Which of these infectious agents do not have nucleic acid?
A. viroids
B. viruses
C. bacteria
D. prions
Therefore, the Correct Answer is D.
More Questions on TEAS 7 Science
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Q #1: Which of the following vessels carries oxygenated blood?
A. Inferior vena cava
B. Pulmonary vein
C. Pulmonary artery
D. Superior vena cava
Answer Explanation
Pulmonary vein carries oxygenated blood from the lungs to the heart. Pulmonary artery carries deoxygenated blood from the heart to the lungs.
Superior and inferior vena cava bring in deoxygenated blood from all other parts of the body to the heart. -
Q #2: Which of the following sequences on a DNA molecule would be complementary to GCTTATAT?
A. TAGGCGCG
B. ATCCGCGC
C. CGAATATA
D. TGCCTCTC
Answer Explanation
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Q #3: Gel electrophoresis To separate genomic DNA fragments by size, which of these laboratory methods is most useful?
A. Filtration
B. Titration
C. Electrophoresis
D. Spectrophotometry
Answer Explanation
Electrophoresis is a lab method that is commonly used to separate charge molecules based on their size. Some of the charged molecules include DNA, RNA, and proteins.
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Q #4: The Life Cycle of HIV Which of the following allows the AIDS virus, which contains RNA, to insert viral DNA into the DNA of a host T-cell after the AIDS virus enters the cell?
A. Receptor proteins located on the surface of the virus
B. The protein that makes up the capsid of the virus
C. Reverse transcriptase, an enzyme encoded by the virus
D. The phospholipids found on the envelope of the virus
Answer Explanation
The AIDS virus (HIV virus) is Class VI or Group VI in the Baltimore Classification. Based on the Baltimore Classification, this specifically involves the reverse transcriptase enzyme and it is encoded by the virus.
This is the enzyme that will produce DNA molecules from the viral RNA. This is the mechanism involved where it will use the reverse transcriptase enzyme to insert viral DNA into the genetic material of the host cell.
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Q #5: Base your answer on the graph and on your knowledge of biology. Which is a true statement about the relationship between pH and enzyme action?
A. All enzymes work best at a neutral pH.
B. Adding more acid does not affect the rate of activity of an enzyme.
C. Enzymes function only in a pH range of 4.0 to 5.5.
D. The activity of an enzyme is affected by pH.
Answer Explanation
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Q #6: In a plant in which fuzzy leaves (F) are dominant over smooth leaves (f), which of the following crosses will produce only offspring with smooth leaves?
A. Ff x ff
B. Ff x Ff
C. FF x FF
D. ff x ff
Answer Explanation
Crossing is the breeding of parents to produce an offspring. Given that f is a recessive allele of smooth leaves while F is the dominant allele of fuzzy leaves. Therefore, where there is F crossing with f, the offspring will have fuzzy leaves over smooth one.
Therefore, for an offspring to have smooth leaves, ff and ff must cross to produce an offspring with smooth leaves. -
Q #7: Contraction of the external intercostal muscles causes which of the following to occur?
A. The diaphragm moves downward
B. The rib cage is compressed
C. The thoracic cavity volume decreases
D. The ribs and sternum move upward
Answer Explanation
The intercostal muscles are muscles are located along the ribs. The intercostal muscles assist in respiration mechanically. This allows the expansion and contraction of the thorax.
Contraction of the external intercostal muscle causes the ribs and sternum move upward. -
Q #8: Metabolism of proteins Which of the following substances is excreted by sweat glands in response to the breakdown of proteins and the formation of ammonia?
A. Sebum
B. Urea
C. Lysozymes
D. Water
Answer Explanation
Proteins are nitrogen-based compounds, which when broken down release ammonia. Ammonia is a toxic substance to the body, and sebaceous glands coverts it to urea.
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Q #9: An atom of lead (Pb) has a mass number of 207. How many neutrons are in the nucleus?
A. 130
B. 125
C. 82
D. 84
Answer Explanation
We find the number of neutrons as follows
Number of neutrons
= mass number – atomic number
= 207 – 82
= 125 neutrons
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Q #10: Which of the following best describes veins?
A. thick walled, small lumens, low pressure, lack valves
B. thin walled, large lumens, low pressure, have valves
C. thin walled, small lumens, high pressure, have valves
D. thick walled, large lumens, high pressure, lack valves
Answer Explanation
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