Cell Environment and Concentration
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Questions and Answers

Match the components of peptidoglycan with their descriptions:

N-acetylglucosamine (NAG) = An amino sugar derivative of glucose N-acetlymuramic acid (NAM) = A component of peptide bridges Peptide bridges = Provide rigid support to the bacterial cell wall Glycan = A polymer of interlocking chains of alternating monomers

Match the types of bacteria with their characteristics:

Gram-positive bacteria = Have a thicker peptidoglycan layer Gram-negative bacteria = Have a thinner peptidoglycan layer Prokaryotes = Have a cell wall and a cell membrane Eukaryotes = Have a cell wall and a glycocalyx

Match the functions of the bacterial cell wall with their descriptions:

Provides rigid support = Function of peptidoglycan in the bacterial cell wall Freely permeable to solutes = Property of peptidoglycan in the bacterial cell wall Aids in cell division = Function of the cell envelope Regulates the movement of substances = Function of the cell membrane

Match the terms with their definitions:

<p>Glycocalyx = A layer of carbohydrate molecules outside the cell wall Slime layer = A layer of carbohydrate molecules outside the cell wall Cell envelope = The bacterial plasma membrane and cell wall together Cell wall = A layer of peptidoglycan in bacterial cells</p> Signup and view all the answers

Match the components of the bacterial cell wall with their functions:

<p>Peptidoglycan = Provides rigid support to the bacterial cell Cell membrane = Regulates the movement of substances Glycocalyx = Aids in cell division Slime layer = Protects the bacterial cell from environmental stress</p> Signup and view all the answers

Match the characteristics of Gram-positive bacteria with their descriptions:

<p>Thicker peptidoglycan layer = Characteristics of Gram-positive bacteria Thinner peptidoglymuramic acid layer = Characteristics of Gram-negative bacteria Have a cell wall and a cell membrane = Characteristics of Prokaryotes Have a glycocalyx and a slime layer = Characteristics of Eukaryotes</p> Signup and view all the answers

Match the terms related to the bacterial cell wall with their functions:

<p>Peptidoglycan = Provides structure to the bacterial cell Cell envelope = Regulates the movement of substances Glycocalyx = Aids in cell division Slime layer = Protects the bacterial cell from environmental stress</p> Signup and view all the answers

Match the components of the bacterial cell envelope with their functions:

<p>Cell membrane = Regulates the movement of substances Cell wall = Provides rigid support to the bacterial cell Glycocalyx = Aids in cell division Slime layer = Protects the bacterial cell from environmental stress</p> Signup and view all the answers

Match the following terms with their definitions in microbiology:

<p>Cytoskeleton = Cellular 'scaffolding' or 'skeleton' within the cytoplasm Animalcules = Tiny living organisms discovered by Anton van Leeuwenhoek Prokaryotes = Type of cells that have a cytoskeleton Osmosis = The process of discovering microorganisms</p> Signup and view all the answers

Match the following structures with their functions in prokaryotes:

<p>Plasma Membrane = Separates the cell from its environment Cytoskeleton = Provides structural support to the cell Peptidoglycan = Provides a semi-permeable barrier Glycocalyx = Maintains the cell's shape</p> Signup and view all the answers

Match the following terms with their characteristics in microbiology:

<p>Prokaryotes = Cells with a true nucleus Gram-positive Bacteria = Bacteria with a thick peptidoglycan layer Slime Layer = A type of glycocalyx Osmosis = The movement of water into a cell</p> Signup and view all the answers

Match the following terms with their functions in bacterial cell walls:

<p>Peptidoglycan = Provides structural support to the cell Glycocalyx = Helps in cell-to-cell interactions Slime Layer = Protects the cell from desiccation Cell Envelope = Maintains the cell's shape</p> Signup and view all the answers

Match the following terms with their importance in microbiology:

<p>Bacterial Cell Wall = Protects the cell from osmotic lysis Gram-positive Bacteria = More susceptible to antibiotics Glycocalyx = Helps in cell-to-cell recognition Prokaryotes = Less complex than eukaryotes</p> Signup and view all the answers

Match the following structures with their main components in microbiology:

<p>Plasma Membrane = Phospholipid molecules and proteins Cell Envelope = Peptidoglycan and lipid bilayer Cytoskeleton = Microtubules and microfilaments Glycocalyx = Proteins and lipids</p> Signup and view all the answers

