Nokea
What is the role of DNA in heredity?
- A. Provides energy for the cell
- B. Determines the structure and function of proteins
- C. Stores and transmits genetic information
- D. Controls cell division
Correct Answer: C
Rationale: DNA (deoxyribonucleic acid) is a molecule that carries the genetic instructions used in the growth, development, functioning, and reproduction of all living organisms. It stores genetic information in the form of a code made up of four chemical bases: adenine (A), thymine (T), cytosine (C), and guanine (G). This genetic information is passed down from parents to offspring and is responsible for determining an organism's traits and characteristics. DNA's primary role is to store and transmit genetic information, making option C the correct answer. DNA does not provide energy for the cell (option A), determine the structure and function of proteins (option B), or control cell division (option D).
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Which mineral is crucial for bone strength and is stored in bones and teeth?
- A. Calcium
- B. Iron
- C. Magnesium
- D. Potassium
Correct Answer: A
Rationale: Calcium is crucial for bone strength as it is a major mineral stored in bones and teeth. It plays a vital role in maintaining bone density and strength, making it essential for overall bone health. Calcium is essential for various physiological functions, including muscle contraction, nerve transmission, and blood clotting. Inadequate calcium intake can lead to conditions like osteoporosis, where bones become weak and brittle. Iron (Choice B) is important for transporting oxygen in the blood, but it is not stored in bones and does not play a significant role in bone strength. Magnesium (Choice C) is essential for bone health, but it is not primarily stored in bones and teeth. Potassium (Choice D) is crucial for various physiological functions, such as fluid balance and muscle function, but it is not a major mineral stored in bones and teeth for bone strength.
Which functional group is commonly found in ketones?
- A. Hydroxyl
- B. Carbonyl
- C. Ester
- D. Amine
Correct Answer: B
Rationale: Ketones contain a carbonyl functional group, which consists of a carbon atom double-bonded to an oxygen atom. This distinguishes ketones from other functional groups such as hydroxyl, ester, and amine. The presence of the carbonyl group, not hydroxyl (choice A), ester (choice C), or amine (choice D), is characteristic of ketones, making choice B, 'Carbonyl', the correct answer.
Which of the following can weaken the immune system and increase susceptibility to infections?
- A. Regular exercise
- B. Balanced diet
- C. Chronic stress
- D. Adequate sleep
Correct Answer: C
Rationale: Chronic stress can weaken the immune system by increasing the production of stress hormones like cortisol, which can suppress the immune response. This suppression can make individuals more susceptible to infections and illnesses. Conversely, regular exercise, a balanced diet, and adequate sleep actually support a healthy immune system and help strengthen it. Choices A, B, and D are incorrect as they are factors that generally contribute positively to the immune system. Regular exercise, a balanced diet, and adequate sleep are crucial for maintaining overall health and boosting the immune system rather than weakening it.
What is the breakdown product of ATP (adenosine triphosphate) that provides energy for muscle contraction?
- A. Glucose
- B. Creatine phosphate
- C. ADP (adenosine diphosphate)
- D. Lactic acid
Correct Answer: C
Rationale: ADP (adenosine diphosphate) is the correct breakdown product of ATP that provides energy for muscle contraction. When ATP is hydrolyzed to ADP, energy is released and utilized by the muscles for various cellular processes, including muscle contraction. Glucose serves as an energy source but is not the direct breakdown product of ATP for muscle contraction. Creatine phosphate plays a role in energy storage and transfer, but it is not the immediate breakdown product of ATP. Lactic acid is produced during anaerobic metabolism and is not the direct provider of energy for muscle contraction.
What is the process of converting glucose into ATP, the cell's primary energy currency, called?
- A. Cellular respiration
- B. Fermentation
- C. Photosynthesis
- D. Hydrolysis
Correct Answer: A
Rationale: A) Cellular respiration is the correct answer. It is the process by which cells convert glucose into ATP, the primary energy currency of the cell. This process involves a series of biochemical reactions that occur in the mitochondria of eukaryotic cells or the cytoplasm of prokaryotic cells. Through cellular respiration, the energy stored in glucose molecules is gradually released and captured in the form of ATP.
B) Fermentation is an anaerobic process that occurs in the absence of oxygen. It involves the partial breakdown of glucose to produce ATP and end products such as lactic acid or ethanol. While fermentation can generate ATP, it is less efficient than cellular respiration in terms of energy production.
C) Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose. This process occurs in chloroplasts and is the opposite of cellular respiration. While photosynthesis produces glucose, it is not the process of converting glucose into ATP.
D) Hydrolysis is a chemical process that uses water to break down molecules into smaller components. It is not specifically related to converting glucose into ATP.