which organelle is responsible for the synthesis of lipids and steroid hormones

HESI RN

Biology Test

1. Which organelle is responsible for the synthesis of lipids and steroid hormones?

A. Rough endoplasmic reticulum
B. Smooth endoplasmic reticulum
C. Golgi apparatus
D. Ribosomes

Correct answer: B

Rationale: The smooth endoplasmic reticulum is the correct organelle responsible for the synthesis of lipids, including phospholipids, cholesterol, and steroid hormones. The rough endoplasmic reticulum is primarily involved in protein synthesis and processing, making choice A incorrect. The Golgi apparatus is responsible for modifying, sorting, and packaging proteins and lipids for transportation, so it is not directly involved in lipid and steroid hormone synthesis, making choice C incorrect. Ribosomes are responsible for protein synthesis and are not involved in lipid or steroid hormone synthesis, making choice D incorrect.

2. A water molecule contains two types of atoms that are covalently bonded. Which of the following makes up a water molecule?

A. One hydrogen atom and one oxygen atom
B. One hydrogen atom and two oxygen atoms
C. Two hydrogen atoms and two oxygen atoms
D. Two hydrogen atoms and one oxygen atom

Correct answer: D

Rationale: The correct answer is D: Two hydrogen atoms and one oxygen atom. A water molecule consists of two hydrogen atoms covalently bonded to one oxygen atom. This forms a stable structure known as H2O. Choice A is incorrect as water molecule contains two hydrogen atoms. Choices B and C are incorrect as they do not reflect the correct composition of a water molecule.

3. Which of the following is a group of three RNA nucleotides?

A. A stop codon
B. A codon
C. An anticodon
D. tRNA

Correct answer: B

Rationale: The correct answer is B - A codon. A codon is a sequence of three RNA nucleotides that specifies a particular amino acid or a stop signal during protein synthesis. Choice A, a stop codon, is a sequence of three nucleotides that signals the termination of protein synthesis. Choice C, an anticodon, is a group of three nucleotides found in tRNA that pairs with the complementary codon in mRNA. Choice D, tRNA, stands for transfer RNA, which is a type of RNA that carries amino acids to the ribosome during protein synthesis.

4. What is the difference between saturated and unsaturated fatty acids?

A. There is no difference between saturated and unsaturated fatty acids.
B. Saturated fatty acids contain double bonds, unlike unsaturated fatty acids.
C. Saturated fatty acids often contain two or more pairs of double bonds, unlike unsaturated fatty acids.
D. Saturated fatty acids contain no double bonds, unlike unsaturated fatty acids.

Correct answer: D

Rationale: The correct answer is D. Saturated fatty acids contain no double bonds between the carbon atoms in their hydrocarbon chains, making them more solid at room temperature. Choice A is incorrect because there is a significant difference between saturated and unsaturated fatty acids. Choice B is incorrect as it inaccurately states that saturated fatty acids contain double bonds, which is a property of unsaturated fatty acids. Choice C is also incorrect as saturated fatty acids do not contain double bonds, let alone two or more pairs of double bonds.

5. During photosynthesis in green plants, light energy is captured and used to convert all except which of the following into oxygen and energy-rich organic compounds?

A. Minerals
B. Water
C. Carbon dioxide
D. Metals

Correct answer: D

Rationale: During photosynthesis in green plants, light energy is utilized to convert water and carbon dioxide into oxygen and energy-rich organic compounds like glucose. Minerals play a role in plant growth but are not directly converted during photosynthesis. Metals are not part of the photosynthesis process, making them the correct answer. Therefore, the correct choice is D. Choices A, B, and C are incorrect as minerals, water, and carbon dioxide are involved in the photosynthesis process.