Match the following terms with their characteristics in microbiology:

<p>Gram-negative Bacteria = Thin peptidoglycan layer Cell Envelope = Outermost layer of the cell Glycocalyx = Layer of carbohydrate molecules Slime Layer = Thick, protective layer</p> Signup and view all the answers

Match the following terms with their functions in microbiology:

<p>Osmosis = Maintains the cell's osmotic balance Peptidoglycan = Provides structural support to the cell Glycocalyx = Helps in cell-to-cell recognition Cytoskeleton = Maintains the cell's shape</p> Signup and view all the answers

Match the type of bacteria with its characteristic cell wall structure:

<p>Gram-positive = Thick peptidoglycan layer Gram-negative = Thin peptidoglycan layer with outer membrane Both = Lipopolysaccharide layer Neither = No peptidoglycan layer</p> Signup and view all the answers

What is the primary function of the glycocalyx in bacteria?

<p>Slime layer = Helps in adhering to solid surfaces Capsule = Adheres to nutrients in the environment Glycocalyx = Provides structural support to the cell Biofilm = Protects bacteria from drying out</p> Signup and view all the answers

Why are the differences in bacterial cell wall structure important?

<p>Pathogenesis = Bacterial diseases initiation Adhesion = Bacteria attachment to surfaces Cell wall function = Supports the cell's shape Environmental adaptation = Helps in surviving in various environments</p> Signup and view all the answers

Match the type of glycocalyx with its characteristic feature:

<p>Slime layer = Loosely associated with the cell wall Capsule = Firmly attached to the cell wall Glycocalyx = A combination of slime layer and capsule Biofilm = A complex community of bacteria</p> Signup and view all the answers

What is the primary function of the peptidoglycan layer in Gram-positive bacteria?

<p>Supports the cell's shape = Maintains cell wall structure Adheres to solid surfaces = Helps in attachment to surfaces Protects from drying out = Maintains cell's hydration Initiates diseases = Pathogenesis</p> Signup and view all the answers

Which bacterium has a slime layer that allows it to accumulate on tooth enamel?

<p>Streptococcus mutans = Causes cavities Staphylococcus = Causes skin infections E. coli = Causes gastrointestinal infections Bacillus = Causes food poisoning</p> Signup and view all the answers

What is the term for the complex community of bacteria attached to a surface?

<p>Biofilm = A complex community of bacteria Slime layer = A layer of glycoproteins Capsule = A layer of polysaccharides Glycocalyx = A general term for bacterial surface layers</p> Signup and view all the answers

What is the primary function of the outer membrane in Gram-negative bacteria?

<p>Maintains cell wall structure = Supports the cell's shape Adheres to solid surfaces = Helps in attachment to surfaces Protects from drying out = Maintains cell's hydration Regulates the flow of molecules = Maintains cellular homeostasis</p> Signup and view all the answers

Match the terms with their definitions in osmosis:

<p>Isotonic = Equal concentration of a solute inside and outside of cell Hypertonic = A higher concentration of solute Hypotonic = A lower concentration of solute Tonicity = The concentration of solutes in a solution</p> Signup and view all the answers

Match the environments with their characteristics:

<p>Hypertonic environment = A higher concentration of solute outside the cell Hypotonic environment = A lower concentration of solute outside the cell Isotonic environment = An equal concentration of solute inside and outside the cell Plasma membrane = A semi-permeable membrane around the cell</p> Signup and view all the answers

Match the terms with their descriptions:

<p>Osmosis = The movement of water from a hypotonic to a hypertonic environment Diffusion = The movement of molecules from a region of high to low concentration Active transport = The movement of molecules against their concentration gradient Tonicity = The ability of a solution to cause water to move into or out of a cell</p> Signup and view all the answers

Match the cell components with their functions:

<p>Plasma membrane = Regulates what enters and leaves the cell Glycocalyx = A layer of carbohydrate molecules on the cell surface Slime layer = A layer of polysaccharides on the cell surface Peptidoglycan = A major component of the bacterial cell wall</p> Signup and view all the answers

Match the types of bacteria with their characteristics:

<p>Gram-positive bacteria = Thick peptidoglycan layer in their cell wall Gram-negative bacteria = Thin peptidoglycan layer in their cell wall Prokaryotes = Lack a true nucleus and membrane-bound organelles Bacteria = Have a cell wall that provides structural support</p> Signup and view all the answers

