Microbiology Chapter 3 Flashcards

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Questions and Answers

Which of the following are processes of life?

Reproduction (correct)

Communication

Metabolism (correct)

Growth (correct)

What kind of cell lacks a nucleus?

Prokaryote

What kind of cell has a nucleus?

Eukaryote

What are specialized structures within a cell that carry out its functions called?

Organelles Signup and view all the answers

What is the term for a gel-like substance that surrounds the outside of a cell?

Glycocalyx Signup and view all the answers

What type of glycocalyx is firmly attached to a cell surface?

Capsule Signup and view all the answers

What is a loose, water-soluble glycocalyx called?

Slime layer Signup and view all the answers

What does 'desiccation' refer to?

Drying out Signup and view all the answers

What are long structures that propel a cell through its environment called?

Flagella Signup and view all the answers

What are the three parts of a flagellum?

Filament, hook, basal body Signup and view all the answers

What type of flagella covers the surface of a cell?

Peritrichous flagella Signup and view all the answers

What term describes movement in response to stimuli?

Taxis Signup and view all the answers

What is the function of fimbriae?

Adhere to substances Signup and view all the answers

What term describes slimy masses of microbes adhering to a substrate?

Biofilms Signup and view all the answers

What is the primary function of ribosomes?

Protein synthesis Signup and view all the answers

What are the types of bacterial cell walls?

Gram-negative Signup and view all the answers

Match the following terms with their definitions:

Cytoplasm = Gelatinous material inside a cell Nucleoid = Region of a prokaryote that contains the cell's DNA Cytosol = Liquid portion of the cytoplasm Endospore = Structure produced by some bacteria to defend against hostile conditions Signup and view all the answers

What is the function of a cell wall?

Provide structure and shape Signup and view all the answers

What is the term for the movement of water across a selectively permeable membrane?

Osmosis Signup and view all the answers

Study Notes

Processes of Life

Four fundamental processes: growth, reproduction, responsiveness, metabolism.

Cell Types

Prokaryotes: Cells lacking a nucleus.
Eukaryotes: Cells containing a nucleus.

Cellular Structures

Organelles: Specialized structures functioning like tiny organs within cells.
Glycocalyx: Gelatinous, sticky covering surrounding a cell.
Capsule: A firm glycocalyx in bacteria composed of organic chemicals.
Slime Layer: A loosely attached, water-soluble glycocalyx that protects against desiccation.

Cell Motility

Flagella: Long structures extending from the cell surface, enabling propulsion.
Three Flagella Parts: Filament, hook, basal body.
Types of Flagella:
- Peritrichous: Cover the entire cell surface.
- Polar: Located at one or both ends of the cell.
- Endoflagella: Tightly spiraled around the cell, not protruding.

Directional Movements

Taxis: Movement in response to environmental stimuli.
Phototaxis: Movement towards or away from light.
Chemotaxis: Movement towards or away from a chemical stimulus.

Adherence Structures

Fimbriae: Bristle-like projections enabling adhesion to surfaces or each other.
Biofilms: Slimy microbial masses adhering via fimbriae and glycocalyces.
Pili: Tubules made of pilin, longer than fimbriae but shorter than flagella.

Cell Wall Functions

Provides structural integrity and shape.
Protects against osmotic pressure.
Assists in cell-to-cell attachment.
Resists antimicrobial agents.

Bacterial Cell Shapes

Cocci: Spherical cells, found singly or in clusters.
Bacilli: Rod-shaped cells, found singly or in chains.

Peptidoglycan Structure

Composed of N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).
Glycan portion: Chains of NAG and NAM linked covalently.
Peptido portion: Crossbridges made of amino acids connecting NAG and NAM chains.

Bacterial Cell Wall Types

Two main types: Gram-positive and Gram-negative.

Cell Membrane Characteristics

Cytoplasmic Membrane: Also known as the cell or plasma membrane, located beneath the glycocalyx and cell wall.
Phospholipid Bilayer: Fundamental structure of the cytoplasmic membrane.
Fluid Mosaic Model: Describes membrane structure, highlighting protein and lipid mobility.

Membrane Functions

Regulates substance passage.
Produces energy storage molecules.
Captures light energy in photosynthetic bacteria.
Selectively permeable: Allows specific substances to cross.

Chemical Gradients

Concentration Gradient: Difference in chemical concentration across the membrane.
Electrical Gradient: Voltage difference across the membrane.

Movement Mechanisms

Diffusion: Movement from high to low concentration areas.
Facilitated Diffusion: Proteins aiding the diffusion of specific molecules.
Osmosis: Water diffusion across a selectively permeable membrane.

Solution Concentrations

Isotonic: Equal solute concentrations on both sides of the membrane.
Hypertonic: Higher solute concentration outside the cell.
Hypotonic: Lower solute concentration outside the cell.

Active Transport Mechanisms

Three types:
- Uniport: One substance at a time.
- Antiport: Two substances in opposite directions.
- Synport: Two substances in the same direction.
Group Translocation: Active transport that chemically alters the substance during movement.

Cytoplasm and Organelles

Cytoplasm: Gel-like material within cells.
Cytosol: Liquid portion of the cytoplasm.
Nucleoid: Region in prokaryotes containing DNA.
Inclusions: Storage deposits within bacterial cytosol (lipids, starch, nitrogen, phosphorus, sulfur).

Energy Storage

Bacteria store carbon and energy in glycogen or polyhydroxybutyrate.

Endospores

Structures produced by some bacteria to survive extreme conditions.

Ribosomes and Cytoskeleton

Ribosomes: Sites for protein synthesis within cells.
Cytoskeleton: Internal fiber network providing cell shape.

Eukaryotic Glycocalyces Functions

Anchors animal cells together.
Strengthens the cell's surface.
Provides protection against dehydration.
Facilitates cell recognition and communication.

Membrane Rafts

Complex lipid-protein assemblies for signaling, protein sorting, and some cell movements.

Endocytosis

Active transport mechanism where pseudopodia engulf substances.
Types:
- Phagocytosis: Solid material intake.
- Pinocytosis: Liquid material intake.

Exocytosis

Process enabling substances to be expelled from the cell, reversing endocytosis.

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Test your knowledge of key concepts in Microbiology Chapter 3 with these flashcards. Covering topics such as cell types, processes of life, and cellular structures, this quiz will enhance your understanding of microbiological principles. Perfect for students preparing for exams or anyone interested in microbiology.