Objectives

The Cellular Basis of Life1. Define cell.

2. List the three major regions of a generalized cell and their functions.

The Plasma Membrane: Structure3. Describe the chemical composition of the plasma membrane and relate it to membrane

functions.

4. Compare the structure and function of tight junctions, desmosomes, and gap junctions.

The Plasma Membrane: Membrane Transport5. Relate plasma membrane structure to active and passive transport processes.

6. Compare and contrast simple diffusion, facilitated diffusion, and osmosis relative to substances transported, direction, and mechanism.

7. Differentiate between primary and secondary active transport.

8. Compare and contrast endocytosis and exocytosis in terms of function and direction.

9. Compare and contrast pinocytosis, phagocytosis, and receptor-mediated endocytosis.

The Plasma Membrane: Generation of a Resting Membrane Potential10. Define membrane potential and explain how the resting membrane potential is

established and maintained.

The Plasma Membrane: Cell-Environment Interactions11. Describe the role of the glycocalyx when cells interact with their environment.

12. List several roles of membrane receptors and that of voltage-gated membrane channel proteins.

The Cytoplasm13. Describe the composition of the cytosol.

14. Discuss the structure and function of mitochondria.

15. Discuss the structure and function of ribosomes, the endoplasmic reticulum, and the Golgi apparatus, including functional interrelationships among these organelles.

16. Compare the functions of lysosomes and peroxisomes.

17. Name and describe the structure and function of cytoskeletal elements.

18. Describe the roles of centrioles in cell division and in formation of cilia and flagella.

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19. Describe how the two main types of cell extensions, cilia and microvilli, differ in structure and function.

The Nucleus20. Outline the structure and function of the nuclear envelope, nucleolus, and chromatin.

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The Cellular Basis of Life pp. 62-63; Figure 3.2

Cell =

Cell Theory:

1.

2.

3.

4.

Cell Diversity:

(a)

(b)

(c)

(d)

(e)

(f)

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Regardless of type, all cells are composed chiefly of _______________________, _________________, ___________________, _____________________, and trace amounts of several other elements.

In additional all cells have the same basic __________ and some common _______________. For this reason it is possible to speak of a ______________________, or _________________ cell.

Figure 3.2 Structure of the Generalized CellUse the diagram below to label all of the parts of a generalized cell.

Then use Table 3.3 to describe the structure and functions of each of these parts.

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The Plasma Membrane: Structure pp. 63-67; Figure 3.3- 3.5

Plasma Membrane =

The Fluid Mosaic Model:

Membrane Lipids

Constructed largely of __________________, with smaller amounts of ______________________,

___________________________, and areas called __________________________________.

_______% Phospholipids (lipid bilayer) Phosphate heads: ___________________ and ______________________ Fatty acid tails: ________________________ and _____________________

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_______% Glycolipids Lipids with _________________________________________________________________________ Found _______________________________________________________________________________

_______% Cholesterol Polar region - _________________ group Nonpolar region- _____________ ring system Increases membrane _________________, while decreasing _________________ of the

phospholipids and the fluidity of the membrane.

Membrane Proteins

Two types:o _______________________________________________

o _______________________________________________

Integral Proteins

o

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Peripheral Proteins

Six Functions of Membrane Proteins

1.

2.

3.

4.

5.

6.

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Lipid Rafts

Lipid rafts make up about ________% of the membrane and serve as platforms for receptors.

The Glycocalyx:

The glycocalyx is the fuzzy, sticky, ________________________-rich area at a cell’s surface

that acts as a ________________________marker allowing cells to __________________ each

other.

Cell Junctions:

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Although certain cell types are “footloose” (free) in the body—e.g. blood cells, sperm cells, and some immune system cells…many other types are knit together into tight communities.

The 3 factors that act to bind cells together:

1.

2.

3.

The 3 ways cells are bound:

________________________________

________________________________

________________________________

Tight Junctions

Desmosomes

Gap Junctions

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Plasma Membrane: Membrane Transport—Passive Processes(pp. 67-79; Fig 3.6-3.14; Tables 3.1-3.2)

Our cells are bathed in an extracellular fluid called ___________________________________ that is derived from the blood.

Interstitial fluid contains thousands of ingredients, including:

To remain healthy, each cell must extract from the interstitial fluid the exact amount of substances it needs at specific times.

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The cell membrane is ___________________________________: it allows _______________to enter the cell and ________________ to leave, but restricts the movement of other substances in or out of the cell.

Substances move through the plasma membrane in two ways:

1. ________________________________________________

2. ________________________________________________

In passive processes:

In active Processes:

Passive ProcessesTwo main types of passive processes:

_______________________________________________

_______________________________________________

Diffusion

Types of diffusion:

_______________________________________________________

_______________________________________________________

o _______________________________________________________

o _______________________________________________________

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_______________________________________________________

Simple diffusion is diffusion through the plasma membrane, without using a ____________________ or ___________________, and is restricted to the movement of very small molecules, or lipids.

