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All questions of Cell Theory And Prokaryotes/bacteria for MCAT Exam
In a histology lab a scientist observes the following features under the microscope. Which of these observations supports cell theory?
I. Cardiac cells are joined by gap junctions and contain three nuclei.
II. Mature platelet cells do not contain a nucleus, but do contain mitochondria.
III. Spermatogonia undergoing mitosis.
IV. The bulk of tissue samples from endocrine glands contain cells as their main building blocks.- a)II only
- b)I and III
- c)II and IV
- d)III and IV
Correct answer is option 'D'. Can you explain this answer?
In a histology lab a scientist observes the following features under the microscope. Which of these observations supports cell theory?
I. Cardiac cells are joined by gap junctions and contain three nuclei.
II. Mature platelet cells do not contain a nucleus, but do contain mitochondria.
III. Spermatogonia undergoing mitosis.
IV. The bulk of tissue samples from endocrine glands contain cells as their main building blocks.
I. Cardiac cells are joined by gap junctions and contain three nuclei.
II. Mature platelet cells do not contain a nucleus, but do contain mitochondria.
III. Spermatogonia undergoing mitosis.
IV. The bulk of tissue samples from endocrine glands contain cells as their main building blocks.
a)
II only
b)
I and III
c)
II and IV
d)
III and IV
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Orion Classes answered |
Cell theory states that cells are the basic structural and functional units of all living organisms, and all cells arise from pre-existing cells. Observations that support cell theory include:
III. Spermatogonia undergoing mitosis: This observation demonstrates cell division, which is a fundamental process in cell reproduction and supports the idea that cells arise from pre-existing cells.
IV. The bulk of tissue samples from endocrine glands contain cells as their main building blocks: This observation confirms that cells are the basic building blocks of tissues. The presence of cells as the main constituents of tissue aligns with the concept that organisms are composed of cells.
Which of the following statements is true about prokaryotes?- a)Prokaryotes have a nucleus.
- b)Prokaryotes are multicellular organisms.
- c)Prokaryotes lack membrane-bound organelles.
- d)Prokaryotes undergo mitosis for cell division.
Correct answer is option 'C'. Can you explain this answer?
Which of the following statements is true about prokaryotes?
a)
Prokaryotes have a nucleus.
b)
Prokaryotes are multicellular organisms.
c)
Prokaryotes lack membrane-bound organelles.
d)
Prokaryotes undergo mitosis for cell division.
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Orion Classes answered |
Prokaryotes are unicellular organisms that lack membrane-bound organelles such as a nucleus, mitochondria, or endoplasmic reticulum. Instead, their genetic material is present in a single circular chromosome located in the nucleoid region.
Which of the following is NOT a premise of cell theory?
I. All cells arise from other cells.
II. All living cells require water for survival.
III. All living things are only composed of cells.- a)I only
- b)II only
- c)I and II
- d)II and III
Correct answer is option 'D'. Can you explain this answer?
Which of the following is NOT a premise of cell theory?
I. All cells arise from other cells.
II. All living cells require water for survival.
III. All living things are only composed of cells.
I. All cells arise from other cells.
II. All living cells require water for survival.
III. All living things are only composed of cells.
a)
I only
b)
II only
c)
I and II
d)
II and III
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Luke Rivera answered |
Understanding Cell Theory
Cell theory is a fundamental principle in biology that outlines the properties of cells. It consists of three main premises:
Identifying the Incorrect Premises
In the given options, we need to find which statements do not align with cell theory. Let's analyze each statement:
Correct Answer Explanation
The correct answer is option 'D', which includes both II and III:
Thus, options II and III diverge from the foundational principles of cell theory, making 'D' the correct choice.
Cell theory is a fundamental principle in biology that outlines the properties of cells. It consists of three main premises:
- All living things are composed of one or more cells.
- The cell is the basic unit of life.
- All cells arise from pre-existing cells.
Identifying the Incorrect Premises
In the given options, we need to find which statements do not align with cell theory. Let's analyze each statement:
- I. All cells arise from other cells. - This is a core tenet of cell theory.
- II. All living cells require water for survival. - While it is true that water is essential for most living organisms, this statement is not a component of cell theory.
- III. All living things are only composed of cells. - This is a simplification; while all living things are indeed composed of cells, they can also include non-cellular structures (like viruses) which are not considered living organisms.
Correct Answer Explanation
The correct answer is option 'D', which includes both II and III:
- II is not a premise of cell theory since it pertains to the requirements for life rather than the characteristics of cells.
- III is inaccurate in strict terms because while living organisms are composed of cells, certain entities like viruses do not fit this definition.
