Omics-C4 Flashcards
Teaching and Questions
What is a major difference between prokaryotic and eukaryotic cells?
Prokaryotic cells lack a membrane-bound nucleus and organelles, while eukaryotic cells have both.
Prokaryotes are simple, single-celled organisms, including bacteria and archaea.
Key Features of Prokaryotic Cells:
Lack a nucleus and membrane-bound organelles.
DNA is located in a nucleoid region.
Have a cell wall, plasma membrane, and ribosomes.
Prokaryotic Cell Size: Prokaryotes are smaller than eukaryotic cells, ranging from 0.1 to 5.0 micrometers in diameter.
What structure contains DNA in prokaryotic cells?
The nucleoid region contains DNA in prokaryotic cells.
Eukaryotic cells are more complex, containing a true nucleus and a variety of membrane-bound organelles.
Components of Eukaryotic Cells:
Nucleus: ____
Ribosomes: ____
Mitochondria: ____
Chloroplasts: ____
Endoplasmic Reticulum (ER):
Rough ER: ____
Smooth ER: ____
Golgi Apparatus:____
Lysosomes: ____
Vacuoles: ____
Eukaryotic cells are more complex, containing a true nucleus and a variety of membrane-bound organelles.
Components of Eukaryotic Cells:
Nucleus: Houses DNA and directs cellular activities.
Ribosomes: Synthesize proteins.
Mitochondria: Produce ATP (the cell’s main energy source) through cellular respiration.
Chloroplasts: Carry out photosynthesis (in plant cells).
Endoplasmic Reticulum (ER):
Rough ER: Involved in protein synthesis.
Smooth ER: Synthesizes lipids and detoxifies.
Golgi Apparatus: Modifies, sorts, and packages proteins and lipids.
Lysosomes: Digest waste and damaged organelles.
Vacuoles: Store materials like water, salts, proteins, and carbohydrates (especially prominent in plant cells).
How do plant cells differ from animal cells?
Plant cells have a cell wall, chloroplasts, and a large central vacuole, while animal cells do not.
The cytoskeleton is a ____
Components:
Microfilaments: ____
Intermediate Filaments: ____
Microtubules: ____
network of protein fibers that maintain cell shape, enable movement, and assist in intracellular transport.
Provide structural support and aid in cell movement.
Anchor organelles and maintain cell shape.
Help in cell division, intracellular transport, and the formation of flagella and cilia.
1) Which of the following is the smallest structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope?
A) mitochondrion
B) microtubule
C) ribosome
D) virus
The correct answer is: A) mitochondrion
Explanation:
Mitochondrion: Mitochondria are large enough to be visible with a standard light microscope, typically ranging from 0.5 to 10 micrometers in size.
Microtubule: Microtubules are about 25 nanometers in diameter, which is too small to be clearly resolved by a standard light microscope.
Ribosome: Ribosomes are approximately 20-30 nanometers in size, which is beyond the resolution capability of a standard light microscope.
Virus: Most viruses are in the range of 20-300 nanometers, which also makes them too small to be visible with a standard light microscope.
A research-grade light microscope typically has a resolution limit of around 200 nanometers, so the mitochondrion is the smallest structure that can be clearly observed with this type of microscope.
2) What is the explanation for how a modern transmission electron microscope (TEM) can achieve a resolution of about 0.2 nanometers, whereas a standard light microscope has a maximum resolution of about 200 nanometers?
A) Glass lenses in light microscopes refract light, which reduces resolution.
B) Contrast is enhanced by staining with atoms of heavy metal.
C) Electron beams have much shorter wavelengths than visible light.
D) The electron microscope has a much greater ratio of image size to real size.
The correct answer is: C) Electron beams have much shorter wavelengths than visible light.
Explanation:
C) Electron beams have much shorter wavelengths than visible light: This is the main reason why a transmission electron microscope (TEM) achieves much higher resolution compared to a standard light microscope. Electrons have much shorter wavelengths than visible light, allowing the TEM to resolve structures at a much finer scale, down to around 0.2 nanometers.
A) Glass lenses in light microscopes refract light, which reduces resolution: While glass lenses do refract light, this isn’t the primary factor limiting the resolution of light microscopes. The main limitation is the wavelength of visible light.
