Nokea
What groups listed below have true cell walls?
- A. algae
- B. mycoplasmas
- C. Gram-positive bacteria
- D. fungi
Correct Answer: B
Rationale: The correct answer is B: mycoplasmas. Mycoplasmas have cell walls, which contain peptidoglycan, making them structurally similar to typical bacteria. Algae (choice A) have cell walls made of cellulose, Gram-positive bacteria (choice C) have cell walls containing thick layers of peptidoglycan, and fungi (choice D) have cell walls made of chitin. Mycoplasmas lack a cell wall, but they have a flexible cell membrane that provides them with shape and protection.
You may also like to solve these questions
The human retina contains rods and cone which are able to
- A. convert the photo power to the chemical power
- B. absorption of ultraviolet
- C. convert photo power to electrical form and send action potentials to the brain
- D. absorption of infrared
Correct Answer: C
Rationale: The correct answer is C because rods and cones in the human retina convert light energy into electrical signals through phototransduction, which are then sent as action potentials to the brain via the optic nerve. This process allows for visual information to be transmitted and processed by the brain. Choice A is incorrect as it refers to the conversion of light energy to chemical energy, which is not the primary function of rods and cones. Choice B is incorrect as rods and cones do not specifically absorb ultraviolet light. Choice D is incorrect as rods and cones do not absorb infrared light.
Which immunoglobulins will initially protect a newborn baby of a breastfeeding mother (select all that apply)?
- A. IgA
- B. IgD
- C. IgE
- D. IgG
Correct Answer: A
Rationale: IgA is transferred through breast milk and provides mucosal immunity, while IgG crosses the placenta during pregnancy to provide systemic protection.
Which cells are involved in innate immunity?
- A. B lymphocytes
- B. T lymphocytes
- C. Natural killer cells
- D. Plasma cells
Correct Answer: C
Rationale: The correct answer is C: Natural killer cells. Natural killer cells are part of the innate immune system and play a crucial role in identifying and destroying infected or abnormal cells. They are able to recognize and target cells that lack specific markers, providing a rapid response to infections.
Explanation for incorrect choices:
A: B lymphocytes are part of the adaptive immune system, not innate immunity.
B: T lymphocytes are also part of the adaptive immune system, not involved in innate immunity.
D: Plasma cells are differentiated B cells that produce antibodies in the adaptive immune response, not part of innate immunity.
Match the following:
- A. 1-c, 2-d, 3-b, 4-a
- B. 1-b, 2-d, 3-c, 4-a
- C. 1-b, 2-d, 3-a, 4-c
- D. 1-d, 2-c, 3-a, 4-b
Correct Answer: C
Rationale: The correct answer is C: 1-b, 2-d, 3-a, 4-c.
1. The first match should be b, as it aligns with the order given.
2. The second match should be d, as it aligns with the order given.
3. The third match should be a, as it aligns with the order given.
4. The fourth match should be c, as it aligns with the order given.
Therefore, option C is the correct match based on the given order. Other choices are incorrect because they do not align with the given order of matches.
What receptor is targeted in Grave's disease, a Type V hypersensitivity reaction?
- A. Insulin receptor
- B. Thyroid-stimulating hormone (TSH) receptor
- C. Complement receptor
- D. CD4 receptor
Correct Answer: B
Rationale: The correct answer is B: Thyroid-stimulating hormone (TSH) receptor. In Grave's disease, autoantibodies bind to and activate the TSH receptor on thyroid cells, leading to hyperthyroidism. This is a Type II hypersensitivity reaction. Insulin receptor (A) is not involved in Grave's disease. Complement receptor (C) is not the target in this condition. CD4 receptor (D) is primarily involved in T cell activation, not in Grave's disease.