Thus, options II and III diverge from the foundational principles of cell theory, making 'D' the correct choice.
Prokaryotes play a vital role in ecosystem functioning by:- a)Decomposing organic matter
- b)Producing oxygen through photosynthesis
- c)Cycling nutrients such as carbon and nitrogen
- d)All of the above
Correct answer is option 'D'. Can you explain this answer?
Prokaryotes play a vital role in ecosystem functioning by:
a)
Decomposing organic matter
b)
Producing oxygen through photosynthesis
c)
Cycling nutrients such as carbon and nitrogen
d)
All of the above
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Orion Classes answered |
Prokaryotes have essential ecological roles, including decomposing organic matter, producing oxygen through photosynthesis (in certain prokaryotes), and cycling nutrients such as carbon and nitrogen. These processes are fundamental for the balance and functioning of ecosystems.
Viruses infect cells and replicate themselves by utilizing various enzymes and cellular components of their host cell. Could you apply the same tenets of cell theory to viral replication?- a)No, viruses do not strictly adhere to cell theory because they are not living organisms.
- b)No, viruses do not strictly adhere to cell theory because viruses do not directly come from other viruses; they require an intermediate cell to replicate.
- c)Yes, viruses strictly adhere to cell theory because an individual virus is a singular cellular unit.
- d)Yes, viruses strictly adhere to cell theory because from one virus directly arises another virus.
Correct answer is option 'B'. Can you explain this answer?
Viruses infect cells and replicate themselves by utilizing various enzymes and cellular components of their host cell. Could you apply the same tenets of cell theory to viral replication?
a)
No, viruses do not strictly adhere to cell theory because they are not living organisms.
b)
No, viruses do not strictly adhere to cell theory because viruses do not directly come from other viruses; they require an intermediate cell to replicate.
c)
Yes, viruses strictly adhere to cell theory because an individual virus is a singular cellular unit.
d)
Yes, viruses strictly adhere to cell theory because from one virus directly arises another virus.
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Orion Classes answered |
t cell to replicate and complete their life cycle. Unlike living cells, viruses do not have the ability to reproduce on their own. Instead, they must infect a host cell and hijack its cellular machinery to produce new viral particles. The process of viral replication involves the synthesis of viral components using the host cell's resources and the assembly of new viruses within the host cell. Once the new viruses are assembled, they are released from the host cell, often causing cell lysis.
Therefore, viruses do not strictly adhere to cell theory because they do not arise directly from other viruses. They require a host cell to act as a replication machinery.
What did Schleiden and Schwann both discover individually?- a)All living things are composed of one or more cells.
- b)Spontaneous generation of cells is an incorrect theory.
- c)All cells have organelles.
- d)All livings things engage in metabolic functions.
Correct answer is option 'A'. Can you explain this answer?
What did Schleiden and Schwann both discover individually?
a)
All living things are composed of one or more cells.
b)
Spontaneous generation of cells is an incorrect theory.
c)
All cells have organelles.
d)
All livings things engage in metabolic functions.
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Orion Classes answered |
Schleiden and Schwann are both credited with making significant contributions to the development of cell theory. Schleiden, a botanist, studied plant tissues and concluded that all plant parts are composed of cells. Schwann, a zoologist, conducted similar studies on animal tissues and came to the conclusion that all animal tissues are made up of cells. Together, their observations and findings led to the formulation of the first two tenets of cell theory: "All plants are composed of cells" and "All animals are composed of cells."
Prokaryotes exhibit a high degree of genetic diversity due to:- a)Sexual reproduction
- b)Genetic recombination
- c)Mitosis
- d)Apoptosis
Correct answer is option 'B'. Can you explain this answer?
Prokaryotes exhibit a high degree of genetic diversity due to:
a)
Sexual reproduction
b)
Genetic recombination
c)
Mitosis
d)
Apoptosis
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Orion Classes answered |
Prokaryotes exhibit genetic diversity through genetic recombination. This occurs through processes such as horizontal gene transfer, transformation, transduction, and conjugation, which allow for the exchange of genetic material between prokaryotic cells.
Prokaryotes obtain energy through various metabolic processes. Which of the following is NOT a common metabolic strategy of prokaryotes?- a)Photosynthesis
- b)Cellular respiration
- c)Fermentation
- d)Endocytosis
Correct answer is option 'D'. Can you explain this answer?
