Biology Chapter: Prokaryotes and Eukaryotes

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Questions and Answers

What is the primary function of the Golgi Apparatus?

Modification and packaging of proteins (correct)

Energy production

Cellular respiration

Storing genetic information

Prokaryotic cells do not contain a nucleus.

True

What is the difference between a photoautotroph and a chemoautotroph?

A photoautotroph uses light for energy, while a chemoautotroph uses chemical reactions.

The basic structural and functional unit of life is the ______.

cell Signup and view all the answers

Match the following organelles with their functions:

Lysosome = Digestive enzyme breakdown Endoplasmic Reticulum = Protein and lipid synthesis Vesicle = Transport of materials Mitochondria = Energy production Signup and view all the answers

Which microscope is best for observing surface structures of cells?

Scanning Electron Microscope Signup and view all the answers

All eukaryotic cells contain a cell wall.

False Signup and view all the answers

What are microtubules and what role do they play in the cell?

Microtubules are structural components of the cytoskeleton, providing shape and support to the cell. Signup and view all the answers

During binary fission, the cell divides into two ______ cells.

daughter Signup and view all the answers

Which scientist is credited with the term 'cell' after observing cork under a microscope?

Robert Hooke Signup and view all the answers

Which of the following structures is NOT a component of the cell membrane?

Cell wall Signup and view all the answers

All prokaryotes obtain nutrition in the same way.

False Signup and view all the answers

What are the two categories of prokaryotes?

Bacteria and Archaea Signup and view all the answers

A pathogen is an organism that can cause a __________.

disease Signup and view all the answers

Match the following prokaryotic reproduction and structures with their descriptions:

Binary fission = A method of asexual reproduction in prokaryotes Endospore = A resistant structure for survival in harsh conditions Conjugation = A process of genetic material exchange between bacteria Signup and view all the answers

What is the primary purpose of the Gram-staining technique?

To classify bacteria based on cell wall composition Signup and view all the answers

Gram-positive bacteria retain the purple crystal violet dye after the staining process.

True Signup and view all the answers

Describe one benefit of endospores for prokaryotic cells.

Endospores provide protection against harsh environmental conditions, allowing the cell to survive extreme temperatures, desiccation, and other stressors. Signup and view all the answers

The extracellular matrix provides __________ support to cells.

structural Signup and view all the answers

Which of these statements is true regarding the diversity of prokaryotes?

Prokaryotes can have a range of metabolic functions and resource acquisition methods. Signup and view all the answers

Study Notes

Prokaryotes and Eukaryotes

Prokaryotes: Lack a nucleus and other membrane-bound organelles. Smaller and simpler
Eukaryotes: Possess a nucleus and membrane-bound organelles; more complex and larger

Microscopy

Light Microscope (LM): Uses visible light to view specimens. Relatively low magnification and resolution
Scanning Electron Microscope (SEM): Creates a 3D image of a specimen surface using a beam of electrons. High magnification and resolution, excellent for surface details, often metal-coated specimen
Transmission Electron Microscope (TEM): Passes a beam of electrons through a very thin specimen. High magnification and resolution, excellent for internal structures
Dissecting Microscope: Used to view larger specimens with lower magnification for detailed visual study

Nutritional Modes

Chemoautotroph: Energy from chemical reactions, carbon from inorganic sources (e.g., CO2)
Chemoheterotroph: Energy and carbon from organic compounds
Photoautotroph: Energy from sunlight, carbon from inorganic sources (e.g., CO2)
Photoheterotroph: Energy from sunlight, carbon from organic compounds

Prokaryotic Reproduction and Processes

Binary Fission: Asexual reproduction in prokaryotes, where the cell divides into two identical daughter cells
Conjugation: Genetic material exchange between prokaryotic cells
Endospore: A protective structure formed by some bacteria under unfavorable conditions for survival

Eukaryotic Organelles

Endoplasmic Reticulum (ER): Network of membranes involved in protein synthesis and lipid metabolism, smooth or rough
Golgi Apparatus: Modifies, sorts, and packages proteins and lipids for secretion
Vesicle: Membrane-bound sac involved in transport and storage
Lysosome: Contains enzymes for intracellular digestion and waste removal
Microfilaments: Protein fibers that form part of the cytoskeleton, involved in cell movement (e.g., muscle contraction)
Microtubules: Hollow tubes that are part of the cytoskeleton, providing support and involved in cell movement (e.g., cilia and flagella)
Cytoskeleton: Network of protein filaments (microfilaments and microtubules) that maintain cell shape, support, and allow movement
Fluid Mosaic Model: Describes the cell membrane as a fluid structure with embedded proteins, phospholipids, and other molecules
Peptidoglycan: Important polysaccharide/amino-acid polymer and part of the bacterial cell wall structure; structural support

