Lecture Notes: Chapters 2-3 Cellular Level Of Organization

Front 1

Cellular Diversity

Back 1

Nervous Cells, Epithelial cells, Smooth Muscle Cells, Red Blood Cells, Sperm Cells

Front 2

Main parts of most cells

Back 2

Cytoplasm, Plasma Membrane, and Nucleus

Front 3

Plasma Membrane

Back 3

Components: Lipid bilayer (basic structural framework of plasma membrane), Membrane proteins (embedded in the plasma membrane)

Front 4

Lipid billayer

Back 4

Formed by phospholipids.

Fluidity maintained by Cholestrol.

Glycolipids are cell identity markers.

Front 5

Types of membrane proteins

Back 5

1. Peripheral proteins (ones that stick out on the outside as well as on the inside of the cell membrane)

2. Integral (transmembrane proteins)

Front 6

Two Special Properties of Plasma Membranes

Back 6

1. Fluidity: allow the cell to be flexible yet sturdy on the outer surface

2. Permeability: selective barrier for normal cellular activities. Highly permeable to non-polar molecules (oxygen, carbon dioxide, water, urea)

Impermeable to ions and large, uncharged polar molecules (glucose is an example)

Front 7

Nucleus Parts

Back 7

1. Nucleolus (brain, inner core)

2. Nuclear Envelope (membrane of the nucleus)

3. Nuclear Pore (entrance points to the nucleus, like selective "holes")

Front 8

Cytoplasm Parts

Back 8

1. Cytosol: the fluid part of the cytoplasm containing water, dissolved solutes and suspended particles. Other known as the ICF

2. Organelles such as the ER, Golgi A., Lysosomes, Mitochondrion.

Front 9

Endoplasmic Reticulum (ER) Parts

Back 9

Series/Network of tubes within the cytoplasm, continuous with the nuclear membrane on the nucleus.

Two types:

1. Rough ER: Continuous with the nuclear envelope, external surface studded with ribosomes

2. Smooth ER: Extend from the rough ER, no ribosomes.

Front 10

Rough ER Function

Back 10

Produces all the proteins secreted from the cell including those embedding in cell membranes (aka membrane factory).

Front 11

Smooth ER Function

Back 11

Detoxifies, stores and releases calcium

Front 12

Golgi Apparatus

Back 12

Looks like flattened sacs, stacked like dinner plates. It is closely associated with the rough ER.

Function: Modifies, concentrates, and packages proteins in the rough ER. Forms lysosomes and is the traffic director for cellular proteins.

Front 13

Lysosomes

Back 13

Round bags that contain digestive enzymes (they demolish things, aka demolition sites)

Front 14

Mitochondrion

Back 14

Structure: double membrane, and has its own DNA and RNA so it can replicate.

Function: produces energy (ATPs) for the cell aerobically.

Found in liver and muscle cells.

Front 15

Passive Processes

Back 15

Input of ATP energy is not needed. Substance is moving down a gradient (ie. downhill).

Examples: Simple diffusion, and facilitated diffusion.

Front 16

Facilitated Diffusion

Back 16

Substances move across the membrane from higher concentration trough designated channels or transporters until equilibrium is reached. This occurs with polar molecules and highly charged molecules.

Front 17

Active Processes

Back 17

Input of energy (ATP) is needed, substance is moving up a gradient (driven to an area of higher concentration). Example primary active transport: Na-K pump / ATPase

Front 18

Endocytosis

Back 18

3 main types:

1. Phagocytosis (cell eating): receptor used, large solid cells are engulfed.

2. Pinocytosis (cell drinking): smaller cells are engulphed but don't need receptors. Easy absorption.

3. Receptor-mediated endocytosis: like pinocytosis but receptors are used and the vesicle after are coated in proteins.

Front 19

Exocytosis

Back 19

Vesticles fuse with the cell membrane and release their contents to the ECF.

Example: the release of neurotransmitters, hormones and digestive enzymes.