Prokaryotes obtain energy through various metabolic processes. Which of the following is NOT a common metabolic strategy of prokaryotes?
a)
Photosynthesis
b)
Cellular respiration
c)
Fermentation
d)
Endocytosis
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Orion Classes answered |
Prokaryotes do not perform endocytosis, which is a process by which eukaryotic cells engulf external materials. Instead, prokaryotes obtain nutrients through processes such as photosynthesis, cellular respiration, or fermentation.
Prokaryotes are found in a wide range of habitats, including:- a)Soil
- b)Freshwater
- c)Extreme environments (e.g., hot springs, deep-sea vents)
- d)All of the above
Correct answer is option 'D'. Can you explain this answer?
Prokaryotes are found in a wide range of habitats, including:
a)
Soil
b)
Freshwater
c)
Extreme environments (e.g., hot springs, deep-sea vents)
d)
All of the above
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Orion Classes answered |
Prokaryotes are incredibly diverse and can be found in various habitats, including soil, freshwater, and extreme environments such as hot springs and deep-sea vents. They have adapted to survive and thrive in a wide range of conditions.
Prokaryotes play a crucial role in the nitrogen cycle by:- a)Fixing nitrogen gas into ammonia
- b)Releasing nitrogen gas into the atmosphere
- c)Converting ammonia into nitrogen gas
- d)Absorbing nitrogen gas from the environment
Correct answer is option 'A'. Can you explain this answer?
Prokaryotes play a crucial role in the nitrogen cycle by:
a)
Fixing nitrogen gas into ammonia
b)
Releasing nitrogen gas into the atmosphere
c)
Converting ammonia into nitrogen gas
d)
Absorbing nitrogen gas from the environment
|
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Orion Classes answered |
Certain prokaryotes, such as nitrogen-fixing bacteria, have the ability to convert atmospheric nitrogen gas (N2) into ammonia (NH3) through a process called nitrogen fixation. This ammonia can then be used by other organisms in the ecosystem.
Cell theory states:
I. All living cells must have a cell wall.
II. All living cells require glucose for survival.
III. The basic unit of life is a cell.- a)I only
- b)II only
- c)III only
- d)I and III
Correct answer is option 'C'. Can you explain this answer?
Cell theory states:
I. All living cells must have a cell wall.
II. All living cells require glucose for survival.
III. The basic unit of life is a cell.
I. All living cells must have a cell wall.
II. All living cells require glucose for survival.
III. The basic unit of life is a cell.
a)
I only
b)
II only
c)
III only
d)
I and III
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Orion Classes answered |
Cell theory is a fundamental principle in biology that consists of three main statements:
I. All living cells must have a cell wall: This statement is incorrect. While some cells, such as plant cells and bacterial cells, have a cell wall, not all living cells possess this structure. Animal cells, for example, do not have a cell wall but are still considered living cells.
II. All living cells require glucose for survival: This statement is incorrect. While glucose is an important energy source for many cells, not all cells require glucose specifically for survival. Cells can utilize different energy sources and metabolic pathways to generate energy.
III. The basic unit of life is a cell: This statement is correct. Cell theory states that all living organisms are composed of one or more cells, and the cell is the basic structural and functional unit of life. Cells carry out all the necessary functions for life, such as metabolism, growth, reproduction, and response to stimuli.
A 19th century scientist investigates cell growth by placing boiled broth in one Erlenmeyer flask and non-boiled broth in another flask. The scientist covered both flasks so that air could not enter the flasks and observed the flasks for two weeks. Neither flask grew any biological matter. From this the scientist concluded that abiogenesis or spontaneous generation was an invalid theory.Select the best evaluation of the above experiment and conclusion- a)The conclusion is an invalid conclusion because living objects often require air to grow regardless if their origin was spontaneous or not.
- b)Since no colonies of cells grew in either flask, the conclusion is a valid conclusion because cells can only grow from other cells.
- c)Since no colonies of cells grew in either flask, the conclusion is a valid conclusion because spontaneous generation predicts that cells should grow spontaneously.
- d)The conclusion is an invalid conclusion because the scientist did not wait long enough for anaerobic cells to grow in the broth.
Correct answer is option 'A'. Can you explain this answer?
A 19th century scientist investigates cell growth by placing boiled broth in one Erlenmeyer flask and non-boiled broth in another flask. The scientist covered both flasks so that air could not enter the flasks and observed the flasks for two weeks. Neither flask grew any biological matter. From this the scientist concluded that abiogenesis or spontaneous generation was an invalid theory.Select the best evaluation of the above experiment and conclusion
a)
The conclusion is an invalid conclusion because living objects often require air to grow regardless if their origin was spontaneous or not.
b)
Since no colonies of cells grew in either flask, the conclusion is a valid conclusion because cells can only grow from other cells.
c)
Since no colonies of cells grew in either flask, the conclusion is a valid conclusion because spontaneous generation predicts that cells should grow spontaneously.
d)
The conclusion is an invalid conclusion because the scientist did not wait long enough for anaerobic cells to grow in the broth.