Other Cellular Structures

Cilia: Short, hair-like projections for cell movement
Pili: Hair-like projections for attachment and conjugation
Glycoprotein: Protein with a carbohydrate chain attached, found in the cell membrane
Peripheral Protein: Membrane protein that is not embedded in the lipid bilayer
Channel Protein: Membrane protein that creates a channel for specific molecules to pass through

Cell Theory and Evolution

Classical Cell Theory: All organisms are composed of one or more cells; the cell is the basic unit of organisms; all cells come from pre-existing cells.
Evolution of Cell Theory: Over time, concepts like the importance of cell's internal components (organelles) and cell diversity have emerged

Scientists' Contributions to Cell Theory

Robert Hooke: First to observe and name cells, seeing cells in cork.
Antonie van Leeuwenhoek: Observed microorganisms, increasing understanding of cellular diversity.
Matthias Schleiden: Determined that plants are composed of cells.
Theodor Schwann: Determined that animals are composed of cells.
Rudolf Virchow: Proposed that cells come from pre-existing cells.

Identifying Prokaryotic vs. Eukaryotic Cells

Presence of a nucleus: Eukaryotic cells have a nucleus; prokaryotic cells do not.
Membrane-bound organelles: Eukaryotes have these; prokaryotes do not.
DNA organization: Eukaryotic DNA is organized into chromosomes within the nucleus; prokaryotic DNA is a circular loop found in the nucleoid region

Light vs. Electron Microscopes

Light microscopes use visible light, have lower resolution and magnification, are suitable for viewing larger specimens, living cells, and thin sections.
Electron microscopes use beams of electrons, offer much higher resolution and magnification. Helpful for viewing internal structures, but cannot be used to view live organisms.

Lab Procedure for Microscopy

Prepare slide: Place sample on a slide(with a solution), cover with a coverslip, ensuring no air bubbles
Adjust light: Align and adjust light source
Select objective: Start with the lowest magnification
Focus: Using the course adjustment knob, focus until a clear image appears
Fine-tune: Use the fine adjustment knob to enhance clarity and details
Observe: Carefully observe and draw your observations.

Specific Microscope Types

Scanning Electron Microscope (SEM): Provides detailed surface view of 3D samples, especially of smaller samples
Transmission Electron Microscope (TEM): Provides extremely high resolution of internal sample details, particularly of thin sections of samples
Compound Light Microscope: A more basic and common type of microscope suitable for specimens that need less magnification
Dissecting Light Microscope: Used for detailed viewing of large and/or three-dimensional objects, like dissections of biological samples.

Endosymbiotic Theory

Process: Suggests that organelles like mitochondria and chloroplasts were once independent prokaryotes that were engulfed by a larger host cell.
Evidence: These organelles have their own DNA, ribosomes, and two membranes; they divide by binary fission similar to bacteria

Cellular Organelles and Function

Cell Boundary

Structure: Plasma membrane (phospholipid bilayer) in all cells; the cell wall is a more complex outer boundary found in plants and bacteria, different from the plasma membrane
Differences: Different cells have different cell walls (plants vs animals); cells need plasma membrane structure

Cell Membrane Structure

Diagram: Draw a fluid mosaic model of the cell membrane with phospholipid layers, cholesterol, glycoproteins, and glycolipids, and membrane proteins.

Prokaryotic Categories

Bacteria: Cell wall contains peptidoglycan.
Archaea: Cell wall does not contain peptidoglycan (often more resistant to harsh environmental conditions)

Gram Staining

Purpose: Classifies bacteria based on their cell wall structure, helping in diagnosis and treatment, often used to see the differences between Gram-positive and Gram-negative bacteria.
Results: Gram-positive bacteria stain purple, gram-negative stain pink/red. These differences help distinguish organisms

Binary Fission, Endospore, and Conjugation

Binary Fission: Cell division producing two identical daughter cells, a form of asexual reproduction
Endospore: A protective, dormant structure allowing survival in harsh conditions.
Conjugation: Transfer of genetic material between two cells; a form of horizontal gene transfer.

Prokaryotic Diversity

Similarities: All share basic characteristics: Cell wall, ribosomes, plasma membrane, single circular chromosome and DNA and prokaryotic characteristics
Differences: Different metabolic pathways, nutritional needs, and reproductive strategies are present; some bacteria have specialized structures or strategies for surviving in harsh environments.

Pathogens and Prokaryotes

Pathogen: Organisms that cause disease.
Relationship: Many prokaryotes are pathogens, causing diseases in humans and other organisms

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Description

This quiz covers key concepts in biology, focusing on the differences between prokaryotes and eukaryotes, as well as various microscopy techniques. Additionally, it explores different nutritional modes utilized by these organisms. Test your knowledge on these fundamental topics in cellular biology!