Nokea
Of all the molecules that are significant to biology, which of the following are considered the most important?
- A. Carbohydrates, lipids, protein, and nucleic acids
- B. Carbohydrates, lipids, protein, and calcium
- C. Carbohydrates, lipids, protein, and sulfur
- D. Carbohydrates, lipids, protein, and iron
Correct Answer: A
Rationale: The correct answer is A: Carbohydrates, lipids, proteins, and nucleic acids are considered the most important molecules in biology. Carbohydrates are essential for energy production, lipids play a role in energy storage and cell membrane structure, proteins are involved in various cellular functions, and nucleic acids carry genetic information. While calcium, sulfur, and iron are important elements in biology, they are not considered as primary biological molecules compared to carbohydrates, lipids, proteins, and nucleic acids.
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What term describes the process of producing the RNA strand from a DNA template?
- A. Metabolism.
- B. Transcription.
- C. Synthesis.
- D. Replication.
Correct Answer: B
Rationale: The correct answer is B: Transcription. Transcription is the process where RNA is synthesized from a DNA template by RNA polymerase. During transcription, the DNA double helix unwinds, and one strand is used as a template to create a complementary RNA molecule. This process occurs in the cell nucleus and is essential for gene expression.
Choice A, Metabolism, refers to the chemical reactions that occur in living organisms to maintain life and is not directly related to RNA synthesis. Choice C, Synthesis, is a general term that does not specifically describe the process of RNA production from a DNA template. Choice D, Replication, is the process of copying DNA to create an identical DNA molecule, not RNA synthesis. Therefore, the correct term for producing an RNA strand from a DNA template is Transcription.
Which genetic descriptor refers to an organism's actual appearance?
- A. Phenotype
- B. Genotype
- C. Homozygote
- D. Karyotype
Correct Answer: A
Rationale: Phenotype refers to the observable characteristics or traits of an organism, including physical appearance, behavior, and physiological properties. It is influenced by the organism's genotype and environmental factors. Genotype, on the other hand, represents the genetic makeup of an organism, while homozygote refers to an individual having two identical alleles for a particular gene. Karyotype, on the other hand, refers to the complete set of chromosomes in an individual.
What type of tissue is fat composed of?
- A. Connective
- B. Muscle
- C. Nervous
- D. Epithelial
Correct Answer: A
Rationale: The correct answer is A: Connective tissue. Fat tissue, also known as adipose tissue, is a type of connective tissue that stores energy in the form of fat. It provides insulation and serves as a reserve of energy. Muscle tissue (choice B) is responsible for movement, nervous tissue (choice C) transmits electrical signals throughout the body, and epithelial tissue (choice D) covers and protects body surfaces.
What part of a light microscope is used to hold the slide in place?
- A. Base
- B. Arm
- C. Rack stop
- D. Stage clips
Correct Answer: D
Rationale: The correct answer is 'Stage clips.' Stage clips are utilized to secure the slide on the stage of a light microscope, ensuring it remains in position while examining the specimen. The base of the microscope provides stability, the arm supports the upper part of the microscope, and the rack stop restricts the movement of the stage. However, specifically, it is the stage clips that hold the slide in place during observations.
Which of the following statements is false?
- A. Animal cells use lysosomes to break down old cells
- B. Animal cells use chloroplasts to gain energy
- C. Plant cells have a cell wall to maintain structure
- D. All of the above are true
Correct Answer: B
Rationale: The correct statement is B. Animal cells do not use chloroplasts to gain energy; instead, they rely on mitochondria for energy production through cellular respiration. Lysosomes in animal cells are responsible for breaking down old cells and cellular waste. Plant cells have a cell wall to provide structural support and protection. Therefore, option B is false, as animal cells do not utilize chloroplasts for energy.