B) Contrast is enhanced by staining with atoms of heavy metal: This is a technique used in electron microscopy to enhance contrast, but it does not directly relate to achieving higher resolution.
D) The electron microscope has a much greater ratio of image size to real size: While electron microscopes can magnify images to a much greater extent than light microscopes, magnification alone does not improve resolution. Resolution depends on the ability to distinguish between two close points, which is governed by the wavelength of the illuminating radiation (light or electrons).
Thus, the shorter wavelength of electron beams is the primary reason for the higher resolution of TEMs.
3) Which of the following is a major difference between prokaryotic cells and eukaryotic cells?
A) Prokaryotic cells have cell walls, while eukaryotic cells do not.
B) Eukaryotic cells have flagella, while prokaryotic cells do not.
C) Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.
D) Prokaryotic cells are generally larger than eukaryotic cells.
The correct answer is: C) Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.
Explanation:
C) Eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not: This is the key difference between eukaryotic and prokaryotic cells. Eukaryotic cells contain a variety of membrane-bound organelles, such as the nucleus, mitochondria, and endoplasmic reticulum. In contrast, prokaryotic cells lack these organelles, and their DNA is not enclosed in a nucleus but instead resides in a nucleoid region.
A) Prokaryotic cells have cell walls, while eukaryotic cells do not: This statement is incorrect because some eukaryotic cells, such as plant and fungal cells, do have cell walls. However, prokaryotic cells (like bacteria) also have cell walls, typically made of peptidoglycan.
B) Eukaryotic cells have flagella, while prokaryotic cells do not: This is incorrect because both prokaryotic and eukaryotic cells can have flagella, though they differ in structure. Prokaryotic flagella are simpler in structure and operate differently from the more complex flagella found in eukaryotic cells.
D) Prokaryotic cells are generally larger than eukaryotic cells: This is incorrect because prokaryotic cells are generally smaller than eukaryotic cells. Prokaryotes typically range from 0.1 to 5 micrometers, while eukaryotic cells are usually 10-100 micrometers in size.
Thus, the major difference is that eukaryotic cells have membrane-bound organelles, while prokaryotic cells do not.
5) Which structure is common to plant and animal cells?
A) chloroplast
B) central vacuole
C) mitochondrion
D) centriole
The correct answer is: C) mitochondrion
Explanation:
C) Mitochondrion: Both plant and animal cells contain mitochondria. Mitochondria are the “powerhouses” of the cell, responsible for producing ATP (energy) through cellular respiration.
A) Chloroplast: Chloroplasts are found in plant cells (and some algae) but are not present in animal cells. Chloroplasts are responsible for photosynthesis.
B) Central Vacuole: A large central vacuole is primarily found in plant cells and is used for storing water and maintaining turgor pressure. Animal cells, if they have vacuoles, usually have much smaller ones.
D) Centriole: Centrioles are found in animal cells and are involved in cell division, but they are generally not found in plant cells.
Thus, the mitochondrion is the organelle common to both plant and animal cells, as it plays a critical role in energy production in both types of cells.
6) Which of the following are found in plant, animal, and bacterial cells?
A) mitochondria
B) ribosomes
C) chloroplasts
D) endoplasmic reticulum
The correct answer is: B) ribosomes
Explanation:
B) Ribosomes: Ribosomes are found in plant, animal, and bacterial cells. They are responsible for synthesizing proteins in all living organisms. In both prokaryotic and eukaryotic cells, ribosomes perform the same essential function, although their structure is slightly different in prokaryotes and eukaryotes.
A) Mitochondria: Mitochondria are found in plant and animal cells (eukaryotes) but not in bacterial cells (prokaryotes). Bacteria generate energy in other ways, often using their cell membrane.
C) Chloroplasts: Chloroplasts are found only in plant cells and some algae for photosynthesis, but not in animal or bacterial cells.
D) Endoplasmic Reticulum: The endoplasmic reticulum is a membrane-bound organelle found in plant and animal cells (eukaryotes) but not in bacterial cells, as bacteria (prokaryotes) lack membrane-bound organelles.
Thus, ribosomes are the structures common to plant, animal, and bacterial cells since they are essential for protein synthesis in all cell types.
7) Which of the following macromolecules leave the nucleus of a eukaryotic cell through pores in the nuclear membrane?
