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C4.1 Populations and Communities
Q: What defines a population?
A: A group of organisms of the same species living in the same area at the same time that typically interbreed.
Q: Why is population size often estimated instead of counted directly?
A: Because some organisms are too numerous or too mobile to count, leading to sampling errors.
Q: What is random quadrat sampling used for?
A: Estimating population size of sessile organisms by randomly sampling squares in a grid.
Q: What method estimates population size for motile organisms?
A: Capture-mark-release-recapture and the Lincoln Index formula:
(Where =initially marked, =recaptured total, =marked in recaptured sample)
Q: What is carrying capacity?
A: The maximum number of organisms an ecosystem can support, determined by resources like food, water, and shelter.
Q: What are density-dependent factors? Give examples.
A: Factors that regulate population size based on density, such as disease, predation, and competition.
Q: What are density-independent factors?
A: Factors like natural disasters or weather that affect populations regardless of density.
Q: Describe the sigmoid (logistic) population growth curve.
A: It shows rapid growth initially (exponential phase), then slows as resources limit growth, eventually stabilizing at carrying capacity.
D4.1 Natural Selection
Q: What is natural selection?
A: A process where organisms with favorable traits reproduce more successfully, causing these traits to become more common over generations.
Q: How do mutations and sexual reproduction contribute to variation?
A: Mutations introduce new alleles, and sexual reproduction reshuffles alleles to create new combinations.
Q: What role does overproduction of offspring play in natural selection?
A: It leads to competition for limited resources, favoring individuals with advantageous traits.
Q: What is fitness in evolutionary terms?
A: The ability of an organism to survive, reproduce, and pass on its genes.
Converting the entire document into flashcards will take some time due to its length. Here’s a start, and I’ll continue adding sections systematically. Let me know if you want adjustments to the format or structure.
C4.1 Populations and Communities
Q: What defines a population?
A: A group of organisms of the same species living in the same area at the same time that typically interbreed.
Q: Why is population size often estimated instead of counted directly?
A: Because some organisms are too numerous or too mobile to count, leading to sampling errors.
Q: What is random quadrat sampling used for?
A: Estimating population size of sessile organisms by randomly sampling squares in a grid.
Q: How is population size estimated for motile organisms?
A: Using capture-mark-release-recapture and the Lincoln Index formula:
(Where =initially marked, =recaptured total, =marked in recaptured sample)
Q: What is carrying capacity?
A: The maximum number of organisms an ecosystem can support, determined by resources like food, water, and shelter.
Q: What are density-dependent factors? Give examples.
A: Factors that regulate population size based on density, such as disease, predation, and competition.
Q: What are density-independent factors?
A: Factors like natural disasters or weather that affect populations regardless of density.
Q: Describe the sigmoid (logistic) population growth curve.
A: It shows rapid growth initially (exponential phase), then slows as resources limit growth, eventually stabilizing at carrying capacity.
C4.2 Interactions in Communities
Q: What is the difference between a population and a community?
A: A population consists of one species, while a community includes all interacting organisms in an ecosystem.
Q: Define herbivory and give an example.
A: Herbivory is when animals eat plants. Example: Deer grazing on grass.
Q: What is mutualism? Provide an example.
A: A relationship where both species benefit. Example: Zooxanthellae in corals (zooxanthellae get protection; corals get nutrients).
Q: How do invasive species impact ecosystems?
A: They outcompete endemic species, disrupting ecosystems. Example: Red-eared sliders outcompeting western pond turtles.
Q: What is interspecific competition?
A: Competition between different species for the same resource, e.g., wolves and coyotes competing for prey.
D4.1 Natural Selection
Q: What is natural selection?
A: A process where organisms with favorable traits reproduce more successfully, causing these traits to become more common over generations.
Q: How do mutations and sexual reproduction contribute to variation?
A: Mutations introduce new alleles, and sexual reproduction reshuffles alleles to create new combinations.
Q: What role does overproduction of offspring play in natural selection?
A: It leads to competition for limited resources, favoring individuals with advantageous traits.
Q: What is fitness in evolutionary terms?
A: The ability of an organism to survive, reproduce, and pass on its genes.
Q: What are density-independent factors in natural selection?
