Discussion:
Human genetics, genetic disease, and gene transcription
Please Explain Each Problem
(Excerpted from attachment)
1: The term phenotype refers to the _________ of an individual.
2: With respect to sickle cell anemia, I write that the genotype of an individual is AS. Which of the following statements are true?
3: If, in the Hershey Chase experiment, only 35S entered the bacterial cell in significant amounts, the conclusions would have:
4: During the replication of DNA:
6: Mutations at more than one gene can cause the same phenotype. For example several enzymes are used to make methionine. Defects in any of them produce an organism that cannot synthesize its own methionine. Oculocutanious albinism can also be caused by defects in several different genes. Of the following statements which are true?
7: In a double-stranded DNA molecule, the percentage of thymine is 28%. What percentage of cytosine is present?
8: Many types of research about genes' roles in cancer employ mice. Why use mice when we wish to cure cancer in humans?
9: If you were going to look for a gene that was often transcribed, where would you look and why?
Questions: Biology Study Guide
Question 1
The term phenotype refers to the _________ of an individual.
a. genetic constitution
b. appearance of a characteristic or trait
c. number of chromosomes
d. number of genes
e. breeding pattern.
Question 2
With respect to sickle cell anemia, I write that the genotype of an individual is AS. Which of the following statements are true?
a. They will have the sickle cell phenotype.
b. The genes they carry are A and S.
c. The alleles they carry are A and S.
d. They are homozygotes.
e. All of the above are true.
Question 3
If, in the Hershey Chase experiment, only 35S entered the bacterial cell in significant amounts, the conclusions would have:
a. indicated that protein is the genetic material.
b. supported the idea that the transforming agent, DNA, was also the genetic material.
c. indicated that DNA is the genetic material.
d. indicated that the transforming material, DNA, was probably not the genetic material.
e. A and D are true.
f. b and c are true.
Question 4
During the replication of DNA:
a. additional nucleotides are always added to the 3' end of the growing DNA strands.
b. additional nucleotides are always added to the 5' end of the growing DNA strands.
c. additional nucleotides are always added to the 5' end of one of the growing DNA strands and to the 3' end of the other growing strand.
d. additional nucleotides are always added to both the 3' and the 5' ends of both the growing DNA strands.
e. it is not known.
Question 5
Which statement is most accurate?
a. DNA is the genetic material.
b. RNA is the genetic material.
c. most always, DNA is the genetic material; rarely, RNA serves this function.
d. most always, RNA is the genetic material; rarely, DNA serves this function.
e. protein is the genetic material.
Question 6
Mutations at more than one gene can cause the same phenotype. For example several enzymes are used to make methionine. Defects in any of them produce an organism that cannot synthesize its own methionine. Oculocutanious albinism can also be caused by defects in several different genes. Of the following statements which are true?
a. An protein may contain polypeptides that are coded for by different genes.
b. Enzymes are proteins (usually).
c. Several different enzymes may be used in a pathway to synthesize a molecule.
d. Gene involved in specifying the structure of a cell component like melanosomes may mutate and lead to changes in phenotype.
e. All of the above are true.
f. Some of the above are true.
Question 7
In a double-stranded DNA molecule, the percentage of thymine is 28%. What percentage of cytosine is present?
a. 14%
b. 28%
c. 44%
d. 22%
e. 56%
Question 8
Many types of research about genes' roles in cancer employ mice. Why use mice when we wish to cure cancer in humans?
a. We cannot study anything about human diseases in humans themselves.
cancers in mice are identical to those found in humans.
c. Mice and humans evolved from a common ancestor. We think that processes in mice may be similar to processes in humans because of this.
d. We use mice because they are inexpensive to maintain, but their cancers seem unlike human cancers.
We think that processes we study in mice may be similar to processes in humans because mice reproduce quickly.
Question 9
There is one specific DNA change associated with the allele which causes sickle cell anemia but there are several alleles which cause cystic fibrosis, each with specific DNA changes. What may explain this difference?
a. The sickle cell anemia allele makes a product which functions normally under some conditions and abnormally under others. This is unusual and only one allele has been found to produce such an effect for the β globin gene.
b. Cystic fibrosis can be caused by lack of the normal protein or a decrease in the protein function produced by this gene and a number of mutations at different sites can produce abnormal protein products.
c. Cystic fibrosis is one phenotype that can be caused by a number of different genes. Any gene that causes cystic fibrosis has only one abnormal allele.
d. A and b are true.
e. A and c are true.
Question 10
If you were going to look for a gene that was often transcribed, where would you look and why?
Heterochromatin because this type of chromatin is available to be transcribed.
Euchromatin because this type of chromatin has fewer tandemly repeated sequences in it.
Heterochromatin because this type of chromatin has more tandemly repeated sequences in it.
d. Euchromatin because this type of DNA is available to be transcribed.
None of the above.