BackCell Biology Study Guide: Chapters 4 & 5 (Cell Structure and Membrane Function)
Study Guide - Smart Notes
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Q1. What do all cells have in common?
Background
Topic: Universal Features of Cells
This question tests your understanding of the basic structures and functions shared by all cells, regardless of type.
Key Terms:
Cell membrane
Cytoplasm
Ribosomes
Genetic material (DNA or RNA)
Step-by-Step Guidance
Recall the four main components that are present in all cells, whether prokaryotic or eukaryotic.
Think about the function of each component: for example, the cell membrane acts as a boundary, ribosomes are involved in protein synthesis, etc.
Consider why these features are essential for life and how they contribute to cell function.
Try solving on your own before revealing the answer!
Final Answer:
All cells have a cell membrane, cytoplasm, ribosomes, and genetic material (DNA or RNA). These components are essential for basic cellular processes such as metabolism, growth, and reproduction.
Q2. Compare and contrast prokaryotes and eukaryotes.
Background
Topic: Cell Types
This question tests your ability to distinguish between prokaryotic and eukaryotic cells based on structure and function.
Key Terms:
Prokaryote: No nucleus, simple structure
Eukaryote: Has nucleus, complex organelles
Organelles
Step-by-Step Guidance
List the defining features of prokaryotic cells (e.g., lack of nucleus, presence of cell wall).
List the defining features of eukaryotic cells (e.g., presence of nucleus, membrane-bound organelles).
Identify similarities (e.g., both have cell membranes, ribosomes).
Identify differences (e.g., complexity, size, organelles).
Try solving on your own before revealing the answer!
Final Answer:
Prokaryotes lack a nucleus and membrane-bound organelles, while eukaryotes have both. Both types have cell membranes, cytoplasm, and ribosomes, but eukaryotes are generally larger and more complex.
Q3. Who are the Archaeans?
Background
Topic: Domains of Life
This question tests your knowledge of the three domains of life and the unique characteristics of Archaea.
Key Terms:
Archaea
Prokaryote
Extremophile
Step-by-Step Guidance
Recall the three domains of life: Bacteria, Archaea, Eukarya.
Identify what makes Archaea distinct from Bacteria and Eukarya.
Think about the environments where Archaea are commonly found.
Try solving on your own before revealing the answer!
Final Answer:
Archaeans are a domain of prokaryotic organisms distinct from bacteria, often found in extreme environments. They have unique membrane lipids and genetic features.
Q4. What are examples of eukaryotes and prokaryotes?
Background
Topic: Cell Types and Examples
This question tests your ability to identify organisms that are prokaryotic or eukaryotic.
Key Terms:
Bacteria
Archaea
Plants
Animals
Fungi
Protists
Step-by-Step Guidance
Recall that prokaryotes include Bacteria and Archaea.
Recall that eukaryotes include plants, animals, fungi, and protists.
Think of specific examples for each category.
Try solving on your own before revealing the answer!
Final Answer:
Examples of prokaryotes: E. coli (bacteria), Methanogens (archaea). Examples of eukaryotes: humans (animals), oak trees (plants), yeast (fungi), amoeba (protists).
Q5. What is the function of the nucleus & nucleolus?
Background
Topic: Eukaryotic Cell Structure
This question tests your understanding of the roles of the nucleus and nucleolus in eukaryotic cells.
Key Terms:
Nucleus: DNA storage, transcription
Nucleolus: Ribosome synthesis
Step-by-Step Guidance
Recall the main function of the nucleus (contains genetic material, controls cell activities).
Recall the main function of the nucleolus (site of ribosome production).
Think about how these structures interact in the cell.
Try solving on your own before revealing the answer!
Final Answer:
The nucleus stores DNA and directs cellular activities; the nucleolus is responsible for synthesizing ribosomal RNA and assembling ribosomes.
Q6. What is a ribosome — describe its function?
Background
Topic: Protein Synthesis
This question tests your understanding of ribosome structure and function in cells.
