1Who first used the term "cell" after observing thin slices of cork?
Discovery of Cell
Easy
A.Robert Hooke
B.Matthias Schleiden
C.Anton van Leeuwenhoek
D.Theodor Schwann
Correct Answer: Robert Hooke
Explanation:
Robert Hooke observed small box-like spaces in cork and named them cells.
Incorrect! Try again.
2Which scientist was among the first to observe living microorganisms using a microscope?
Discovery of Cell
Easy
A.Robert Hooke
B.Rudolf Virchow
C.Anton van Leeuwenhoek
D.Robert Brown
Correct Answer: Anton van Leeuwenhoek
Explanation:
Anton van Leeuwenhoek used powerful simple microscopes to observe living microorganisms.
Incorrect! Try again.
3What is the basic structural and functional unit of life?
Basic Properties of Cell
Easy
A.The organism
B.The organ
C.The tissue
D.The cell
Correct Answer: The cell
Explanation:
All living organisms are made of cells, which perform essential life functions.
Incorrect! Try again.
4Which process allows cells to produce new cells?
Basic Properties of Cell
Easy
A.Cell diffusion
B.Cell division
C.Cell fixation
D.Cell staining
Correct Answer: Cell division
Explanation:
Cell division produces new cells for growth, repair, or reproduction.
Incorrect! Try again.
5Which structure controls the movement of many substances into and out of a cell?
Basic Properties of Cell
Easy
A.Nucleolus
B.Cell membrane
C.Cell wall
D.Ribosome
Correct Answer: Cell membrane
Explanation:
The cell membrane is selectively permeable and regulates movement of substances.
Incorrect! Try again.
6What does the unity of cells refer to?
Unity and diversity of Cells
Easy
A.Cells live in identical habitats
B.Cells are all the same size
C.Cells have common basic features
D.Cells have identical shapes
Correct Answer: Cells have common basic features
Explanation:
Cells share features such as genetic material, cytoplasm, and a cell membrane.
Incorrect! Try again.
7Why do cells have different shapes and structures?
Unity and diversity of Cells
Easy
A.They lack cell membranes
B.They contain no genetic material
C.They perform different functions
D.They are all different species
Correct Answer: They perform different functions
Explanation:
Cell shape and structure are often specialized to support a cell's particular function.
Incorrect! Try again.
8Which instrument is commonly used to observe cells?
Cell under the microscope
Easy
A.Microscope
B.Barometer
C.Thermometer
D.Centrifuge
Correct Answer: Microscope
Explanation:
A microscope magnifies objects that are too small to be seen clearly with the unaided eye.
Incorrect! Try again.
9What is magnification?
Cell under the microscope
Easy
A.Cutting of a specimen
B.Coloring of a specimen
C.Drying of a specimen
D.Enlargement of an image
Correct Answer: Enlargement of an image
Explanation:
Magnification makes an object appear larger than its actual size.
Incorrect! Try again.
10Which tool is often used to add color to cell structures for easier observation?
Cell under the microscope
Easy
A.Lens cap
B.Thermometer
C.Stain
D.Ruler
Correct Answer: Stain
Explanation:
Stains increase contrast and make particular cell structures easier to see.
Incorrect! Try again.
11Which type of cell lacks a membrane-bound nucleus?
Prokaryotic and eukaryotic cells
Easy
A.Prokaryotic cell
B.Animal cell
C.Eukaryotic cell
D.Plant cell
Correct Answer: Prokaryotic cell
Explanation:
Prokaryotic cells do not have a membrane-bound nucleus.
Incorrect! Try again.
12Which type of cell contains a membrane-bound nucleus?
Prokaryotic and eukaryotic cells
Easy
A.Viroid
B.Prokaryotic cell
C.Viral particle
D.Eukaryotic cell
Correct Answer: Eukaryotic cell
Explanation:
Eukaryotic cells contain a nucleus surrounded by a nuclear membrane.
Incorrect! Try again.
13Which organism is made of prokaryotic cells?
