뒤로General Biology: Cell Structure, Function, and Microscopy Study Guide
스터디 가이드 - 스마트 노트
자료에 맞춘 맞춤형 노트, 핵심 정의, 예시, 맥락을 확장해 제공합니다.
Q1. Describe differences between light and electron microscopes, and how each is used to visualize the structure of cells.
Background
Topic: Microscopy in Cell Biology
This question tests your understanding of the different types of microscopes used in biology, their capabilities, and what cellular structures they can visualize.
Key Terms and Concepts:
Light Microscope (LM): Uses visible light to illuminate specimens; can view living cells and larger organelles.
Electron Microscope (EM): Uses beams of electrons for much higher resolution; includes Transmission (TEM) and Scanning (SEM) types.
Step-by-Step Guidance
Define what a light microscope is and what its resolution limits are (can see cells, nuclei, some organelles).
Describe what an electron microscope is and how it differs in terms of resolution and magnification.
Explain the difference between TEM and SEM: TEM is for internal structures, SEM is for surface details.
List examples of cell structures visible with each type (e.g., ribosomes with EM, whole cells with LM).
Try solving on your own before revealing the answer!
Final Answer:
Light microscopes use visible light and can resolve structures down to about 200 nm, allowing visualization of whole cells and some organelles. Electron microscopes use electron beams, achieving much higher resolution (down to 2 nm), and are used to see much smaller structures like ribosomes and membranes. TEM shows internal details, SEM shows surface details.
Q2. Explain how the surface area-to-volume ratio affects cell size and the efficiency of cellular processes, and why cells must remain small.
Background
Topic: Cell Size and Surface Area-to-Volume Ratio
This question is about why cells are small and how their size impacts their ability to exchange materials with their environment.
Key Terms and Formulas:
Surface Area (SA): Total area of the cell's membrane.
Volume (V): Space inside the cell.
Surface Area-to-Volume Ratio (SA:V):
Step-by-Step Guidance
Recall that as a cell grows, its volume increases faster than its surface area.
Understand that a high SA:V ratio allows efficient exchange of materials (nutrients, waste) across the membrane.
Explain what happens to the SA:V ratio as the cell gets larger (the ratio decreases).
Discuss why a low SA:V ratio limits cell size and efficiency of transport.
Try solving on your own before revealing the answer!
Final Answer:
As cells increase in size, their volume grows faster than their surface area, causing the SA:V ratio to decrease. This limits the rate at which materials can enter or leave the cell, making large cells inefficient. Therefore, cells must remain small to maintain a high SA:V ratio for efficient transport.
Q3. Describe the key structures and functions of prokaryotic and eukaryotic cells.
Background
Topic: Cell Structure and Function
This question asks you to compare the main features of prokaryotic and eukaryotic cells, including their organelles and functions.
Key Terms:
Prokaryote: Cell without a nucleus or membrane-bound organelles (e.g., bacteria).
Eukaryote: Cell with a nucleus and membrane-bound organelles (e.g., plants, animals).
Step-by-Step Guidance
List the structures found in all cells (plasma membrane, cytoplasm, ribosomes, DNA).
Describe unique features of prokaryotes (cell wall, nucleoid, plasmids, no membrane-bound organelles).
Describe unique features of eukaryotes (nucleus, mitochondria, ER, Golgi, etc.).
Explain the function of at least two organelles in each cell type.
Try solving on your own before revealing the answer!
Final Answer:
Prokaryotic cells have a plasma membrane, cytoplasm, ribosomes, and circular DNA in a nucleoid region, but lack membrane-bound organelles. Eukaryotic cells have all of these plus a nucleus and various organelles (mitochondria, ER, Golgi, etc.), each with specialized functions.
Q4. Describe the structural differences in gram-positive vs gram-negative bacteria.
Background
Topic: Bacterial Cell Walls and Antibiotic Action
This question focuses on the differences in cell wall structure between gram-positive and gram-negative bacteria, which is important for understanding antibiotic effectiveness.
Key Terms:
Gram-positive: Thick peptidoglycan layer, no outer membrane.
Gram-negative: Thin peptidoglycan layer, outer membrane with lipopolysaccharides.
Step-by-Step Guidance
Identify the main components of gram-positive and gram-negative cell walls.
Compare the thickness of the peptidoglycan layer in each type.
Describe the presence or absence of an outer membrane.
