(A) Heterotrophs produce some organic nutrients, and must absorb inorganic nutrients from the environment.

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1 MCAT Biology - Problem Drill 09: Prokaryotes and Fungi Question No. 1 of 10 Instructions: (1) Read the problem and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 1. Which describes how heterotrophs obtain their energy and organic nutrients? Question #01 (A) Heterotrophs produce some organic nutrients, and must absorb inorganic nutrients from the environment. (B) Heterotrophs can produce all of their own nutrients. (C) Heterotrophs are unable to synthesize organic compounds and must obtain their nutrition from another heterotroph or autotroph. (D) Heterotrophs require no nutrients. Heterotrophs cannot produce organic compounds on their own. Autotrophs are capable of producing their own nutrients, not heterotrophs. C. Correct! Heterotrophs require other organisms for organic or carbon based nutrients. All living organisms require nutrition from some source. Remember that the word heterotroph comes from the Greek heterone (another) and trophe (nutrition), and needs others for survival, while autotroph comes from the Greek autos (self) and trophe (nutrition), and are self-sustaining. The correct answer is (C).

2 Question No. 2 of 10 Instructions: (1) Read the problem and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 2. Which is/are true about the reproductive capabilities of fungi? Question #02 (A) Fungi only undergo asexual reproduction. (B) Fungi only undergo sexual reproduction. (C) Fungi can undergo both sexual and asexual reproduction. (D) Fungi use binary fission to reproduce. Fungi are not restricted to just asexual reproduction like bacteria is. Fungi are not restricted to only sexual reproduction. C. Correct! Fungi are capable of both sexual and asexual reproduction; asexual reproduction usually occurs when nutrients and water are abundant and sexual reproduction when nutrients and water are scarce. Bacteria use binary fission; fungi are eukaryotes with a more complicated reproductive cycle. Review the reproductive processes of fungi. The correct answer is (C).

3 Question No. 3 of 10 Instructions: (1) Read the problem and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 3. Bacterial pilli play a role in. Question #03 (A) Chromosomal replication. (B) Binary fission. (C) Conjugation. (D) None of the above. Pilli do not participate in chromosomal replication. Binary fission does not require pilli. C. Correct! Pilli serve as the bridge through which plasmid DNA moves from one bacterial cell to another in conjugation. There is one correct answer. Binary fission is the asexual reproduction of bacteria in which two identical daughter cells are created from the parental bacterium. Conjugation is the major source of genetic variation in bacteria and occurs through the transfer of plasmid DNA from one cell to another cell. This transfer of DNA occurs through the pilli of bacteria. Transformation is the incorporation of extracellular DNA into the genome of a bacterium. The correct answer is (C).

4 Question No. 4 of 10 Instructions: (1) Read the problem statement and answer choices carefully; (2) Work the problems on paper as needed; (3) Pick the correct answer; and (4) Go back to review the core concept tutorial as needed. 4. The individual filaments that make up a mycelium are called, which are long strings of cells that may be divided by. Question #04 (A) Spindle fibers; Septa. (B) Septa; Spindle fibers. (C) Hypha; Septa. (D) Chitin; Coenocytic. Myceliums are not made up of spindle fibers. Septa are not filaments in mycelium. C. Correct! Hyphae are divided by septa and together make up mycelium. Chitin is a cell wall component in fungi. Fungi are eukaryotic non-vascular organisms. Their cell walls have chitin. A characteristic structure of fungi is hyphae, which are long branching filaments that function in vegetative growth. A single hypha consists of one or more cells surrounded by a cell wall and the divisions within a hypha are called septa. Several hyphae that occur together in fungi are called mycelium. The correct answer is (C).

