Nokea
What is the primary purpose of cellular respiration?
- A. To copy DNA
- B. To facilitate breathing
- C. To convert nutrients to energy
- D. To enable cell division
Correct Answer: C
Rationale: Cellular respiration is a fundamental metabolic process in cells where nutrients are broken down to produce energy in the form of ATP. This energy is essential for powering various cellular functions and activities. Therefore, the primary goal of cellular respiration is to convert nutrients into energy, providing the cell with the necessary fuel to efficiently carry out its functions.
You may also like to solve these questions
Which base has two carbon rings?
- A. N
- B. C
- C. T
- D. G
Correct Answer: D
Rationale: The correct answer is G. In organic chemistry, the base Guanine (G) contains two carbon rings in its structure. Guanine is one of the four main nucleobases found in DNA and RNA. The other options, N, C, and T, do not have two carbon rings in their structures. Therefore, Guanine is the only option that fits the description of a base with two carbon rings.
Why is the nucleus important in a cell?
- A. It stores the DNA.
- B. It provides structural support.
- C. It synthesizes proteins.
- D. It produces energy from food.
Correct Answer: A
Rationale: The correct answer is A. The nucleus is crucial in a cell because it stores the DNA, which contains the genetic information necessary for directing the cell's activities and determining its characteristics. The nucleus does not provide structural support, synthesize proteins, or produce energy from food; these functions are carried out by other cell organelles. Therefore, the main role of the nucleus is to safeguard and regulate the genetic material of the cell, ensuring proper cell function and inheritance of traits.
Why can animal cells use a contractile ring but plant cells cannot?
- A. Plant cells can divide using both methods.
- B. Animal cells divide faster, requiring them to pinch apart.
- C. Plant cells are too rigid to utilize a contractile ring.
- D. Plant cells have a cell wall that hinders the formation of a contractile ring.
Correct Answer: D
Rationale: The correct answer is D because plant cells have a cell wall surrounding them, which provides structural support but makes it challenging for them to form a contractile ring during cell division. The cell wall restricts the flexibility needed for the contractile ring to constrict and separate the cells. In contrast, animal cells do not have a cell wall, allowing them to form a contractile ring composed of actin filaments that constrict during cytokinesis, facilitating cell division.
What term describes the process of producing the RNA strand from a DNA template?
- A. Metabolism.
- B. Transcription.
- C. Synthesis.
- D. Replication.
Correct Answer: B
Rationale: The correct answer is B: Transcription. Transcription is the process where RNA is synthesized from a DNA template by RNA polymerase. During transcription, the DNA double helix unwinds, and one strand is used as a template to create a complementary RNA molecule. This process occurs in the cell nucleus and is essential for gene expression.
Choice A, Metabolism, refers to the chemical reactions that occur in living organisms to maintain life and is not directly related to RNA synthesis. Choice C, Synthesis, is a general term that does not specifically describe the process of RNA production from a DNA template. Choice D, Replication, is the process of copying DNA to create an identical DNA molecule, not RNA synthesis. Therefore, the correct term for producing an RNA strand from a DNA template is Transcription.
What enzyme is used to catalyze the elongation of the DNA strand during replication?
- A. DNA polymerase
- B. Primase
- C. DNA Ligase
- D. Helicase.
Correct Answer: A
Rationale: Correct Answer: A: DNA polymerase
Rationale:
1. DNA polymerase is responsible for adding nucleotides to the growing DNA strand during replication.
2. It catalyzes the formation of phosphodiester bonds between incoming nucleotides.
3. DNA polymerase also possesses proofreading abilities to ensure accuracy.
4. Primase is responsible for synthesizing RNA primers, not elongating the DNA strand.
5. DNA ligase joins Okazaki fragments and seals nicks in the DNA backbone.
6. Helicase unwinds the DNA double helix during replication, not involved in elongation.