Key Terms:
Ribosome
Translation
Protein synthesis
Step-by-Step Guidance
Recall what ribosomes are made of (rRNA and proteins).
Think about where ribosomes are located (free in cytoplasm or attached to ER).
Describe the process of translation and the role of ribosomes in it.
Try solving on your own before revealing the answer!
Final Answer:
Ribosomes are cellular structures made of rRNA and proteins; they facilitate translation, assembling amino acids into proteins based on mRNA instructions.
Q7. Explain how the endomembrane system, along with ribosomes, functions to produce products.
Background
Topic: Endomembrane System
This question tests your understanding of how cellular organelles work together to synthesize, modify, and transport proteins and other molecules.
Key Terms:
Endoplasmic reticulum (ER)
Golgi apparatus
Vesicles
Ribosomes
Step-by-Step Guidance
Recall the role of ribosomes in protein synthesis.
Describe how proteins enter the ER for folding and modification.
Explain how proteins are transported via vesicles to the Golgi apparatus for further processing.
Consider how the final products are sorted and sent to their destinations.
Try solving on your own before revealing the answer!
Final Answer:
Ribosomes synthesize proteins, which enter the ER for modification. Vesicles transport these proteins to the Golgi apparatus, where they are further processed and sorted for delivery inside or outside the cell.
Q8. What is the role of the E.R.?
Background
Topic: Endoplasmic Reticulum
This question tests your knowledge of the functions of the endoplasmic reticulum in cells.
Key Terms:
Rough ER: Protein synthesis
Smooth ER: Lipid synthesis, detoxification
Step-by-Step Guidance
Recall the two types of ER and their main functions.
Think about how the ER contributes to the production and processing of cellular products.
Consider the role of the ER in transporting molecules within the cell.
Try solving on your own before revealing the answer!
Final Answer:
The ER is involved in synthesizing proteins (rough ER) and lipids (smooth ER), as well as detoxifying chemicals and transporting molecules within the cell.
Q9. How are smooth and rough E.R. the same and different?
Background
Topic: Endoplasmic Reticulum Types
This question tests your ability to compare the structure and function of smooth and rough ER.
Key Terms:
Rough ER: Ribosomes attached
Smooth ER: No ribosomes
Protein vs. lipid synthesis
Step-by-Step Guidance
Identify the structural difference (presence or absence of ribosomes).
Compare their main functions (protein vs. lipid synthesis).
Consider their roles in the cell's overall metabolism.
Try solving on your own before revealing the answer!
Final Answer:
Rough ER has ribosomes and synthesizes proteins; smooth ER lacks ribosomes and synthesizes lipids and detoxifies substances. Both are part of the endomembrane system.
Q10. What is the role of the Golgi?
Background
Topic: Golgi Apparatus
This question tests your understanding of the Golgi's function in processing and sorting cellular products.
Key Terms:
Golgi apparatus
Protein modification
Vesicle transport
Step-by-Step Guidance
Recall the Golgi's role in modifying proteins and lipids received from the ER.
Think about how the Golgi sorts and packages these molecules for transport.
Consider the importance of vesicles in this process.
Try solving on your own before revealing the answer!
Final Answer:
The Golgi apparatus modifies, sorts, and packages proteins and lipids for delivery to their final destinations inside or outside the cell.
Q11. What is the purpose for the vacuole?
Background
Topic: Vacuole Function
This question tests your understanding of the role of vacuoles in cells, especially plant cells.
Key Terms:
Vacuole
Storage
Osmoregulation
Structural support
Step-by-Step Guidance
Recall the main functions of vacuoles (storage, waste disposal, water regulation).
Think about how vacuoles contribute to cell structure, especially in plants.
Consider differences in vacuole function between plant and animal cells.
Try solving on your own before revealing the answer!
Final Answer:
Vacuoles store nutrients, waste products, and water; in plant cells, they help maintain turgor pressure and structural support.
Q12. How are vacuoles different in plants and animals?
Background
Topic: Vacuole Differences
This question tests your ability to compare vacuole structure and function in plant and animal cells.