In facilitated diffusion, ________________________, __________________________, or ions are moved through the plasma membrane by binding to _______________________ carriers in the membrane or by moving though channels.

Carrier-mediated facilitated diffusion

Channel-mediated facilitated diffusion

Osmosis is the diffusion of ______________________ through a selectively permeable membrane.

Osmosis occurs whenever the water concentration differs on two sides of a membrane.

Water will move into areas where the osmolarity, the total concentration of particles in the solution, is greater.

Tonicity =

Isotonic Solution Hypertonic Solution Hypotonic Solution

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Isotonic =

Hypertonic =

Hypotonic =

Figure 3.7 Diffusion through the plasma membrane

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Table 3.1 Passive Membrane Transport ProcessesProcess Energy Source Description Examples

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Plasma Membrane: Membrane Transport—Active Processes(pp. 67-79; Fig 3.6-3.14; Tables 3.1-3.2)

Whenever a cell uses _______________ to move solutes across the membrane, the process is referred to as _______________________.

Substances moved actively across the plasma membrane are usually ______________ to pass in the necessary direction by _______________________________ processes.

Substances may be moved across the plasma membrane using ATP (active transport) because:

o _______________________________________________

o _______________________________________________

o _______________________________________________

Two Major Means of Active Transport:

1. __________________________________________________________

2. __________________________________________________________

Active transport requires ___________________ proteins (solute pumps) that combine ______________________________ and _______________________ with the transported substance.

Active transport moves solutes _______________________ concentration gradient and therefore requires ___________________________.

Two Types of Active Transport:

Primary Active Transport

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Secondary Active Transport

Primary Active TransportEnergy from the _______________________________ of ATP causes changes in transport protein that “pumps” solute (ions) across the membrane.

Primary active transport systems include:o _____________________________________o _____________________________________o _____________________________________

Sodium-Potassium Pump

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Secondary Active Transport

Depends on _____________ gradient created by ________________ active transport.

Energy stored in _____________ gradients used indirectly to drive transport of other solutes.

Cotransport

Always transports more than one on substance at a time.

Symport System:

Antiport System:

Figure 3.11 Secondary active transport is driven by the concentration gradient created by primary active transport.

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Vesicular Transport

Functions:

o Exocytosis-

o Endocytosis-

o Phagocytosis

o Pinocytosis

o Receptor-mediated

o Endocytosis

o Transcytosis-

o Vesicular trafficking-

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Figure 3.12 Events of Endocytosis mediated by protein-coated pits.

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Figure 3.13 Comparison of three types of endocytosis

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Figure 3.15 Exocytosis

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The Plasma Membrane: Generation of a Resting Membrane Potential (pp. 79-80; Fig. 3.15)

Resting Membrane Potential

A ___________________________ is a voltage across the cell membrane that occurs due to separation of oppositely charged particles (ions).

o Voltage =

The resting membrane potential is a condition in which the inside of the cell membrane is ________________________ charged compared with the outside, and ranges in voltage from –_______ to –_________ millivolts.

Cells are described as _______________________________.

Selective Diffusion Establishes RMP

The resting membrane potential is determined mainly by the concentration gradient of __________________________(K+).

There is a higher concentration of _____________________ (K+) inside body cells than outside and the extracellular fluid contains relatively more ____________________ (Na+) which is balanced by CI-.

Plasma Membrane: RMP

The unstimulated plasma membrane is somewhat permeable to ______ anions, but impermeable to the protein anions.

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Figure 3.15 The key role of K+ in generating the resting membrane potential.

Active Transport Maintains Electrochemical GradientActive transport pumps ensure that passive ion movement does not lead to an electrochemical equilibrium across the membrane, thus maintaining the resting membrane potential.

Na+-K+ pump continuously ejects _____Na+ from cell and carries _____K+ in

Steady state maintained because rate of active transport equal to and depends on rate of Na+ diffusion into cell

Neuron and muscle cells "upset" RMP by opening _____________ Na+ and K+ channels.

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The Plasma Membrane: Cell-Environment Interactions (pp. 80-81; Fig 3.16)

Cells can interact directly with other cells, respond to extracellular chemicals, and interact with molecules that direct migration.

Roles of Cell Adhesion Molecules (CAMs)

Cell adhesion molecules (CAMs) are glycoproteins that act as attachment sites or signals during embryonic development, wound repair, and immunity.

Roles of Plasma Membrane Receptors

___________________signaling involves touch between membrane receptors of neighboring cells to facilitate recognition between cells.

__________________signaling involves the binding of a chemical signal to a membrane receptor, resulting in the initiation of cellular responses.

Ligands =

Cell response to receptor binding:

o Catalytic receptor proteins:

o Chemically gated channel-link receptors:

o G protein–linked receptors: Activate G protein, affecting an ion channel or enzyme, or causing release of internal second messenger, such as cyclic AMP.

Role of Voltage-Gated Membrane Channel Proteins: Electrical Signaling

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In excitable tissues, such as neurons or muscle cells, certain ion channels in the cell membrane open or close in response to a change in membrane potential, allowing electrical signaling between cells.

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