Movement through the cell:Molecules have to move

around the cell to do their jobs.

Sometimes they go into, or out of an organelle.Our cells use Diffusion and Osmosis to do this job.But,……. How do large

molecules get in?

Crossing the Membrane

Nutrients must get in and wastes must get out.

Signaling molecules received by a cell may need to get in, while signaling molecules sent by a cell need to get out.

Fluid must be able to get in and out.

Certain ions must be able to get in and out.

Types of transport:Passive Transport:

Either by simple diffusion or through a membrane protein

Requires NO Energy

Active Transport:

Requires Energy - ATP

Always happens through a membrane protein and uses ATP to force a molecule across a membrane against concentration grandient

Big Stuff?

Membrane Proteins are adequate for bring small molecules into the cell or out of the cell.

However, a different kind of active transport is necessary to move large things into/out of the cell – vesicular transport.

There are 2 types of vesicular transport:

exocytosis and endocytosis

Exocytosis Exocytosis literally means “out of the cell” It accounts for hormone secretion, neurotransmitter

release, mucus secretion, and, sometimes, ejection of wastes. Inside the cell, the substance to be exported is enclosed in a

membranous sac called a vesicle. The vesicle will migrate to the PM fuse with it, and then rupture,

spilling the contents into the extracellular space.

Endocytosis

Reverse of exocytosis. Allows macromolecules to enter cells. The substance is progressively enclosed by an enfolding portion of the

plasma membrane. This forms a vesicle which will pinch off the plasma membrane and enter

the cytosol where it is typically digested.

Types of endocytosis are: Phagocytosis Pinocytosis (a.k.a. bulk-phase endocytosis) Receptor-mediated endocytosis

Phagocytosis Literally “cell-eating.” Cytoplasmic extensions

called pseudopods “reach out and grab” large, solid material such as a clump of bacteria or cell debris, and then engulf it.

The resulting vesicle is called a phagosome.

Usually, the phagosome fuses with a lysosome, a membranous organelle that contains digestive enzymes, and its contents are digested.

Macrophages and white blood cells are the most phagocytic cells in the body.

Pinocytosis Literally means “cell-drinking.” A bit of infolding plasma membrane

surrounds a droplet of extracellular fluid containing dissolved molecules. This creates a tiny membranous vesicle.

Most cells routinely perform this. Unlike phagocytosis, pinocytosis is

unselective!

Photosynthesis and RespirationWhere does your energy come from?

Autotroph: - having the ability to make ones own energy (food).

Heterotroph: - having to take energy from another organism.

Plants

Chemo-Autotrophs

Us!

Your Body uses Chemical Energy

ATP Adenosine Triphosphate

AdenineRibose Sugar

Three phosphatesADP - Adenosine Diphosphate (only two phosphates) is

converted to ATP In cells to store energy for cells!

Using the energy - Cells break off the 3rd phosphate and use the released energy.

PhotosynthesisThe PROCESS of using the energy from the sun to Convert CO2 and Water into Glucose and O2

The Equation:

6CO2 + 6H2O C6H12O6 + 6O2

6 Carbon Dioxides

6 Waters1 Glucose (sugar)

6 Oxygens

But it happens in two different Reactions

Light ReactionLight Reaction

and Dark Reaction

Light ReactionTake place inside the

Chloroplast at a specific place.

Stacks of individual “disks” called Thylakoids

A stack of these thylakoids is called a Granum

(grana = plural)

Chlorophyll molecules are arranged in Photosystems.When a PHOTONPHOTON of light strikes anywhere on the photosystem, electrons are passed to the center and ATP and NADPH are made.

ADPP

NADP+

H2O

ATP NADPHO2

The ATP and NADPH go outside the Grana into the space in the Chloroplasts called the Stroma

This is where the “Light Light Independent reactionIndependent reaction” takes place.a.k.a. : Calvin Cycle or

“Dark Reaction” because it can happen in the dark.

Melvin Calvin

The Light Independent Reaction goes as follows:

CO2 enters

ATP

ADP

CO3

NADPH

NADP+C6H12O6

glucose

Remaining CO units

ATP

ADP 3 – CO5

For every 6 Carbon dioxide and 6 water molecules that enter the Chloroplast, 1 glucose and 6 Oxygen is created or

6CO2 + 6H2O C6H12O6 + 6O2

But what happens if we reverse the arrow?

Now we are burning Sugar with Oxygen to get Water and Carbon dioxide.

What burns Sugar (glucose) and Oxygen together?

All living things!This Process is called

Cellular Respiration

C6H12O6 + 6O2 6CO2 + 6H2O

ENERGY

Cellular Respiration Starts

when Glucose enters the cell !

nucleus

mitochondria

Glucose

Glucose

Glycolysis: First step in

Cellular Respiration where Glucose is split in half inside the cytoplasm.Process:

Pyruvic Acids

C C

C C C

C

2-ADP 2-ATP

2-NAD+ 2-NADHto the

Mitochondria

Inside the Mitochondria: 2 Pyruvate

Molecules2 CO2

Krebs Cycle

4 CO2

8-NADH and 2-FADH2

2 ATP

Electron Transport

H2O

32 ATP

Total 34 ATP

The Two Pyruvate Molecules enter the Krebs Cycle. A total of 6 CO2 and 2 ATP are Produced.NADH and FADH2 enter the Electron Transport Chain.Water and 32 ATP are produced giving 34 total ATP produced in the Mitochondria.

O2 Enters

What happens if you can’t give the cell enough O2?

Pyruvic Acids

C C

C C C

C

2-NAD+ 2-NADH

2-ADP 2-ATP

After Glycolysis, if there is not enough O2 to go through cellular respiration, the cell converts the NADH into ATP and the Pyruvic acid breaks down into Lactic Acid

Lactic Acid FermentationGlycolysis

Lactic Acid

O2X

Let’s RecapPhotosynthesis converts Light energy from the sun into

Sugar

6CO2 + 6H2O C6H12O6 + 6O2

6CO2 + 6H2O C6H12O6 + 6O2

ATP

Respiration converts Sugar into usable energy – A T P

Notice any similarities?

Review1. Active Transport 2. Passive Transport 3. Pinocytosos

4. Exocytosis 5. Phagocytosis 6. Autotroph

7. Heterotroph 8. ATP 9. ADP

10. Light Reaction 11. Light Independent Reaction 12. Photon

13. Chlorophyll 14. Cellular respiration 15. Glycolysis

16. Pyruvic Acid 17. Electron Transport Chain 18. Krebs Cycle

19. Lactic Acid Fermentation

Questions:1. Be able to describe the process of photosynthesis.

2. What is the difference between the light and light independent reactions?

3. Describe the steps in Cellular respiration.

4. What is the difference between Cellular respiration and Lactic Acid Fermentation?