Nokea
Among all the molecules that are significant to biology, which of the following are considered the most important?
- A. Carbohydrates, lipids, protein, and nucleic acids
- B. Carbohydrates, lipids, protein, and calcium
- C. Carbohydrates, lipids, protein, and sulfur
- D. Carbohydrates, lipids, protein, and iron
Correct Answer: A
Rationale: The correct answer is A: Carbohydrates, lipids, protein, and nucleic acids. These four types of molecules are essential for various biological processes. Carbohydrates provide energy, lipids are important for energy storage and cell membrane structure, proteins are involved in nearly all cell functions, and nucleic acids carry genetic information. While the other choices contain important components, nucleic acids play a crucial role in storing and transmitting genetic information, making them indispensable in biology.
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Many control, both positive and negative, maintain body processes. What is this phenomenon called?
- A. Homeostasis.
- B. Endothermy.
- C. Metabolism.
- D. Respiration.
Correct Answer: A
Rationale: Correct Answer: A: Homeostasis.
Rationale:
1. Homeostasis refers to the ability of the body to maintain internal stability despite external changes.
2. It involves various control mechanisms to keep key physiological parameters within a narrow range.
3. Positive and negative feedback loops regulate processes to achieve homeostasis.
4. Choices B, C, and D do not specifically relate to the concept of maintaining internal stability like homeostasis does.
Enzymes can ................. reactions.
- A. Catalyze
- B. Inhibit
- C. Stop
- D. None of the above
Correct Answer: A
Rationale: Enzymes function to catalyze reactions, which means they accelerate the rate of chemical reactions without being consumed in the process. Enzymes do not inhibit or stop reactions; instead, they facilitate and enable reactions to occur more efficiently. Therefore, the correct answer is 'Catalyze.'
AIDS is caused by what type of infectious agent?
- A. Protist.
- B. Bacterium.
- C. Insect.
- D. Virus.
Correct Answer: D
Rationale: The correct answer is D: Virus. AIDS is caused by the Human Immunodeficiency Virus (HIV), which attacks the immune system and weakens the body's ability to fight infections. Viruses are unique infectious agents that require a host cell to replicate and cause disease, which is the case with HIV.
A: Protists are eukaryotic organisms like parasites, but they are not known to cause AIDS.
B: Bacteria are prokaryotic organisms that can cause various infections, but they do not cause AIDS.
C: Insects are not infectious agents themselves but can transmit diseases, they do not cause AIDS.
In summary, the correct answer is D because HIV, a virus, specifically causes AIDS by targeting and damaging the immune system.
Which macromolecule is an example of a nucleic acid?
- A. Glucose.
- B. DNA.
- C. Albumin.
- D. HCl.
Correct Answer: B
Rationale: Correct Answer: B - DNA
Rationale:
1. Nucleic acids are macromolecules that store genetic information.
2. DNA (Deoxyribonucleic acid) is a type of nucleic acid that carries genetic instructions.
3. Glucose (A) is a carbohydrate, not a nucleic acid.
4. Albumin (C) is a protein, not a nucleic acid.
5. HCl (D) is a compound, not a nucleic acid.
Summary:
The correct answer is B because DNA is a nucleic acid that specifically functions to store genetic information, unlike the other choices which are not nucleic acids.
Which term means the movement of water across a semi-permeable membrane from a low solute concentration to a high solute concentration?
- A. Active Transport.
- B. Passive Transport.
- C. Osmosis.
- D. Diffusion.
Correct Answer: C
Rationale: The correct answer is C: Osmosis. Osmosis is the movement of water molecules across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. This process occurs passively, without the need for energy input.
Rationale:
1. Osmosis specifically refers to the movement of water molecules.
2. It occurs across a semi-permeable membrane.
3. The direction of movement is from low solute concentration to high solute concentration.
4. Osmosis is a passive transport process, as it does not require energy.
Summary:
A: Active Transport involves the movement of molecules against the concentration gradient, requiring energy input.
B: Passive Transport includes processes like diffusion and osmosis but does not involve active energy expenditure.
D: Diffusion is the movement of molecules from high concentration to low concentration, not specific to water movement across a membrane.