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level: Level 1

Questions and Answers List

level questions: Level 1

Question	Answer
the gene variation an individual possesses for a particular trait	Genotype
different variations of the same gene trait represented as uppercase and lowercase letters; genotypes consist of two allele letters, one comes from and one from dad	Alleles
hides the expression of the other allele’s trait	Dominant Allele (uppercase letter) -
how the genotype is physically expressed; the physical appearance	Phenotype
Father of Genetics	Gregor Mendel
-an organism’s offspring will look like the parent due to its homozygous purebred genotype	True breeding
alleles separate during the formation of sex cell gametes	Law of Segregation
Dominant alleles are not always the most common and not always the most advantageous either…	True
Dominant alleles are not always the most common and not always the most advantageous either… ex	Ex: Huntington’s Disease is a rare, dominant disorder
hidden by the dominant allele’s trait	Recessive Allele (lowercase letter)
- predicts the outcome probability of genetic crosses	Punnett Square
two gene punnett square	Dihybrid Cross
genes can separate during the formation of sex cells gametes and do not have to be linked or inherited together	Law of Independent Assortment
genes can separate during the formation of gametes and do always have to be inherited or linked together	false, they do not
ow did Mendel figure out the possible gamete combinations written along the two axes of his dihybrid cross?	He “foiled” each parent’s genotype.
1 TT : 2 Tt : 1 tt	Genotypic Ratio:
3 Tall : 1 Short	Phenotypic Ratio:
In ratios, the more ----- version comes first	dominant
Axes are ------- genotypes	parent’s
boxes are ------- genotypes	offsprings
both alleles are equally as dominant so both are expressed side by side at the same time in a third phenotype	Codominance
when one allele is not completely dominant over another resulting in a third mixed phenotype	Incomplete Dominance
BLOOD) genes with more than two alleles resulting in more than just two phenotypes	Multiple Alleles
Type A heterozygus is also	Ao
what does oo stand for	resessive/type o
Positive (+) and negative (-) blood type is not determined by multiple alleles. They are just carried on the blood type alleles. Positive blood types are dominant over negative blood types.	true
EX: Skin, hair- traits controlled by two or more genes resulting in many phenotypes	Polygenic Traits
the sex of an individual depends on the presence or absence of a Y chromosome. A male’s sex genotype is XY while a female’s is XX.	Sex Chromosomes
only located on the “X” sex chromosome	X-Linked Traits
Since males do have a second back up X they are less susceptible to expressing X-linked traits making these traits more uncommen in men.	False, they are more susceptible
Pedigrees	Trace a family’s genotypes and phenotypes and therefore autosomal or X-linked traits
Circle	Female
Square	Male
Shaded	Expresses Trait
Half-shaded	Carrier
Crossed out	Deceased
What is the first step in solving a pedigree	Identify whether the trait is Dominant or Recessive.
If every “affected” child in the pedigree has a least one parent who is also affected, then the trait is	Dominant
If there are “affected” children where neither of their parents are also affected, then it’s	Recessive
Step two in solving a pedigree is	Identify whether the trait is Autosomal or X-linked.