Smallest unit of all living things

Composed of organelles

Each organelle performs specific jobs so the cell can do it’s job

The Cell

Cell membrane Nucleus Chromatin Nuclear envelope Microvilli Cytoplasm

Mitochondria Golgi body Rough ER Smooth ER Ribosome Centrioles

Organelles Know location of and function of the following sructures

The barrier surrounding each cell Separates the cells contents from the

surrounding environment Is selectively permeable This is the cells way of maintaining

boundaries

Plasma Membrane

Phospholipid bi-layer Meaning two layers Each layer consists

of a lipid tail connected to a surface protein

The tails face each other, away from the external or internal environments

Structure of plasma membrane

Hydrophobic◦ The lipid tails are

water insoluble◦ They are “water

fearing”◦ They are non-polar

Hydrophilic◦ The protein heads of

each Phospholipid is water soluble

◦ They are “water loving”

◦ They are polar and interact well with other polar objects

Phospholipid bi-layer

1. Proteins◦ a. Peripheral proteins act as binding sites or

receptors◦ b. Integral proteins- proteins that span the

membrane act as transport protein◦ c. Glycoprotein- act as markers, which allow your

cells to be recognized as “self” cells 2. cholesterol

◦ Help to stabilize the plasma membrane

Throughout the membrane you will find

Channel Proteins◦ Passive movement

of material through pores

Carrier proteins◦ Material binds to

carrier proteins and is moved by the protein through the membrane

Types of transport proteins

Use passive transport◦ Do NOT require energy◦ 1. diffusion- molecules move across membrane

through pores along a concentration gradient (high to low)

◦ 2. filtration-movement of water and other solutes from high to low concentration Based on a hydrostatic pressure, water gradient

which creates a pressure Occurs in the kidneys

Channel proteins

Facilitated diffusion- ◦ concentration gradient still needed◦ Protein carrier is used because molecules are too

large to enter pores◦ Still passive transport, just needs help◦ No energy because it is using a gradient

Solute Pump (page 70, figure 3.10)◦ Moves molecules or ions too large to enter on own◦ Moves materials AGAINST a concentration

gradient (usually)◦ REQUIRES ENERGY (active transport)

Carrier proteins

Several junctions are present in order for the cells to continue doing their jobs, while communicating with adjacent cells all the while staying anchored to each other!

Cells join to form tissue

Membrane junctions:◦ Tight junctions◦ Desmosomes◦ Gag junctions

Define the following terms and provide an example of where it occurs page 59