Nokea
Which macromolecule will always contain nitrogen?
- A. Fatty acid
- B. Protein
- C. Lipid
- D. Carbohydrate
Correct Answer: B
Rationale: The correct answer is B: Protein. Proteins always contain nitrogen, as it is a key element in amino acids, the building blocks of proteins. Fatty acids (choice A), lipids (choice C), and carbohydrates (choice D) do not always contain nitrogen. Fatty acids consist of long chains of hydrocarbons, lipids are mainly composed of carbon, hydrogen, and oxygen, and carbohydrates are composed of carbon, hydrogen, and oxygen as well, but not nitrogen.
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Which part of the cell is responsible for storing genetic information?
- A. Ribosome
- B. Mitochondrion
- C. Nucleus
- D. Cytoplasm
Correct Answer: C
Rationale: The correct answer is C, Nucleus. The nucleus is responsible for storing genetic information in the form of DNA. The DNA within the nucleus controls the activities of the cell by directing the synthesis of proteins and regulating gene expression. Choices A, Ribosome, B, Mitochondrion, and D, Cytoplasm, do not store genetic information. Ribosomes are involved in protein synthesis, mitochondria produce energy for the cell, and cytoplasm is a gel-like substance that houses organelles and where many cellular activities occur.
Which of the following is produced by Natural Killer Cells to create pores for target cell rupture?
- A. Interferon
- B. Apoptosis
- C. Perforin
- D. Antibody
Correct Answer: C
Rationale: The correct answer is C, Perforin. Natural Killer cells release perforin, which forms pores in the membrane of target cells, leading to their lysis. Interferon (choice A) is a protein released by cells in response to viral infections, apoptosis (choice B) is programmed cell death, and antibodies (choice D) are produced by B cells to neutralize pathogens but are not directly involved in creating pores for cell rupture like perforin.
Which of the following is a function of the large intestine?
- A. Absorption of water
- B. Production of vitamin K
- C. Production of vitamin B
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, 'All of the above.' The large intestine performs various functions, including the absorption of water, production of vitamin K, and production of some B vitamins. Water absorption is a crucial function of the large intestine, helping to concentrate waste material into feces. Additionally, the large intestine hosts beneficial bacteria that produce vitamin K and some B vitamins, which are absorbed into the body. Choices A, B, and C individually represent specific functions of the large intestine, while choice D correctly encompasses all these functions, making it the most comprehensive and accurate answer.
Which part of the brain is responsible for controlling involuntary functions like breathing and heart rate?
- A. Cerebrum
- B. Medulla oblongata
- C. Cerebellum
- D. Thalamus
Correct Answer: B
Rationale: The medulla oblongata is located at the base of the brainstem and is responsible for controlling vital involuntary functions such as breathing, heart rate, and blood pressure. The cerebrum, although the largest part of the brain, is primarily responsible for higher brain functions like thinking and voluntary muscle movements. The cerebellum is involved in coordination, balance, and muscle control. The thalamus acts as a relay station for sensory information but is not directly responsible for regulating involuntary functions like breathing and heart rate. Therefore, the correct answer is the medulla oblongata.
What is the primary function of white blood cells?
- A. To carry oxygen
- B. To fight infection
- C. To transport nutrients
- D. To transport waste
Correct Answer: B
Rationale: The correct answer is B: "To fight infection." White blood cells are primarily responsible for fighting infections and foreign invaders in the body, making them a critical component of the immune system. Choice A, "To carry oxygen," is incorrect as red blood cells are responsible for oxygen transport. Choice C, "To transport nutrients," is incorrect as this function is mainly attributed to blood plasma and other specialized cells. Choice D, "To transport waste," is also incorrect as waste removal is primarily handled by the kidneys and the lymphatic system, not white blood cells.