Nokea
The bilayer of the cellular membrane consists of phospholipids with all except which of the following scattered throughout?
- A. Nucleic acids
- B. Cholesterol
- C. Proteins
- D. Glycoproteins
Correct Answer: A
Rationale: The cellular membrane is composed of a phospholipid bilayer with cholesterol, proteins, and glycoproteins distributed throughout. Nucleic acids are not found within the cellular membrane. Cholesterol helps maintain membrane fluidity, while proteins and glycoproteins play important roles in cell signaling, transport, and structural support.
You may also like to solve these questions
Asexual reproduction is a type of reproduction by which offspring arise from:
- A. Two identical cells
- B. A single cell
- C. Two cells
- D. Four daughter cells
Correct Answer: B
Rationale: Asexual reproduction is a type of reproduction where a single parent cell divides to produce genetically identical offspring. The correct answer is 'B: A single cell' because asexual reproduction does not involve the fusion of two cells. Choice A ('Two identical cells') is incorrect because asexual reproduction does not involve two cells. Choice C ('Two cells') is incorrect because asexual reproduction typically involves only one parent cell. Choice D ('Four daughter cells') is incorrect because asexual reproduction does not necessarily involve the production of four daughter cells.
Which two items react during cellular respiration?
- A. Glucose and water
- B. Carbon dioxide and water
- C. Carbon dioxide and oxygen
- D. Glucose and oxygen
Correct Answer: D
Rationale: The correct answer is D: Glucose and oxygen. During cellular respiration, glucose and oxygen react in the presence of enzymes to produce carbon dioxide, water, and energy in the form of ATP. Choice A (Glucose and water) is incorrect because water is a product of cellular respiration, not a reactant. Choice B (Carbon dioxide and water) is incorrect as carbon dioxide is produced during cellular respiration, not a reactant. Choice C (Carbon dioxide and oxygen) is incorrect because oxygen is a reactant in cellular respiration, not a product.
Which of the following is responsible for the synthesis of carbohydrates, lipids, and steroid hormones?
- A. Smooth endoplasmic reticulum (ER)
- B. Rough endoplasmic reticulum (ER)
- C. Golgi apparatus
- D. Ribosomes
Correct Answer: A
Rationale: The smooth endoplasmic reticulum (ER) is the correct answer. It is responsible for the synthesis of lipids, including steroids, and also plays a role in carbohydrate metabolism. The rough endoplasmic reticulum (ER) is involved in protein synthesis and processing, not lipid or carbohydrate synthesis. The Golgi apparatus is responsible for modifying, sorting, and packaging of proteins and lipids, but not for their synthesis. Ribosomes are the cellular organelles responsible for protein synthesis, not lipid or carbohydrate synthesis.
Which of the following processes produces nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FADH2) for the electron transport chain during cellular respiration?
- A. Electron transport chain
- B. Glycolysis
- C. Citric acid cycle (the Krebs cycle)
- D. None of these
Correct Answer: C
Rationale: The correct answer is C, the citric acid cycle (the Krebs cycle). This cycle generates NADH and FADH2, which play a crucial role in providing electrons to the electron transport chain during cellular respiration. Choice A, the electron transport chain itself, is where NADH and FADH2 donate their electrons, not where they are produced. Choice B, glycolysis, produces NADH but not FADH2. Choice D, 'None of these,' is incorrect as the citric acid cycle specifically produces NADH and FADH2.
What is the composition of the cellular membrane?
- A. A bilayer of phospholipid molecules
- B. A single layer of phospholipid molecules
- C. Proteins that act as transport highways
- D. Carbohydrates
Correct Answer: A
Rationale: The cellular membrane is primarily composed of a phospholipid bilayer, which consists of two layers of phospholipid molecules. These molecules have a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tail, creating a barrier that separates the internal cellular environment from the external surroundings. While proteins are embedded within this bilayer and act as transport channels, receptors, and structural support, carbohydrates are found on the outer surface of the membrane for cell recognition and signaling purposes. Therefore, the correct answer is a bilayer of phospholipid molecules.