Prokaryotic and eukaryotic cells
Easy
A.Oak tree
B.Human
C.Bacterium
D.Mushroom
Correct Answer: Bacterium
Explanation:
Bacteria are prokaryotes and do not have membrane-bound nuclei.
Incorrect! Try again.
14Which structure is found in plant cells but not usually in animal cells?
Cell Architecture: Animal cell and plant cell
Easy
A.Cell membrane
B.Ribosome
C.Cytoplasm
D.Chloroplast
Correct Answer: Chloroplast
Explanation:
Chloroplasts are plant-cell organelles that carry out photosynthesis.
Incorrect! Try again.
15Which structure gives additional support and protection to plant cells?
Cell Architecture: Animal cell and plant cell
Easy
A.Nucleus
B.Cell wall
C.Mitochondrion
D.Golgi apparatus
Correct Answer: Cell wall
Explanation:
The plant cell wall provides strength and helps maintain cell shape.
Incorrect! Try again.
16Which organelle is commonly called the control center of a eukaryotic cell?
Cell Architecture: Animal cell and plant cell
Easy
A.Lysosome
B.Ribosome
C.Nucleus
D.Vacuole
Correct Answer: Nucleus
Explanation:
The nucleus contains most of the cell's genetic material and helps control cell activities.
Incorrect! Try again.
17Which cell component contains the cell's genetic material in most eukaryotic cells?
Cell Size and components
Easy
A.Nucleus
B.Cell wall
C.Cytoplasm
D.Vacuole
Correct Answer: Nucleus
Explanation:
In eukaryotic cells, most genetic material is contained inside the nucleus.
Incorrect! Try again.
18What is the jelly-like material that fills much of a cell called?
Cell Size and components
Easy
A.Cytoplasm
B.Chromatin
C.Capsid
D.Cellulose
Correct Answer: Cytoplasm
Explanation:
Cytoplasm fills the cell and contains organelles suspended in a fluid medium.
Incorrect! Try again.
19Why are viruses generally not considered cellular organisms?
Viruses and Viroids
Easy
A.They are always larger than cells
B.They contain too many organelles
C.They perform photosynthesis
D.They lack cellular structure
Correct Answer: They lack cellular structure
Explanation:
Viruses are acellular particles and do not have the complete structure of a cell.
Incorrect! Try again.
20What is a viroid?
Viruses and Viroids
Easy
A.A small infectious RNA molecule
B.A membrane-bound organelle
C.A complete eukaryotic cell
D.A protein-only bacterium
Correct Answer: A small infectious RNA molecule
Explanation:
Viroids are very small infectious agents made of short, circular RNA molecules without a protein coat.
Incorrect! Try again.
21A scientist observes repeated box-like compartments in a thin slice of cork. Which conclusion is most directly supported by this observation?
Discovery of Cell
Medium
A.Cork contains organized structural units
B.Cork cells actively perform photosynthesis
C.Cells can survive without any internal contents
D.All living cells contain chloroplasts
Correct Answer: Cork contains organized structural units
Explanation:
Hooke’s observation of cork revealed small compartments, which he called cells, although the cork cells were no longer living.
Incorrect! Try again.
22Why was Leeuwenhoek’s work important in the history of cell biology?
Discovery of Cell
Medium
A.He proved that cells arise only from nonliving matter
B.He discovered the cell nucleus in plant tissues
C.He established that all cells contain mitochondria
D.He observed living microorganisms with improved lenses
Correct Answer: He observed living microorganisms with improved lenses
Explanation:
Leeuwenhoek used powerful single-lens microscopes to observe living microorganisms, including bacteria and protists.
Incorrect! Try again.
23A cell is placed in an environment where nutrients are available, but its plasma membrane becomes unable to regulate transport. Which function would be most directly disrupted?
Basic Properties of Cell
Medium
A.Production of ribosomal subunits
B.Storage of hereditary information
C.Control of substances entering and leaving
D.Formation of chromosomes during division
Correct Answer: Control of substances entering and leaving
Explanation:
The plasma membrane is selectively permeable and regulates the movement of substances into and out of the cell.