Key Terms:
Central vacuole (plants)
Small vacuoles (animals)
Turgor pressure
Step-by-Step Guidance
Recall that plant cells have a large central vacuole, while animal cells have smaller, multiple vacuoles.
Think about the functions of vacuoles in each cell type.
Consider how vacuoles contribute to cell structure and function.
Try solving on your own before revealing the answer!
Final Answer:
Plant cells have a large central vacuole for storage and maintaining turgor pressure; animal cells have smaller vacuoles mainly for storage and waste disposal.
Q13. What is the role of the lysosome?
Background
Topic: Lysosome Function
This question tests your understanding of lysosomes and their role in cellular digestion.
Key Terms:
Lysosome
Hydrolytic enzymes
Intracellular digestion
Step-by-Step Guidance
Recall the main function of lysosomes (digesting cellular waste and macromolecules).
Think about the types of enzymes found in lysosomes.
Consider how lysosomes protect the cell from damage.
Try solving on your own before revealing the answer!
Final Answer:
Lysosomes contain hydrolytic enzymes that break down waste materials, cellular debris, and foreign substances within the cell.
Q14. How do the substances in the lysosome get there?
Background
Topic: Lysosome Formation and Function
This question tests your understanding of how lysosomes acquire their contents.
Key Terms:
Endocytosis
Vesicle fusion
Autophagy
Step-by-Step Guidance
Recall the process of endocytosis and how vesicles deliver substances to lysosomes.
Think about autophagy and how cellular components are recycled.
Consider the role of the Golgi apparatus in lysosome formation.
Try solving on your own before revealing the answer!
Final Answer:
Substances enter lysosomes via endocytosis (vesicle fusion) or autophagy, and lysosomal enzymes are delivered from the Golgi apparatus.
Q15. Compare and contrast the outside of plant and animal cells.
Background
Topic: Cell Surface Structures
This question tests your ability to distinguish between the cell wall and extracellular matrix in plant and animal cells.
Key Terms:
Cell wall (plants)
Extracellular matrix (animals)
Pectin
Collagen
Step-by-Step Guidance
Recall that plant cells have a rigid cell wall made of cellulose and pectin.
Recall that animal cells have an extracellular matrix composed of proteins like collagen.
Compare the structural and functional roles of these components.
Try solving on your own before revealing the answer!
Final Answer:
Plant cells have a cell wall (cellulose, pectin) for rigidity; animal cells have an extracellular matrix (collagen, glycoproteins) for support and signaling.
Q16. What is the ECM?
Background
Topic: Extracellular Matrix
This question tests your understanding of the ECM's composition and function in animal cells.
Key Terms:
Extracellular matrix (ECM)
Collagen
Glycoproteins
Step-by-Step Guidance
Recall the main components of the ECM.
Think about the functions of the ECM (support, adhesion, communication).
Consider how the ECM differs from the plant cell wall.
Try solving on your own before revealing the answer!
Final Answer:
The ECM is a network of proteins and carbohydrates outside animal cells, providing structural support, cell adhesion, and communication.
Q17. How are pectin and collagen the same and how are they different?
Background
Topic: Cell Surface Molecules
This question tests your ability to compare pectin (plant cell wall) and collagen (animal ECM).
Key Terms:
Pectin: Plant cell wall polysaccharide
Collagen: Animal ECM protein
Step-by-Step Guidance
Recall the chemical nature of pectin and collagen.
Compare their roles in cell structure and support.
Consider their presence in plant vs. animal cells.
Try solving on your own before revealing the answer!
Final Answer:
Pectin is a polysaccharide in plant cell walls; collagen is a protein in animal ECM. Both provide structural support, but are found in different organisms.
Q18. What is a peroxisome? Glyoxysome?
Background
Topic: Specialized Organelles
This question tests your knowledge of peroxisomes and glyoxysomes and their functions.
Key Terms:
Peroxisome: Detoxification, fatty acid breakdown
Glyoxysome: Specialized peroxisome in plants
Step-by-Step Guidance
Recall the main function of peroxisomes (breakdown of hydrogen peroxide, fatty acids).
