BIO101-Prokaryotes
Prokaryotes
Quick Rules
-
Time limit: 27 minutes
-
Multiple attempts are not allowed
-
All questions must be answered to submit
Share Quiz
Quiz Questions Preview
Question 1
Prokaryotic DNA is located in the nucleus of the cell.
Explanation
Prokaryotes lack a true nucleus, and their DNA is located in the cytoplasm, not enclosed within a membrane-bound nucleus.
Question 2
All prokaryotes reproduce sexually.
Explanation
Prokaryotes primarily reproduce asexually through processes like binary fission. Sexual reproduction is not a common method in prokaryotes.
Question 3
Archaea and bacteria are distinguished by their cell wall composition.
Explanation
Archaea have cell walls composed of different components, such as polysaccharides and proteins, while bacteria have cell walls made primarily of peptidoglycan.
Question 4
Cyanobacteria are known for being photoautotrophic organisms.
Explanation
Cyanobacteria are indeed photoautotrophic, meaning they capture light energy to produce their own food, and they also release oxygen as a by-product of photosynthesis.
Question 5
Cyanobacteria are known for their ability to perform photosynthesis and produce oxygen.
Explanation
Cyanobacteria are photoautotrophic prokaryotes that convert light energy into chemical energy and release oxygen as a by-product, classifying them as oxygenic photosynthetic bacteria.
Question 6
Nitrogen-fixing prokaryotes are essential for converting atmospheric nitrogen into forms usable by plants.
Explanation
Nitrogen-fixing prokaryotes, such as certain bacteria, convert atmospheric nitrogen (N2) into ammonia (NH3), which can then be incorporated by plants, thus playing a crucial role in the nitrogen cycle.
Question 7
What is a key characteristic of prokaryotic cells?
Explanation
Prokaryotic cells are defined by their lack of membrane-bound organelles, including a true nucleus. Their internal structures are relatively simple compared to eukaryotic cells.
Question 8
Which domain of prokaryotes includes extremophiles?
Explanation
Domain Archaea is known for including extremophiles, organisms that thrive in extreme environmental conditions, such as high temperatures, salinity, or acidity.
Question 9
What distinguishes Gram-positive bacteria from Gram-negative bacteria?
Explanation
Gram-positive bacteria are distinguished by their thick peptidoglycan layer, which retains crystal violet dye during Gram staining, while Gram-negative bacteria have a thinner layer and an outer membrane.
Question 10
During a laboratory experiment, a student is tasked with classifying two newly discovered bacteria. One exhibits a thin layer of peptidoglycan and has an outer membrane; the other has a thick peptidoglycan layer and lacks an outer membrane. What classifications do these bacteria belong to?
Explanation
Gram-negative bacteria have a thin layer of peptidoglycan and an outer membrane, while Gram-positive bacteria have a thick peptidoglycan layer without an outer membrane. This understanding is crucial in bacterial classification.
Question 11
A researcher observes a bacterial culture thriving in the presence of oxygen and reports that it can survive in both anaerobic and aerobic conditions. How should this bacteria be classified based on its metabolic capabilities?
Explanation
The correct classification is 'Facultative anaerobe' because the bacteria can grow in both oxygen-rich and oxygen-poor environments. The other classifications either restrict the organism to one condition or misapply its metabolic abilities.
Question 12
A biologist is studying a type of cyanobacteria that fix nitrogen. She finds that during nitrogen starvation, these organisms undergo heterocyst formation. What is the primary function of the heterocyst in cyanobacteria?
Explanation
Heterocysts primarily function to provide an anaerobic environment needed for the nitrogen-fixing enzyme nitrogenase, preventing the inhibition caused by oxygen. The other proposed functions do not apply to heterocyst formation.
Question 13
In a genetic engineering experiment, scientists are attempting to introduce a new trait into a bacterial population through conjugation. Which elements are essential for successful genetic transfer during this process?
Explanation
The correct answer is 'Pilus and plasmids' as pili form the connection between the two bacterial cells facilitating the transfer of plasmids, which often carry genetic information. Other options do not relate to the conjugation process.
Question 14
Prokaryotes have membrane-bound organelles.
Explanation
Prokaryotes lack membrane-bound organelles, which is one of their distinct characteristics compared to eukaryotes, which do have such organelles.