Match the processes with their descriptions:

<p>Passive transport = Movement of molecules down their concentration gradient Facilitated diffusion = Movement of molecules down their concentration gradient with the help of a transport protein Osmosis = Movement of water from a hypotonic to a hypertonic environment Active transport = Movement of molecules against their concentration gradient using energy</p> Signup and view all the answers

Match the cell envelope components with their functions:

<p>Cell wall = Provides structural support and maintains cell shape Plasma membrane = Regulates what enters and leaves the cell Peptidoglycan = Provides additional structural support to the cell wall Glycocalyx = Helps with cell-cell interactions and recognition</p> Signup and view all the answers

Match the following components with their functions in bacterial cell walls:

<p>Peptidoglycan = Maintains cell shape and provides structural support Glycocalyx = Protects bacteria from host immune system Slime layer = Helps bacteria adhere to surfaces Lipopolysaccharide = Barrier against external environment</p> Signup and view all the answers

Match the following types of bacteria with their cell wall characteristics:

<p>Gram-positive bacteria = Thick peptidoglycan layer, no outer membrane Gram-negative bacteria = Thin peptidoglycan layer, outer membrane present Both Gram-positive and Gram-negative bacteria = Have a plasma membrane and cytoplasm Neither Gram-positive nor Gram-negative bacteria = Lack a cell wall</p> Signup and view all the answers

Match the following cell envelope components with their functions:

<p>Peptidoglycan = Provides structural support and maintains cell shape Lipopolysaccharide = Triggers host immune response Glycocalyx = Helps bacteria adhere to surfaces Outer membrane = Barrier against external environment</p> Signup and view all the answers

Match the following cell components with their functions in maintaining osmotic balance:

<p>Cell wall = Prevents cell from bursting in hypotonic environment Plasma membrane = Regulates solute transport Osmotic pressure = Helps maintain water balance within the cell Active transport = Pumps water out of the cell</p> Signup and view all the answers

Match the following terms with their definitions related to bacterial cell walls:

<p>Peptidoglycan = Protein-carbohydrate composite layer Glycocalyx = Thick, rigid layer outside the plasma membrane Slime layer = Thin, flexible layer outside the plasma membrane Lipopolysaccharide = Toxic component of Gram-negative bacteria</p> Signup and view all the answers

Match the following functions with the components that perform them in bacterial cell walls:

<p>Maintaining cell shape = Peptidoglycan Protecting bacteria from host immune system = Glycocalyx Triggers host immune response = Lipopolysaccharide Regulating solute transport = Plasma membrane</p> Signup and view all the answers

Match the following components with their importance in bacterial cell walls:

<p>Peptidoglycan = Essential for maintaining cell shape Glycocalyx = Important for bacterial adhesion Lipopolysaccharide = Crucial for Gram-negative bacteria's outer membrane Plasma membrane = Regulates solute transport and maintains osmotic balance</p> Signup and view all the answers

Match the following bacterial cell wall components with their functions in maintaining cell integrity:

<p>Peptidoglycan = Maintains cell shape and provides structural support Glycocalyx = Protects bacteria from host immune system Slime layer = Helps bacteria adhere to surfaces Outer membrane = Barrier against external environment</p> Signup and view all the answers

Match the terms related to osmosis with their descriptions:

<p>Isotonic = equal concentration of solute inside and outside of cell Hypertonic = a higher concentration of solute Hypotonic = a lower concentration of solute Plasmolysis = shrinkage of cell membrane</p> Signup and view all the answers

Match the environments with their characteristics:

<p>Hypertonic environment = water will move out of the cell Hypotonic environment = water will move into the cell Isotonic environment = no net movement of water Plasma membrane = regulates movement of solutes</p> Signup and view all the answers

Match the cell components with their functions in maintaining osmotic balance:

<p>Plasma membrane = regulates movement of solutes Cell wall = provides structural support Cytoplasm = maintains cellular processes Osmotic pump = regulates water movement</p> Signup and view all the answers

Match the terms with their effects on cell membrane:

<p>Hypertonic shock = cell membrane shrinks Plasmolysis = cell membrane detaches from cell wall Isotonic environment = no effect on cell membrane Osmotic pressure = pushes water out of cell</p> Signup and view all the answers