Recall the function of glyoxysomes in plants (conversion of fats to sugars).
Compare their roles in different cell types.
Try solving on your own before revealing the answer!
Final Answer:
Peroxisomes break down fatty acids and detoxify hydrogen peroxide; glyoxysomes (in plants) convert fats to sugars during seed germination.
Q19. Know all the components of a cell membrane and their functions.
Background
Topic: Cell Membrane Structure
This question tests your knowledge of the cell membrane's composition and the function of each component.
Key Terms:
Phospholipids
Proteins (integral, peripheral)
Cholesterol
Carbohydrates (glycoproteins, glycolipids)
Step-by-Step Guidance
List the main components of the cell membrane.
Describe the function of each component (e.g., phospholipids form the bilayer, proteins act as channels, etc.).
Consider how these components contribute to membrane fluidity and function.
Try solving on your own before revealing the answer!
Final Answer:
The cell membrane is composed of phospholipids (bilayer), proteins (channels, receptors), cholesterol (fluidity), and carbohydrates (cell recognition).
Q20. Membrane proteins: cell markers, enzymatic proteins, channels & carriers, receptor proteins, junction proteins.
Background
Topic: Membrane Protein Functions
This question tests your understanding of the different types of membrane proteins and their roles.
Key Terms:
Cell markers (glycoproteins)
Enzymatic proteins
Channels & carriers
Receptor proteins
Junction proteins
Step-by-Step Guidance
List each type of membrane protein.
Describe the function of each (e.g., cell markers for recognition, channels for transport).
Consider examples of each type in cell biology.
Try solving on your own before revealing the answer!
Final Answer:
Membrane proteins include cell markers (glycoproteins), enzymatic proteins (catalysis), channels & carriers (transport), receptor proteins (signal reception), and junction proteins (cell adhesion).
Q21. Phospholipids — hydrophobic/hydrophilic
Background
Topic: Phospholipid Structure
This question tests your understanding of the amphipathic nature of phospholipids and their role in membrane formation.
Key Terms:
Hydrophobic tail
Hydrophilic head
Amphipathic
Step-by-Step Guidance
Recall the structure of a phospholipid (head and tail).
Describe how the hydrophobic and hydrophilic regions interact with water.
Explain how this leads to bilayer formation.
Try solving on your own before revealing the answer!
Final Answer:
Phospholipids have hydrophilic heads (interact with water) and hydrophobic tails (avoid water), forming a bilayer in cell membranes.
Q22. Cholesterols — Rigidity/fluidity
Background
Topic: Membrane Fluidity
This question tests your understanding of cholesterol's role in regulating membrane rigidity and fluidity.
Key Terms:
Cholesterol
Fluidity
Rigidity
Step-by-Step Guidance
Recall how cholesterol is embedded in the membrane.
Describe how cholesterol affects membrane fluidity at different temperatures.
Consider the balance between rigidity and flexibility in cell membranes.
Try solving on your own before revealing the answer!
Final Answer:
Cholesterol stabilizes cell membranes, increasing rigidity at high temperatures and preventing excessive rigidity at low temperatures, thus maintaining fluidity.
Q23. Compare and contrast active and passive transport.
Background
Topic: Membrane Transport
This question tests your understanding of the mechanisms and energy requirements of active and passive transport.
Key Terms:
Active transport: requires energy (ATP)
Passive transport: no energy required
Concentration gradient
Step-by-Step Guidance
Recall the definition of passive transport (diffusion, facilitated diffusion, osmosis).
Recall the definition of active transport (uses ATP, moves against gradient).
Compare the direction of movement relative to concentration gradients.
Try solving on your own before revealing the answer!
Final Answer:
Passive transport moves substances down their concentration gradient without energy; active transport moves substances against their gradient using ATP.
Q24. Predict how water would flow and understand how hypertonic, hypotonic, and isotonic are related.
Background
Topic: Osmosis and Tonicity
This question tests your understanding of water movement across membranes and the concepts of hypertonic, hypotonic, and isotonic solutions.
