Genetics Flashcards
(103 cards)
1
Q
Genetics definition
A
The scientific study of heredity
2
Q
Heredity definition
A
The transmission of trait from one generation to the next.
3
Q
Who was the first person to analyze patterns of inheritance?
A
G. Mendel
4
Q
Why did G Mendel study garden peas?
A
They were easy to grow Came in many varieties Easily manipulated Can self Fertilize Readily available
5
Q
Importance of G. Mendel studying peas?
A
Deduced fundamentals of genetics
6
Q
Monohybrid Cross definition
A
A cross between purebred parent plants that differ in only one character/trait
7
Q
What are Hybrids?
A
The offspring of two different purebred varieties
8
Q
Parental plants are the ___ generation
A
P
9
Q
Parents hybrid offsprings are the ____ offsprings
A
F1
10
Q
Across of the F1 plants form the ____ generation
A
F2
11
Q
Phenotype definition
A
An organism’s physical appearance
12
Q
Genotype definition
A
An organisms genetic makeup
13
Q
Mendel developed how many hypotheses from the monohybrid cross
A
4 Hypotheses
14
Q
Mendel Hypotheses from Monohybrid Cross (1)
A
The alternative version of genes are called alleles
15
Q
Mendel Hypotheses from Monohybrid Cross (2)
A
For each inherited character, organism inherits two alleles, one from each parent. Can be Homozygous or Heterozygous
16
Q
Homozygous definition
A
An organism is homozygous for that gene if both alleles are identical
17
Q
Heterozygous Definition
A
AN organism is heterozygous for that gene if the alleles are different
18
Q
Mendel Hypotheses from Monohybrid Cross (3)
A
If two alleles of inherited pair differ,
- ) one determines organism’s appearance and is called dominant allele
- ) Not relevant, is called recessive allele.
19
Q
Mendel Hypotheses from Monohybrid Cross (4)
A
Each organism contains two alleles for each trait and the alleles segregate (separate_ during the formation of gametes. This is called the Law of Segregation
20
Q
Gene Locus definition
A
A specific location of a gene along a chromosome
21
Q
Can they have multiple alleles of a gene at the same locus?
A
Yes, Homologous chromosomes have alleles of a gene at the same locus
22
Q
What does a genotype of PP get you?
A
Homozygous for the dominant allele
23
Q
What does a genotype of aa get you?
A
Homozygous for the recessive allele
24
Q
What does a geotype of Bb get you?
A
Heterozygous, with one dominant and one recessive allele
25
Rules of Probability
Apply to the inheritance of single gene traits. If genotypes of parents, it is possible to establish a childs chances for inheriting a particular genotype and thus for having a particular trait
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Punnet Square Highligts
Four possible combination of gametes and the four possible offspring are in the F2 generation
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In a normal Punnet Square, how many PP would you get?
One
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In a normal Punnet Square, how many Pp would you get?
Two
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In a normal Punnet Square, how many pp would you get?
One
30
Dihybrid Cross
The mating of parental varieties differing in two characters
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What would result from a dihybrid cross?
Dependent Assortment
| Independent Assortment
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Law of Segregation
During gamete formation, the alleles of each gene segregate from each other so that each gamete caries only one allele for each gene
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Law of Independent Assortment
Genes for different traits can segregate independently of the other genes during the formation of gametes
34
Testcross
Is a mating between an individual of dominant phenotype (but unknown genotype (Bb or BB?) and a homozygous recessive individual.
35
Example of Family Pedigree, Mendel's Principles on the inheritance of many human traits
```
Earlobe Attachment
Toungue Rolling
Dimples
Handednes
Freckles
Curly-Straight Hair
```
36
Dominant TRaits are not necessarily
Normal or More Common
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Wild-Type traits are
typical form as it occurs most often in nature and not necessarily specified by dominant alleles
38
How can inbreeding occur?
Prolonged geographic isoloation of certain populations can lead to this, through the mating of close relatives
39
Why can inbreeding by harmful?
Inbreeding increases the chance of offspring that are homozygous for a harmful recessive trait
40
Many human traits show..
simple inheritance patterns and are controlled by a single gene of autosomes
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Most human genetic disorders are ____
Recessive
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How can someone be a carrier of a disorder
Individuals who have the recessive allele but appear normal are carriers of the disorder
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Lethel Recesive; what if you have aa?
You are affected
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Lethel Recesive; what if you have Aa?
You are a carrier
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Lethel Recesive; what if you have AA?
You are normal
46
What falls under Lethal Recessive
PKU
Sickle Cell Anemia
Tay Sachs
Cystic Fibrosis
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Lethal Dominant; what if you have aa?
You are normal
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Lethal Dominant; what if you have Aa?
You are affected
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Lethal Dominant; what if you have AA?
