Unit 3 lecture 2 10/17/22 Flashcards
The __________ is the idea that genetic material from the two parents blends together (the way blue and yellow paint blend to make green)
“blending” hypothesis
The __________ is the idea that parents pass on discrete heritable units (genes)
“particulate” hypothesis
The true-breeding parents are the __________
P generation
The hybrid offspring of the P generation are called the __________
F1 generation
When F1 individuals self-pollinate or cross- pollinate with other F1 hybrids, the __________ is produced
F2 generation
He called the purple flower color a 1.__________ and the white flower color a 2.__________
1.dominant trait
2.recessive trait
What Mendel called a “heritable factor” is what we now call a __________
gene
Alternative versions of 1.__________ account for 2.__________ in inherited characters
- genes
- variations
These alternative versions of a gene are now called __________
alleles
Each gene resides at a specific __________ on a specific chromosome
locus
For each character, an organism inherits __________ alleles, one from each __________
- two
- parent
If the two alleles at a locus differ, then one (the 1.__________) determines the organism’s appearance, and the other (the 2.__________) has no noticeable effect on appearance
- dominant allele
- recessive allele
In the flower-color example, the F1 plants had purple flowers because the allele for that trait is dominant Fourth (now known as the __________), the two alleles for a heritable character separate (__________) during gamete formation and end up in different gametes
law of segregation
segregate
This __________ of alleles corresponds to the distribution of homologous chromosomes to different gametes in meiosis
segregation
The possible combinations of sperm and egg can be shown using a __________, a diagram for predicting the results of a genetic cross between individuals of known genetic makeup
punnett square
A __________ represents a dominant allele, and a __________ represents a recessive allele
- capital letter
- lowercase letter
An organism with two identical alleles for a character is said to be __________ for the gene controlling that character
homozygous
An organism that has two different alleles for a gene is said to be __________ for the gene controlling that character
heterozygous
Unlike homozygotes, heterozygotes are __________ true breeding
not
Therefore, we distinguish between an organism’s 1.__________, or physical appearance, and its 2.__________, or genetic makeup
1.phenotype
2.genotype
One common mechanism is a __________ in the recessive allele
loss of function
Mendel derived the __________ by following a single character
law of segregation
A cross between such heterozygotes is called a __________
monohybrid cross
Mendel identified his ____________________ by following two characters at the same time
second law of inheritance
Crossing two true-breeding parents differing in two characters produces __________ in the F1 generation, heterozygous for both characters
dihybrids
A dihybrid cross, a cross between F1 dihybrids, can determine whether two characters are transmitted to offspring as a package or __________
independently
The results of Mendel’s dihybrid experiments are the basis for the ____________________
Law of independent assortment
Mendel’s laws of segregation and independent assortment reflect the rules of __________
probability
The __________ states that the probability that two or more independent events will occur together is the product of their individual probabilities
multiplication rule
The __________ states that the probability that any one of two or more mutually exclusive events will occur is calculated by adding together their individual probabilities
addition rule
A __________ is equivalent to two or more independent monohybrid crosses occurring simultaneously
dihybrid cross
When alleles are __________ completely dominant or recessive
not
When a gene has __________ alleles
more than 2
When a single gene influences __________
multiple phenotypes
__________ occurs when phenotypes of the heterozygote and dominant homozygote are identical
complete dominance
In __________, the phenotype of F1 hybrids is somewhere between the phenotypes of the two parental varieties
incomplete dominance
In __________, two dominant alleles affect the phenotype in separate, distinguishable ways
codominance
Traits influenced by multiple alleles are termed __________
polygenic
Most genes have multiple phenotypic effects, a property called __________
pleiotropy
In __________, a gene at one locus alters the phenotypic expression of a gene at a second locus
epistasis
____________________ are those that vary in the population along a continuum
quantitative continuous characters
The __________ is the phenotypic range of a genotype influenced by the environment
norm of reaction
The phenotypic range is generally broadest for __________ characters
polygenic
Such characters are called __________ because genetic and environmental factors collectively influence phenotype
multifactorial
