - Sickled red blood cells - Physical weakness - Damage to many tissues
44
Define genome
Complete set of genetic information
45
How many chromosomes do humans have?
22 pairs of autosomes 1 pair of allosomes (X + Y)
46
Which chromosome determines sex?
Y chromosome
47
Where are sex-linked genes located?
Most are located on X chromosome - Y chromosome is smaller & contains few genes
48
List the sex-linked disorders
Color blindness Hemophilia Duchenne Muscular Dystrophy
49
What are the causes of color blindness?
X chromosome contains 3 genes associated with color vision - 2 recessive alleles causes color blindness
50
What are the causes of hemophilia?
Recessive allele in which a protein necessary for normal blood clotting is missing
51
What are the causes and effects of Duchenne Muscular Dystrophy?
Causes - Defective version of certain gene coding for muscle protein Effects - Weakening & loss of skeletal muscle - Rarely live past adulthood
52
Define hemizygous
Males are hemizygous since they only have 1 copy of most sex-linked genes
53
How do females function with 2 X chromosomes when only 1 is needed for basic living? Example of effects
In females, 1 X chromosome is switched off & formed into dense region in the nucleus (Barr body) - Ex. Color of coat spots is located on X chromosome - One X chromosome has alleles for brown/black spots, if 1 X chromosome is switched off, fur will have both brown & black spots on various places
54
Define nondisjunction
Failure of separation of homologous chromosomes/ sister chromatid
55
List the autosomal chromosome nondisjunction disorders & their basic effects
Down syndrome: Trisomy 21 - Mental retardation - Increased susceptibility to diseases Edwards syndrome: Trisomy 18 - Increase in infant mortality - Development delay Patau syndrome: Trisomy 13 - Small head - Heart, vision, hearing problems - Weak muscle tone - Brain disorders
56
List the sex chromosomal nondisjunction disorders & their basic effects
Turner syndrome: XO - Sex organs do not develop at puberty Metafemale: XXX - Taller than normal - Slender torso Klinesfelter syndrome: XXY - High pitch voice - No facial hair - Mental retardation Jacobs syndrome: XYY - Tall (super males)
57
What is a mutation
- Mistakes in gene duplication/ nondisjunction - Changes in nucleotide-base sequence of a gene or DNA molecule
58
List the types of chromosomal mutations
Deletion: loss of piece of chromosome Inversion: segment of chromosome breaks/flipts/ reattaches to same chromosome Translocation: segment breaks & reattaches to nonhomologous chromosome

Science - Living Earth (11 decks)

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