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Orion Classes answered |
The experiment described involves the use of boiled broth and non-boiled broth, both of which are covered to prevent the entry of air. The observation that no growth occurred in either flask cannot be solely attributed to the rejection of spontaneous generation. The absence of growth could be due to the lack of essential nutrients or gases necessary for cell growth, such as oxygen. Therefore, the conclusion that spontaneous generation is an invalid theory based solely on this experiment is not justified, as it does not account for the potential influence of other factors necessary for cell growth.
Prokaryotes can exchange genetic material through a process called conjugation. What is conjugation?- a)The fusion of two prokaryotic cells to form a new organism
- b)The exchange of genetic material between two prokaryotic cells through a pilus
- c)The transfer of genetic material from a prokaryote to a eukaryote
- d)The replication of genetic material within a prokaryotic cell
Correct answer is option 'B'. Can you explain this answer?
Prokaryotes can exchange genetic material through a process called conjugation. What is conjugation?
a)
The fusion of two prokaryotic cells to form a new organism
b)
The exchange of genetic material between two prokaryotic cells through a pilus
c)
The transfer of genetic material from a prokaryote to a eukaryote
d)
The replication of genetic material within a prokaryotic cell
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Orion Classes answered |
Conjugation is a process in which genetic material, usually in the form of plasmids, is transferred between two prokaryotic cells. This transfer occurs through a pilus, a structure that connects the two cells, allowing for the exchange of genetic information.
Prokaryotes reproduce through a process called:- a)Mitosis
- b)Meiosis
- c)Binary fission
- d)Conjugation
Correct answer is option 'C'. Can you explain this answer?
Prokaryotes reproduce through a process called:
a)
Mitosis
b)
Meiosis
c)
Binary fission
d)
Conjugation
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Orion Classes answered |
Prokaryotes reproduce through binary fission, a process in which a single prokaryotic cell divides into two identical daughter cells. This process allows for rapid population growth in prokaryotic organisms.
Which of the following is a potential exception to cell theory?- a)Fungal spores
- b)Asexual reproduction
- c)Mitochondria
- d)Amoebas
Correct answer is option 'C'. Can you explain this answer?
Which of the following is a potential exception to cell theory?
a)
Fungal spores
b)
Asexual reproduction
c)
Mitochondria
d)
Amoebas
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Orion Classes answered |
Cell theory states that all living organisms are composed of cells, and that cells are the basic units of structure and function in living organisms. However, mitochondria pose a potential exception to cell theory because they have their own genetic material (DNA) and can replicate independently of the cell. Mitochondria are thought to have originated from free-living bacteria that were engulfed by ancestral eukaryotic cells in a process called endosymbiosis. This led to the formation of a symbiotic relationship between the host cell and the engulfed bacteria, which eventually evolved into the mitochondria found in eukaryotic cells today. The presence of mitochondria with their own genetic material challenges the idea that all cellular functions are carried out solely by the cell itself. However, it's important to note that mitochondria are still considered essential organelles within cells, and their functions are tightly integrated with the overall functioning of the cell.
Rapid growth of cells is observed in tumors. One hypothesis of rapid tumor growth is that the creation of new cells uses old cells only as a scaffold to promote rapid growth similar to how crystal solids form. In this hypothesis, new cellular material is not created from preexisting cells. First a new nucleus of a cell attaches to the preexisting cells followed by the formation of the cytoplasm and lastly a cellular membrane forms around the cytoplasm-nucleus complex. This process can only happen if there is a pre-existing lattice network of cells that can function as a site of nucleation.- a)This hypothesis is not supported by cell theory because new cells are not created from older, preexisting cells.
- b)This rapid growth hypothesis is supported by cell theory because the basic unit of life is the cell.
- c)This rapid growth hypothesis is supported by cell theory because all living things are made of cells.
- d)This hypothesis is not supported by cell theory because cell walls are required to grow new cells.
Correct answer is option 'A'. Can you explain this answer?
