Nokea
What is the endoplasmic reticulum?
- A. A network of tubules that transport proteins and lipids throughout the cell
- B. A sac-like structure that stores water and nutrients
- C. The site of protein synthesis
- D. The site of cellular respiration
Correct Answer: A
Rationale: A) The endoplasmic reticulum (ER) is a network of tubules that are involved in the transport of proteins and lipids throughout the cell. It plays a crucial role in protein synthesis, folding, and transport within the cell. The ER can be further divided into rough ER, which has ribosomes attached to its surface and is involved in protein synthesis, and smooth ER, which is involved in lipid metabolism and detoxification. Therefore, option A is the most accurate description of the endoplasmic reticulum compared to the other options provided.
B) A sac-like structure that stores water and nutrients does not accurately describe the endoplasmic reticulum. While some organelles like vacuoles or vesicles may store water and nutrients, the ER's primary function is not storage.
C) The site of protein synthesis is partially
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Which of the following is NOT a type of vaccine?
- A. Live attenuated vaccine
- B. Toxoid vaccine
- C. Conjugate vaccine
- D. Antibiotic
Correct Answer: D
Rationale: A) Live attenuated vaccine: This type of vaccine contains a weakened form of the virus or bacteria that causes the disease. When administered, it stimulates an immune response without causing the disease itself.
B) Toxoid vaccine: Toxoid vaccines are made from toxins produced by bacteria that have been inactivated. They stimulate the immune system to produce antibodies against the toxin, providing immunity against the disease.
C) Conjugate vaccine: Conjugate vaccines are made by combining a weak antigen with a strong antigen to enhance the immune response. They are commonly used to protect against bacterial infections.
D) Antibiotic: Antibiotics are medications used to treat bacterial infections by killing or inhibiting the growth of bacteria. They are not a type of vaccine but rather a class of antimicrobial drugs.
Therefore, the correct answer is D) Antibiotic, as it is not a type of vaccine.
How did life most likely arise on Earth?
- A. From simple organic molecules in a primordial soup
- B. By spontaneous generation from non-living matter
- C. Through the arrival of extraterrestrial life forms
- D. We still don't know for sure
Correct Answer: A
Rationale: The most widely accepted scientific theory for the origin of life on Earth is abiogenesis, which suggests that life arose from simple organic molecules in a primordial soup. This theory is supported by experiments such as the Miller-Urey experiment, which demonstrated that the basic building blocks of life could have formed under early Earth conditions. While there are other hypotheses and ongoing research in this field, the primordial soup theory is currently the most plausible explanation for the origin of life on Earth. Option B, spontaneous generation from non-living matter, has been disproven and is not considered a valid explanation. Option C, the arrival of extraterrestrial life forms, lacks evidence and is not a widely accepted theory. Option D, stating that we still don't know for sure, is true to some extent as the origin of life is a complex topic, but current scientific understanding leans towards abiogenesis from simple organic molecules in a primordial soup.
What is the difference between a sensory neuron and a motor neuron?
- A. Sensory neurons carry signals from sensory receptors towards the central nervous system, while motor neurons carry signals away from the central nervous system to muscles and glands.
- B. Sensory neurons control voluntary muscles, while motor neurons control involuntary muscles.
- C. Sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system.
- D. Sensory neurons detect light, while motor neurons detect sound.
Correct Answer: A
Rationale: Sensory neurons are responsible for carrying signals from sensory receptors towards the central nervous system (brain and spinal cord), allowing the brain to receive information about the external environment. On the other hand, motor neurons carry signals away from the central nervous system to muscles and glands, enabling the brain to control voluntary and involuntary movements. Choice B is incorrect because sensory neurons do not control muscles, and motor neurons control both voluntary and involuntary muscles. Choice C is incorrect as sensory neurons are located in the peripheral nervous system, while motor neurons are located in the central nervous system. Choice D is incorrect because sensory neurons detect various stimuli such as touch, taste, smell, and sound, while motor neurons are not involved in detecting sensory stimuli.
What is the primary function of the lymphatic system?
- A. Transporting nutrients throughout the body
- B. Removing excess fluids and waste products from tissues
- C. Producing red blood cells
- D. Regulating body temperature
Correct Answer: B
Rationale: The primary function of the lymphatic system is to remove excess fluids, waste products, and toxins from tissues. It maintains fluid balance and supports the immune system by transporting lymph, which contains white blood cells, throughout the body. Choice A is incorrect as nutrient transport is primarily handled by the circulatory system. Choice C is incorrect because red blood cells are produced in the bone marrow, not the lymphatic system. Choice D is incorrect as the regulation of body temperature is mainly controlled by the endocrine system and thermoregulatory mechanisms in the body. Therefore, the correct answer is B.
Passive transport does not require energy input from the cell. Which of the following is an example of passive transport?
- A. Active transport of ions across a membrane
- B. Diffusion of small molecules across a concentration gradient
- C. Movement of large molecules using vesicles
- D. Endocytosis of particles into the cell
Correct Answer: B
Rationale: Passive transport refers to the movement of molecules across a cell membrane without the input of energy. Diffusion of small molecules across a concentration gradient is a classic example of passive transport, as it occurs spontaneously from an area of high concentration to an area of low concentration. Active transport (option A) requires energy input in the form of ATP to move substances against their concentration gradient. Movement of large molecules using vesicles (option C) involves processes like endocytosis and exocytosis that require energy in the form of ATP. Endocytosis of particles into the cell (option D) is an active process that requires energy expenditure by the cell to engulf and internalize extracellular substances.