Cell Transport

PLASMA MEMBRANE

Structure Cell or Plasma membrane = Polar PHOSPHATE HEADS - which are water-loving (hydrophilic) Nonpolar FATTY ACID TAILS - are hydrophobic (water-fearing) Cell or Plasma membrane = (AKA – PHOSPHOLIPID bilayer Structure CARBOHYDRATE PLASMA PERIPHERAL PROTEIN Membrane PHOSPHOLIPID INTEGRAL PROTEIN

Fluid Mosaic Model The plasma membrane is FLUID not rigid or unmoving. It is made up of many parts like a mosaic. The majority of the cell membrane is made up of PHOSPHOLIPIDS PLASMA Membrane

PLASMA Membrane Function Main Function is to CONTROLS WHAT GOES IN & OUT OF THE CELL to maintain homeostasis. Homeostasis – MAINTAINING A STABLE INTERNAL ENVIRONMENT EVEN IF THE OUTSIDE CHANGES The plasma membrane is SELECTIVELY PERMEABLE, which means only certain substances can get through Plasma Membrane Animation

Cholesterol (Steroids) Parts of the Membrane: TYPES: FUNCTION: PICTURES: LIPIDS Phospholipids Polar versus Nonpolar Cholesterol (Steroids) Hydrophillic: WATER LOVING (POLAR) PHOSPHATE HEADS Hydrophobic: WATER FEARING (NONPOLAR) FATTY ACID TAILS Keep the membrane fluid IF THE TEMP IS TOO HOT THE MEMBRANE DOESN’T FALL APART AND IF TOO COLD THEN IT DOESN’T FREEZE UP Polars and nonpolars DON’T mix!!! Nonpolar Polar

Parts of the Membrane: TYPES: FUNCTION: PICTURES: PROTEINS Integral Peripheral PROTEINS THAT GO ALL THE WAY THROUGH THE MEMBRANE TO TRANSPORT THINGS PROTEINS THAT ARE ON THE EDGE OF THE MEMBRANE THAT RECEIVE SIGNALS CARBOHYDRATES IDENTIFY A CELL (NAME TAG)

Matching

The CELL (PLASMA) MEMBRANE separates the cell from its surroundings. The plasma is made up of three of the four organic compounds, they are PROTEINS, LIPIDS and CARBOHYDRATES. Which type of organic compounds makes up the majority of the cell membrane? LIPIDS (PHOSPHOLIPIDS) The heads of the plasma membrane are HYDROPHILIC which means they are water loving. The tails of the plasma membrane are HYDROPHOBIC which means they are water fearing.

5. The cell membrane is also called the FLUID MOSAIC model. 6. How many layers make up the cell membrane? TWO (BILAYER) 7. What type of compound forms channels that allow large molecules to pass through the membrane? PROTEIN 8. Which type of compound acts as an identification marker? CARBOHYDRATE 9. What are the primary functions of the cell membrane? CONTROL WHAT ENTERS AND LEAVES write these: Small molecules go directly thru the membrane. Large molecules and water use a protein channel.

PASSIVE TRANSPORT

Hill Diagram High Low Passive Transport Active Transport - no energy D = Diffusion – high to low O = Osmosis – water transport F = Facilitated Diffusion – through protein Active Transport – needs energy (ATP) P = Pump – protein channel E = Endocytosis – move into cell E = Exocytosis – move out of cell High Low

Passive 3 Types Doesn’t require ENERGY occurs because there is a CONCENTRATION GRADIENT_ movement is from HIGH concentration to LOW concentration 3 Types DIFFUSION OSMOSIS FACILITATED DIFFUSION Before After A B A B molecules move to side B and become EQUAL Cell Transport

Passive Transport Dilute Concentrated Equilibrium

Selectively Permeable Membrane Diffusion Osmosis

Miscellaneous terms SOLUTE Part of a solution that is dissolved (Salt) The dots are the solute and solvent is the white space or water. The water dissolves the dots. SOLVENT Part of a solution that does the dissolving (Water) HYPERTONIC a solution with a higher concentration than another solution. (Water out & cell will shrink) HYPOTONIC a solution with a lower concentration than another solution. (Water in & cell will grow) water water

water Miscellaneous terms ISOTONIC a solution with an equal concentration to another solution (Water moves in & out & stays the same size) CYTOLYSIS the bursting of an animal cell when placed in a hypotonic solution. PLASMOLYSIS the shrinking of a plant cell placed in a hypertonic solution. TURGOR PRESSURE the force that pushes out on a plant’s cell wall when it is placed into a hypotonic solution. water

FACILITATED DIFFUSION Term Definition Example/Picture Passive Transport DIFFUSION Movement of molecules (dots) from high concentration to low concentration The circle is a cell. Dots are molecules and white space is water. OSMOSIS Movement of water (white space) from where there is more water to where there is less. In other words the water moves to dilute the dots. Causes a cell to shrink or swell. FACILITATED DIFFUSION Movement of molecules (dots) from high concentration to low concentration but through a protein channel in the cell membrane dots water dots Protein channel

Cell Transport Practice Use each diagram below to answer the questions about the movement of molecules across the cell membrane. The process taking place is osmosis The dots represent sugar molecules What molecules are moving in this example? WATER Draw the arrows on the diagram above to show the direction of movement in this example. What will happen to this cell? IT WILL SWELL OR GROW

The process taking place is facilitated diffusion The dots represent Calcium ions (Ca+) 4. What molecules are moving in this example? CALCIUM IONS Draw the arrows on the diagram above to show the direction of movement in this example. What does the calcium have to go through? PROTEIN CHANNEL

7. What molecules are moving in this example? OXYGEN The process taking place is diffusion The dots represent oxygen (O2). 7. What molecules are moving in this example? OXYGEN Draw the arrows on the diagram above to show the direction of movement in this example. All three of the above problems are examples of what type of transport, passive or active???? How do you know? PASSIVE TRANSPORT BECAUSE THE MOLECULES MOVE FROM HIGH TO LOW AND NO ENERGY NEEDED.

ACTIVE TRANSPORT

Active 3 Types Requires ENERGY (ATP) Movement is against the CONCENTRATION GRADIENT, from LOW concentration to HIGH concentration 3 Types PUMP ENDOCYTOSIS EXOCYTOSIS Before After A B A B molecules move to side A and become more CONCENTRATED Cell Transport Active Transport Endocytosis Phagocytosis Exocytosis

Active Transport PUMP Movement of large or charged particles from low concentration to high concentration through a protein channel ENDOCYTOSIS Movement of larger particles into the cell EXOCYTOSIS Movement of larger particles outside the cell Protein channel dots

What is moving? PROTEINS The process taking place is exocytosis The dots (particles) represent proteins; the space represents water What is moving? PROTEINS Draw the arrows on the diagram above to show the direction of movement in this example. All three of the above problems are examples of what type of transport, passive or active???? How do you know? ACTIVE TRANSPORT BECAUSE MOLECULES GO FROM LOW TO HIGH AND ENERGY IS NEEDED.

Cell Transport Video