Incorrect! Try again.
24A cell maintains a stable internal pH despite changes in its surroundings. This ability is an example of:
Basic Properties of Cell
Medium
A.Differentiation
B.Endocytosis
C.Evolution
D.Homeostasis
Correct Answer: Homeostasis
Explanation:
Homeostasis is the maintenance of relatively stable internal conditions despite external changes.
Incorrect! Try again.
25A mutation prevents a cell from producing proteins needed for energy metabolism. Which cellular property would be affected most immediately?
Basic Properties of Cell
Medium
A.Ability to increase its surface-to-volume ratio
B.Ability to obtain and use energy
C.Ability to maintain a rigid cell wall
D.Ability to transmit light through cytoplasm
Correct Answer: Ability to obtain and use energy
Explanation:
Proteins involved in metabolism help cells convert nutrients into usable energy, so energy processing would be impaired.
Incorrect! Try again.
26Muscle cells and nerve cells have different shapes and functions, yet both contain DNA and ribosomes. What does this best illustrate?
Unity and diversity of Cells
Medium
A.Cell specialization eliminates all common structures
B.Cells share core features but can be specialized
C.Only cells with identical shapes can contain DNA
D.Different cell types must belong to different kingdoms
Correct Answer: Cells share core features but can be specialized
Explanation:
Cells show unity through shared basic structures and processes, while diversity arises through specialization in structure and function.
Incorrect! Try again.
27Two organisms have cells with plasma membranes, ribosomes, and genetic material. One organism is unicellular, while the other is multicellular. Which conclusion is most appropriate?
Unity and diversity of Cells
Medium
A.The multicellular organism must lack ribosomes
B.Both organisms share fundamental cellular features
C.Their cells cannot have a common evolutionary history
D.The unicellular organism cannot carry out metabolism
Correct Answer: Both organisms share fundamental cellular features
Explanation:
All cells have several fundamental features, even though organisms differ in complexity and the degree of cellular specialization.
Incorrect! Try again.
28A student switches from a objective lens to a objective while using a ocular lens. What is the new total magnification?
Cell under the microscope
Medium
A.
B.
C.
D.
Correct Answer:
Explanation:
Total magnification equals ocular magnification multiplied by objective magnification: .
Incorrect! Try again.
29A specimen appears enlarged but blurry when viewed under a light microscope. Which adjustment would most directly improve sharpness without changing magnification?
Cell under the microscope
Medium
A.Remove the coverslip from the slide
B.Replace the specimen with a thicker one
C.Increase the objective magnification immediately
D.Adjust the fine-focus knob
Correct Answer: Adjust the fine-focus knob
Explanation:
The fine-focus knob makes small focusing adjustments that improve image sharpness after the specimen has been brought into approximate focus.
Incorrect! Try again.
30A stain is added to an unstained cheek-cell sample before microscopy. What is the primary purpose of the stain?
Cell under the microscope
Medium
A.To replace the cells’ missing organelles
B.To reduce the microscope’s resolving power
C.To make the cells divide more rapidly
D.To increase contrast between cell structures
Correct Answer: To increase contrast between cell structures
Explanation:
Many cell structures are nearly transparent, so stains increase contrast and make them easier to distinguish.
Incorrect! Try again.
31A newly discovered cell contains DNA in a nucleoid region but has no membrane-bound nucleus. How should it be classified?
Prokaryotic and eukaryotic cells
Medium
A.As a eukaryotic cell
B.As a virus particle
C.As a prokaryotic cell
D.As a nonliving cell fragment
Correct Answer: As a prokaryotic cell
Explanation:
Prokaryotic cells lack a membrane-bound nucleus; their DNA is located in a nucleoid region.
Incorrect! Try again.
