Nokea
Do enzymes catalyze reactions?
- A. Catalyze
- B. Inhibit
- C. Stop
- D. None of the above
Correct Answer: A
Rationale: Enzymes function as biological catalysts, which means they speed up chemical reactions without being consumed in the process. The correct term that describes what enzymes do to reactions is 'catalyze.' Enzymes do not inhibit or stop reactions; instead, they facilitate and accelerate them by lowering the activation energy required for the reaction to occur.
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Which of the following molecules are considered the most important in biology?
- 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: Carbohydrates, lipids, proteins, and nucleic acids are the four main types of molecules that are fundamental to biological systems. Carbohydrates provide energy, lipids are essential for cell structure and signaling, proteins carry out diverse functions in cells, and nucleic acids store and transfer genetic information. These molecules are considered the most important in biology due to their critical roles in various biological processes.
A plant cell is placed in a solution and it shrinks from water loss. In what type of environment was the cell placed?
- A. Plasmolytic
- B. Hypertonic.
- C. Hypotonic.
- D. Isosmotic.
Correct Answer: B
Rationale: Correct Answer: B - Hypertonic
Rationale:
1. A hypertonic solution has a higher solute concentration than the cell, causing water to move out of the cell by osmosis.
2. Water loss results in the cell shrinking, as observed in this scenario.
3. Plasmolytic refers to the process of cytoplasm shrinking due to water loss in a hypertonic environment.
4. Hypotonic and isosmotic environments would not cause the cell to shrink from water loss.
What are the two catabolic pathways that lead to cellular energy production?
- A. Fermentation and cellular respiration
- B. Fermentation and external respiration
- C. Fermentation and anaerobic respiration
- D. Fermentation and internal respiration
Correct Answer: A
Rationale: The correct answer is A: Fermentation and cellular respiration. Fermentation and cellular respiration are two catabolic pathways that lead to cellular energy production. Fermentation occurs in the absence of oxygen and involves glycolysis followed by the conversion of pyruvate to various byproducts. Cellular respiration, on the other hand, occurs in the presence of oxygen and involves glycolysis, the citric acid cycle, and the electron transport chain to produce ATP. While fermentation and anaerobic respiration involve partial breakdown of glucose without the complete utilization of oxygen, the term 'internal respiration' is not a commonly used concept in the context of cellular energy production.
What is the second part of an organism's scientific name?
- A. species
- B. phylum
- C. population
- D. kingdom
Correct Answer: A
Rationale: The correct answer is A: species. In binomial nomenclature, an organism's scientific name consists of two parts: the genus name (first part) and the species name (second part). The second part, the species name, is essential for precisely identifying a specific organism within the genus. Therefore, when determining an organism's scientific name, the second part is the species.
Which of the following nucleotides is not a component of DNA?
- A. Adenine
- B. Thymine
- C. Uracil
- D. Cytosine
Correct Answer: C
Rationale: The four nucleotides that make up DNA are Adenine, Thymine, Cytosine, and Guanine. Uracil is a nucleotide base that is present in RNA but not in DNA. Therefore, Uracil is the correct answer as it is not a component of DNA.