Question 15
The cell wall of bacteria is composed of peptidoglycan.
Explanation
The cell wall of bacteria is indeed composed of peptidoglycan, a polymer made of sugars and amino acids, which gives bacteria their structural integrity.
Question 16
Archaea cell walls always contain peptidoglycan.
Explanation
Archaea do not have peptidoglycan in their cell walls; instead, they contain a variety of components, which may include polysaccharides, glycoproteins, and protein-based S-layers.
Question 17
What is the main feature that distinguishes prokaryotic cells from eukaryotic cells?
Explanation
Prokaryotic cells are characterized by the absence of a true nucleus; their DNA is not enclosed within a membrane, unlike eukaryotic cells which have a defined nucleus.
Question 18
What component is primarily found in the cell wall of bacteria?
Explanation
Bacterial cell walls are made primarily of peptidoglycan, a polymer of sugars and amino acids, which is distinct from the components found in plant and fungal cell walls.
Question 19
Which type of prokaryote thrives in high-salinity environments?
Explanation
Halophiles are specific types of archaea that flourish in high-salinity environments, such as salt lakes and salt mines, making them uniquely adapted to these conditions.
Question 20
What is the primary method by which prokaryotes reproduce?
Explanation
Prokaryotes reproduce asexually primarily through binary fission, a process where a single cell divides into two identical daughter cells.
Question 21
In gram staining, what color do gram-positive bacteria typically appear?
Explanation
During gram staining, gram-positive bacteria retain the crystal violet stain and appear purple, while gram-negative bacteria do not retain the violet stain and appear pink.
Question 22
A researcher is studying a new prokaryotic species discovered in a hot spring. This organism is found to thrive in high temperatures and low pH, suggesting it belongs to a specific domain. Which of the following classifications best describes this organism, and what unique characteristic can you expect to find in its cellular structure that distinguishes it from other prokaryotes?
Explanation
The correct answer is 'Domain Archaea; it lacks peptidoglycan in its cell wall.' Archaea are known for thriving in extreme environments, and one notable characteristic is that they do not contain peptidoglycan, which is present in the cell walls of bacteria. This distinguishes them from both bacteria and eukaryotes. The other distractors present common misconceptions about prokaryotic classification and structure.
Question 23
What is a distinguishing feature of prokaryotic cells?
Explanation
Prokaryotic cells lack membrane-bound organelles, which distinguishes them from eukaryotic cells that contain structures such as the nucleus and mitochondria.
Question 24
Assertion (A): Prokaryotes lack membrane-bound organelles and a true nucleus. Reason (R): This characteristic allows prokaryotes to reproduce rapidly in favorable conditions due to less compartmentalization of cellular processes.
Explanation
The lack of membrane-bound organelles and a true nucleus in prokaryotes indeed facilitates their rapid reproduction as there are fewer barriers to managing cellular functions, allowing prokaryotes to divide quickly under favorable conditions.
Question 25
Assertion (A): Gram-negative bacteria can be more resistant to antibiotics compared to Gram-positive bacteria. Reason (R): This resistance is primarily due to the presence of an outer membrane that Gram-negative bacteria possess, which acts as a barrier to many antibiotics.
Explanation
Gram-negative bacteria's outer membrane provides a significant barrier, which indeed contributes to their higher resistance to antibiotics compared to Gram-positive bacteria, thereby validating the assertion with the reason as an accurate explanation.
Question 26
Assertion (A): Nitrogen-fixing prokaryotes convert atmospheric N2 into NH3, making nitrogen available for plant uptake. Reason (R): Nitrogen-fixing bacteria can only perform this function in symbiotic relationships with certain plants.
Explanation
While nitrogen-fixing prokaryotes do convert N2 to NH3, they are capable of performing this process both in symbiotic relationships and independently. Therefore, the assertion is true, but the reason does not fully explain the assertion, as some nitrogen-fixing organisms can work without such partnerships.
Question 27
A lab technician is analyzing an environmental sample for the presence of prokaryotes. She finds a group of microorganisms that thrive in low pH environments and has a unique cell wall structure different from bacteria. Which of the following classifications best describes these microorganisms?
Explanation
The correct answer is 'Acidophiles' as they are prokaryotes that thrive in acidic environments. The other options represent different classifications of extremophiles based on their respective environments but do not relate to acidity.