You are affected
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What falls under Lethal Dominant
Huntingtons Disease
Neurofibromatosis
Brachy/Polydactyly
Marfan's Syndrome
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(R) Albinism
Lack of pigment in skin, hair, and eyes
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(R) Cystic Fibrosis
Excess mucus in lungs, digestive tract, liber; increased suspectibility to infections, death in early childhood
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(R) Phenyketonuria (PKU)
Accumation of phenylalanine in blood; lack of normal skin pigment, Mental Retardation unless trated
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Diseases more common among certain ethnic groups
There is no referenence to discrimination, can run in certain groups
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(R) Sickle-Cell Disease
Sickled red blood cells; damage to many tissues
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(R) Tay Sachs Disease
Lipid accumulation in brain cells; mental deficiency; blindness; death in childhood
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(D) Achondroplasia
Dwarfism
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(D) Alzheimers Disease
Mental Deterioration; Usually strikes late in life
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(D) Hungintons Disease
Mental Deterioration and uncontrollable movements; strikes in middle age
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(D) Hypercholesterolemia
Excess Cholesterol in blood; heart disease
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PKU Symptoms ; Deficiency on Phe Hydroxylase
An enzyme needed to conver essential amino acid phe to tyr
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PKU Symptoms; Phenylacetate Accumulation
Progessive intellectual disabilities or mental retardation until puberty
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PKU Symptoms
```
Seizures
Tremors or Jerky Hand/Leg
Hyperactivity, stunted growth
Eczema
Distinct odor in breath, skin, or urine.
Orange urine
Lighter Skin
```
64
High Phenylanine Foods
```
Fish
Beans
Dairy
Diet Soda
What
Eggs
Nuts & Legumes
Meat
```
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Low Phenylanine Foods
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Most Vegetables
Sugars
Low-Protein
Most Fruit
Special Breaks/Cookies/Crackers
```
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Cystic Fibrosis
Most common lethal genetic disease USA.
| Caused by a recessive allele carried by about 1/31 Americans.
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How does Cystic Fibrosis work
Impaired transport of CL- ions in lungs
Asthma
Salty Skin, "big" appetite
Large Greasy stools
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Achondroplasia
Is a form of dwarfism
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Achondroplasia works how?
Homozygous dominant genotype causes death of the embryo. Thus the only heterozygotes have this disorder
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Huntingtons disease
Leads to the degeneration of the nervous system, does not usually begin until middle age.
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Huntingtons Disease details
Causes involuntary movements
| Causes degeneration in many regions of the brain and spinal cord
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What faulty gene causes Huntingtons Disease
Cause by a fauly gene for a protein called Huntingtin
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What are the chances of getting Huntingtons if your parents has it?
You have a 50% chance of inheriting it
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Huntingtons Disease appear when?
Symptoms manifested at a middle age = family planning problems
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Marfan Syndrome - Autosomal Dominant
```
Range of Symptoms
Disorder of human CT
DEfects of Heart Valves
Affect lungs, eyes, skeleton
Tall, long limbs, thin fingers
Scoliosis
Flat Feet
Crowded teeth
```
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Polydactyly - Autosomal Dominant
Having extra fingers growing on a hand
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Brachydactyly - Autosomal Dominant
Shortening of fingers & toes
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Neurofibromatosis
Tumor Disorder; Tumors along the nervous sytem. Scoliosis, learning disabilities, vision disorder, epilepsy
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Proteus Syndrome
(Elephant Man) ; Mutation in Neurobibromin (Involved in RAS pathway)
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Progeria - Autosomal Dominant
Accelerated Aging
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Amniocentesis ; Genetic Test Performed During Pregnancy
Collects cells from amniotic fluid
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Chorionic Villus Sampling; Pregnancy Test Performed During Pregnancy
Removes cell from placental tissue
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What happens in Incomplete Dominance?
F1 hybrids have an appearance between the phenotype of the two parents
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What happens in Hypercholesterolemia? (Codominant)
Heterozygotes have blood cholesterol levels about twice as normal. About five times the normal amount of blood cholesterol. Heart attacks as early as 2
85
ABO Blood Groups
Humans blood groups have three alleles. IA, IB, & i
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ABO Blood Groups info
More than 2 alleles of a gene are present in the population
An individual can have only two of the many alleles for each trait
87
Polygenic Inheritance
The additive effects of two or more genes on a single phenotype
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Role of Environment and Genetics
Human characters a result from a combination of heredity and environment. Only genetic influences are inherited.
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Linked Genes
Are located close together on a chromosome and tend to be inherited together
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Thomas Hunt Morgan
Used the fruit fly Drosophila Melaogaster
Determined that some genes were linked based on the inheritance patterns of their traits
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Sex Chromosomes for male?
XY
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Sex chromosomes for females?
XX
93
Sex-Linked Gene
Any gene that is located on a sex chromosome
94
Where are most sex-linked genes found?
On the X Chromosome
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Sex linked genes exhibit ______
unusual patterns of inheritance.
Examples include color blindness, hemophilia, Duchenne Muscular Dystrophy
96
Red-Green Colorblindness
A common human sex-linked disorder and caused by a malfunction of light-sensitive cells in the eyes
97
Sex linked traits are expressed more frequently in which gender?
Males, due to the fact that genes are located exclusively on the X chromosome
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A female will be color blind if she recives the recessive color blind gene ____
blind gene on both Xs
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A male will be color blind if he receives the recessive color blind gene on ____
one X Chromosome
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Hemophilia
Is a sex-linked resessive blood-clotting trait that may result in excessive bleeding and perhaps death after minor cuts.
101
How many different factors come into affect with clotting?
13
102
Autosomal Trait
Is expressed differently in males and females
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Male Pattern Baldness
Trait influenced by Dihydroxy TEstosterone and Androgen Receptor Gene on X.
