Chapter 14 & 15
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The term used to describe the composition of an organism's alleles for a gene is what?
The termed to describe the "expression of the genotype" or the physical appearance of an organism is ____.
What is the difference between genotype & phenotype?
Genotype is the composition of an organisms alleles for a gene where as phenotype is the organism's physical appearance or "expression of the gene"
What is an allele?
Different forms of a gene that occupy the same locus or position on a chromosome
A trait that is expressed preferentially over another trait is known as the ____ trait.
A trait that is preferentially masked is a ____ trait.
What term describes the situation when 2 different alleles at a locus are responsible for different phenotypes & both alleles affect the phenotype of the heterozygote?
Where do we see codominance come into play?
When looking at blood types
____ ____ is the term used to describe a situation when 1 allele is not completely dominant over another & you wind up w/something in the middle.
When speaking of alleles what letters are used for dominant & recessive traits?
Capital letters for Dominant
Lower case letters for recessive
What happens when alleles fr 1 gene cover up or alter expression of alleles of another gene?
What is meant by pleiotropic alleles?
This occurs when a single allele has more than 1 phenotypic effect
Color pattern & crossed eyes in siamese cats are caused by the same allele. What is this phenomenon called?
What is Mendel's First Law & what does it say?
Law of Segregation says that alleles segregate fr one another during formation of gametes
Mendel's 2nd Law, the Law of ____ ____says alleles of different genes are assorted independently of one another during the formation of gametes.
According to Mendel's Law of ____ 2 copies of a gene separate & each gamete receives 1 member of the pr of alleles.
When is a test cross utilized?
When we want to determine the genotype of an organism
The breeding of an organism of an unk genotype w/a homozygous rec individual to determine what the unk genotype is is known as a ____ ____.
When doing a test cross how do we determine the unk genotype?
By breeding the organism w/unk geno w/homozygous rec individual & examining phenotype of offspring
Homozygous describes what allele makeup?
2 copies of the same allele
Heterozygous describes what allele makeup?
Individuals w/2 different alleles of the same gene
What is difference between homozygous & heterozygous?
In a homozygous individual both alleles for a trait are the same (YY or yy) & can be rec or dom whereas heterozygous individuals have different alleles for a trait (Yy)
An organism that is heterozygous w/respect to a SINGLE gene of interest is a ___.
An organism that is heterozygous w/respect to 2 genes of interest is a ____.
A gene coded on a sex chromosome is known as a ___-___ gene.
What is the genotype for Type A blood?
IA IA or IA i
What is the genotype for Type B blood?
IB IB or IB i
If blood has the genotype IA IB it is Type ___ blood.
What is the genotype for Type O blood?
In human blood types, the alleles __ & __ are codominant & ____ over the recessive allele ___.
IA & IB
What is the term used to describe a situation where 1 trait is controlled by 3 genes?
Give 1 example of polygenic inheritance.
Production of melatonin
3 genes are responsible
Each allele is additive
A diagram that shows phenotypes of several different generations is called a ____.
What is a pedigree used for?
Mostly in clinical evaluation & counseling of pts w/inherited abnormalities
What shape is used to symbolize females on a pedigree chart?
What shape is used to symbolize males on a pedigree chart?
A black square/circle on a pedigree chart shows what?
Presence of the cond being studied
A white square/circle on a pedigree chart means what?
The condition being studied is absent
What did Thomas Morgan figure out?
That genes are carried on chromosomes
The Y chromosome carries very few genes where as the X carries approx ____.
Chapter 14 & 15
Ch 14-15 12-3-12