Nokea
Which characteristic is true of prokaryotic cells?
- A. Have a nucleus
- B. Have a capsule
- C. Have membrane-bound organelles
- D. Cannot move on their own
Correct Answer: B
Rationale: Prokaryotic cells are characterized by the absence of a nucleus; instead, they have a nucleoid region where the genetic material is located. Prokaryotic cells often have a capsule, a protective layer outside the cell wall that plays a role in protection and adherence to surfaces. While eukaryotic cells have membrane-bound organelles, prokaryotic cells lack these membrane-bound structures. Prokaryotic cells are capable of movement, facilitated by structures like flagella or pili.
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Which combination of cell cycle phase and descriptor is correct?
- A. S phase - the cell synthesizes DNA and doubles its cytoplasm
- B. G� phase - the amount of chromosomes is doubled
- C. GÄ‚‚ phase - the phase prior to the start of mitosis in which the cell continues to grow in size and make proteins
- D. Interphase - the cell increases in mass and number of organelles to prepare for cell division
Correct Answer: C
Rationale: The correct answer is C. The GÄ‚‚ phase is the phase before mitosis within interphase where the cell grows in size and synthesizes proteins needed for cell division. Option A incorrectly describes the S phase, which is primarily for DNA synthesis. Option B is incorrect as the doubling of chromosomes does not occur in GÄ‚� phase. Option D is inaccurate because interphase encompasses GÄ‚�, S, and GÄ‚‚ phases, during which the cell prepares for division by increasing its mass and organelles, rather than specifically focusing on mitosis preparation.
Which disease is caused by a bacterium?
- A. AIDS (HIV).
- B. Strep throat.
- C. Mumps.
- D. Common cold.
Correct Answer: B
Rationale:
The structure of a bacteria is circular. Which bacteria fits this criteria?
- A. Mycobacterium.
- B. Actinomyces.
- C. Clostridium.
- D. Neisseria.
Correct Answer: C
Rationale: Rationale:
1. The correct answer is C: Clostridium.
2. Clostridium is a type of bacteria that has a circular structure known as a plasmid.
3. Plasmids are small, circular DNA molecules found in bacteria.
4. Mycobacterium (A) has a rod-shaped structure with a linear chromosome.
5. Actinomyces (B) has a filamentous structure, not circular.
6. Neisseria (D) has a diplococci shape, not circular.
In summary, Clostridium fits the criteria of having a circular structure due to its plasmid, making it the correct choice.
Why is homeostasis necessary?
- A. It maintains temperature.
- B. It maintains pH.
- C. It maintains glucose levels.
- D. All of the above.
Correct Answer: D
Rationale: Homeostasis is essential for maintaining the internal balance and stability of the body. It regulates various factors, such as temperature, pH levels, and glucose levels, to ensure optimal physiological function. Therefore, all the choices (temperature, pH, and glucose levels) are correct as they are all essential components of homeostasis, working together to keep the body's internal environment stable and functioning properly.
Using the information provided in question #44, what would be the phenotype if the offspring is Bb?
- A. Black
- B. Black and tan
- C. Tan
- D. Not enough information
Correct Answer: A
Rationale: In genetics, when discussing the phenotype of an offspring with a genotype of Bb, the dominant trait 'Black' would be expressed. In this case, the dominant allele 'B' leads to the expression of the black color, overriding the recessive allele 'b,' which would signify tan. Therefore, the correct answer is A, 'Black.' The dominant allele 'B' in the genotype Bb expresses the black color, as it is dominant over the recessive allele 'b.' Hence, the phenotype of the offspring with the genotype Bb would be 'Black.'