Nursing Elites

1. What type of transport moves substances across the cell membrane using energy?

• A. Passive Transport
• B. Active Transport
• C. Facilitated Diffusion
• D. Osmosis

Correct answer: B

Rationale: The correct answer is B: Active Transport. Active transport moves substances across the cell membrane by utilizing energy from the cell, typically in the form of ATP. This process allows the cell to move molecules against their concentration gradient, requiring energy expenditure. Choices A, C, and D are incorrect because passive transport does not require energy input, facilitated diffusion involves the assistance of proteins but does not directly use energy, and osmosis is the diffusion of water molecules specifically, not substances, across a selectively permeable membrane.

2. How many chromosomes do sperm and egg produce in meiosis?

• A. 46
• B. 23
• C. 45
• D. 24

Correct answer: B

Rationale: Sperm and egg cells undergo meiosis to form gametes with half the number of chromosomes found in somatic cells. Each sperm and egg cell produces 23 chromosomes through meiosis. Choice A is incorrect because 46 chromosomes represent the diploid number found in somatic cells. Choice C is incorrect as it is an uncommon number for chromosome production in human gametes. Choice D is incorrect as the total number of chromosomes in sperm or egg cells is 23, not 24.

3. Which molecules contain only carbon, hydrogen, and oxygen?

• A. Lipids and proteins
• B. Carbohydrates and lipids
• C. Proteins and carbohydrates
• D. Nucleic acids and proteins

Correct answer: B

Rationale: Carbohydrates and lipids are the molecules that contain only carbon, hydrogen, and oxygen. Carbohydrates such as sugars and starches are made up of carbon, hydrogen, and oxygen in a ratio of 1:2:1, while lipids such as fats and oils are composed of carbon, hydrogen, and oxygen as well. Lipids typically contain more carbon and hydrogen atoms compared to oxygen atoms. Proteins contain nitrogen in addition to carbon, hydrogen, and oxygen, while nucleic acids contain phosphorus in addition to carbon, hydrogen, and oxygen. Therefore, choices A, C, and D are incorrect as they include molecules that contain elements other than carbon, hydrogen, and oxygen.

4. The mixture of gases surrounding a planet is referred to as its ______.

• A. Atmosphere
• B. Stratosphere
• C. Biosphere
• D. Troposphere

Correct answer: A

Rationale: The mixture of gases surrounding a planet is referred to as its atmosphere. The atmosphere plays a crucial role in supporting life on Earth by providing oxygen, regulating carbon dioxide levels, and shielding the planet from harmful radiation. While the stratosphere, troposphere, and other layers are part of the atmosphere, the term 'atmosphere' encompasses the entire gaseous envelope surrounding a planet. The stratosphere, troposphere, mesosphere, thermosphere, and exosphere are specific layers within the atmosphere, each with distinct characteristics and functions.

5. Where is DNA stored?

• A. The nucleus
• B. Ribosomes
• C. Endoplasmic reticulum
• D. Mitochondria

Correct answer: A

Rationale: DNA is stored in the nucleus of a cell. The nucleus houses the cell's genetic material, including the DNA, which contains the instructions for building and operating the cell. The nucleus controls the activities of the cell and is essential for proper cell function and reproduction. Ribosomes are responsible for protein synthesis, not DNA storage. The endoplasmic reticulum is involved in protein and lipid synthesis, storage, and transport but does not store DNA. Mitochondria are known as the powerhouse of the cell, producing energy in the form of ATP, but they do not store DNA.

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