32A drug blocks the function of the endoplasmic reticulum in a cell. The drug would affect eukaryotic cells more directly because they:
Prokaryotic and eukaryotic cells
Medium
A.Contain membrane-bound organelles
B.Lack genetic material in the cytoplasm
C.Always have a cell wall
D.Use ribosomes only outside the cell
Correct Answer: Contain membrane-bound organelles
Explanation:
The endoplasmic reticulum is a membrane-bound organelle found in eukaryotic cells and is absent from prokaryotic cells.
Incorrect! Try again.
33Which observation would provide the strongest evidence that a cell is eukaryotic?
Prokaryotic and eukaryotic cells
Medium
A.It contains a membrane-bound nucleus
B.It contains DNA as genetic material
C.It has a plasma membrane
D.It contains ribosomes in its cytoplasm
Correct Answer: It contains a membrane-bound nucleus
Explanation:
A membrane-bound nucleus is a defining feature of eukaryotic cells and is absent in prokaryotes.
Incorrect! Try again.
34A plant cell is placed in bright light and supplied with carbon dioxide. Which organelle is most directly involved in converting light energy into chemical energy?
Cell Architecture: Animal cell and plant cell
Medium
A.Lysosome
B.Golgi apparatus
C.Chloroplast
D.Centriole
Correct Answer: Chloroplast
Explanation:
Chloroplasts contain pigments and internal membranes that support photosynthesis, converting light energy into chemical energy.
Incorrect! Try again.
35A cell has a large central vacuole, a cellulose cell wall, and chloroplasts. Which type of cell is it most likely to be?
Cell Architecture: Animal cell and plant cell
Medium
A.A typical plant cell
B.A bacterial cell
C.A viral particle
D.A typical animal cell
Correct Answer: A typical plant cell
Explanation:
Large central vacuoles, cellulose cell walls, and chloroplasts are characteristic features of plant cells.
Incorrect! Try again.
36If lysosomes in an animal cell stop functioning, which process would be most directly impaired?
Cell Architecture: Animal cell and plant cell
Medium
A.Synthesis of glucose from sunlight
B.Breakdown of worn-out cell materials
C.Formation of the plant cell wall
D.Replication of bacterial chromosomes
Correct Answer: Breakdown of worn-out cell materials
Explanation:
Lysosomes contain digestive enzymes that break down cellular waste, damaged organelles, and some engulfed materials.
Incorrect! Try again.
37Why are most cells relatively small rather than extremely large?
Cell Size and components
Medium
A.Large cells always lack a plasma membrane
B.Small cells do not require energy for metabolism
C.Large cells cannot contain genetic material
D.Small cells have a favorable surface-area-to-volume ratio
Correct Answer: Small cells have a favorable surface-area-to-volume ratio
Explanation:
As a cell grows, its volume increases faster than its surface area, making exchange with the environment less efficient.
Incorrect! Try again.
38A cell’s volume increases substantially while its surface area increases only slightly. Which consequence is most likely?
Cell Size and components
Medium
A.Complete disappearance of the cytoplasm
B.Automatic conversion into a prokaryotic cell
C.Immediate loss of all hereditary information
D.Slower exchange of materials relative to cell demand
Correct Answer: Slower exchange of materials relative to cell demand
Explanation:
A lower surface-area-to-volume ratio reduces the membrane area available for exchanging materials relative to the cell’s internal needs.
Incorrect! Try again.
39A toxin damages ribosomes but leaves the plasma membrane intact. Which cellular activity would be affected first?
Cell Size and components
Medium
A.Separation of chromosomes by spindle fibers
B.Storage of water in vacuoles
C.Diffusion of oxygen
D.Protein synthesis
Correct Answer: Protein synthesis
Explanation:
Ribosomes assemble amino acids into proteins, so damaging them directly disrupts protein synthesis.
Incorrect! Try again.
40A virus can reproduce only after entering a host cell. What does this indicate about viruses?
Viruses and Viroids
Medium
A.They contain all organelles needed for protein synthesis
B.They are complete cells with independent metabolism
C.They depend on host-cell machinery for replication
D.They reproduce through ordinary cell division
Correct Answer: They depend on host-cell machinery for replication
Explanation:
Viruses lack the complete machinery needed for independent reproduction and use components of host cells to make new virus particles.
