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CELL Structure REVIEW Cell Theory/Cell size

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Presentation on theme: "CELL Structure REVIEW Cell Theory/Cell size"— Presentation transcript:

1 CELL Structure REVIEW Cell Theory/Cell size
Types of cells: Prokaryotes VS Eukaryotes Cell Membrane and how substances move across the membrane Cell Organelles

PASSIVE TRANSPORT : Diffusion, Osmosis Crossing the membrane ACTIVE TRANSPORT: Moving against a concentration gradient Moving in Vessicles Membrane Receptor Proteins

3 Cell Theory 1) All Living things are made of one or more cells
Cells are the basic units of life All cells come from existing cells

4 Cell Size Small cells can exchange substances more readily than large cells because small objects have a higher surface area to volume ratio than larger objects SMALL CELLS FUNCTION MORE EFFICIENTLY THAN LARGE CELLS. 100 TRILLION CELLS IN HUMAN BODY

5 Common features of cells
Cell Membrane: Encloses the cell and separates the cell interior, the cytoplasm, from its surroundings.Regulates what enters and leaves the cells-including gases, nutrients and wastes. Cytoskeleton: Small fibers in cell providing structural support. Ribosomes:Cell structures where proteins are made. DNA:Provides instruction for making proteins and allows cell to reproduce.

6 PROKARYOTES Smallest, simplest cells.
Single celled organism that lacks a nucleus and other internal compartments. (Therefore, not able to carry our specialized functions) 3.5 billion yrs old

7 Prokaryotes continued
For two billion yrs, they were the only organisms on earth. Bacteria=most common prokaryote. Can cause infections and cause food to spoil.

8 Characteristics of a Prokaryote
They can live in a broad range of environmental conditions. Many grow and divide rapidly. Some do not need oxygen to survive. Some make their own food. Circular molecule of DNA. Have Cell Wall Some have polysaccharide capsule Flagella

9 Eukaryotic Cell Evolved 2.5 billion yrs ago. NUCLEUS!
Has internal compartments called organelles! Cilia and/or flagella Cytoskeleton (Actin fibers, Microtubules, Intermediate fibers)

10 Eukaryote continued Cell membrane: Fluid like soap bubbles!
Double layer of polar heads and non polar tails Allows lipids and substances that dissolve in lipids to pass through. Contains different kinds of proteins.

11 Membrane proteins of cell membrane
Proteins are made of amino acids. Some amino acids are polar and some are non polar. This attraction holds the proteins in the bilayer. MARKER PROTEINS: attach to carbohydrate on the surface and advertise the cell type. Receptor PROTEINS: bind specific substances , such as signal molecules, outside the cell. TRANSPORT PROTEINS: Help in movement of substances in/out of cell.

The nucleus Ribosomes Endoplasmic Reticulum (smooth and rough) Vesicle Golgi apparatus Lysosomes Mitochondria (Mitochondrial DNA)

13 Plant cell Features unique to plant cells (Eukaryotes too!): Cell Wall
Chloroplasts Central Vacuole

14 Cells and their Environment
This section describes how substances move through other substances according to their concentrations in solutions. It also describes how substances move across cell membranes through channels.

15 Passive Transport Passive Transport: Movement across the cell membrane that does not require energy from the cell. Concentration Gradient: Difference in the concentration of a substance across a space.

16 Diffusion and Osmosis: Types of Passive Transport
Diffusion: Movement of a substance from an area of high to low concentration, Until equilibrium is reached. This is a movement DOWN the concentration gradient Osmosis: The diffusion of water through a selectively permeable membrane down a concentration gradient.

17 Possibilities for the direction of water movement:Hypertonic
If the Fluid outside of the cell has low concentration of water molecules than inside, then the outside fluid is hypertonic. The water will diffuse out of the cell and the cell will shrink

18 Hypotonic If the fluid outside has a higher concentration of water than inside the cell, Then the outside solution is hypotonic and water will diffuse into the cell and the cell will swell!

19 Isotonic Solution If the fluid outside the cell has the same amount of water concentration as the fluid inside the cell, then the fluid outside is ISOTONIC and water will diffuse into and out of the cell at equal rates. Cell stays same size.

20 How do polar molecules pass over the membrane?
Remember, most ions and polar molecules cannot pass across the cell membranes because they cannot pass through the non polar interior of the lipid bilayer. They can cross if they have help from a transport protein. These proteins have channels in them. Diffusion through ion channels is still a type of passive transport!

21 Facilitated Diffusion
CARRIER PROTEINS are used to carry substances across the membrane and release them on the other side. (Example: Transporting sugars and amino acids DOWN the concentration gradient.) This transport is called Facilitated diffusion.

22 Carrier proteins used to transport substances

23 Active Transport: Transporting substances UP the concentration gradient
Movement against a concentration gradient. Active transport requires the cell to use energy. Most of this energy is supplied by ATP!

24 Example of Active Transport: Sodium potassium pump

25 What about stuff that is too big to be transported by carrier proteins?
Vesicles move large substances across the membrane. Movement of substances into the cell by a vesicle is called ENDOCYTOSIS Movement of a substance out of the cell by a vesicle is called EXOCYTOSIS.

26 Cell Cycle

27 Binary Fission

28 Mitosis (PMAT)

29 Meiosis

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