Key Terms:
Osmosis
Hypertonic
Hypotonic
Isotonic
Step-by-Step Guidance
Recall the definitions of hypertonic, hypotonic, and isotonic solutions.
Think about how water moves in response to solute concentration differences.
Predict the direction of water flow in each scenario.
Try solving on your own before revealing the answer!
Final Answer:
Water flows from hypotonic (low solute) to hypertonic (high solute) solutions; isotonic solutions have no net water movement.
Q25. What is diffusion?
Background
Topic: Diffusion
This question tests your understanding of the process of diffusion in cells.
Key Terms:
Diffusion
Concentration gradient
Step-by-Step Guidance
Recall the definition of diffusion.
Think about how molecules move in relation to concentration gradients.
Consider examples of diffusion in cell biology.
Try solving on your own before revealing the answer!
Final Answer:
Diffusion is the passive movement of molecules from an area of high concentration to low concentration.
Q26. What is osmosis?
Background
Topic: Osmosis
This question tests your understanding of osmosis and its importance in cells.
Key Terms:
Osmosis
Water movement
Semi-permeable membrane
Step-by-Step Guidance
Recall the definition of osmosis.
Think about the role of the semi-permeable membrane.
Consider how osmosis affects cell volume and function.
Try solving on your own before revealing the answer!
Final Answer:
Osmosis is the movement of water across a semi-permeable membrane from low solute concentration to high solute concentration.
Q27. What is the Na+/K+ pump?
Background
Topic: Active Transport
This question tests your understanding of the sodium-potassium pump and its role in maintaining cell potential.
Key Terms:
Na+/K+ pump
ATP
Electrochemical gradient
Step-by-Step Guidance
Recall the function of the Na+/K+ pump (moves Na+ out, K+ in).
Think about the energy requirement (uses ATP).
Consider the importance of this pump in nerve and muscle cells.
Try solving on your own before revealing the answer!
Final Answer:
The Na+/K+ pump actively transports sodium out and potassium into the cell, using ATP to maintain electrochemical gradients.
Q28. Explain the difference between phagocytosis and pinocytosis.
Background
Topic: Endocytosis Types
This question tests your understanding of the two main types of endocytosis.
Key Terms:
Phagocytosis: "cell eating"
Pinocytosis: "cell drinking"
Step-by-Step Guidance
Recall the definition of phagocytosis (engulfing large particles).
Recall the definition of pinocytosis (engulfing fluids).
Compare the processes and their purposes in cells.
Try solving on your own before revealing the answer!
Final Answer:
Phagocytosis engulfs large particles or cells; pinocytosis engulfs fluids and small molecules. Both are forms of endocytosis.
Q29. Predict the NET flow of water across a membrane.
Background
Topic: Osmosis and Water Movement
This question tests your ability to predict water movement based on solute concentrations.
Key Terms:
Osmosis
Concentration gradient
Net flow
Step-by-Step Guidance
Recall that water moves from areas of low solute concentration to high solute concentration.
Think about the direction of net water flow based on the relative concentrations inside and outside the cell.
Consider how this affects cell volume.
Try solving on your own before revealing the answer!
Final Answer:
Net water flow is toward the hypertonic side (higher solute concentration), causing cells to shrink or swell depending on the environment.
Q30. Why are cells small? How does the size of a molecule make a difference for diffusion?
Background
Topic: Cell Size and Diffusion
This question tests your understanding of the relationship between cell size, surface area-to-volume ratio, and diffusion efficiency.
Key Terms:
Surface area-to-volume ratio
Diffusion
Efficiency
Step-by-Step Guidance
Recall that smaller cells have a higher surface area-to-volume ratio.
Think about how this ratio affects the rate of diffusion and transport of molecules.
Consider how molecule size impacts diffusion speed.
Try solving on your own before revealing the answer!
Final Answer:
Cells are small to maximize surface area-to-volume ratio, allowing efficient diffusion; smaller molecules diffuse faster than larger ones.