A: Abiotic factors like temperature, salinity, or drought that affect survival regardless of population density.
Q: Define directional, stabilizing, and disruptive selection.
A:
• Directional:Favors one extreme phenotype.
• Stabilizing:Favors intermediate phenotypes.
• Disruptive:Favors two extreme phenotypes, which may lead to speciation.
D4.2 Stability and Change
Q: What is ecosystem stability?
A: The ability of an ecosystem to remain consistent over time, often dependent on factors like genetic diversity and nutrient recycling.
Q: How can deforestation affect ecosystem stability?
A: Loss of forests disrupts water cycles, reduces biodiversity, and destabilizes the ecosystem.
Q: What is a keystone species? Give examples.
A: A species that has a disproportionate impact on its ecosystem. Examples: Wolves, sea otters, beavers.
Q: What is competitive exclusion?
A: The principle that two species competing for the same resources cannot coexist indefinitely; one will outcompete the other.
Q: What is niche partitioning?
A: The process by which competing species use resources differently to coexist.
Q: Define primary and secondary succession.
A:
• Primary succession:Occurs on bare rock, starting with pioneer species like lichen.
• Secondary succession:Occurs in areas where soil already exists.
C4.2 Transfer of Energy and Matter
Q: How does energy flow in an ecosystem?
A: Energy flows through food chains and food webs, starting with producers and moving through various consumer levels.
Q: Why are there fewer organisms at higher trophic levels?
A: Energy is lost at each trophic level due to respiration, heat, and inefficiencies, reducing available energy.
Q: What is an energy pyramid?
A: A diagram showing the energy transfer between trophic levels in an ecosystem, with producers at the base and top predators at the apex.
Q: What is primary production?
A: The accumulation of carbon compounds in autotroph biomass, measured in .
Q: What is secondary production?
A: The accumulation of carbon compounds in heterotroph biomass, which is lower than primary production due to energy loss.
Converting the entire document into flashcards will take some time due to its length. Here’s a start, and I’ll continue adding sections systematically. Let me know if you want adjustments to the format or structure.
C4.1 Populations and Communities
Q: What defines a population?
A: A group of organisms of the same species living in the same area at the same time that typically interbreed.
Q: Why is population size often estimated instead of counted directly?
A: Because some organisms are too numerous or too mobile to count, leading to sampling errors.
Q: What is random quadrat sampling used for?
A: Estimating population size of sessile organisms by randomly sampling squares in a grid.
Q: How is population size estimated for motile organisms?
A: Using capture-mark-release-recapture and the Lincoln Index formula:
(Where =initially marked, =recaptured total, =marked in recaptured sample)
Q: What is carrying capacity?
A: The maximum number of organisms an ecosystem can support, determined by resources like food, water, and shelter.
Q: What are density-dependent factors? Give examples.
A: Factors that regulate population size based on density, such as disease, predation, and competition.
Q: What are density-independent factors?
A: Factors like natural disasters or weather that affect populations regardless of density.
Q: Describe the sigmoid (logistic) population growth curve.
A: It shows rapid growth initially (exponential phase), then slows as resources limit growth, eventually stabilizing at carrying capacity.
C4.2 Interactions in Communities
Q: What is the difference between a population and a community?
A: A population consists of one species, while a community includes all interacting organisms in an ecosystem.
Q: Define herbivory and give an example.
A: Herbivory is when animals eat plants. Example: Deer grazing on grass.
Q: What is mutualism? Provide an example.
A: A relationship where both species benefit. Example: Zooxanthellae in corals (zooxanthellae get protection; corals get nutrients).
Q: How do invasive species impact ecosystems?
A: They outcompete endemic species, disrupting ecosystems. Example: Red-eared sliders outcompeting western pond turtles.
Q: What is interspecific competition?
A: Competition between different species for the same resource, e.g., wolves and coyotes competing for prey.
D4.1 Natural Selection
Q: What is natural selection?
A: A process where organisms with favorable traits reproduce more successfully, causing these traits to become more common over generations.
Q: How do mutations and sexual reproduction contribute to variation?
A: Mutations introduce new alleles, and sexual reproduction reshuffles alleles to create new combinations.
Q: What role does overproduction of offspring play in natural selection?
A: It leads to competition for limited resources, favoring individuals with advantageous traits.
