BELL WORK:Answer the following questions on your bell work page:

1. A scientist finds a unicellular organism. He can see its DNA is free-floating in the center of the cell. What kind of cell is this, and how do you know?

2. Which organelles help produce and move proteins in a cell? (hint: there are THREE)

Today’s Standard (B.4B): Investigate and explain cellular processes including…transport of molecules

Set up page 17 in your journal for Cornell notes

• Essential Question: How do I describe molecules and the cell membrane?

• Biology= study of life

• Chemistry= study of matter, its composition, and properties

• Biochemistry: The Chemistry of Life

• Matter: anything that takes up space– Matter is created by the organization of atoms

• Atom: basic unit of matter (building block of a molecule) smallest amount of an element. (Contains protons, neutrons, electrons etc)– Ex: Hydrogen

• Element: Substance Made up of only ONE type of atom– Ex: Pure iron consists of only the atom, iron

• Molecule: two or more atoms bonded together– Ex: H-H (2 Hydrogen atoms bonded together make a molecule) Diatomic Nitrogen

Molecule vs Compound• Compound: when two or more DIFFERENT atoms combine.

– Ex: H2O

– So H-H is a molecule and H-H-O is a compound….

– With a partner discuss and decide:• Is H20 considered a molecule as well as a

compound?• Is H-H considered a compound as well as a

molecule?**Hint- breakdown the definitions, the answer is there**

AnalogyImagine going to an ice cream store. Let's say that they have 30 different flavors of ice cream. Those are elements, the things that I have available to build my dessert from. The smallest amount of ice cream that the store will sell to me is a scoop. This is an atom. If I want, I can put two or more scoops of ice cream together. This is a molecule. If my molecule has more than one flavor of ice cream, I can call it a compound.

Atom Molecule / Compound

http://education.jlab.org/qa/atoms_and_elements.html

Element/Molecule/Compound Sort

• Sort the following pictures into elements, molecules and compounds with your shoulder partner

CELL MEMBRANE: a thin, flexible barrier surrounding ALL cells

What is the cell membrane’s function (job)?

(2 things)

Two main functions: 1) regulate what enters (food, water, &

oxygen) & leaves (waste) **HOMEOSTASIS**

2) provide protection & support

What is the cell membrane composed (made) of?

(3 types of molecules)

LIPIDS: the main component of a cell membrane–Found in a double layer called the lipid

bilayer–Also called the phospholipid bilayer–hydrophobic (afraid of water)

DRAW THIS!

PROTEINS: embedded into the lipid bilayer–Form channels or pumps (pathways)

to help move large molecules

CARBOHYDRATES: attached to many proteins on the outside of the bilayer– allow cells to communicate with each

other carbohydrates

Debrief: Answer the essential question in the summary section of your journal

Bellwork 9/10: Copy the question and answer them

1. How does the cell membrane help the cell maintain homeostasis?

2. What are other names for the cell membrane?

• **Make sure your table of contents is up to date.**

(Page 19 for Cornell notes) EQ: How do molecules move in or out

through the cell membrane?

Why does food coloring spread out in water?

• In a solution, particles are constantly moving.

• They collide with one another and spread out randomly.

DIFFUSION: particles move from an area of HIGH concentration to an area of LOW concentration Ex. Food coloring in water, a perfume in class

Could temperature affect the rate of diffusion? Why? When would it hurt the cell? What about if I diffused the food coloring in oil?

CONCENTRATION: the amount of solute (stuff) dissolved into a solvent (liquid)

KOOL-AID is the solute

WATER is the solvent

CONCENTRATION is how much Kool-Aid you put in

CONCENTRATION GRADIENT: a difference between two concentrations

If diffusion is going from high concentration to low concentration, what direction is it moving on the concentration gradient?

High Concentration

Low Concentration

Concentration Gradient

Moving WITH the concentration gradient (high to low) requires no energy from the cell.

*Go with the flow

EQUILIBRIUM: the concentration of a solute is the same throughout a system–particles continue to move–the goal of diffusion!

The rate (speed) at which molecules pass through a membrane depends

on its permeability.

PERMEABLE membranes allow all substances to

pass through

IMPERMEABLE membranes allow no

substances to pass through

Biological (cell) membranes are SELECTIVELY permeable–Some substances can pass through, while

others cannot (ex. Screen door)

The lipid bilayer will allow most small molecules to diffuse in and out but not large or charged

molecules.

Given what we just learned, how would substances move across the following membranes?

So, if the cell needs these larger or charged molecules to function, how are they able to get

through?

Facilitated Diffusion: transport of molecules across a membrane using specific transport proteins.

Facilitate: to make easier or to assist

Diffuse: when molecules move from high to low concentration or with the concentration gradient

High

Low

Facilitated Diffusion

Diffusion and Facilitated Diffusion both go with the concentration gradient. (high to low)

Modeling with mats

1. Use your eraser to move the sequins 2. Make sure you listen to the scenarios.3. Sketch each scenario on page 18 in your

journal. (Beginning and ending cell).