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IN: Label structures and arrows.

Color similar structures with the same color.

What is a catalyst?

Why are catalysts important?

More on Matter in Ecosystems Macromolecules to Organelles to Cells

Where are cells on the biological scale?

• Sub-Atomic Particles • Atoms • Molecules • Macromolecules (proteins, lipids, nucleic acids, carbohydrates) • Organelles • Cells • Tissue • Organs • Organ System • Organism • Population • Community • Ecosystems • Biome • Biosphere • Solar System • Universe

Atom

Molecule

Macromolecule

Organelle

Cell

Tissue

Organ

System

Organism

Population

Community

Ecosystem

Biome

Biosphere

Let’s scale up!

Another quick look at where we are….

I. Macromolecules Make up the Organelles of a Cell

A. Proteins

B. Carbohydrates

C. Lipids

D. Nucleic acids

Cell Organelles

II. Cell Organelles A.Nucleus

a. Has a nuclear envelope and a nucleolus

b.Contains DNA c. Controls all cell activities

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B. Mitochondria a.Double membrane; football shape b. “Power House” of the cell

1. Food converted into ATP energy (adenosine triphosphate= “gasoline of cells”) 2. Uses Oxygen, produces CO2

C. Endoplasmic Reticulum a. Site where cell membrane and proteins are

made b. Two types of ER membrane: Rough (ribosomes attached) and Smooth c. “Highways” of the cell

D. Golgi Apparatus - Receives and modifies proteins

E. Lysosomes a. Cellular digestion b. Breakdown of waste

F. Cytoplasm (cytosol) -

Water based, gel-like material where chemical reactions occur

G. Cytoskeleton -

Filaments move organelles and the cell

H. Vesicles -

Sacs of material from the cell membrane, ER, and Golgi

I. Chloroplast (plant cells only)

a. Bean-shaped; with numerous membranes

b. Contains chlorophyll

c. Where photosynthesis takes place

J. Ribosomes a. tiny molecular machine made of two

subunits b. the site of protein synthesis

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K. Cell Membrane (plasma membrane) a. Encloses cell and organelles

b. Membrane is fluid-like and is constantly in motion

c. Made of a “phospholipid bilayer” d. Phospholipids have non-polar, hydrophobic (water hating) ends that stick together and polar, hydrophilic (water loving) ends

II. Importance of the Cell Membrane A. Proteins on the surface and

embedded in the cell membrane interact with “lipid bilayer”

B. Membrane and proteins control what goes in and out of cell

C. Proteins act like pores, channels, pumps and carriers

D. Many enzymes in the cell membrane speed up chemical reactions

E. Carbohydrate “antenna” embedded in membrane allows cells to communicate

carbohydrates

III. Crossing the Cell Membrane A. The membrane is

selectively permeable which means some things can get through and some cannot.

B. Small, polar molecules pass through the membrane with ease Ex: Water, carbon dioxide, and oxygen

C. Large, non-polar molecules and ions do not pass through without help Ex: glucose

OUT: Cell Membrane Model • Use the contents in the baggy to build a model of the cell

membrane. Color and label the proteins, carbohydrates, lipid bilayer, fatty acids, and phosphate group.

STOP

I. Cells Respond to their Environment A. Homeostasis – cells maintain a constant internal

environment in response to environmental changes

B. Assures balance and equilibrium to keep cells healthy

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II. Maintaining Cell Homeostasis with and without Energy

A. Passive Transport

(Requires no Energy)

a. Diffusion – Molecules move from an area of higher concentration to an area of lower concentration

b. Simple Diffusion –Molecules move directly through the membrane. Molecules move with the concentration gradient (a difference in the concentration of molecules across a distance.)

Diagram what happens after diffusion in your notes.

Draw arrows into your notes to show molecule movement.

c. Facilitated Diffusion – carrier proteins help transport larger molecules and ions WITH their concentration gradient (from HIGH to LOW concentration)

• Solute – molecule being dissolved

• Solvent – the substance that dissolves the solute; usually water.

d. Osmosis – water molecules diffuse across a cell membrane

1. Water moves from an area of higher (water) concentration to an area of lower (water) concentration.

2. Water always moves in the direction of high solute.

Add to your notebook!

3. Osmosis affects cells. Types of Solutions: • Hypotonic – Solute concentration is

lower outside the cell compared to inside the cell. (water moves in)

• Hypertonic – Solute concentration is higher outside the cell compared to inside the cell. (water moves out)

• Isotonic – Solute concentration is equal inside and outside the cell.

B. Active Transport (Requires Energy)

a. Carrier proteins move molecules against concentration gradient

From LOW to HIGH

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b. Movement in Vesicles - Some molecules are too large to transport through carrier proteins. 1. Endocytosis – cell

membrane pinches in and creates a vesicle enclosing macromolecules and large particles

Ex: food and bacteria

2. Exocytosis - membrane vesicle fuses with cell membrane and releases material outside cell

Ex: proteins, waste, and toxins

Need Energy