Genetics Flashcards
What is heredity?
The passing of traits from parent to offpspring.
What is genetics?
The study of heredity.
How things get passed from one generation to the next is called what?
Genetics
What is a trait?
Inherited characteristics that an organism has.
Can traits have lots of variation?
Yes (eye color, hair color)
Can traits only have a couple forms?
Yes (hairlines, earlobes, freckles, dimples)
What was Gregor Mendel’s nickname?
Father of Modern Genetics
Who was Gregor Mendel?
An Austrian Monk
What did Gregor Mendel work with?
Pea plants
What did Gregor Mendel do with his observations?
Made calculations based off of them
Why did Gregor Mendel use pea plants for his experiments?
Because there’s only two possiblilites for each trait.
What’s a dominant gene?
A gene that covers up or masks the other gene.
When do dominant genes show up?
Always
What’s a recessive gene?
A gene that gets covered up by the dominant gene.
When do recessive genes show up?
Only when there are two copies.
What’s are alleles?
Different forms of a gene.
What are alleles represented with?
Capital and lowercase letters.
What’s a genotype?
The genetic makeup of an organism.
What are these examples of? TT, Pp, hh, Kk
Genotypes
What’s a phenotype?
The observable trait of a gene.
What are these examples of? Height, color
Phenotypes
What determines what?
Genotypes determine phenotypes
What does heterozygous mean?
Different alleles, hybrid
What genotype is this an example of? Rr
Heterozygous
What does homozygous mean?
Same alleles, pure
What genotype are these examples of? RR, rr
Homozygous
What type of genotype is this? TT
Homozygous Dominant
What type of genotype is this? Tt
Heterozygous
What type of genotype is this? tt
Homozygous Recessive
What is a Punnet Square?
A tool used to predict the genetic possibilities for offspring.
Where do the parent’s genotypes go on a Punnet Square?
One parent’s genotypes go on the side and one parent’s genotypes go on the top.
What is incomplete dominance?
Heterozygous individuals have an in-between phenotype compared to the parents.
What inheritance pattern is this an example of? Red*White=Pink
Incomplete Dominance
What is codominance?
Heterozygous individuals have both phenotypes show up.
What inheritance pattern is this an example of? Red*White=Red and White
Codominance
What is polygenic inheritance?
Many genes work together to code for a trait.
Polygenic inheritance has lots of what?
Phenotypes
Eye color, hair color, skin color, and nose shape is an example of what inheritance pattern?
Polygenic Inheritance
What is multiple alleles?
A trait is controlled by more than 2 alleles.
What’s an example of multiple alleles?
Blood types: A, B, O
What can affect phenotypes?
The Environment
What environmental factor can affect the color of hydrangea plants?
Acidity of the soil.
What environmental factor can affect the color of butterflies?
Temperature during metamorphosis.
What environmental factor can affect the coloration of Siamese cats?
Temperature of areas on the body.
What environmental factor can affect the health of humans?
Diet and exercise.
What and what factors affect phenotypes?
Genetic and environmental.
Nature vs. Nurture is an example of what?
Environment affecting phenotypes.
What’s a pedigree?
A chart that shows how traits are passed through genetics.
What’s a carrier?
Heterozygous and can pass the gene on but doesn’t show the trait.
Is eye color, height, a zebra’s stripes, and nose shape inherited or acquired?
Inherited
Is knowing how to ride a bike, a bird’s ability to fly, a scar on your forehead, the ability to sing well, and the ability to speak a language inherited or acquired?
Acquired
What are epigenetics?
The study of how behavior and environment affect how genes work.
What’s complete dominance?
When one phenotype completely covers up the other.
TT and tt are both considered what type of genotype?
Homozygous
Which of the following is homozygous dominant? AA, Tt, Hh, rr
AA
What does hetero mean in the word heterozygous?
Different
In pea plants, purple flowers are dominant over white flowers. What is the genotype of a purple flower?
PP and Pp
Which of the following is a phenotype? Blue eyes, BB, homozygous, or Bb
Blue eyes
A pea plant with yellow seeds is crossed with a pea plant with green seeds. All of the offspring are yellow. What trait is recessive?
Green seeds
Using the letter A, write the correct way to express a heterozygous genotype.
Aa
Using the letter A, write the correct way to express a homozygous recessive genotype.
aa
Why do genotypes consist of 2 alleles?
Because you get one from each parent.
How many genes are needed to cause a trait?
2
If an organism has two alleles that are the same, it is considered what?
Homozygous
If a heterozygous person is crossed with a homozygous recessive person, what are the chances that they will have a child that is heterozygous?
50%
Tongue rolling (R) is dominant over non-tongue rolling (r). What is the genotype of a homozygous recessive person? (assume complete dominance)
rr
On a pedigree, what do squares represent?
Males
If a homozygous black guinea pig (BB) is crossed with a homozygous white guinea pig (bb), what is the probability that an offspring will have black fur?
100%
What’s another term for heterozygous?
Hybrid
What’s another term for homozygous?
Purebred
The study of how traits are inherited through the interaction of alleles is called what?
Genetics
What does it mean if someone is a carrier for a disorder?
They have one allele for the trait, but do not show the phenotype. (Heterozygous for a recessive disorder)
An organism that has two recessive or two dominant alleles is said to be what for that trait?
Homozygous
Dad is colorblind and Mom is not. How is it possible that a daughter has colorblindness?
Mom is a carrier for colorblindness.
Why do males get sex-linked disorders more often than females?
They have one X and one Y chromosome. If a gene is carried on one of those, there is no other chromosome to cover up the trait.
The genotype for a female is what?
XX
The genotype for a male is what?
XY
