Nokea
The covalent bonds between the monomers of an enzyme macromolecule are
- A. phosphodiester bonds
- B. glycosidic bonds
- C. ester bonds
- D. peptide bonds
Correct Answer: D
Rationale: Enzymes are proteins, and proteins are made up of amino acid monomers linked together by peptide bonds. Therefore, the covalent bonds between the monomers of an enzyme macromolecule are peptide bonds.
You may also like to solve these questions
A group of students performed an experiment to test terminal velocity, which is the greatest speed obtained by a falling object. The students dropped different numbers of coffee filters and measured the resulting terminal velocity. Data Table: Mass (g): 1.01, 1.99, 3.02, 4.0, 5.01; Terminal Velocity (m/s): 1.74, 2.48, 3.04, 3.50, 3.80. Which of the following conclusions is supported by the data?
- A. Terminal velocity is reached when the force of gravity equals air resistance.
- B. The greater the number of filters, the smaller the terminal velocity.
- C. Heavier objects reach terminal velocity more quickly.
- D. Heavier objects fall faster than lighter objects.
Correct Answer: B
Rationale: The data indicates that as the number of coffee filters increases, the terminal velocity decreases, supporting the conclusion in Choice B. Terminal velocity is reached when the force of gravity equals air resistance, which is not explicitly shown in the data. Heavier objects reaching terminal velocity more quickly and heavier objects falling faster than lighter objects are not supported by the provided data, as the experiment was conducted with coffee filters of different masses, not different objects.
Which laboratory method is most useful to separate genomic DNA fragments by size?
- A. Titration
- B. Spectrophotometry
- C. Electrophoresis
- D. Filtration
Correct Answer: C
Rationale: Electrophoresis is the most suitable laboratory method for separating genomic DNA fragments by size. It works by subjecting DNA fragments to an electric field, causing them to migrate through a gel matrix based on size differences. Smaller fragments move faster and travel farther than larger ones, allowing for separation and analysis based on size. Titration is a technique used to determine the concentration of a solution, not to separate DNA fragments by size. Spectrophotometry is used to measure the amount of light absorbed by a substance at different wavelengths, not for DNA fragment size separation. Filtration is a method used to separate solid particles from a liquid or gas by passing it through a filter medium, not for separating DNA fragments by size.
A patient goes to the doctor with a cold and sore throat and asks for antibiotics. The doctor refuses to prescribe antibiotics because the illness is caused by which of the following pathogens?
- A. Protist
- B. Fungus
- C. Virus
- D. Bacteria
Correct Answer: C
Rationale: The correct answer is C: Virus. Antibiotics are ineffective against viral infections, such as colds and sore throats caused by viruses. They are only effective against bacterial infections. In this case, the doctor refuses to prescribe antibiotics because the patient's illness is viral, not bacterial. It is important to differentiate between viral and bacterial infections to ensure appropriate treatment and avoid unnecessary use of antibiotics, which can contribute to antibiotic resistance.
What causes osteoporosis?
- A. An increase in osteocyte activity while osteoclast activity continues at expected levels
- B. A decline in osteoblast activity while osteoclast activity continues at expected levels
- C. An increase in osteocyte activity while osteoblast activity continues at expected levels
- D. A decline in osteoclast activity while osteoblast activity continues at expected levels
Correct Answer: B
Rationale: Osteoporosis is a condition characterized by reduced bone density and mass, leading to brittle bones. Osteoblasts are cells responsible for forming new bone tissue, while osteoclasts break down old or damaged bone. In osteoporosis, there is a decrease in osteoblast activity, causing a net loss of bone as the breakdown surpasses formation. Meanwhile, osteoclast activity remains relatively stable. This imbalance between bone formation (osteoblast activity) and bone resorption (osteoclast activity) contributes to the development of osteoporosis by reducing bone strength and increasing susceptibility to fractures.
Which hormone regulates blood calcium levels?
- A. Growth hormone
- B. Melatonin
- C. Norepinephrine
- D. Parathyroid hormone
Correct Answer: D
Rationale: Parathyroid hormone is the correct answer. It plays a crucial role in regulating blood calcium levels by increasing calcium levels in the blood through stimulating the release of calcium from bones and enhancing calcium absorption in the intestines. Produced by the parathyroid glands, this hormone helps maintain calcium homeostasis in the body.