Nokea
Which of the following describes a genetic mutation that results in uncontrolled division of a single cell within the body?
- A. Gene therapy
- B. Stem cell
- C. Translai
- D. Cancer
Correct Answer: D
Rationale: The correct answer is D, Cancer. Cancer is characterized by uncontrolled cell division caused by genetic mutations. These mutations disrupt normal cell growth regulation processes, leading to the development of malignant tumors. Gene therapy and stem cells are not related to genetic mutations causing uncontrolled cell division. 'Translai' is an irrelevant choice and does not pertain to the question.
You may also like to solve these questions
Which structure of the female reproductive system is the source of the blood and mucosal tissue during menstruation?
- A. Fallopian Tubes
- B. Endometrium
- C. Cervix
- D. Ovaries
Correct Answer: B
Rationale: The correct answer is B: Endometrium. The endometrium is the inner lining of the uterus where an embryo implants during pregnancy. If no pregnancy occurs, the endometrial lining sheds during menstruation, leading to the discharge of blood and mucosal tissue. The fallopian tubes are responsible for transporting the egg from the ovary to the uterus. The cervix is the lower part of the uterus that connects to the vagina. The ovaries produce eggs and hormones, but they are not the source of blood and mucosal tissue during menstruation.
A student conducts an experiment where they dissolve 1 g each of several substances in 50 mL of water. They have 12 identical plastic cups of water and place 1 g of salt into three of the cups, 1 g of sugar into three of the cups, and 1 g of baking soda into three of the cups. The three remaining cups contain only water. All the cups are put in a freezer, and the temperature of the solution in each cup is recorded every 15 minutes for 4 hours. What question is the student most likely investigating?
- A. What effect do different concentrations of solute have on the freezing point of water?
- B. How does the volume of water affect the rate at which it cools?
- C. What effect does cooling have on the solubility of different solutes?
- D. How is the cooling rate of water affected by different solutes?
Correct Answer: A
Rationale: The student is most likely investigating the effect of different concentrations of solutes (salt, sugar, baking soda) on the freezing point of water. By monitoring the temperature changes during freezing, the student can observe how each solute affects the freezing point. This experiment helps understand the concept of colligative properties, where the presence of solutes lowers the freezing point of a solvent like water. Therefore, the correct answer is A: 'What effect do different concentrations of solute have on the freezing point of water?'
Which laboratory method is most useful for separating genomic DNA fragments by size?
- A. Titration
- B. Spectrophotometry
- C. Electrophoresis
- D. Filtration
Correct Answer: C
Rationale: Electrophoresis is the most suitable method for separating genomic DNA fragments by size. In electrophoresis, DNA fragments are separated based on their size through an electric field. The smaller fragments move faster towards the positive electrode, while the larger fragments move slower, allowing for differentiation based on size. Titration is a technique used to determine the concentration of a substance in a solution, not for separating DNA fragments. Spectrophotometry is a method used to measure how much a substance absorbs light at different wavelengths, not for separating DNA fragments. Filtration is a process of separating solids from liquids using a filter, not commonly used for separating DNA fragments by size.
Blockage and inflammation of which of the following structures most often leads to facial acne?
- A. Lacrimal glands
- B. Sebaceous glands
- C. Ceruminous glands
- D. Sudoriferous glands
Correct Answer: B
Rationale: Sebaceous glands are responsible for producing sebum, an oily substance that can clog pores when overproduced or combined with dead skin cells. This blockage promotes the growth of acne-causing bacteria and leads to inflammation. The other glands listed in the choices do not play a significant role in the development of facial acne. Ceruminous glands produce earwax (cerumen) to protect the ear canal, sudoriferous glands produce sweat to regulate body temperature, and lacrimal glands produce tears to lubricate and protect the eyes.
Which of the following organic molecules contains both an amine and a carboxyl group?
- A. Lipids
- B. Cellulose
- C. Chitin
- D. Proteins
Correct Answer: D
Rationale: Proteins are composed of amino acids, which contain both an amine (NH2) and a carboxyl (COOH) functional group. The amine group is found at one end of the amino acid molecule, while the carboxyl group is located at the other end. When amino acids join together through peptide bonds, the amine of one amino acid reacts with the carboxyl group of another, forming a protein chain. Therefore, the correct answer is proteins.