bio lab exam 3 (11/04/21)

Question 1

1. know the characteristics of mitotic AND meiotic prophase, metaphase, anaphase and telophase and know what is different from meiosis 1 and 2

Answer 1

skip

Question 2

2. what symbols do yoy put into punnet squares and what do they represent

Answer 2

lowercase and uppercase letters and they represent the parent alleles

Question 3

3. what is the difference between a chromosome and a chromatid

Answer 3

chromosomes carry DNA which is the genetic material of the organism.

chromatids help the cells to duplicate

Question 4

4. at what stage of meiosis do chromatids seperate?

Answer 4

anaphase (1?)

Question 5

5. explain why it is easier to establish genetically uniform (pure bred) colonies of plants or animals with homozygous recessive traits.

Answer 5

because homozygous recessive traits will always result in their traits being presented.

think of curly hair

Question 6

6. what are alleles? what are dominant and recessive?

Answer 6

allele: forms of a gene that are found on a chromosome
dominant: show their effect even if the individual only has one copy or the allele. also known as heterozygous
recessive: must have both alleles for a gene to be expressed. only if there are two copies in the genome.

Question 7

7. Process of mitosis

Answer 7

interphase: the cell grows and prepares to divide
prophase: nuclear membrane breaks down, spindle fibers begin to form
metaphase: sister chromatids line up at the center
anaphase: sister chromatids are pulled apart and move to opposite poles of the cells.
telophase: spindle fibers breakdown, nuclear membrane forms, and chromosomes begin to uncoil.
cytokinesis: cytoplasm splits in two and the cell divides

Question 8

8. where do the 2 members of an homologous pair of chromosomes come from?

Answer 8

our parents

Question 9

9 what does it mean to be diploid

Answer 9

the term diploid refers to a cell or an organism that has two sets of chromosomes

Question 10

10. what are the names of the 3 phases of interphase and what is happening?

Answer 10

• G1 phase (cell growth) Longest
• S phase (DNA synthesis)
• G2 phase (cell growth)

Question 11

11. what do genotype and phenotype mean?

Answer 11

genotype: genetic makeup
phenotype: physical expression of genetic makeup

Question 12

12. we often refer to gametes as haploid. what are hammered and what process makes them haploid?

Answer 12

gametes: sex cells

fertilization makes them haploid

Question 13

13. why is it important for gametes to be haploid?

Answer 13

so the number of chromosomes does not double every generation.

Question 14

7.1. what is dihybrid cross

Answer 14

is a cross between two individuals who differs in two observed traits that are controlled by two distinct genes

Example: Imagine a chart // S is color Y is texture

      Sy Sy sY sy
Sy
Sy
sY
sy

Question 15

7.4. List 2 human disease that are sex linked

Answer 15

hemophilia and colorblindess

Question 16

7.5. what is a pedigree

Answer 16

a pedigree chart shows occurrence of one phenotypes of a particular gene or organism

Question 17

7.7. how many alleles control hair color in humans? how many for eye color? what do we call the kind of dominance these traits represent?

Answer 17

hair: 8
eyes: 4

partial or incomplete dominance

Question 18

7.8. what does the 9:3:3:1 ratio refer to?

Answer 18

simply means that nine are wild-type (not normal), six exhibit one mutant and one is normal.

Question 19

7.9: what is the difference between a gene and an allele

Answer 19

gene: a portion of DNA that determines a certain trait.
allele: a specific form of a gene.

Question 20

7.10: how many alleles are involved in a di hybrids cross? how many genes?

Answer 20

2 different alleles.

2 different genes

Question 21

7. 11. which it these dominant?
       
       • tounge-rolling
       • color blindness
       • ability to taste PTC
       • widows peak

Answer 21

tounge-rolling
PTC tasting
widows peak

Question 22

8.1.
The number of alleles for a given trait were about equal at the start of the lab. That is, for the
trait “freeze reflex”, for example, there were an equal number of dominant and recessive alleles.
Because of this,
- how many people in class probably began the simulation as heterozygotes?
- How many were homozygous dominant?
- Homozygous recessive?

Answer 22

50% heterozygous, 25% dominant homozygous, 25% recessive homozygous

Question 23

8.2. What types of selection did you simulate this week?

Answer 23

natural selection and sexual selection

Question 24

8. 3. How many individuals that were homozygous recessive for both freeze reflex and disguise
      (camouflage) survived in most cases?

Answer 24

approximately 90%

Question 25

8.4. Did the numbers of genotypes change over the generations?

Answer 25

No because no genes went away all together.

Question 26

8.5. Did the allele frequencies (%) change over the generations?

Answer 26

The frequency of recessive alleles increased because they were favorable for survival. The dominant alleles decreased because they were not favored.

Question 27

8.6. Thinking about the bright males and choosy females, what trait was selection favoring?

Answer 27

bright coloration

Question 28

8.7. Did the frequency of Bright males increase? How about choosy females? Did their numbers
increase, decrease, or stay the same?

Answer 28

The frequency of bright males increased. Choosy females also increased.

Question 29

8.8. Why wasn’t it necessary to roll dice to see if you survived for the second investigation?

Answer 29

Because we were looking at sexual selection so we did not need the dice. If you didn’t find a mate then you died.

Question 30

8.9. Did the allele for brightness affect the females?

Answer 30

no

Question 31

8.10. Did the allele for choosiness affect the males?

Answer 31

no

Question 32

8.11. At the end of the exercise, did females who had the alleles for choosiness (or “picky-ness”)
also carry the allele for brightness? (Look at the genotypes for females).

Answer 32

yes because they only mated with the brightly colored “more attractive” birds