Chapter 3-study Guide
1. Explain the cell theory.
A cell is the structural and functional unit of life
2. Explain cell diversity.
Types differ in size, shape, and subcellular components
3. What are the three basic parts of a human cell?
1. Plasma membrane
2. Nucleus
3. Cytoplasm
4. Describe the components of extracellular materials.
Extracellular fluids:
Interstitial fluid: cells are submersed (bathed) in this fluid
Blood plasma: fluid of the blood
Cerebrospinal fluid: fluid surrounding nervous system organs
Cellular secretions (e.g., saliva, mucus)
Extracellular matrix: substance that acts as glue to hold cells together
5. Describe the cell membrane in detail. What does the fluid mosaic model depict?
Controls what enters and what leaves cell. Separates the intracellular fluid (ICF) from extracellular fluid (ECF).
6. What are the 2 main types of membrane proteins? Describe them.
Integral proteins- Firmly inserted into membrane
Most are transmembrane proteins (span membrane)
Have both hydrophobic and hydrophilic regions
Peripheral proteins- Found on the intracellular and extracellular surfaces
used for plasma membrane support and cell connections
7. List all of the different types of integral proteins and explain the function of each.
Ion Channels- Allow specific ions to flow across the membrane through a pore-like structure, crucial for
maintaining ion gradients and electrical signaling.
Carrier Proteins- Bind to specific molecules and facilitate their transport across the membrane through
confirmational changes, often involved in active transport requiring energy.
Receptor Proteins- Bind to signaling molecules (ligands) on the cell surface, triggering intracellular responses.
Glycoproteins- Integral proteins with attached carbohydrate groups, important for cell-cell recognition and
adhesion.
8. What is glycocalyx and what is its function?
A protective, carbohydrate-rich layer that covers the surface of many cells, acting as a barrier to protect the cell
membrane, regulates cell-to-cell interactions, and play a crucial role in functions like maintaining vascular
permeability, immune recognition, and cell adhesion. Functions as a ‘fuzzy coat’ that helps identify a cell and
control what can interact with it.
9. Describe the 3 types of cell junctions. Where would you find each? What is their function?
1. Tight junctions- Found epithelial tissues. Forms a continuous seal around cells, preventing leakage of fluids
and molecules between them.
, 2. Desmosomes- Found in tissues with high mechanical stress in skin and heart muscle. Provide strong adhesion
between cells by anchoring their cytoskeletons together.
3. Gap Junctions- Found in tissues requiring rapid communication like cardiac muscle. Form channels between
adjacent cells, allowing for the rapid exchange of small molecules, ions and electrical signals.
10. What is the difference between active and passive transport?
Active transport, carrier proteins require energy. Passive transport, carrier proteins do not require energy.
11. Define diffusion and list and describe the 4 types in detail (Figure 3.6).
Nonpolar, hydrophobic lipid core of plasma membranes stop diffusion and create concentration gradients by
acting as selectively permeable barriers.
Simple diffusion- Nonpolar lipid-soluble (hydrophobic) substances diffuse directly through phospholipid bilayer
Facilitated diffusion- Certain hydrophobic molecules (e.g., glucose, amino acids, and ions) are transported
passively down their concentration gradient.
Carrier-mediated facilitated diffusion- Carriers are transmembrane integral proteins.
Channel-mediated facilitated diffusion- Channels with aqueous-filled cores are formed by transmembrane
proteins.
Osmosis- Movement of solvent (not molecules), such as water, across a selectively permeable membrane
12. What factors can influence the speed of diffusion.
The concentration gradient, temperature, particle size, and the medium through which the particles are
diffusing, including factors like membrane permeability and viscosity.
13. Define osmolarity and equilibrium.
Osmolarity: measure the concentration of the total number of solute particles in solvent
Equilibrium: Same concentration of solutes and water molecules on both sides, with equal volume on both sides
14. What is hydrostatic and osmotic pressure.
Hydrostatic pressure: outward pressure exerted on cell side of membrane caused by increases in volume of cell
due to osmosis
Osmotic pressure: inward pressure due to tendency of water to be “pulled” into a cell with higher osmolarities
15. What is tonicity? Describe an isotonic, hypertonic, and hypotonic solution. Explain what would happen to a
erythrocyte placed in each.
Tonicity- Ability of a solution to change the shape or tone of cells by altering the cells’ internal water volume
Isotonic solution- has same osmolarity as inside the cell, so volume remains unchanged
Hypertonic solution- has higher osmolarity than inside cells, so water flows out of cell, resulting in cells shrinking
Shrinking is referred to as crenation
Hypotonic solution- has lower osmolarity than inside cells, so water flows into cell, resulting in cell swelling
Can lead to cell bursting, referred to as lysing
16. What are the two major types of active membrane transport? What is required for both?
Active transport and Vesicular transport. Both require ATP to move solutes across a plasma membrane
17. Describe antiporters and symporters.
Antiporters transport- one substance into cell while transporting a different substance out of cell
Symporters transport- two different substances in the same direction
18. What is the difference between primary and secondary active transport?
Primary active transport- Required energy comes directly from ATP hydrolysis
Secondary active transport- Required energy is obtained indirectly from ionic gradients created by primary