Q: What is fitness in evolutionary terms?
A: The ability of an organism to survive, reproduce, and pass on its genes.
Q: What are density-independent factors in natural selection?
A: Abiotic factors like temperature, salinity, or drought that affect survival regardless of population density.
Q: Define directional, stabilizing, and disruptive selection.
A:
• Directional:Favors one extreme phenotype.
• Stabilizing:Favors intermediate phenotypes.
• Disruptive:Favors two extreme phenotypes, which may lead to speciation.
D4.2 Stability and Change
Q: What is ecosystem stability?
A: The ability of an ecosystem to remain consistent over time, often dependent on factors like genetic diversity and nutrient recycling.
Q: How can deforestation affect ecosystem stability?
A: Loss of forests disrupts water cycles, reduces biodiversity, and destabilizes the ecosystem.
Q: What is a keystone species? Give examples.
A: A species that has a disproportionate impact on its ecosystem. Examples: Wolves, sea otters, beavers.
Q: What is competitive exclusion?
A: The principle that two species competing for the same resources cannot coexist indefinitely; one will outcompete the other.
Q: What is niche partitioning?
A: The process by which competing species use resources differently to coexist.
Q: Define primary and secondary succession.
A:
• Primary succession:Occurs on bare rock, starting with pioneer species like lichen.
• Secondary succession:Occurs in areas where soil already exists.
C4.2 Transfer of Energy and Matter
Q: How does energy flow in an ecosystem?
A: Energy flows through food chains and food webs, starting with producers and moving through various consumer levels.
Q: Why are there fewer organisms at higher trophic levels?
A: Energy is lost at each trophic level due to respiration, heat, and inefficiencies, reducing available energy.
Q: What is an energy pyramid?
A: A diagram showing the energy transfer between trophic levels in an ecosystem, with producers at the base and top predators at the apex.
Q: What is primary production?
A: The accumulation of carbon compounds in autotroph biomass, measured in .
Q: What is secondary production?
A: The accumulation of carbon compounds in heterotroph biomass, which is lower than primary production due to energy loss.
C4.2 Transfer of Energy and Matter (continued)
Q: What role do decomposers play in an ecosystem?
A: Decomposers recycle nutrients by breaking down dead organisms, feces, and organic matter into simpler compounds.
Q: What is the difference between autotrophs and heterotrophs?
A:
• Autotrophs:Use external energy sources (e.g., sunlight or chemical reactions) to synthesize carbon compounds.
• Heterotrophs:Obtain carbon compounds from other organisms.
Q: What is the carbon cycle?
A: The process by which carbon is recycled in ecosystems through photosynthesis, feeding, respiration, and decomposition.
Q: How do ecosystems act as carbon sinks or sources?
A:
• Carbon sink:More carbon is absorbed (photosynthesis > respiration).
• Carbon source:More carbon is released (respiration > photosynthesis).
Q: What causes energy loss in trophic levels?
A: Energy is lost as heat during respiration, in waste materials, and through inefficiencies in energy transfer between organisms.
Q: What is the Keeling Curve?
A: A graph showing annual fluctuations in atmospheric CO₂ due to seasonal changes in photosynthesis, as well as a long-term increase due to human activities.
Q: How does combustion contribute to the carbon cycle?
A: Burning of biomass, fossil fuels, or peat releases stored carbon dioxide back into the atmosphere.
D4.3 Climate Change
Q: What are anthropogenic causes of climate change?
A: Human activities, such as burning fossil fuels and deforestation, increase greenhouse gases like CO₂ and methane in the atmosphere.
Q: What is the greenhouse effect?
A: The process where greenhouse gases trap heat in the atmosphere, warming the Earth.
Q: What are positive feedback loops in global warming?
A:
• Melting ice reduces reflectivity, increasing heat absorption.
• Thawing permafrost releases methane, amplifying warming.
• Forest fires release CO₂, leading to more fires.
Q: How can boreal forests reach a tipping point?
A: Warmer temperatures, reduced snowfall, and increased drought can lead to forest browning, fires, and carbon loss instead of accumulation.
D4.2 Ecological Succession
Q: What is ecological succession?
A: The gradual process of change in species composition and ecosystem structure over time.