Match the cell components with their roles in cell membrane transport:

<p>Plasma membrane = regulates solute movement Cell wall = provides structural support Cytoplasm = plays no role in transport Osmotic pump = regulates water movement</p> Signup and view all the answers

Match the terms with their definitions in osmosis:

<p>Osmosis = movement of water from high to low concentration Diffusion = movement of molecules from high to low concentration Active transport = movement of molecules against concentration gradient Passive transport = movement of molecules with concentration gradient</p> Signup and view all the answers

Match the following terms with their descriptions related to osmotic pressure:

<p>Hypotonic environment = A solution that has a lower solute concentration than the cell Hypertonic shock = A condition where a cell bursts due to an influx of water Isotonic environment = A solution that has the same solute concentration as the cell Plasmolysis = A process where a cell's water is removed due to a hypertonic environment</p> Signup and view all the answers

Match the following cell components with their functions related to osmotic balance:

<p>Cell membrane = Regulates the movement of water and solutes into and out of the cell Cell wall = Provides structural support and maintains cell shape Plasma membrane = Acts as a selective barrier for molecules entering or leaving the cell Glycocalyx = Helps to maintain osmotic balance and prevent dehydration</p> Signup and view all the answers

Match the following types of transport with their descriptions related to cell membrane transport:

<p>Active transport = The movement of molecules against their concentration gradient, requiring energy Passive transport = The movement of molecules down their concentration gradient, without energy Facilitated diffusion = The movement of molecules down their concentration gradient, with the help of transport proteins Osmosis = The movement of water molecules into or out of the cell through a selectively permeable membrane</p> Signup and view all the answers

Match the following terms with their effects on bacterial cells:

<p>Hypertonic environment = Causes water to leave the cell, leading to dehydration Hypotonic environment = Causes water to enter the cell, leading to swelling Isotonic environment = Does not cause a change in cell volume Plasmolysis = Causes the cell membrane to shrink away from the cell wall</p> Signup and view all the answers

Match the following cell components with their functions related to osmotic balance:

<p>Plasma membrane = Regulates the movement of water and solutes into and out of the cell Cell wall = Provides structural support and maintains cell shape Glycocalyx = Helps to maintain osmotic balance and prevent dehydration Cytoplasm = Maintains the balance of solutes and water within the cell</p> Signup and view all the answers

Match the following terms with their descriptions related to osmotic pressure:

<p>Osmosis = The movement of water molecules into or out of the cell through a selectively permeable membrane Plasmolysis = The process of a cell's water being removed due to a hypertonic environment Hypertonic shock = A condition where a cell bursts due to an influx of water Isotonic environment = A solution that has the same solute concentration as the cell</p> Signup and view all the answers

Match the types of transport with their descriptions:

<p>Active transport = Movement of substances against the concentration gradient using ATP energy Passive transport = Movement of substances from high to low concentration without using ATP energy Facilitated diffusion = Passive transport of substances with the aid of carrier molecules ATP-driven active transport = Movement of substances across the plasma membrane using ATP energy</p> Signup and view all the answers

Match the cell membrane transport processes with their characteristics:

<p>Simple diffusion = Movement of substances from high to low concentration without using carrier molecules Active transport = Movement of substances against the concentration gradient using ATP energy Osmosis = Movement of water molecules from high to low concentration Facilitated diffusion = Passive transport of substances with the aid of carrier molecules</p> Signup and view all the answers

Match the cell membrane transport types with their energy requirements:

<p>Active transport = Requires ATP energy Passive transport = Does not require ATP energy Facilitated diffusion = Does not require ATP energy Simple diffusion = Does not require ATP energy</p> Signup and view all the answers

Match the osmotic environments with their characteristics:

<p>Hypertonic environment = Higher solute concentration than the cell Hypotonic environment = Lower solute concentration than the cell Isotonic environment = Equal solute concentration as the cell Plasmolysis = Shrinkage of the cell membrane due to water loss</p> Signup and view all the answers

Match the cell membrane transport processes with their directions:

<p>Exocytosis = Movement of substances out of the cell Endocytosis = Movement of substances into the cell Active transport = Movement of substances against the concentration gradient Facilitated diffusion = Movement of substances from high to low concentration</p> Signup and view all the answers