active transport
19. Explain how the sodium/potassium pumps works.
1. Explain the cell theory.
A cell is the structural and functional unit of life
2. Explain cell diversity.
Types differ in size, shape, and subcellular components
3. What are the three basic parts of a human cell?
1. Plasma membrane
2. Nucleus
3. Cytoplasm
4. Describe the components of extracellular materials.
Extracellular fluids:
Interstitial fluid: cells are submersed (bathed) in this fluid
Blood plasma: fluid of the blood
Cerebrospinal fluid: fluid surrounding nervous system organs
Cellular secretions (e.g., saliva, mucus)
Extracellular matrix: substance that acts as glue to hold cells together
5. Describe the cell membrane in detail. What does the fluid mosaic model depict?
Controls what enters and what leaves cell. Separates the intracellular fluid (ICF) from extracellular fluid (ECF).
6. What are the 2 main types of membrane proteins? Describe them.
Integral proteins- Firmly inserted into membrane
Most are transmembrane proteins (span membrane)
Have both hydrophobic and hydrophilic regions
Peripheral proteins- Found on the intracellular and extracellular surfaces
used for plasma membrane support and cell connections
7. List all of the different types of integral proteins and explain the function of each.
Ion Channels- Allow specific ions to flow across the membrane through a pore-like structure, crucial for
maintaining ion gradients and electrical signaling.
Carrier Proteins- Bind to specific molecules and facilitate their transport across the membrane through
confirmational changes, often involved in active transport requiring energy.
Receptor Proteins- Bind to signaling molecules (ligands) on the cell surface, triggering intracellular responses.
Glycoproteins- Integral proteins with attached carbohydrate groups, important for cell-cell recognition and
adhesion.
8. What is glycocalyx and what is its function?
A protective, carbohydrate-rich layer that covers the surface of many cells, acting as a barrier to protect the cell
membrane, regulates cell-to-cell interactions, and play a crucial role in functions like maintaining vascular
permeability, immune recognition, and cell adhesion. Functions as a ‘fuzzy coat’ that helps identify a cell and
control what can interact with it.
9. Describe the 3 types of cell junctions. Where would you find each? What is their function?
1. Tight junctions- Found epithelial tissues. Forms a continuous seal around cells, preventing leakage of fluids
and molecules between them.
, 2. Desmosomes- Found in tissues with high mechanical stress in skin and heart muscle. Provide strong adhesion
between cells by anchoring their cytoskeletons together.
3. Gap Junctions- Found in tissues requiring rapid communication like cardiac muscle. Form channels between
adjacent cells, allowing for the rapid exchange of small molecules, ions and electrical signals.
10. What is the difference between active and passive transport?
Active transport, carrier proteins require energy. Passive transport, carrier proteins do not require energy.
11. Define diffusion and list and describe the 4 types in detail (Figure 3.6).
Nonpolar, hydrophobic lipid core of plasma membranes stop diffusion and create concentration gradients by
acting as selectively permeable barriers.
Simple diffusion- Nonpolar lipid-soluble (hydrophobic) substances diffuse directly through phospholipid bilayer
Facilitated diffusion- Certain hydrophobic molecules (e.g., glucose, amino acids, and ions) are transported
passively down their concentration gradient.
Carrier-mediated facilitated diffusion- Carriers are transmembrane integral proteins.
Channel-mediated facilitated diffusion- Channels with aqueous-filled cores are formed by transmembrane
proteins.
Osmosis- Movement of solvent (not molecules), such as water, across a selectively permeable membrane
12. What factors can influence the speed of diffusion.
The concentration gradient, temperature, particle size, and the medium through which the particles are
diffusing, including factors like membrane permeability and viscosity.
13. Define osmolarity and equilibrium.
Osmolarity: measure the concentration of the total number of solute particles in solvent
Equilibrium: Same concentration of solutes and water molecules on both sides, with equal volume on both sides
14. What is hydrostatic and osmotic pressure.
Hydrostatic pressure: outward pressure exerted on cell side of membrane caused by increases in volume of cell
due to osmosis
Osmotic pressure: inward pressure due to tendency of water to be “pulled” into a cell with higher osmolarities
15. What is tonicity? Describe an isotonic, hypertonic, and hypotonic solution. Explain what would happen to a
erythrocyte placed in each.
Tonicity- Ability of a solution to change the shape or tone of cells by altering the cells’ internal water volume
Isotonic solution- has same osmolarity as inside the cell, so volume remains unchanged
Hypertonic solution- has higher osmolarity than inside cells, so water flows out of cell, resulting in cells shrinking
Shrinking is referred to as crenation
Hypotonic solution- has lower osmolarity than inside cells, so water flows into cell, resulting in cell swelling
Can lead to cell bursting, referred to as lysing
16. What are the two major types of active membrane transport? What is required for both?
Active transport and Vesicular transport. Both require ATP to move solutes across a plasma membrane
17. Describe antiporters and symporters.
Antiporters transport- one substance into cell while transporting a different substance out of cell
Symporters transport- two different substances in the same direction
18. What is the difference between primary and secondary active transport?
Primary active transport- Required energy comes directly from ATP hydrolysis
Secondary active transport- Required energy is obtained indirectly from ionic gradients created by primary
active transport
19. Explain how the sodium/potassium pumps works.