Q: What is the difference between primary and secondary succession?
A:
• Primary succession:Starts on bare rock or new land without soil (e.g., after a volcanic eruption).
• Secondary succession:Starts in areas where soil is present (e.g., after a forest fire).
Q: What is cyclical succession?
A: In some ecosystems, communities cycle repeatedly rather than forming a stable climax community (e.g., wetlands).
Q: What are climax communities?
A: Stable ecosystems that arise when succession reaches an endpoint under specific environmental conditions.
Q: How can human activities cause arrested succession?
A: Activities like grazing or draining wetlands can prevent ecosystems from reaching their climax community.
A3.2 Classification and Cladistics
Q: What is the purpose of classifying organisms?
A: To organize species into groups for easier study and to reflect evolutionary relationships.
Q: What is a clade?
A: A group of organisms with a common ancestor and shared characteristics.
Q: How are cladograms constructed?
A: Using DNA, RNA, or amino acid sequence data to show evolutionary relationships.
Q: What is a molecular clock?
A: A method of estimating divergence times between species based on the accumulation of mutations.
Q: What are homologous structures?
A: Structures with similar anatomy due to shared ancestry but different functions (e.g., pentadactyl limbs).
Q: What are analogous structures?
A: Structures with similar functions but different evolutionary origins (e.g., wings of birds and insects).
A4.1 Evolution and Speciation
Q: What is speciation?
A: The process by which one species splits into two or more distinct species.
Q: What are the roles of reproductive isolation and differential selection in speciation?
A:
• Reproductive isolation prevents gene flow.
• Differential selection pressures lead to divergence in traits.
Q: Compare allopatric and sympatric speciation.
A:
• Allopatric:Caused by geographic isolation.
• Sympatric:Occurs without geographic barriers, often due to behavioral or temporal isolation.
Q: What is adaptive radiation?
A: Rapid diversification of a species into multiple forms that occupy different ecological niches (e.g., Darwin’s finches).
Q: What are prezygotic and postzygotic barriers?
A:
• Prezygotic:Prevent mating or fertilization (e.g., behavioral differences).
• Postzygotic:Result in infertile or nonviable offspring (e.g., mules).
C4.1.17 Top-Down vs. Bottom-Up Control
Q: What is top-down control in ecosystems?
A: Population size is controlled by predators at the top of the food chain.
Q: What is bottom-up control in ecosystems?
A: Population size is limited by the availability of nutrients and primary producers.
C4.1.18 Allelopathy and Antibiotics
Q: What is allelopathy?
A: A process where plants release toxic compounds to limit the growth of other plants. Example: Black walnut trees.
Q: What are antibiotics in plants?
A: Compounds produced to kill bacteria, such as those from California bay and coffeeberry.
D4.1 Natural Selection (continued)
Q: What is sexual selection?
A: Selection based on traits that increase an organism’s chance of attracting a mate (e.g., peacock feathers).
Q: What is the gene pool?
A: The total collection of genes and alleles in a population.
Q: How does natural selection affect allele frequency?
A: Traits that increase survival or reproduction become more common, altering allele frequencies over generations.
Q: What are the three types of natural selection?
A:
• Directional:Favors one extreme phenotype.
• Stabilizing:Favors intermediate traits.
• Disruptive:Favors two extremes, potentially leading to speciation.
Q: What is the Hardy-Weinberg equation?
A:
Used to calculate allele and genotype frequencies in a population.
Q: What are the conditions for Hardy-Weinberg equilibrium?
A:
1. No mutations.
2. No gene flow.
3. Random mating.
4. Large population size.
5. No natural selection.
Q: What is artificial selection?
A: Human-driven selection for specific traits in crops or animals, like high-yield crops or dog breeds.
A4.1 Evolution and Speciation (continued)
Q: What is convergent evolution?
A: When unrelated species evolve similar traits due to similar environments (e.g., shark and dolphin body shapes).
Q: What is divergent evolution?
A: When a single species evolves into multiple species with different traits, often due to environmental pressures.
Q: What is polyploidy?
A: A condition where a plant has more than two sets of chromosomes, often leading to rapid speciation (e.g., knotweed).
A3.2 Classification and Cladistics (continued)
Q: Why is rRNA used in classification?