Match the cell membrane transport processes with their carrier molecules:

<p>Facilitated diffusion = Uses carrier molecules to facilitate transport Simple diffusion = Does not use carrier molecules Active transport = Uses ATP energy to pump substances across the membrane Passive transport = Does not use carrier molecules</p> Signup and view all the answers

Match the osmotic effects with their descriptions:

<p>Cytolysis = Bursting of the cell due to excessive water intake Plasmolysis = Shrinkage of the cell membrane due to water loss Hypertonic shock = Rupture of the cell due to excessive solute concentration Isotonic balance = Equal solute concentration inside and outside the cell</p> Signup and view all the answers

Match the cell membrane transport processes with their energy sources:

<p>Active transport = Uses ATP energy to pump substances across the membrane Passive transport = Does not use ATP energy Facilitated diffusion = Does not use ATP energy Simple diffusion = Does not use ATP energy</p> Signup and view all the answers

Match the following terms related to osmosis with their definitions:

<p>Isotonic = Equal concentration of solutes inside and outside the cell Hypertonic = Lower concentration of solutes outside the cell Hypotonic = Higher concentration of solutes outside the cell Osmosis = Movement of water from higher to lower concentration</p> Signup and view all the answers

Match the following concepts with their effects on cells:

<p>Hypotonic environment = Cells swell and may burst Hypertonic environment = Cells shrink and may die Plasmolysis = Cell contents shrink away from the cell wall Isotonic environment = Cells maintain their normal shape</p> Signup and view all the answers

Match the following environments with their characteristics:

<p>Isotonic environment = No net movement of water Hypertonic environment = Water leaves the cell Hypotonic environment = Water enters the cell Plasma membrane = Regulates what enters and leaves the cell</p> Signup and view all the answers

Match the following terms with their effects on cell membrane:

<p>Osmosis = Water movement from higher to lower concentration Plasmolysis = Shrinkage of cell membrane from water loss Hypertonic shock = Cell rupture due to excess water loss Isotonic balance = Stable internal environment</p> Signup and view all the answers

Match the following terms with their definitions related to osmosis:

<p>Osmotic pressure = Pressure exerted by water to equalize solute concentrations Hypertonic shock = Death of cells due to extreme osmotic pressure Isotonic = Solution with the same solute concentration as the cell Plasmolysis = Contraction of the cell membrane from the cell wall</p> Signup and view all the answers

Match the following cell components with their functions in maintaining osmotic balance:

<p>Plasma membrane = Regulates solute concentration Cell wall = Provides structural support Cytoplasm = Maintains internal environment Nucleus = Controls gene expression</p> Signup and view all the answers

Match the following types of transport with their characteristics:

<p>Active transport = Requires energy to move molecules across the membrane Passive transport = Does not require energy to move molecules across the membrane Osmosis = Movement of water from high to low concentration Facilitated diffusion = Assisted movement of molecules across the membrane</p> Signup and view all the answers

Match the following environments with their effects on cells:

<p>Hypotonic environment = Cells swell and may burst Hypertonic environment = Cells shrink and may die Isotonic environment = Cells maintain their normal shape Plasmolyzing environment = Cell contents shrink away from the cell wall</p> Signup and view all the answers

Match the following types of transport with their descriptions related to cell membrane transport:

<p>Active transport = Energy-dependent movement of molecules Passive transport = Energy-independent movement of molecules Osmosis = Movement of water from higher to lower concentration Diffusion = Random movement of molecules</p> Signup and view all the answers

Match the following terms with their definitions related to osmotic pressure:

<p>Osmosis = Movement of water from higher to lower concentration Osmotic pressure = Force of water movement Isotonic = Equal concentration of solutes inside and outside the cell Hypertonic = Higher concentration of solutes outside the cell</p> Signup and view all the answers

Match the following terms with their effects on cell membranes:

<p>Osmotic pressure = Pressure exerted by water to equalize solute concentrations Plasmolysis = Contraction of the cell membrane from the cell wall Hypertonic shock = Death of cells due to extreme osmotic pressure Isotonic environment = Cells maintain their normal shape</p> Signup and view all the answers

Match the following concepts with their effects on cell membrane transport:

<p>Active transport = Requires energy to move molecules across the membrane Passive transport = Does not require energy to move molecules across the membrane Facilitated diffusion = Assisted movement of molecules across the membrane Osmosis = Movement of water from high to low concentration</p> Signup and view all the answers

Match the following terms with their definitions related to osmosis:

<p>Isotonic = A solution that has the same solute concentration as the cell Hypotonic = A solution that has a higher solute concentration than the cell Hypertonic = A solution that has a lower solute concentration than the cell Plasmolysis = The process of cell shrinkage due to water loss</p> Signup and view all the answers

Match the components of bacterial cell membrane transport with their functions:

<p>ATP-driven pumps = Active transport of substances across the membrane Channel proteins = Facilitated diffusion of substances across the membrane Carrier proteins = Passive transport of substances across the membrane Lipid bilayer = Regulation of solute transport across the membrane</p> Signup and view all the answers

Match the following environments with their characteristics:

<p>Hypertonic environment = A solution that causes water to leave the cell Isotonic environment = A solution that has the same solute concentration as the cell Hypotonic environment = A solution that causes water to enter the cell Plasmolysis environment = A solution that causes cell shrinkage</p> Signup and view all the answers

Match the following terms with their effects on cell membrane transport:

<p>Osmotic pressure = The pressure exerted by solutes on the cell membrane Plasmolysis = The process of cell shrinkage due to water loss Active transport = The use of ATP to move substances across the membrane Facilitated diffusion = The movement of substances across the membrane without ATP</p> Signup and view all the answers

Match the following components with their functions in maintaining osmotic balance:

<p>Cell membrane = Regulation of solute transport across the membrane Carrier proteins = Passive transport of substances across the membrane Channel proteins = Facilitated diffusion of substances across the membrane ATP-driven pumps = Active transport of substances across the membrane</p> Signup and view all the answers

Match the following types of transport with their descriptions related to cell membrane transport:

<p>Passive transport = Movement of substances across the membrane without ATP Active transport = Use of ATP to move substances across the membrane Facilitated diffusion = Movement of substances across the membrane through channel proteins Osmosis = Movement of water across the membrane</p> Signup and view all the answers

Match the following terms with their effects on bacterial cells:

<p>Hypertonic shock = Rapid water loss and cell shrinkage Plasmolysis = Cell shrinkage due to water loss Isotonic environment = No net water movement across the membrane Osmotic pressure = The pressure exerted by solutes on the cell membrane</p> Signup and view all the answers

Match the following components with their functions in cell membrane transport:

<p>Lipid bilayer = Regulation of solute transport across the membrane Channel proteins = Facilitated diffusion of substances across the membrane Carrier proteins = Passive transport of substances across the membrane ATP-driven pumps = Active transport of substances across the membrane</p> Signup and view all the answers

Study Notes

Environment Surrounding Cells

  • The environment surrounding cells may contain dissolved substances (solutes) that are equal to, less than, or greater than those found within the cell.
  • The concentration of solutes inside and outside the cell affects the movement of water into or out of the cell.

Osmosis and Tonicity

  • Isotonic: equal concentration of solutes inside and outside the cell.
  • Hypertonic: a higher concentration of solutes outside the cell.
  • Hypotonic: a lower concentration of solutes outside the cell.
  • Water will always move towards a hypertonic environment.

Prokaryotes - Plasma Membrane as a Barrier

  • The plasma membrane is a barrier that separates the cell from its environment.
  • It is semi-permeable, allowing certain substances to pass through while keeping others out.

Active Transport

  • Active transport is the movement of molecules across the plasma membrane with the aid of carrier molecules.
  • ATP-driven active transport uses energy from adenosine triphosphate (ATP) to drive substances across the plasma membrane.

Prokaryotes - Cell Wall

  • Peptidoglycan is a huge polymer of interlocking chains of alternating monomers that provides rigid support and is freely permeable to solutes.
  • The backbone of peptidoglycan is composed of two amino sugar derivatives of glucose: N-acetylglucosamine (NAG) and N-acetyl muramic acid (NAM).
  • NAG/NAM strands are connected by interlocking peptide bridges.

Bacterial Cell Wall

  • Gram-positive bacteria have a thicker peptidoglycan layer, while Gram-negative bacteria have a thinner peptidoglycan layer and an outer membrane.
  • The cell envelope consists of the plasma membrane and cell wall.