Explain how these differences affect staining and antibiotic susceptibility.
Try solving on your own before revealing the answer!
Final Answer:
Gram-positive bacteria have a thick peptidoglycan cell wall and no outer membrane, making them more susceptible to antibiotics like penicillin. Gram-negative bacteria have a thin peptidoglycan layer and an additional outer membrane, which provides extra protection and makes them less susceptible to certain antibiotics.
Q5. Describe the endosymbiosis theory and evidence supporting it.
Background
Topic: Evolution of Eukaryotic Cells
This question is about the origin of mitochondria and chloroplasts in eukaryotic cells and the evidence for the endosymbiosis theory.
Key Terms:
Endosymbiosis Theory: The idea that mitochondria and chloroplasts originated as free-living prokaryotes engulfed by ancestral eukaryotic cells.
Step-by-Step Guidance
Define the endosymbiosis theory and what it proposes about mitochondria and chloroplasts.
List at least two features mitochondria and chloroplasts share with prokaryotes (e.g., circular DNA, double membranes).
Describe how these features support the theory.
Mention additional evidence, such as similarities in ribosomes and reproduction by binary fission.
Try solving on your own before revealing the answer!
Final Answer:
The endosymbiosis theory proposes that mitochondria and chloroplasts originated from prokaryotic cells engulfed by ancestral eukaryotes. Evidence includes their own circular DNA, double membranes, prokaryote-like ribosomes, and reproduction by binary fission.
Q6. A patient has excessive glycogen granules and high levels of fat in the liver. Which organelle is likely malfunctioning?
Background
Topic: Organelle Function and Disease
This question asks you to connect symptoms and lab results to the function of specific organelles in the cell.
Key Terms:
Smooth Endoplasmic Reticulum (SER): Involved in lipid metabolism, detoxification, and calcium storage.
Lysosome: Breaks down macromolecules and cellular waste.
Step-by-Step Guidance
Review the symptoms: enlarged liver, muscle weakness, excessive glycogen, high fat, abnormal calcium balance.
Recall which organelle is responsible for breaking down glycogen and metabolizing fats.
Consider the role of the SER in the liver for lipid metabolism and detoxification.
Think about how a malfunction in this organelle could lead to the observed symptoms.
Try solving on your own before revealing the answer!
Final Answer:
The smooth endoplasmic reticulum (SER) is likely malfunctioning, as it is responsible for lipid metabolism, detoxification, and calcium storage. Dysfunction can lead to fat accumulation, abnormal calcium balance, and issues with hormone synthesis.
Q7. What are the independent and dependent variables in the experiment testing antibiotic effectiveness on bacterial growth?
Background
Topic: Experimental Design in Biology
This question tests your ability to identify variables in a scientific experiment.
Key Terms:
Independent Variable: The variable that is changed or controlled by the experimenter.
Dependent Variable: The variable that is measured or observed.
Step-by-Step Guidance
Identify what is being changed in the experiment (type of antibiotic used).
Identify what is being measured (amount of bacterial growth).
Relate these to the definitions of independent and dependent variables.
Try solving on your own before revealing the answer!
Final Answer:
The independent variable is the type of antibiotic used. The dependent variable is the amount of bacterial growth measured (e.g., number of colonies or optical density).
Q8. For each disease or syndrome listed, identify the affected organelle and its normal function.
Background
Topic: Organelle Dysfunction and Disease
This question asks you to connect symptoms of diseases to the malfunction of specific organelles.
Key Terms:
Cystic Fibrosis: Involves membrane proteins regulating ion movement.
ALD: Involves breakdown of fatty acids (peroxisomes).
Pompé Disease: Involves breakdown of glycogen (lysosomes).
Kartagener Syndrome: Involves movement of cilia (cytoskeleton/microtubules).
Step-by-Step Guidance
Read the symptoms and normal function for each disease.
Recall which organelle is responsible for each function (e.g., peroxisomes for fatty acid breakdown).
Match the symptoms to the malfunctioning organelle.
Consider how the loss of function leads to the observed symptoms.
Try solving on your own before revealing the answer!
Final Answer:
Cystic Fibrosis: Affected organelle is the plasma membrane (ion channel proteins).
ALD: Affected organelle is the peroxisome.
Pompé Disease: Affected organelle is the lysosome.
Kartagener Syndrome: Affected organelle is the cytoskeleton (microtubules in cilia).