A: rRNA base sequences provide evidence of evolutionary relationships due to their slow mutation rates.
Q: What are the three domains of life?
A: Archaea, Bacteria, and Eukarya.
Q: What is parsimony analysis?
A: A method to construct cladograms by assuming the smallest number of evolutionary changes is most likely.
B4.1 Adaptation to Environment
Q: What is a habitat?
A: The place where a species, population, or community lives, including geographical and physical locations.
Q: What is range of tolerance?
A: The range of abiotic conditions (e.g., temperature, pH) a species can survive in. Moving outside this range leads to stress or death.
Q: What abiotic factors affect species distribution?
A: Temperature, pH, salinity, oxygen, and humidity.
Q: What are the requirements for coral reef formation?
A:
1. Temperature: 23-29°C.
2. High salinity: 32-42 ppt.
3. Clear, shallow water (<25m depth).
4. pH above 7.7.
Q: What are biomes?
A: Groups of ecosystems with similar abiotic conditions and organisms. Examples: tundra, taiga, tropical forests.
Q: Give an example of an adaptation in a hot desert species.
A: Camels store fat in their humps to convert to water when needed.
B4.2 Ecological Niches
Q: What is an ecological niche?
A: The role of a species in its ecosystem, including interactions with biotic and abiotic factors.
Q: What is the difference between obligate aerobes and anaerobes?
A:
• Obligate aerobes:Require oxygen.
• Obligate anaerobes:Cannot survive in the presence of oxygen.
Q: What is mixotrophic nutrition?
A: Organisms, like Euglena, can switch between autotrophic and heterotrophic modes of nutrition.
Q: What are saprotrophs?
A: Organisms, such as fungi, that digest organic material externally and absorb the nutrients.
C4.2 Energy and Matter Flow
Q: What is the difference between producers and consumers?
A:
• Producers:Autotrophs that create biomass using sunlight or chemicals.
• Consumers:Heterotrophs that eat other organisms for energy.
Q: What is the role of decomposers?
A: Recycle nutrients by breaking down dead organic matter.
Q: Why are energy transfers inefficient?
A: Energy is lost as heat, in respiration, or as waste at each trophic level.
Q: What limits the number of trophic levels?
A: Energy loss at each level results in insufficient energy for higher levels.
D4.2 Ecosystem Stability
Q: What are keystone species?
A: Species that have a disproportionately large impact on ecosystem stability, like wolves or beavers.
Q: What is eutrophication?
A: Nutrient enrichment of aquatic systems causing algal blooms, oxygen depletion, and dead zones.
Q: What is biomagnification?
A: The increasing concentration of toxins, like DDT or mercury, in organisms at higher trophic levels.
Q: What is rewilding?
A: Restoring natural processes in ecosystems by reintroducing species and reducing human impacts (e.g., Hinewai Reserve).
D4.3 Climate Change (continued)
Q: What is a carbon sink?
A: An ecosystem that absorbs more carbon than it releases (e.g., forests).
Q: How does deforestation contribute to climate change?
A: Reduces carbon sinks and increases atmospheric CO₂ through combustion and decomposition.
Q: What are the long-term effects of global warming?
A: Rising sea levels, increased droughts, loss of biodiversity, and ecosystem tipping points.
Here’s a detailed flashcard breakdown for Transcription and Translation concepts:
Transcription
Q: What is transcription?
A: The process of synthesizing RNA from a DNA template. It occurs in the nucleus (eukaryotes) or cytoplasm (prokaryotes).
Q: What are the steps of transcription?
A:
1. Initiation:RNA polymerase binds to the promoter region of DNA.
2. Elongation:RNA polymerase synthesizes a complementary RNA strand using one DNA strand as a template.
3. Termination:RNA polymerase reaches a termination sequence and releases the RNA transcript.
Q: What is the role of RNA polymerase?
A: It unzips the DNA strands and synthesizes the RNA strand by adding complementary RNA nucleotides (e.g., U instead of T).
Q: What is the difference between the sense and antisense strands of DNA in transcription?
A:
• Sense strand:Matches the RNA sequence (except T is replaced by U).
• Antisense strand:Serves as the template for RNA synthesis.
Q: What modifications occur to the pre-mRNA in eukaryotes?