History of Microbiology

  • Anton van Leeuwenhoek discovered "micro" organisms, including bacteria, protozoans, and cells of the human body.

Prokaryotes - Cytoskeleton

  • The cytoskeleton provides cellular "scaffolding" or "skeleton" within the cytoplasm.
  • It was previously thought to be a feature only of eukaryotic cells.

Prokaryotes - Glycocalyx

  • Some bacteria have an additional layer outside of the cell wall called the glycocalyx.
  • The glycocalyx can come in two forms: slime layer and capsule.
  • Slime layer: a loose association of glycoproteins with the cell wall that helps bacteria adhere to solid surfaces and prevents drying out.
  • Capsule: a polysaccharide firmly attached to the cell wall that helps bacteria adhere to solid surfaces and nutrients.

Environment Surrounding Cells

  • The environment surrounding cells may contain dissolved substances (solutes) that are equal to, less than, or greater than those found within the cell.
  • This affects the movement of water into or out of the cell.

Tonicity and Osmosis

  • Isotonic: equal concentration of solutes inside and outside the cell.
  • Hypertonic: a higher concentration of solutes outside the cell, causing water to move out of the cell.
  • Hypotonic: a lower concentration of solutes outside the cell, causing water to move into the cell.
  • Water will always move towards a hypertonic environment.

Cells and Water: Osmotic Pressure

  • Water is an important reactant in many metabolic reactions.
  • Most cells die in the absence of water.
  • Cell walls of bacteria and plants prevent them from exploding in a hypotonic environment.
  • Many bacteria can be plasmolyzed by high concentrations of solutes, leading to death by desiccation.

Active Transport

  • Active transport is the movement of molecules across the plasma membrane using energy.
  • It is analogous to a pump moving water uphill.
  • Types of active transport are classified by the type of energy used to drive molecules across the membrane.
  • ATP drives substances across the plasma membrane with the aid of carrier molecules.

Bacterial Cell Wall

  • Prokaryotes have a cell wall that provides rigid support and is permeable to solutes.
  • The cell wall is composed of peptidoglycan, a polymer of interlocking chains of alternating monomers.
  • The peptidoglycan molecule is composed of two amino sugar derivatives of glucose: N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).
  • NAG and NAM strands are connected by interlocking peptide bridges.

Gram-Positive and Gram-Negative Bacteria

  • Bacteria can be classified as Gram-positive or Gram-negative based on their cell wall structure.
  • The bacterial plasma membrane and cell wall together are called the cell envelope.

Environment Surrounding Cells

  • The environment surrounding cells may contain dissolved substances (solutes) that are equal to, less than, or greater than those found within the cell.
  • This affects the movement of water into or out of the cell.

Tonicity and Osmosis

  • Isotonic: equal concentration of solutes inside and outside the cell.
  • Hypertonic: a higher concentration of solutes outside the cell, causing water to move out of the cell.
  • Hypotonic: a lower concentration of solutes outside the cell, causing water to move into the cell.
  • Water will always move towards a hypertonic environment.

Cells and Water: Osmotic Pressure

  • Water is an important reactant in many metabolic reactions.
  • Most cells die in the absence of water.
  • Cell walls of bacteria and plants prevent them from exploding in a hypotonic environment.
  • Many bacteria can be plasmolyzed by high concentrations of solutes, leading to death by desiccation.

Active Transport

  • Active transport is the movement of molecules across the plasma membrane using energy.
  • It is analogous to a pump moving water uphill.
  • Types of active transport are classified by the type of energy used to drive molecules across the membrane.
  • ATP drives substances across the plasma membrane with the aid of carrier molecules.

Bacterial Cell Wall

  • Prokaryotes have a cell wall that provides rigid support and is permeable to solutes.
  • The cell wall is composed of peptidoglycan, a polymer of interlocking chains of alternating monomers.
  • The peptidoglycan molecule is composed of two amino sugar derivatives of glucose: N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM).
  • NAG and NAM strands are connected by interlocking peptide bridges.

Gram-Positive and Gram-Negative Bacteria

  • Bacteria can be classified as Gram-positive or Gram-negative based on their cell wall structure.
  • The bacterial plasma membrane and cell wall together are called the cell envelope.

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This quiz is about the concentration of dissolved substances in cells and their surroundings. It involves understanding the comparison of solute concentrations inside and outside the cell.

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