Heredity B/Designer Genes C

[jxxu20]

Mmm, I'll take a shot at this:
1. Mitochondrial DNA is maternally linked because only the nuclear region of the sperm cell meets the ovum. Sperm travels by using the energy generated by its mitochondria, which are located at the tail end of the cell. Hence, the mitochondria never make it to the ovum, so the zygote formed by the union of the gametes will only possess the mother's set of mtDNA.

2. I = lacI, P = promoter, O = operator, X = lacZ, Y = lacY, Z = lacA

3. lacI is a regulatory gene that codes for the lac repressor protein; the promoter is a sequence/region of DNA that tells RNA polymerase where to begin transcription; the operator is a region of DNA where the repressor can bind to and halt transcription; lacZ codes for beta-galactosidase (which breaks down lactose into glucose and galactose); lacY codes for galactoside permease (which allows the cell to import lactose); and lacA codes for galactoside transacetylase (whose function is not clearly understood). I was sort of confused on questions 2 and 3, especially with the lettering on the diagram and all ... hope I gave you what you were looking for.

[platypusomelette]

Mmm, I'll take a shot at this:
1. Mitochondrial DNA is maternally linked because only the nuclear region of the sperm cell meets the ovum. Sperm travels by using the energy generated by its mitochondria, which are located at the tail end of the cell. Hence, the mitochondria never make it to the ovum, so the zygote formed by the union of the gametes will only possess the mother's set of mtDNA.

2. I = lacI, P = promoter, O = operator, X = lacZ, Y = lacY, Z = lacA

3. lacI is a regulatory gene that codes for the lac repressor protein; the promoter is a sequence/region of DNA that tells RNA polymerase where to begin transcription; the operator is a region of DNA where the repressor can bind to and halt transcription; lacZ codes for beta-galactosidase (which breaks down lactose into glucose and galactose); lacY codes for galactoside permease (which allows the cell to import lactose); and lacA codes for galactoside transacetylase (whose function is not clearly understood). I was sort of confused on questions 2 and 3, especially with the lettering on the diagram and all ... hope I gave you what you were looking for.

Yo sorry for the late reply but yes that's correct. Your turn

[jxxu20]

Questions:

1. Colorblindness is an X-linked recessive disorder. A couple has 4 children -- 2 are unaffected, 1 is a carrier, and 1 is affected by colorblindness. What are the genotypes of the parents?

2. Dwarfism in humans is a dominant trait that is also lethal if an individual inherits two copies. Show the genotypes of a family where both parents are dwarfs and they have 2 children, where one is a dwarf and the other is not.

3a. Describe each of the following enzymes' role(s) in DNA replication:
- Topoisomerase
- Helicase
- Primase
- Ligase
3b. What is the difference between DNA polymerase I vs. DNA polymerase III?

4. Many eukaryotic genes have a __________ located 25-35 base pairs before the transcription site of the gene. What does this structure do?

5. What is a Barr body?

6. In a certain African population, 4 % of the population is born with sickle cell anemia (aa). What is the percentage of individuals who enjoy the selective advantage of the sickle-cell gene (increased resistance to malaria)? Assume that the population is in Hardy-Weinberg Equilibrium.

[isotelus]

Wow, these are good questions! Here's my best shot:

1. (assuming they are male) parent 1- X^B, X^b | parent 2- X^B, Y

2. Bb, Bb

3.a.i. controls winding of DNA

3.a.ii. breaks hydrogen bonds between nucleotides to form replication fork

3.a.iii. catalyzes synthesis and placement of primers

3.a.iv. fills gaps between Okazaki fragments

3.b. DNA polymerase I replaces the RNA primers
DNA polymerase III adds onto RNA primers

4. TATA boxes state where the sequence can be decoded. It initiates the transcription of the genes.

5. a dense inactive X chromosome that diagnoses the mammal as a female

6. 32%

[jxxu20]

Yup, all correct -- your turn!

[isotelus]

1. When did the Human Genome Project end?

2. Describe and explain how CRISPR works.

3. Why does DNA and RNA head to one side of the gel during gel electrophoresis?

[greenmilktea]

1. When did the Human Genome Project end?

2. Describe and explain how CRISPR works.

3. Why does DNA and RNA head to one side of the gel during gel electrophoresis?

:0 (Click to Show Hidden Text)

1. 2003
2. The Cas9 endonuclease enzyme is guided by RNA (CRISPR sequences) to recognize and cleave specific sections of the genetic DNA that are complementary to the RNA sequence.
3. Gel electrophoresis consists of gel with a positively charged electrode on the far end and a negatively charged electrode on the close end. The DNA begins in the negatively charged end. Because DNA and RNA have negative charges, they will move through the gel as a result of the attraction.

[isotelus]

Looks good, go ahead!

[greenmilktea]

1. Name several similarities and differences between miRNA and siRNA.
2. What role does the TATA box play in RNA transcription?
3. Why does it make sense for the substitution of a valine for a glutamine in the hemoglobin protein to cause the red blood cell to adopt a sickle-like shape? Think amino acid interactions.

[Tailsfan101]

Since this is kind of dead:
Name the genetic disorder referred to by each question.
1. When a man inherits an extra X chromosome
2. When a woman only inherits one X chromosome
3. Also known as Trisomy 21