what type of molecules are enzymes

ATI TEAS 7

ATI TEAS 7 Science Practice Test

1. What type of molecules are enzymes?

A. Water molecules
B. Protein molecules
C. Tripolar molecules
D. Inorganic molecules

Correct answer: B

Rationale: The correct answer is B: Protein molecules. Enzymes are biological catalysts made up of proteins. They function by facilitating and speeding up chemical reactions in living organisms. Therefore, enzymes are primarily composed of protein molecules, not water, tripolar, or inorganic molecules. Choice A (Water molecules), Choice C (Tripolar molecules), and Choice D (Inorganic molecules) are incorrect because enzymes are specifically classified as proteins due to their structure and function in biological systems.

2. Which organelle is responsible for the final stages of protein modification and packaging for secretion in animal cells?

A. Rough endoplasmic reticulum (RER)
B. Smooth endoplasmic reticulum (SER)
C. Ribosomes
D. Golgi apparatus

Correct answer: D

Rationale: The Golgi apparatus is responsible for the final stages of protein modification and packaging for secretion in animal cells. After proteins are synthesized in the rough endoplasmic reticulum (RER), they are transported to the Golgi apparatus for further processing, sorting, and packaging before being sent to their final destination within or outside the cell. The smooth endoplasmic reticulum (SER) is mainly involved in lipid metabolism and detoxification processes, not protein modification. Ribosomes are the cellular organelles responsible for protein synthesis, not the final stages of protein modification and packaging for secretion, which is the role of the Golgi apparatus.

3. What is the function of introns in eukaryotic genes?

A. They code for protein sequences.
B. They are involved in gene regulation.
C. They are removed during mRNA processing.
D. They are non-functional remnants of ancient DNA.

Correct answer: C

Rationale: A) Introns do not code for protein sequences. Exons are the segments of DNA that code for proteins. B) While introns can indirectly influence gene regulation, their primary function is not directly involved in gene regulation. C) Introns are non-coding regions of DNA that are transcribed into pre-mRNA but are removed during mRNA processing through a process called splicing. This allows only the exons to be included in the mature mRNA that will be translated into proteins. D) While introns were once thought to be non-functional remnants of ancient DNA, research has shown that they can have regulatory functions and play a role in gene expression.

4. Identify the element with the electron configuration: 1s2 2s2 2p6 3s2 3p6. To which group and period does this element belong?

A. Group 16, Period 3
B. Group 14, Period 3
C. Group 18, Period 3
D. Group 17, Period 2

Correct answer: C

Rationale: The given electron configuration matches that of Argon, an element found in Group 18 of the periodic table. This element is in the third period, as indicated by the highest energy level (n=3) where electrons are present. Therefore, the correct answer is Group 18, Period 3. Choice A (Group 16, Period 3) corresponds to sulfur, not the given electron configuration. Choice B (Group 14, Period 3) corresponds to silicon, not the given electron configuration. Choice D (Group 17, Period 2) corresponds to chlorine, which is in Period 3 but not in Group 18, making it incorrect for the given electron configuration.

5. Which gland located in the neck is responsible for regulating metabolism, growth, and development?

A. Parathyroid gland
B. Thyroid gland
C. Pituitary gland
D. Thymus gland

Correct answer: B

Rationale: The thyroid gland, located in the neck, is responsible for regulating metabolism, growth, and development. It produces hormones such as thyroxine (T4) and triiodothyronine (T3) that play a crucial role in these functions. The parathyroid gland regulates calcium levels, the pituitary gland controls various hormonal functions, and the thymus gland is involved in immune system development. Therefore, choices A, C, and D are incorrect as they have different functions compared to the thyroid gland.