Tuesday October 4, 2011

Tuesday, October 4, 2011

Today we had a quiz in everything we've learned so far in the cells unit. We read over and completed day 1 of the Egg Osmosis DEMO in class. Also we did the "Diffusion Through a Cell Membrane" lab. Due today was to read pages 37-39 in UP.

The Egg Osmosis DEMO

The Egg Osmosis Demo, found on pages 45-47 in the unit packet, talks about hows osmosis is the diffusion of water across a semi-permeable membrane. It also talks about homeostasis and how it is maintained in part by controlling the movement of materials into and out of the cell.

In class Mrs. Andrews held up an egg and we drew a picture of it and made observations like; white, hard shell, and oblong. This was recorded under day 1-raw egg on page 46 in the unit packet.

Diffusion Through a Cell Membrane Lab

1. We drew a diagram of what our materials will look like when they are set up. There is the dialysis tubing that

contains glucose, starch, and water that is placed in a beaker which contains 50mL of water and iodine (brownish yellow color).

2. We proceeded with the lab by adding glucose and starch to the tubing and tying it off then placing it in a beaker filled with iodine and water for 15 minutes.

3. After 15 minutes we came back and the starch in the tubing had turned a blue black color and settled to the bottom. Also the iodine diffused in the tubing because the liquid inside the tubing was a brownish yellow color.

4. By dipping a piece of Tes-Tape (glucose indicator paper) into the liquid in the beaker we found that there was a

presence of glucose outside the tubing because the tape turned a to light green. From this we

concluded that the glucose diffused from inside the dialysis tubing to the beaker.

After 15 minutes the beaker looked like this. With the starch dyed blue/black because of the iodine and iodine diffused into the tubing as well as the glucose diffused into the beaker although you cannot see it.

From these results we concluded that:

1. The iodine diffused from the high concentration in the beaker to the low concentration in the dialysis tubing.

2. The glucose diffused from the high concentration in the tubing to the low concentration on the beaker.

3. The water did a little bit of diffusing both into the tubing and out.

4. Starch molecules are a lot larger than glucose, water, and iodine molecules because they couldn't diffuse through the dialysis tubing membrane.

Due tomorrow is the Diffusion Through a Membrane lab (p.37-39)

up next-Austin

At the beginning of class on Friday, we turned in both of our labs that we had finished. After turning in our labs we immediately began taking notes in our Basics of Organic Chemistry notes packet (yellow packet). It was a rushed day because of the shortened periods but we managed to finish taking notes from the "CELLS Structure and Functions" part of our notes to most of the "Plasma Membrane" section of our notes.

1. Sections of our notes that we recognized as important were

• "World of Cells Theory"
• "Membrane Structure"

2. Bullet points in our notes packet we underlined :

• Scanning Electron Microscope- detailed architecture of the surface of a cell Transmission Electron Microscope- exploring the internal structure of a cell
• Nuclear Envelope: double membrane with pores that surrounds the nucleus

• DNA attached to protein is found in the nucleus in the form of chromatin
• Ribosomes are responsible for assisting in protein synthesis by making enzymes and proteins for the organism
• In the Endomembrane Review we circled Rough ER, Golgi apparatus,Vacuole, Lysosome, and Plasma membrane because they all work together
• Stroma- thick fluid inside the inner membrane (of chloroplasts)

3.Ideas discussed to help us comprehend what we learned better:

• Ribosomes go from the nucleus to the Rough Endoplasmic Reticulum (Rough ER) because it transports the ribosomes to where they need to go.
• In diagrams, proteins will always be purple
• The Golgi Apparatus is like a UPS system because it finishes, stores, and distributes chemical products of the cell.
• Lysosomes are like garbage centers.
• In diagrams, Grana (located in chloroplasts) looks like stacks of pancakes.

• When you hear ATP, think 'energy'.

4. Concepts/ideas we should be sure to review

• shapes and organelles unique to bacteria

• different parts of plant and animal cells

• being able to tell the difference between smooth ER and the golgi apparatus

Homework

• pages 33-55 in unit packet
• read chapter 5 pages 80-86
• everyday homework: review notes!
• EC: create your own cell doctor

next - Xavier

9/23/11

Today in class, we picked up where we left off in our yellow notes packet (from "What is an ENZYME?"). Some key vocabulary as defined in the packet:

1. Enzyme: specialized proteins which function as catalysts
2. Catalysts: speed up the rate of a chemical reaction without being used up itself (it is reused, or recycled)
3. Activation Energy: the amount of energy needed to stimulate the reactants to react in a chemical reaction.
   
4. pH: (potential hydrogen) the measurement of how acidic or basic a liquid solution is
5. Ion: a charged particle that has either gained or lost an electron
6. Acids: chemical compounds that give H+ ions to solutions
7. Bases: compounds that accept H+ ions and remove them from a solution
8. Neutral: a solution in which the concentration of H+ and OH- ions are equal
9. Substrate: a specific molecule that an enzyme recognizes to bind with

And then important ideas we discussed in class (also from the yellow notes packet):

• Protein Structure:

a. Primary Structure:

a SPECIFIC sequence of amino acids (any slight change could cause the protein to

not function properly)

b. Secondary Structure:

Held together by hydrogen bonds along the backbone (an alpha helix/pleated sheet)

c. Tertiary Structure:

Held together by chemical bonds between the side groups (3D in shape)

d. Quaternary Structure:

protein that consists of 2 or more polypeptide chains + the bonding of these chains

• Proteins are polymers of amino acid monomers
• Types of proteins= structural, storage, contractile, transport, defensive, signal, enzymes (important for our bodies to function)

• Ways to speed up a chemical reaction:
  

1. heat mixture in a lab (however, not for cells--too much heat may result in the shutting down of cells)
2. decrease in activation energy:

the enzyme binds to the reactant molecules making it easier to break their bonds

• Enzymes are affected by:
• temperature
• pH
• concentration
• specificity

Homework:

• UP p. 7-18 ("Enzymes are Everywhere" lab)
• Extra Credit Sheet
• Internet Biochemistry Tutorial p. 4 (for review)... Site on p. 5, #3 under "More Internet Activities"

Also, we got our Chapter 18 and 19 quiz back. Be sure to prepare for Monday's "Enzymes are Everywhere" lab!

Next Scribe: Michael