Chapter 20 - Inheritance Flashcards
The sequence of bases in DNA is transcribed to ____
RNA
The 3 base-pair code of RNA translates to _______
amino acids
Within ribosomes, amino acids are strung together to produce _______
proteins
What are proteins?
Proteins are molecules that facilitate or regulate chemical reactions, provide movement or transport, or provide structural support
(don’t memorize this definition of a protein, just try to get the general idea)
Basic model of gene expression
DNA (Gene) -> RNA - > Protein -> Phenotype
physical expression of proteins determines the ‘traits’ or ‘characteristics’ of an organism
gene expression
individuals with identical copies of an allele (AA)
homozygous
individuals with different alleles (Bb)
heterozygous
an allele that determines phenotype, regardless of the other allele present. (Capital letter)
dominant
an allele whose effect is masked by the dominant allele
recessive
how does someone express the recessive trait?
Have two copies of the recessive trait
Punnett square example: freckles vs no freckles.
Female is FF, male is ff
What will there child be?
heterozygous zygote Ff, they will have freckles
In incomplete dominance, each copy of a dominant allele provides _______ expression
some
Homozygote dominant expresses _______
fully
In incomplete dominance, heterozygotes only produce ______ of the expression
half
one functioning protein, one nonfunctioning protein
Example of incomplete dominance
sickle cell anemia
Most genes have more than two alleles
multiple alleles
Any given individual has no more than _____ of the potential alleles
two
People only have ____ homologous copies of a gene. Identical or two alleles
two
Multiple alleles - blood types are determined by what?
polysaccharides on surface of blood cells
Having type AB blood is known as
codominance
What are most traits determined (influenced) by?
multiple genes, each with their own multiple alleles
phenotypic expression is often strongly influenced by _________
environment
in a population, the phenotypic expression is a ________
continuum (smooth curve)
Example of polygenic inheritance
height
is determined by multiple genes, each with its own alleles
Within sickle cell anemia, the sickle cell trait “bleeds through” the _______ trait
dominant
abnormal red blood cell (abnormal hemoglobin)
sickle cell trait
What are the phenotypes of blood types?
Type A, B, O, AB
What are the genotypes of blood types?
AA, Ao, BB, Bo, oo, AB
When does nondisjunction occur?
Meiosis I or II
Your alleles are _______ when appearing in heterozygote states
codominants
How is the blood type AB codominant?
Both A and B aren’t dominant over the other
Example of incomplete dominance
Red and white flowers make a heterozygote (pink flower) because red is not fully dominant
What is Gregor Mendel known for?
laws of inheritance
What is the law of independent assortment?
increases genetic variation in offspring
What will be the phenotype of an Ao genotype?
A because A is dominant