A) DNA
B) amino acids
C) mRNA
D) phospholipids
The correct answer is: C) mRNA
Explanation:
C) mRNA: Messenger RNA (mRNA) is synthesized in the nucleus from a DNA template through a process called transcription. Once mRNA is produced, it leaves the nucleus through nuclear pores and enters the cytoplasm, where it is translated into proteins by ribosomes.
A) DNA: DNA remains in the nucleus and does not leave. It serves as the genetic blueprint for the cell and directs protein synthesis indirectly via RNA.
B) Amino acids: Amino acids do not travel out of the nucleus; they are found in the cytoplasm and are used by ribosomes to assemble proteins during translation.
D) Phospholipids: Phospholipids are components of the cell membrane and are not synthesized or transported out of the nucleus.
Thus, mRNA is the macromolecule that leaves the nucleus through nuclear pores to participate in protein synthesis in the cytoplasm.
8) The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells?
A) rough endoplasmic reticulum
B) smooth endoplasmic reticulum
C) Golgi apparatus
D) nuclear envelope
The correct answer is: B) smooth endoplasmic reticulum
Explanation:
B) Smooth Endoplasmic Reticulum (Smooth ER): The smooth ER is involved in the detoxification of drugs and poisons, as well as lipid synthesis and metabolism. Liver cells, which play a major role in detoxification, have a large amount of smooth ER to process and neutralize toxic substances.
A) Rough Endoplasmic Reticulum (Rough ER): The rough ER is primarily involved in protein synthesis, particularly of proteins destined for secretion or for membranes. It is not directly involved in detoxification.
C) Golgi Apparatus: The Golgi apparatus is responsible for modifying, sorting, and packaging proteins and lipids, but it does not play a significant role in detoxification.
D) Nuclear Envelope: The nuclear envelope surrounds the nucleus and regulates the exchange of materials between the nucleus and the cytoplasm, but it is not involved in detoxification processes.
Thus, the smooth ER is the structure primarily responsible for detoxifying poisons and drugs, making it abundant in liver cells.
11) If plant cells are grown on media containing radioactively labeled thymine for one generation, radioactively labeled macromolecules will be detected in which of the following?
A) only in the nucleus
B) only in the nucleus and mitochondria
C) only in the nucleus and chloroplasts
D) in the nucleus, mitochondria, and chloroplasts
The correct answer is: D) in the nucleus, mitochondria, and chloroplasts
Explanation:
Thymine is a nitrogenous base found in DNA (but not in RNA). When plant cells are grown with radioactively labeled thymine, the thymine will be incorporated into newly synthesized DNA.
Nucleus: The DNA in the nucleus will incorporate the labeled thymine, as the nucleus contains the cell’s primary genome.
Mitochondria: Mitochondria have their own circular DNA, separate from the nuclear DNA, and will also incorporate labeled thymine into their DNA.
Chloroplasts (in plant cells): Like mitochondria, chloroplasts also have their own circular DNA, which will incorporate the labeled thymine.
Thus, radioactively labeled thymine would be detected in the nucleus, mitochondria, and chloroplasts, since all three organelles contain DNA and replicate it.
12) Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to ________.
A) form cleavage furrows during cell division
B) migrate by amoeboid movement
C) separate chromosomes during cell division
D) maintain the shape of the nucleus
The correct answer is: C) separate chromosomes during cell division
Explanation:
Microtubules are essential components of the mitotic spindle, which is responsible for separating chromosomes during cell division (mitosis and meiosis). If a drug like vinblastine inhibits microtubule polymerization, the microtubules cannot form properly, and the cell would be unable to pull apart the sister chromatids to opposite poles during division.
A) Form cleavage furrows during cell division: Cleavage furrows form during cytokinesis (the division of the cytoplasm) in animal cells. This process is driven by microfilaments, not microtubules, so vinblastine would not affect the formation of cleavage furrows.
B) Migrate by amoeboid movement: Amoeboid movement is also driven by microfilaments (actin), not microtubules, so vinblastine would not directly affect this process.
D) Maintain the shape of the nucleus: The shape of the nucleus is maintained by the nuclear lamina, which consists of intermediate filaments, not microtubules.
Thus, the main effect of vinblastine is to inhibit the separation of chromosomes during cell division, as this process relies on microtubules.
