Mendelian Genetics

Question 1

What are the 5 reasons why the garden pea plant was an ideal organism for Mendels experiments?

Answer 1

• Easy to grow
• Short life cycle
• Large # of progeny
• Self-fertilizers
• Easy to cross-fertilize

Question 2

How many different traits were individually analyzed during the pea plant experiments?

Answer 2

7

Question 3

What are the 5 reasons mendels experiments were so successful?

Answer 3

1. The garden pea is an ideal organism
2. Traits were analyzed individually
3. Pure-breeding lines were etablished (always same trait made)
4. Reciprocal crosses performed (male purple x female white) and (male white x female purple)
5. Performed statistical analyses to provide accurate conclusions

Question 4

What is the law of segregation?

Answer 4

During gamete formation, each each pair of genes separate randomly so each gamete receives either with equal likelihood.

Question 5

What is a test cross?

Answer 5

crossing unknown genotype w/ homozygous recessive to reveal genotype.

Question 6

What is the definition of a dihybrid cross?

Answer 6

A cross between 2 hybrids differing in 2 traits.

Question 7

What is the law of independent assortment?

Answer 7

Genes on different, nonhomologous chromosomes separate independently of one another during meiosis.

Question 8

what is the binomial expansion equation and what are each of the variables related to?

Answer 8

P= n! / x! (n - x)! * p^x * q^n-x

n - total # of events
! - factorial
x - # of events one category
q - probability one category
p - probability other category

Question 9

Describe the process for performing the Chi-Square (X^2) Test. what is a null hypothesis? What does the p value indicate?

Answer 9

1. Null hypothesis - No significant difference between expected and observed results.
2. List each phenotype and # of observed
3. calculate number of expected for each phenotype
4. Perform X^2 analysis: [(observed - expected)^2 / expected
5. determine degrees of freedom (df): N - 1 (N= # of classes)
6. Find the p-value using df and X^2 value.

The P value indicates how accurate the null hypothesis is. if its greater than 0.05, there is greater than 5% chance that the null is accepted and the deviation is likely due to chance.

If the p-value is less than 0.05, it is less than 5% likely that the deviation is due to random chance. Therefore the null hypothesis can be objected.