Incorrect! Try again.
41Why did Robert Hooke's observations of cork lead to the term "cell" without establishing that all living organisms are cellular?
Discovery of Cell
Hard
A.He observed only empty compartments in dead tissue
B.He examined bacteria before observing plant tissue
C.He used a microscope incapable of resolving membranes
D.He identified nuclei but not surrounding cytoplasm
Correct Answer: He observed only empty compartments in dead tissue
Explanation:
Cork consists of dead cells whose contents have disappeared, leaving box-like walls. Hooke named these compartments, but he did not observe living cellular organization.
Incorrect! Try again.
42Which observation most directly supported Schleiden and Schwann's cell theory while also exposing a limitation later corrected by Virchow?
B.All cells arise spontaneously from nonliving material
C.Cells contain identical organelles in every organism
D.Only plants are composed of repeating compartments
Correct Answer: Different tissues contain membrane-bound compartments
Explanation:
Schleiden and Schwann recognized plants and animals as cellular, but early formulations did not correctly emphasize that new cells arise from preexisting cells.
Incorrect! Try again.
43A synthetic compartment contains enzymes, genetic material, and a selectively permeable boundary but cannot maintain internal conditions or reproduce independently. Which conclusion is most appropriate?
Basic Properties of Cell
Hard
A.It is a prokaryote because it lacks membrane-bound organelles
B.It is a virus because it contains genetic material
C.It is a eukaryote because it contains several enzymes
D.It has some cellular features but is not a complete cell
Correct Answer: It has some cellular features but is not a complete cell
Explanation:
A cell must integrate metabolism, information storage, boundary control, and reproduction. Possessing individual components does not guarantee autonomous cellular life.
Incorrect! Try again.
44Why is compartmentalization especially important for a large metabolically active cell?
Basic Properties of Cell
Hard
A.It allows genetic material to remain outside all membranes
B.It eliminates the need for membrane transport proteins
C.It creates localized conditions and shortens diffusion distances
D.It makes every reaction occur at the same pH
Correct Answer: It creates localized conditions and shortens diffusion distances
Explanation:
Internal compartments concentrate reactants, maintain distinct chemical conditions, and reduce the distances over which molecules must travel.
Incorrect! Try again.
45A bacterium and a human cell both synthesize proteins using ribosomes. Which inference best illustrates cellular unity without ignoring cellular diversity?
Unity and diversity of Cells
Hard
A.Their metabolic pathways must be identical in every detail
B.Their ribosomes must have identical structures and sizes
C.Their protein synthesis reflects conserved ancestry despite different organization
D.Their genomes must be located inside membrane-bound nuclei
Correct Answer: Their protein synthesis reflects conserved ancestry despite different organization
Explanation:
Core processes such as translation are widely conserved, whereas ribosome structure, cellular compartments, and regulatory mechanisms can differ substantially.
Incorrect! Try again.
46Two cells have similar genomes but differ greatly in shape, metabolism, and function. Which mechanism most plausibly accounts for this difference?
Unity and diversity of Cells
Hard
A.Replacement of DNA with unrelated hereditary molecules
B.Random loss of all genes unrelated to cell shape
C.Differential gene expression and environmental regulation
D.Complete absence of ribosomes in the less active cell
Correct Answer: Differential gene expression and environmental regulation
Explanation:
Cell specialization commonly results from expressing different subsets of genes in response to developmental signals and environmental conditions.
Incorrect! Try again.
47A specimen appears blurred because structures outside the focal plane contribute light to the image. Which method would most directly improve optical sectioning?
Cell under the microscope
Hard
A.Confocal microscopy with focused illumination
B.Bright-field microscopy with lower magnification
C.Phase-contrast microscopy without optical sectioning
D.Electron microscopy using thicker sections
Correct Answer: Confocal microscopy with focused illumination
Explanation:
Confocal microscopy rejects much out-of-focus light and can generate optical sections through fluorescently labeled specimens.
Incorrect! Try again.
