Nokea
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.
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Where is the slide placed on a light microscope?
- A. Stage
- B. Arm
- C. Lens
- D. Base
Correct Answer: A
Rationale: In a light microscope, the slide is placed on the stage, which is a flat platform designed to hold the specimen being observed. The stage provides stability for the slide and allows for adjustments to focus the lens on the specimen. The arm, lens, and base have specific functions in the operation of the microscope but are not where the slide is placed.
What is the first step in the process of respiration?
- A. Fermentation
- B. Krebs cycle
- C. Electron transport chain
- D. Glycolysis
Correct Answer: D
Rationale: The correct answer is Glycolysis. Glycolysis is the initial step in cellular respiration where glucose is broken down into pyruvate, producing a small amount of ATP and NADH in the cytoplasm. This step is crucial as it initiates the breakdown of glucose, setting the stage for further energy production in subsequent stages like the Krebs cycle and electron transport chain.
Why is the nucleus important in a cell?
- A. It stores the DNA.
- B. It provides structural support.
- C. It synthesizes proteins.
- D. It produces energy from food.
Correct Answer: A
Rationale: The correct answer is A. The nucleus is crucial in a cell because it stores the DNA, which contains the genetic information necessary for directing the cell's activities and determining its characteristics. The nucleus does not provide structural support, synthesize proteins, or produce energy from food; these functions are carried out by other cell organelles. Therefore, the main role of the nucleus is to safeguard and regulate the genetic material of the cell, ensuring proper cell function and inheritance of traits.
Which of the following is the best example of a hypothesis?
- A. Dogs like treats
- B. Red is the best color
- C. If I eat 100 donuts, then I will feel sick
- D. If a plant is exposed to red light, then it will show less growth than natural light.
Correct Answer: D
Rationale: A hypothesis is a testable statement that predicts the outcome of an experiment based on observations or research. Option D is the best example of a hypothesis as it presents a clear cause-and-effect relationship that can be tested through an experiment. Options A, B, and C do not provide a clear prediction or testable statement, making them weaker examples of hypotheses. In contrast, option D clearly states the expected outcome of exposing a plant to red light, allowing for a specific experiment to test this hypothesis.
Why is DNA crucial for the metabolic activities of the cell?
- A. It initiates cellular mitosis.
- B. It provides cell wall stability.
- C. It increases glucose absorption.
- D. It controls the synthesis of enzymes.
Correct Answer: D
Rationale: DNA is crucial for the metabolic activities of the cell because it contains the genetic information necessary to regulate the synthesis of enzymes. Enzymes are essential for catalyzing biochemical reactions involved in metabolic processes within the cell. DNA controls the production of enzymes, which are vital for driving various metabolic pathways. Therefore, the correct answer is D, as DNA's role in controlling enzyme synthesis is fundamental for the cell's metabolic activities.