ANFS 300 EXAM 1 QUESTIONS WITH VERIFIED
ANSWERS
What did we know about basic rules of inheritance prior to 1866? - Answers - blending
hypothesis
- traits from parents were thought to blend together and offspring display intermediate
characteristics
What are some limitations for the blending hypothesis? - Answers - loss of genetic
diversity & irreversibility
Why were pea plants a good choice of experimental subject? - Answers - - easy to
cultivate
- short generation interval
- produce many offspring
- differed in various traits
- genetically pure
What is a monohybrid cross? - Answers - a cross between two parents that differ in a
single characteristic
What is the average phenotype ratio of a monohybrid cross? - Answers - 3:1
What conclusions did Mendel make? - Answers - - one character is encoded by two
genetic factors
- two genetic factors (alleles) separate when gametes are formed
- the concept of dominant and recessive traits
- two alleles separate with equal probability into the gametes
What is the Principle of Segregation? - Answers - each individual possesses two alleles
for any particular characteristic, which segregate when gametes are formed and only
one goes into each gamete
What is the Chromosome Theory of Inheritance? - Answers - chromosomes come in
pairs, separate during reproduction, and then come together with another chromosome
during fertilization
What is a Test Cross? - Answers - a genetic cross to determine the genotype of an
individual expressing a dominant phenotype by mating it with a homozygous recessive
individual
What is a dihybrid cross? - Answers - a cross of individuals that differs in two
characteristics
, What is the predicted phenotype ratio of a dihybrid cross? - Answers - 9:3:3:1
What is Independent Assortment? - Answers - alleles of different genes are transmitted
independently of one another
What is the Product Law? - Answers - - the probability of two or more independent
events occurring simultaneously
- P(A) x P(B)
What is a Null Hypothesis? - Answers - there is no significant difference between
observed and expected data (or frequencies)
What is an Alternative Hypothesis? - Answers - there is a significant difference between
observed and expected data
What is a Significance Level? - Answers - the predetermined threshold for accepting or
rejecting the null hypothesis (commonly set at 0.05)
Chi-Square Test Step-by-Step - Answers - 1. calculate chi-square statistic using
observed and expected data
- Σ (o-e)^2 / e
2. calculate degrees of freedom
- number of outcomes - 1
3. find critical value
- using significance level of 0.05
4. compare calculated chi square to critical chi square
- calculated higher than critical = reject
- calculated lower than critical = accept
5. reject or accept null hypothesis
6. conclude whether there is a significant difference between observed and expected
datar
- accept = no significant difference
- reject = significant difference
What is a locus? - Answers - the specific physical location of a gene on a chromosome
What are alleles? - Answers - different versions of the same gene
What is a genotype? - Answers - the combination of alleles an individual has for a
particular gene
What is a phenotype? - Answers - the observable characteristics of an individual
What is a genome? - Answers - it encompasses all the DNA in an organism
ANSWERS
What did we know about basic rules of inheritance prior to 1866? - Answers - blending
hypothesis
- traits from parents were thought to blend together and offspring display intermediate
characteristics
What are some limitations for the blending hypothesis? - Answers - loss of genetic
diversity & irreversibility
Why were pea plants a good choice of experimental subject? - Answers - - easy to
cultivate
- short generation interval
- produce many offspring
- differed in various traits
- genetically pure
What is a monohybrid cross? - Answers - a cross between two parents that differ in a
single characteristic
What is the average phenotype ratio of a monohybrid cross? - Answers - 3:1
What conclusions did Mendel make? - Answers - - one character is encoded by two
genetic factors
- two genetic factors (alleles) separate when gametes are formed
- the concept of dominant and recessive traits
- two alleles separate with equal probability into the gametes
What is the Principle of Segregation? - Answers - each individual possesses two alleles
for any particular characteristic, which segregate when gametes are formed and only
one goes into each gamete
What is the Chromosome Theory of Inheritance? - Answers - chromosomes come in
pairs, separate during reproduction, and then come together with another chromosome
during fertilization
What is a Test Cross? - Answers - a genetic cross to determine the genotype of an
individual expressing a dominant phenotype by mating it with a homozygous recessive
individual
What is a dihybrid cross? - Answers - a cross of individuals that differs in two
characteristics
, What is the predicted phenotype ratio of a dihybrid cross? - Answers - 9:3:3:1
What is Independent Assortment? - Answers - alleles of different genes are transmitted
independently of one another
What is the Product Law? - Answers - - the probability of two or more independent
events occurring simultaneously
- P(A) x P(B)
What is a Null Hypothesis? - Answers - there is no significant difference between
observed and expected data (or frequencies)
What is an Alternative Hypothesis? - Answers - there is a significant difference between
observed and expected data
What is a Significance Level? - Answers - the predetermined threshold for accepting or
rejecting the null hypothesis (commonly set at 0.05)
Chi-Square Test Step-by-Step - Answers - 1. calculate chi-square statistic using
observed and expected data
- Σ (o-e)^2 / e
2. calculate degrees of freedom
- number of outcomes - 1
3. find critical value
- using significance level of 0.05
4. compare calculated chi square to critical chi square
- calculated higher than critical = reject
- calculated lower than critical = accept
5. reject or accept null hypothesis
6. conclude whether there is a significant difference between observed and expected
datar
- accept = no significant difference
- reject = significant difference
What is a locus? - Answers - the specific physical location of a gene on a chromosome
What are alleles? - Answers - different versions of the same gene
What is a genotype? - Answers - the combination of alleles an individual has for a
particular gene
What is a phenotype? - Answers - the observable characteristics of an individual
What is a genome? - Answers - it encompasses all the DNA in an organism
