Chapter 2.2: Genetic Analysis According to Mendel Flashcards
How does a specific gene affect phenotype?
o A specific gene determines a specific enzyme whose activity may affect the phenotype in any number of ways depending on the biochemical pathway
What does Mendel’s Law of Segregation state?
Mendel’s Law of Segregation: the two alleles for each trait separate (segregate) during gamete formation, and then unite at random, one from each parent at fertilization
What do monohybrid crosses reveal?
• Monohybrid Crosses Reveal Units of Inheritance and the Law of Segregation
What is an observable characteristic?
phenotype
What is an individual with a homozygous genotype?
homozygote
Define phenotype
an observable characteristic
What is a mating in which an individual showing the dominant phenotype is crossed with an individual expressing the recessive phenotype?
testcross
What is a dihybrid?
o A dihybrid individual is one that is heterozygous for 2 genes at the same time
How do alleles relate to encoding proteins?
o The dominant allele determines a normally functioning protein, while the recessive allele does not encode a functional protein
Define heterozygote
an individual with a heterozygous genotype
Define genotype
alleles present in an individual
What was the first filial (F1) generation in Mendel’s experiment?
When crossed peas were all yellow; first filial (F1) generation
What is an individual with a heterozygous genotype?
heterozygote
What is a monohybrid cross?
cross between single trait hybrids
Define gametes
the specialized cells—eggs within the ovules of the female parent and sperm cells within the pollen grains—that carry genes between generations
What are recombinant types?
o New phenotypic combinations in offspring are called recombinant types
What are individuals having two different alleles for a single trait?
monohybrids
Define alleles
alternative forms of a single gene
What is a branched-line diagram?
A branched-line diagram shows all the possibilities for a gene in a sequence of columns
What are the alleles present in an individual?
genotype
Define monohybrids
individuals having two different alleles for a single trait
Define punnett square
a simple and convenient method for tracking the kinds of gametes produced as well as all the possible combinations that might occur at fertilization
Define homozygous
two of the same alleles for a trait
What are alternative forms of a single gene?
alleles
What reveals units of inheritance and the law of segregation?
monohybrid crosses
What are the specialized cells—eggs within the ovules of the female parent and sperm cells within the pollen grains—that carry genes between generations?
gametes
What is the product rule?
o The product rule states that the probability of 2 or more independent events occurring together is the product of the probabilities that each event will occur by itself
What is the sum rule?
o The sum rule states that the probability of either of 2 such mutually exclusive events occurring is the sum of their individual probabilities
What was the parental (P) generation in Mendel’s experiment?
o Mendel planted pure-breeding green and pure-breeding yellow peas and allowed them to grow into the parental (P) generation
What are matings between the F1 progeny of pure-breeding parents that differed in 3 or more unrelated traits?
multihybrid cross
Define homozygote
an individual with a homozygous genotype
What is a cross between single trait hybrids?
monohybrid cross
Define testcross
a mating in which an individual showing the dominant phenotype is crossed with an individual expressing the recessive phenotype
What are two different alleles for a trait?
heterozygous
What was the second filial (F2) generation in Mendel’s experiment?
Resulted in 3:1 ratio of yellow to green; second filial (F2) generation
Define heterozygous
two different alleles for a trait
What are two of the same alleles for a trait?
homozygous
What does the Law of Independent Assortment state?
Law of Independent Assortment: During gamete formation, different pairs of alleles segregate independently of each other
Define multihybrid cross
matings between the F1 progeny of pure-breeding parents that differed in 3 or more unrelated traits
What is a simple and convenient method for tracking the kinds of gametes produced as well as all the possible combinations that might occur at fertilization?
punnett square