Rapid growth of cells is observed in tumors. One hypothesis of rapid tumor growth is that the creation of new cells uses old cells only as a scaffold to promote rapid growth similar to how crystal solids form. In this hypothesis, new cellular material is not created from preexisting cells. First a new nucleus of a cell attaches to the preexisting cells followed by the formation of the cytoplasm and lastly a cellular membrane forms around the cytoplasm-nucleus complex. This process can only happen if there is a pre-existing lattice network of cells that can function as a site of nucleation.
a)
This hypothesis is not supported by cell theory because new cells are not created from older, preexisting cells.
b)
This rapid growth hypothesis is supported by cell theory because the basic unit of life is the cell.
c)
This rapid growth hypothesis is supported by cell theory because all living things are made of cells.
d)
This hypothesis is not supported by cell theory because cell walls are required to grow new cells.
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Orion Classes answered |
According to cell theory, all cells arise from preexisting cells. This fundamental principle states that cells are the basic units of life and that new cells are generated through cell division. In the given hypothesis, the suggestion is that new cellular material is not created from preexisting cells, but rather by attaching a new nucleus to preexisting cells and forming the cytoplasm and cellular membrane. This contradicts the principle of cell theory, which states that new cells are derived from preexisting cells through processes such as mitosis or meiosis. Therefore, this hypothesis is not supported by cell theory.
What did Louis Pasteur’s crooked neck flask experiment disprove?- a)Most cells require oxygen in order to survive.
- b)The cell is the basic unit of life.
- c)Spontaneous generation is a method for the creation of new cells.
- d)All living organism are composed of cells.
Correct answer is option 'C'. Can you explain this answer?
What did Louis Pasteur’s crooked neck flask experiment disprove?
a)
Most cells require oxygen in order to survive.
b)
The cell is the basic unit of life.
c)
Spontaneous generation is a method for the creation of new cells.
d)
All living organism are composed of cells.
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Orion Classes answered |
Louis Pasteur's crooked neck flask experiment was designed to disprove the theory of spontaneous generation, which proposed that living organisms could arise spontaneously from non-living matter. In his experiment, Pasteur used flasks with curved necks that prevented airborne microorganisms from directly entering the flask while still allowing the exchange of air. He boiled the broth contained in the flask to kill any existing microorganisms and then observed that no growth of microorganisms occurred in the broth over time, even when the flask remained open to the air. This experiment provided evidence against the concept of spontaneous generation, as it showed that the absence of microbial growth was not due to lack of oxygen but rather the prevention of contamination from pre-existing microorganisms in the air. Pasteur's experiment supported the idea that living cells only arise from pre-existing cells, reinforcing the concept that cells are the basic unit of life.
Which of the following statements is NOT a premise of cell theory?- a)All living things are composed of cells.
- b)Cells are the basic unit of structure and function in living organisms.
- c)All cells arise from preexisting cells.
- d)Cells can only arise from nonliving materials through spontaneous generation.
Correct answer is option 'D'. Can you explain this answer?
Which of the following statements is NOT a premise of cell theory?
a)
All living things are composed of cells.
b)
Cells are the basic unit of structure and function in living organisms.
c)
All cells arise from preexisting cells.
d)
Cells can only arise from nonliving materials through spontaneous generation.
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Orion Classes answered |
Cell theory states that cells arise from preexisting cells, not from nonliving materials through spontaneous generation. This principle was demonstrated through experiments by Louis Pasteur, which disproved the theory of spontaneous generation.
Which of the following is NOT a domain of prokaryotes?- a)Bacteria
- b)Archaea
- c)Eukarya
- d)Cyanobacteria
Correct answer is option 'C'. Can you explain this answer?
Which of the following is NOT a domain of prokaryotes?
a)
Bacteria
b)
Archaea
c)
Eukarya
d)
Cyanobacteria
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Orion Classes answered |
Prokaryotes are classified into two domains: Bacteria and Archaea. The domain Eukarya includes organisms with eukaryotic cells, which have a true nucleus and membrane-bound organelles.
Which of the following is a characteristic feature of prokaryotes?- a)Presence of membrane-bound organelles
- b)Presence of a nucleus
- c)Presence of mitochondria
- d)Presence of a cell wall
Correct answer is option 'D'. Can you explain this answer?
Which of the following is a characteristic feature of prokaryotes?
a)
Presence of membrane-bound organelles
b)
Presence of a nucleus
c)
Presence of mitochondria
d)
Presence of a cell wall
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Orion Classes answered |
Prokaryotes have a cell wall that provides structural support and protection. The cell wall composition varies among different types of prokaryotes, with bacteria having peptidoglycan in their cell wall, while archaea have different types of cell wall structures.
Chapter doubts & questions for Cell Theory And Prokaryotes/bacteria - Biology for MCAT 2025 is part of MCAT exam preparation. The chapters have been prepared according to the MCAT exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for MCAT 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
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