5 Question No. 5 of Which of the following differences between Archaea and Eubacteria is not true? Question #05 (A) Eubacteria contain murein peptidoglycan cell walls. (B) Archaea exist in extreme environmental conditions. (C) Only Eubacteria are human pathogens. (D) Archaea undergo sexual reproduction. This is a true statement. Murein is a large component of Eubacterial cell walls. This is a true statement. Archaea exist in high temperature, extreme ph and organically toxic environments. C. Incorrect! This is a true statement. Archaea do not infect humans. D. Correct! This is the only false statement among the choices. Archaea undergo binary fission like other prokaryotes; a form of asexual reproduction in single-celled organisms. Review the differences between Archeae and Eubacteria. Remember that Archaea and Eubacteria are both prokaryotes and reproduce as such. The two groups used to be classified together, but are now considered two separate groups within the prokaryotes. The Eubacteria are true bacteria. The special aspects of Archaea are the extreme environments where they live, their cell wall components, and their inability to infect humans. The correct answer is (D).

6 Question No. 6 of Which of these organelles are found in prokaryotic cells? Question #06 (A) Mitochondria. (B) Ribosomes. (C) Centrioles. (D) Lysosomes. Prokaryotes do not possess mitochondria. B. Correct! Ribosomes are founding prokaryotes. C. Incorrect! Prokaryotes do not have any nuclear organization structures. Prokaryotes do not have lysosomes. Ribosomes are the only membrane bound organelles a prokaryote contains. The correct answer is (B).

7 Question No. 7 of Bacteria replication is best described by. Question #07 (A) Mitosis. (B) Meiosis. (C) Binary fission. (D) Log phase growth. Mitosis does not occur in bacteria. Bacteria do not undergo sexual reproduction. C. Correct! Bacteria undergo binary fission in which two identical cells are produced from a single precursor cell. While bacterial growth can be described as log phase growth, it is not a method of replication. Bacteria cannot undergo any segregation of DNA due to the lack of nuclear organelles such as centrioles. Binary fission is the method of replication in bacteria. The correct answer is (C).

8 Question No. 8 of Which of the following statements best describes fungi? Question #08 (A) All are eukaryotic, multicellular autotrophs. (B) All are eukaryotic heterotrophs that feed by absorption. (C) All are prokaryotic, multicellular autotrophs. (D) All are eukaryotic heterotrophs that feed by ingestion. Not all fungi are multicellular. B. Correct! Fungi are eukaryotic heterotrophs and feed by absorption. C. Incorrect! Fungi are not prokaryotic. Fungi cannot ingest food. Notice this question asks which best describes fungi. Fungi are eukaryotic and heterotrophic. However, while some fungi are multicellular, not all are. Therefore, the best description is eukaryotic heterotrophs. The correct answer is (B).

9 Question No. 9 of Which of the following statements is not true of prokaryotic cells? Question #09 (A) Prokaryotic cells are uni-cellular. (B) Prokaryotic cells have a nucleus. (C) Prokaryotic cells have circular DNA. (D) Prokaryotic cells have flagella. This statement is true. Prokaryotes are single-celled organisms that may live in groups. B. Correct! This statement is false. Prokaryotes lack a nucleus. C. Incorrect! This statement is true. DNA in prokaryotes is circular. This statement is true. Prokaryotes may have flagella. Remember this question asks which is NOT true of prokaryotes. Prokaryotes are single-celled organisms that lack organelles, except ribosomes. Their DNA is circular and some may have flagella for movement. Gene exchange may occur through conjugation and transformation. Cell division, or reproduction, occurs through binary fission. The correct answer is (B).

10 Question No. 10 of One type of DNA found in a prokaryotic cell is. Question #10 (A) Circular and located in the nucleus. (B) A plasmid and located in the cytoplasm. (C) Circular and located in the endoplasmic reticulum. (D) None of the above. Prokaryotes have no membrane bound nucleus. B. Correct! Smaller plasmid DNA structures can be found in the cytoplasm. C. Incorrect! Prokaryotes do not contain endoplasmic reticular structures. There is one correct answer above. Remember that prokaryotes have no nucleus or individual chromosomes. They have one large circular chromosome that resides in the nucleoid, and may have smaller circular plasmids in the cytoplasm. The correct answer is (B).