Heredity Test

Question 1

How to find degrees of freedom for the chi square table

Answer 1

Number of phenotypes minus 1

Question 2

Homologous vs nonhomologous chromsomes

Answer 2

Homologous chromosomes are the same size, and contain the same gene sequence, and the same genes in the same loci. Nonhomologous chromosomes are different sizes and do not pair in meiosis.

Question 3

What would a null hypothesis be for the results of a genetic cross, and what does this mean

Answer 3

There is no statistical significance between the observed and expected results
Basically, this means that the observed results match the expected mendelian genetics results (most likely 9:3:3:1).

Question 4

How to calculate the chi square value, and what does it mean if you have more or less than the critical value on the table

Answer 4

(observed-expected)^2/expected
If you have more than the critical value, then the difference between observed and expected results are statistically significant.
How to remember: More=significant
If you have less than the critical value, the difference between observed and expected results are not statistically significant.
Less= not significant

Question 5

Law of Independent Assortment

Answer 5

alleles for different traits are inherited separately based on them being on different chromosomes, or far apart on the same chromosome.

Question 6

Is 1% equal to one map unit or .1 map units

Answer 6

ONE map unit

Question 7

What is a diploid vs a haploid cell

Answer 7

A diploid cells is any cell with 2 sets of chromsomes. For example, someone with 46 chromosomes has 2 sets of 23 chromsomes, 23 from the mom and 23 from the dad. A haploid cell only has one set of chromosomes. An example of a haploid cell is a gamete.

Question 8

What are sister chromatids

Answer 8

Two copies of one chromosome

Question 9

When does crossing over occur

Answer 9

Prophase 1 of meiosis 1

Question 10

random fertilization

Answer 10

The chance that any sperm can create a zygote with any egg

Question 11

Pedigree Inheritance: If an unaffected male passes on the trait to his offspring it cannot be _____

Answer 11

It cannot be x linked recessive.
This is because there needs to be a recessive gene from the father for the kid to have the trait. Since the father is unaffected, his only x cannot be that trait.

Question 12

How do you know if a phenotype is the result of crossing over?

Answer 12

If the phenotype doesn’t match either of the parent’s phenotypes

Question 13

SRY gene

Answer 13

Its the gene that creates the proteins needed to develop male characteristics.

Question 14

How does mitochondrial inheritance work

Answer 14

It is only passed on through the mother, and ALL offspring recieve the trait (because all offspring use the mother’s mitochondria).

Question 15

Pedigree inheritance: If the trait is x linked then the trait cannot be passed from father to ___

Answer 15

Son. Only the mother can give the trait to the son, since the father gives only the Y chromsomes.

Question 16

Explain the amount of DNA in chromatids

Answer 16

One chromatid is equal to one DNA, so the cells at the end of meiosis have 1/4 of the amount of DNA as the zygote in the beginning of meiosis.