48A researcher wants to observe organelle ultrastructure at nanometer-scale resolution but must examine fixed, nonliving material. Which choice is most suitable?
Cell under the microscope
Hard
A.Phase-contrast microscopy of a hydrated specimen
B.Light microscopy of an unstained living culture
C.Scanning electron microscopy of a transparent monolayer
D.Transmission electron microscopy of thin sections
Correct Answer: Transmission electron microscopy of thin sections
Explanation:
Transmission electron microscopy provides high-resolution internal images from thin sections, but fixation and preparation prevent observation of living dynamics.
Incorrect! Try again.
49A fluorescent label is visible only when its target is abundant, even though the target is present throughout the cell. Which limitation most likely explains this result?
Cell under the microscope
Hard
A.Fluorescent probes convert all low-abundance targets to DNA
B.Fluorescence always reveals only membrane proteins
C.Detection depends on signal above background noise
D.The microscope cannot detect molecules smaller than cells
Correct Answer: Detection depends on signal above background noise
Explanation:
Microscopy detects a signal only when it is sufficiently strong relative to background, so low-abundance targets may remain undetectable.
Incorrect! Try again.
50A cell contains circular DNA, 70S ribosomes, and a plasma membrane but no nucleus. Which additional observation would most strongly distinguish it from a typical bacterium?
Prokaryotic and eukaryotic cells
Hard
A.A membrane-bound compartment containing its genome
B.A chromosome associated with basic proteins
C.Ribosomes attached to messenger RNA
D.A cell wall containing peptidoglycan
Correct Answer: A membrane-bound compartment containing its genome
Explanation:
A membrane-bound nuclear compartment is a defining eukaryotic feature. The other observations can occur in bacteria or are not decisive alone.
Incorrect! Try again.
51Why can a prokaryotic cell divide rapidly despite lacking the extensive internal membrane system of a eukaryotic cell?
Prokaryotic and eukaryotic cells
Hard
A.Its smaller, less compartmentalized organization reduces replication overhead
B.It lacks DNA replication and copies only its plasma membrane
C.Its ribosomes operate without messenger RNA or transfer RNA
D.It stores all metabolic enzymes outside the cell boundary
Correct Answer: Its smaller, less compartmentalized organization reduces replication overhead
Explanation:
Prokaryotes generally have fewer internal structures to duplicate and coordinate, although their division rate also depends on nutrients, temperature, and regulation.
Incorrect! Try again.
52An antibiotic inhibits bacterial ribosomes but has little immediate effect on cytosolic protein synthesis in a human cell. Which explanation is most defensible?
Prokaryotic and eukaryotic cells
Hard
A.Bacterial ribosomes are located inside human nuclei
B.Antibiotics cannot enter any eukaryotic cell
C.Human cells synthesize proteins without ribosomes
D.Bacterial and cytosolic eukaryotic ribosomes differ structurally
Correct Answer: Bacterial and cytosolic eukaryotic ribosomes differ structurally
Explanation:
Bacterial ribosomes are 70S, whereas cytosolic eukaryotic ribosomes are 80S. Structural differences can create selective drug effects.
Incorrect! Try again.
53A plant cell placed in a hypotonic solution does not normally burst, whereas an animal cell may lyse. Which structural difference best explains this outcome?
Cell Architecture: Animal cell and plant cell
Hard
A.The plant nucleus actively pumps water outward
B.The plant cell wall resists excessive expansion
C.Animal cells contain chloroplasts that absorb water
D.Plant ribosomes prevent osmotic movement across membranes
Correct Answer: The plant cell wall resists excessive expansion
Explanation:
Water enters both cells by osmosis, but the rigid plant cell wall generates resistance and turgor pressure that limits swelling.
Incorrect! Try again.
54A mutation prevents formation of functional plasmodesmata in a plant tissue. Which process would be most directly disrupted?
