CLEP Science and Mathematics: Biology, Calculus, Chemistry, College Algebra & Mathematics, Precalculus, Natural Sciences Exam Questions PDF download

QUESTION: 61 Exam Topic: 1, Biology

If the frequency of a dominant allele for a particular trait goes up in a population, what would be expected to happen to the frequency of individuals who are recessive for that trait in this population?

It would decrease regardless of what type of trait was coded for by this allele.
It would increase regardless of what type of trait was coded for by this allele.
It would remain the same.
It would increase only if the dominant condition were harmful.
The frequency of recessive individuals would not be affected by changes in the frequency of dominant alleles.

Answer(s): D

Explanation:

According to the Hardy-Weinberg equations, p + q = 1 and p2 + 2pq + q2 = 1, an increase in the frequency of the dominant allele (p) would result in a decrease in the frequency of the recessive allele (q), which would mean a decrease in the frequency of q2 individuals. However, if the dominant allele is a harmful one, then it becomes likelier that both homozygous dominant individuals and carriers (p2 + 2pq) would decrease in frequency and recessive individuals would increase.

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QUESTION: 62 Exam Topic: 1, Biology

Ammonia and other nitrogen-containing organic matter is generally decomposed and converted into nitrogen gas by reactions within the cells of

denitrifying bacteria
nitrifying bacteria
nitrogen-fixing bacteria
photosynthetic bacteria
green plants and algae

Answer(s): A

Explanation:

While nitrogen fixing (nitrifying) bacteria convert atmospheric nitrogen into nitrates and nitrites for plant use in protein and nucleic acid synthesis, denitrifying bacteria take organic nitrogencontaining matter (usually ammonia) and free up nitrogen from it so that the gas can return to the atmosphere.

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QUESTION: 63 Exam Topic: 1, Biology

In response to attack by a pathogen or allergen, basophils and mast cells around the body release large amounts of which of the following substances, which is responsible for dilating walls of blood vessels and making capillaries leaky?

Interleukins
Antibodies
Lysozyme
Acetylcholine
Histamine

Answer(s): D

Explanation:

Histamine is released in large amounts during the inflammatory response. It causes localized and sometimes systemic swelling, as it opens up capillaries and makes them permeable to large white blood cells, so that the cells can reach the sites of injury. Antihistamines, such as Benadryl, counter histamine, which can cause life-threatening swelling especially around the face and throat.

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