A:
1. 5’ capping:Addition of a methyl cap to protect the RNA and assist in ribosome binding.
2. Polyadenylation:Addition of a poly-A tail to stabilize the RNA and prevent degradation.
3. Splicing:Removal of introns (non-coding regions) and joining of exons (coding regions).
Q: How does transcription differ between prokaryotes and eukaryotes?
A:
• Prokaryotes: Transcription and translation occur simultaneously in the cytoplasm.
• Eukaryotes: Transcription occurs in the nucleus, and mRNA must be processed and transported to the cytoplasm for translation.
Translation
Q: What is translation?
A: The process of synthesizing a polypeptide chain (protein) from an mRNA template. It occurs in the cytoplasm on ribosomes.
Q: What are the steps of translation?
A:
1. Initiation:The small ribosomal subunit binds to the mRNA, and the first tRNA carrying methionine (AUG start codon) binds.
2. Elongation:Ribosomes read mRNA codons, and tRNAs bring the corresponding amino acids, which are linked by peptide bonds.
3. Termination:The ribosome reaches a stop codon, and the polypeptide is released.
Q: What is the role of tRNA in translation?
A:
• Anticodon:Matches the codon on mRNA to ensure the correct amino acid is added.
• Amino acid attachment site:Carries the specific amino acid corresponding to its anticodon.
Q: What is a codon?
A: A sequence of three nucleotides on mRNA that specifies a single amino acid (e.g., AUG = methionine).
Q: What are stop codons?
A: Codons that signal the end of translation: UAA, UAG, and UGA.
Q: What are the roles of the ribosome’s sites?
A:
• A site (Aminoacyl):Holds the incoming tRNA with its amino acid.
• P site (Peptidyl):Holds the tRNA with the growing polypeptide chain.
• E site (Exit):Releases tRNA after its amino acid is added to the chain.
Q: What is the genetic code, and why is it considered universal and degenerate?
A:
• Universal:Almost all organisms use the same codons to specify amino acids.
• Degenerate:Multiple codons can code for the same amino acid (e.g., UUU and UUC both code for phenylalanine).
Q: What is a polysome?
A: A structure where multiple ribosomes translate a single mRNA simultaneously, increasing protein synthesis efficiency.
Connections Between Transcription and Translation
Q: What is the central dogma of molecular biology?
A: DNA → RNA → Protein. This describes the flow of genetic information from transcription to translation.
Q: How does mRNA travel in eukaryotes after transcription?
A: Processed mRNA leaves the nucleus through nuclear pores and enters the cytoplasm for translation.
Q: What is the relationship between a gene and a protein?
A: A gene contains the instructions (DNA sequence) for synthesizing a specific protein via transcription and translation.
Here’s an expanded set of 15 flashcards per section for the requested IB Biology HL standards.
A.1.1 Relationship Between Structure and Function
1. Q:How does the structure of mitochondria relate to its function?
A: The folded cristae increase surface area for ATP production during cellular respiration.
2. Q:Why are villi in the small intestine important?
A: Their finger-like structure increases surface area for nutrient absorption.
3. Q:How does the shape of neurons assist their function?
A: Long axons allow rapid transmission of signals over long distances.
4. Q:What is the structural adaptation of stomata in leaves?
A: They open and close to regulate gas exchange and water loss.
5. Q:Why are the phospholipids in membranes arranged as a bilayer?
A: Hydrophobic tails face inward, while hydrophilic heads face outward, creating a semi-permeable barrier.
6. Q:How does the structure of hemoglobin relate to oxygen transport?
A: Its quaternary structure allows four oxygen molecules to bind.
7. Q:Why are enzymes specific to substrates?
A: Their active site’s shape complements the substrate, enabling precise binding.
8. Q:How does the shape of DNA allow replication?
A: The double helix structure allows strands to separate and serve as templates.
9. Q:What structural feature enables chloroplasts to perform photosynthesis?
A: Thylakoid membranes house pigments like chlorophyll for light absorption.
10. Q:How do root hair cells increase water absorption?
A: Their elongated shape increases surface area for water and nutrient uptake.
11. Q:Why are arteries thick-walled?
A: To withstand high blood pressure as blood is pumped from the heart.
