which if any of the following statements about the biosphere are correct

HESI A2

Biology HESI A2 Practice Test

1. Which, if any, of the following statements about the biosphere is correct?

A. The biosphere is the part of the Earth that supports life.
B. The biosphere encompasses the entire surface of the Earth.
C. A and B are correct.
D. None of these statements is correct.

Correct answer: A

Rationale: Statement A is correct. The biosphere refers to the part of the Earth where life exists, including the land, water bodies, and atmosphere. It is the zone where living organisms and ecosystems exist. Statement B is incorrect because the biosphere covers various ecosystems on Earth but does not encompass the entire surface of the planet. The biosphere includes regions such as the lithosphere (land), hydrosphere (water bodies), and atmosphere, but not every part of the Earth's surface. Therefore, option C, stating both A and B are correct, is inaccurate. The correct answer is option A, as it accurately defines the biosphere.

2. Which of the following is not true about enzymes?

A. They catalyze reactions
B. They lower the activation energy needed
C. They have an active site
D. They are typically proteins

Correct answer: B

Rationale: Enzymes lower the activation energy needed for a reaction to occur, not raise it. By lowering the activation energy, enzymes facilitate reactions, making them occur more easily and rapidly. Choice A is correct as enzymes indeed catalyze reactions. Choice C is correct as enzymes have specific active sites where substrates bind. Choice D is correct as enzymes are commonly proteins, although some RNA molecules also exhibit catalytic properties.

3. In which phase of mitosis do new nuclear membranes form around sets of chromosomes?

A. Prophase
B. Anaphase
C. Telophase
D. Interphase

Correct answer: C

Rationale: The correct answer is C, Telophase. During telophase, the final phase of mitosis, new nuclear membranes form around sets of chromosomes at the opposite poles of the cell. This process marks the completion of nuclear division in mitosis. Choices A, B, and D are incorrect because in prophase, chromosomes condense but nuclear membranes are not formed; in anaphase, chromosomes separate and move to opposite poles but no new nuclear membranes are formed; and in interphase, the cell prepares for division but nuclear membranes are not forming around sets of chromosomes.

4. Muscles are connected to bones by , and bones are connected to each other by .

A. Muscles
B. Tendons, ligaments
C. Muscles
D. Ligaments

Correct answer: B

Rationale: Muscles are connected to bones by tendons, which allow the muscle to exert force on the bone for movement. Bones are connected to each other by ligaments, which provide stability and support to the joints between bones. This relationship between muscles, tendons, bones, and ligaments is essential for proper movement and function of the musculoskeletal system. Choice A is incorrect because muscles are not directly connected to bones; tendons serve as the connection between muscles and bones. Choice D is incorrect because ligaments connect bones to each other, not muscles to bones.

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.