Cell Architecture: Animal cell and plant cell
Hard
A.Direct exchange of signals and solutes between adjacent cells
B.Assembly of cellulose within the extracellular wall
C.Synthesis of ATP within the mitochondrial matrix
D.Replication of DNA inside the plant cell nucleus
Correct Answer: Direct exchange of signals and solutes between adjacent cells
Explanation:
Plasmodesmata are cytoplasmic channels connecting neighboring plant cells and permit intercellular transport and communication.
Incorrect! Try again.
55A cell has chloroplasts, a large central vacuole, and cellulose walls but lacks mitochondria. Which prediction is most accurate?
Cell Architecture: Animal cell and plant cell
Hard
A.It must be an animal cell with unusually strong membranes
B.It will function normally because chloroplasts replace all mitochondria
C.It will compensate by converting chloroplasts into nuclei
D.It cannot sustain normal cellular respiration and energy balance
Correct Answer: It cannot sustain normal cellular respiration and energy balance
Explanation:
Chloroplasts perform photosynthesis, whereas mitochondria provide major respiratory ATP production. Photosynthesis does not fully replace mitochondrial functions.
Incorrect! Try again.
56If a spherical cell doubles its radius while retaining the same composition, how do its surface-area-to-volume ratio and diffusion challenge change?
Cell Size and components
Hard
A.The ratio quadruples, making internal transport unnecessary
B.The ratio remains constant, so diffusion is unchanged
C.The ratio doubles, making exchange relatively more efficient
D.The ratio halves, making exchange relatively less efficient
Correct Answer: The ratio halves, making exchange relatively less efficient
Explanation:
For a sphere, surface area scales as and volume as , so surface-area-to-volume ratio scales as . Doubling radius halves the ratio.
Incorrect! Try again.
57A cell's volume increases eightfold while its radius changes proportionally. Which change would occur if its shape remained spherical?
Cell Size and components
Hard
A.Its radius doubles and its surface area quadruples
B.Its radius triples and its surface area increases eightfold
C.Its radius doubles and its surface area doubles
D.Its radius quadruples and its surface area doubles
Correct Answer: Its radius doubles and its surface area quadruples
Explanation:
Because volume is proportional to , an eightfold volume increase requires a twofold radius increase. Surface area, proportional to , then increases fourfold.
Incorrect! Try again.
58Which cell design most effectively maintains rapid exchange with the environment while increasing total metabolic capacity?
B.A thickened cell boundary with no transport proteins
C.A large smooth sphere with minimal membrane area
D.A folded or elongated form with numerous internal membranes
Correct Answer: A folded or elongated form with numerous internal membranes
Explanation:
Folding and elongation increase effective exchange area, while internal membranes provide additional surfaces for metabolic reactions.
Incorrect! Try again.
59A pathogen contains a short circular RNA molecule, has no capsid, and replicates only within plant cells. Which classification best fits it?
Viruses and Viroids
Hard
A.Viroid
B.Bacteriophage
C.Enveloped animal virus
D.Cellular plasmid with ribosomes
Correct Answer: Viroid
Explanation:
Viroids are small, circular, infectious RNA molecules without protein coats, primarily known as plant pathogens.
Incorrect! Try again.
60Why is a virus generally excluded from definitions of autonomous cellular life even when it carries genetic information and evolves?
Viruses and Viroids
Hard
A.It reproduces only through ordinary binary fission
B.It cannot contain nucleic acids or undergo genetic variation
C.It is always smaller than every known cellular organelle
D.It lacks independent metabolism and depends on host machinery
Correct Answer: It lacks independent metabolism and depends on host machinery
Explanation:
Viruses contain genetic information and evolve, but they generally lack autonomous metabolism and replication machinery, requiring a host cell for reproduction.
Incorrect! Try again.
Did this save you a night before the exam?
LPU Notes is free, and it stays free. Ads cover part of the server bill.
The rest comes out of a student's own pocket: the domain, the storage,
and keeping the site up through the weeks everyone needs it at once.
The payment button didn't load. An ad blocker or a filtered network is the usual reason.
to try again.
Nothing here is ever locked, and nothing unlocks. Chip in only if it was worth it.
What it pays for →