12. Q:How do fish gills maximize oxygen uptake?
A: Lamellae provide a large surface area for gas exchange.
13. Q:What is the role of the nucleus in eukaryotic cells?
A: It stores DNA, which directs cellular activities.
14. Q:How does the skeletal system’s structure support movement?
A: Bones provide leverage for muscles to exert force.
15. Q:Why do polar bears have thick fur and fat layers?
A: To insulate against cold temperatures in Arctic environments.
B.1.1 Cell Theory
1. Q:Who first observed cells, and in what material?
A: Robert Hooke, in cork.
2. Q:What did Antonie van Leeuwenhoek contribute to cell theory?
A: He observed living cells, including bacteria and protozoa, using a microscope.
3. Q:How does Pasteur’s experiment disprove spontaneous generation?
A: Sterile broth remained free of life unless exposed to microorganisms.
4. Q:What is the smallest unit of life?
A: The cell.
5. Q:How does the cell theory apply to unicellular organisms?
A: Even single cells carry out all functions of life.
6. Q:Why are viruses not considered living under cell theory?
A: They cannot reproduce or metabolize without a host cell.
7. Q:What is the significance of cell division in cell theory?
A: It demonstrates that all cells arise from pre-existing cells.
8. Q:What modern evidence supports cell theory?
A: Molecular biology confirms that all cells share a common genetic code.
9. Q:How do multicellular organisms demonstrate cell theory?
A: Their complex functions arise from interactions among specialized cells.
10. Q:Why is cell theory fundamental to biology?
A: It provides a unifying explanation for the structure and function of all living things.
11. Q:What distinguishes prokaryotic and eukaryotic cells?
A: Eukaryotic cells have a nucleus and membrane-bound organelles.
12. Q:How do chloroplasts support cell theory in plants?
A: They enable photosynthesis, fulfilling the energy requirements of cells.
13. Q:Why are ribosomes essential for all cells?
A: They produce proteins, vital for cell structure and function.
14. Q:How does mitosis support cell theory?
A: It ensures genetic continuity by producing identical daughter cells.
15. Q:What is an exception to the cell theory?
A: Muscle fibers and fungal hyphae are multinucleated and not strictly cellular.
B.1.2 Prokaryotic and Eukaryotic Cells
1. Q:What is the size range of prokaryotic cells?
A: Typically 1–5 µm in diameter.
2. Q:What is the function of the nucleoid region in prokaryotic cells?
A: It contains the circular DNA molecule.
3. Q:How do prokaryotes and eukaryotes differ in ribosome size?
A: Prokaryotes have 70S ribosomes; eukaryotes have 80S ribosomes.
4. Q:What is the role of the prokaryotic cell wall?
A: It provides structural support and protection.
5. Q:How do prokaryotic flagella differ from eukaryotic flagella?
A: Prokaryotic flagella rotate, while eukaryotic flagella use a whip-like motion.
6. Q:What are plasmids, and why are they important in prokaryotes?
A: Extra-chromosomal DNA that often carries genes for antibiotic resistance.
7. Q:How do prokaryotic cells reproduce?
A: By binary fission.
8. Q:What is the function of pili in prokaryotic cells?
A: They aid in attachment to surfaces and horizontal gene transfer.
9. Q:Why is compartmentalization a key feature of eukaryotic cells?
A: It allows specialized functions to occur in different organelles.
10. Q:How does the rough ER differ from the smooth ER in eukaryotic cells?
A: The rough ER synthesizes proteins, while the smooth ER synthesizes lipids.
11. Q:What is the role of lysosomes in eukaryotic cells?
A: They break down waste and cellular debris.
12. Q:How do mitochondria and chloroplasts support the endosymbiotic theory?
A: Both have their own DNA and ribosomes, similar to prokaryotes.
13. Q:What is the significance of the Golgi apparatus in eukaryotic cells?
A: It modifies, packages, and transports proteins and lipids.
14. Q:How do plant cells differ from animal cells?
A: Plant cells have cell walls, chloroplasts, and large central vacuoles.
15. Q:What is the cytoskeleton, and why is it important?
A: A network of protein filaments that maintains cell shape and enables movement.
Let me know which sections you’d like me to expand further into 15 flashcards or if you’d prefer me to continue systematically for all sections!