Biology Forums - Study Force

1. Which of the following states a valid conclusion based on the pedigree above?
Select one:
a. Individual I-2 does not carry the red-green colour blindness allele.
b. All children of individuals I-1 and I-2 could be carriers of the red-green colour blindness allele.
c. Individuals II-5 and II-6 are carriers of the red-green colour blindness allele.
d. It is not possible to determine whether individuals III-2 and III-3 are carriers of the colour blindness allele.
e. Individual II-2 passed on the red-green colour blindness allele to individual II-1.

2. Duchenne muscular dystrophy is an inheritable disorder that results in muscle weakness, leading to walking and breathing difficulties and heart disease.

Duchenne Muscular Dystrophy
 

Which of the following is a valid conclusion about the Duchenne muscular dystrophy pedigree shown above?

Select one:
a. Without further evidence, the genotypes of individuals II-2 and III-2 cannot be determined.
b. Individual II-3 can only pass on the affected allele to individuals III-2 and III-4.
c. Only individuals I-2 and II-4 are confirmed carriers of the Duchenne muscular dystrophy allele.
d. Only individuals I-1 and II-3 are confirmed carriers of the Duchenne muscular dystrophy allele.


3. A defective gene on chromosome 15 causes Tay-Sachs disease. It is a central nervous system neurodegenerative disease that most often affects infants, though older children and adults can have late-onset forms of the disease. The defective gene prevents the body from making a protein called hexosaminidase A. Without, hexosaminidase A, chemicals called gangliosides build up in the nerve cells of the brain, destroying brain cells.

A couple has one daughter with Tay-Sachs disease and three other unaffected children. Neither the mother, nor father, nor any of the biological grandparents of the affected daughter have had the disease. Tay-Sachs disease most likely demonstrates what type of inheritance?

Select one:
a. autosomal recessive
b. X-linked recessive
c. X-linked dominant
d. autosomal dominant

4. Achondroplasia is a form of dwarfism caused by a mutation in a single gene. Two individuals with achondroplasia marry and have an affected child and later have a second child that is average in height.

From this you can conclude
Select one:
a. achondroplasia is a result of incomplete dominance
b. achondroplasia is produced by a dominant allele
c. achondroplasia is produced by a recessive allele
d. achondroplasia is a result of codominance

Post Merge: 4 years ago

@bio_man need much help; I have to hand this in soon

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Please limit topics to two questions per thread.

I've answered questions 1 and 2 above. If you need the rest answered, start a new thread.

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