Nokea
Which disease is caused by a bacterium?
- A. Mumps
- B. Strep throat
- C. AIDS (HIV+)
- D. Common cold
Correct Answer: B
Rationale: Strep throat is caused by the bacterium Streptococcus pyogenes. Unlike mumps, which is a viral infection, AIDS caused by the HIV virus, and the common cold usually caused by rhinoviruses, strep throat is specifically a bacterial infection that can be treated with antibiotics.
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Which option demonstrates complementary base pairing in DNA?
- A. A and G
- B. A and C
- C. A and A
- D. A and T
Correct Answer: D
Rationale: In DNA, adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G). This is known as complementary base pairing. Adenine always pairs with thymine via two hydrogen bonds, forming a strong bond essential for DNA structure and replication. Therefore, the correct option that demonstrates complementary base pairing in DNA is A and T (D). This pairing is crucial during DNA replication and ensures the accurate transmission of genetic information.
Which method of glucose conversion generates the most usable and efficient form of ATP within the human body?
- A. Aerobic respiration
- B. Anaerobic respiration
- C. Lactic acidosis
- D. Fermentation conversion
Correct Answer: A
Rationale: Aerobic respiration generates the most ATP (around 36-38 ATP molecules per glucose molecule). It uses oxygen and occurs in the mitochondria, making it the most efficient way for the body to produce energy. In contrast, anaerobic respiration and fermentation produce significantly less ATP and are less efficient processes. Lactic acidosis is a medical condition involving the buildup of lactic acid in the body and is not a method of glucose conversion for energy production.
Which of the following statements is not true about enzymes?
- A. They catalyze reactions
- B. They raise the activation energy needed
- C. They have an active site
- D. They are typically proteins
Correct Answer: B
Rationale: Enzymes function by lowering the activation energy required for a reaction to occur, not by raising it. This catalytic property allows enzymes to accelerate reactions without being consumed in the process. Enzymes are biological catalysts that are typically proteins and have specific active sites where substrates bind and reactions take place. The statement that enzymes raise the activation energy needed is incorrect as their role is to lower this energy barrier. Therefore, the correct answer is B.
Select the cell parts that are present in plant cells but not animal cells (there may be more than one answer):
- A. Cell membrane
- B. Cell wall
- C. Ribosome
- D. Chloroplast
Correct Answer: D
Rationale: Chloroplasts are unique to plant cells and are responsible for photosynthesis, a process that converts light energy into chemical energy. Animal cells do not contain chloroplasts as they do not perform photosynthesis. Therefore, the correct answer is D - Chloroplast. The cell membrane is found in both plant and animal cells, serving as a protective barrier, while the cell wall is a rigid structure present in plant cells that provides support and protection. Ribosomes are cellular structures responsible for protein synthesis and are present in both plant and animal cells.
What type of bond holds molecules of water together with other water molecules?
- A. Ionic
- B. Covalent
- C. Hydrogen
- D. Molecular
Correct Answer: C
Rationale: The correct answer is 'C: Hydrogen.' Molecules of water are held together by hydrogen bonds. These bonds form between the hydrogen atom of one water molecule and the oxygen atom of another water molecule. Hydrogen bonds are weaker than covalent bonds but are crucial in various biological processes, such as maintaining the unique properties of water and facilitating specific interactions in biological molecules.