October 13, 2011

Today in class, we went through the notes about viruses and watched a video about the flu. Here's a basic overview of the notes.

Viruses: Living or non-living?

• viruses are between life and non-life
• Living characteristics: contain genes (RNA or DNA), are highly organized (complex protein structure
• Non-living characteristics: not made of cells, cannot reproduce on thier own: viruses don't have the necessary structures to reproduce so they must use the structures of living cells

Structure

• nucleic acid, the genetic material, is inside a protein coat
• often include: head (where genes are held), tail, tail fibers

The virus in the animation on the left is called a T4 Bacteriophage. It is easy to see the structure of this virus.

http://www.emc.maricopa.edu/faculty/farabee/biobk/biobookdiversity_1.html

Reproduction: Lytic and Lysogenic Cycles

Lytic Cycle

1. virus injects genes into a host cell
2. "hijacks" cell structures and uses them to make copies of itself
3. viruses eventually causes the cell to lyse (burst)
4. viruses are released to find a new host cell

Lysogenic Cycle

1. virus injects genes into host cell
2. viral genes are incorporated into normal cell genes
3. genes are passed on without the cell making copies of the virus
4. while in lysogenic cycle, cell does not lyse
5. environmental changes will trigger the viral genes to switch to the lytic cycle

http://terra.dadeschools.net/Books/Biology/BiologyExploringLife04/0-13-115075-8/text/chapter16/concept16.5.html

Plant Viruses

• affect plants: interfere with growth and damages crops
• most plant viruses have RNA not DNA
• viruses are designed to get past plant epidermis and cell walls
• no cure for the majority of plant viruses
• humans have created plants that are resistant to certain viruses

Examples: Tobacco mosiac virus (TMV) and tomatoes, PRSV and papaya

Animal Viruses

• many have a phosolipid outer layer, just like a cell's plasma membrane: allows viruses to slip in and out of the cell through endocytosis and exocytosis
• reproduce in cell's cytoplasm: needs ribosomes to make viral proteins
• RNA and DNA viruses
• RNA viruses: HIV, mumps, common cold, polio
• DNA viruses: chicken pox, herpes, hepatitis

http://www.sciencegateway.org/resources/biologytext/cb/virus/virus.html

HIV: the cause of AIDs

• Retrovirus: reproduces by the use of viral DNA molecules
• normally, cells use DNA to produce RNA (transcription)
• HIV has cells use RNA to produce DNA (reverse transcription)
• RNA then makes proteins
• viral genes now in cell's genes, cell is producing viral proteins
• Drugs for HIV: inhibit reverse transcription or inhibit production of the viral proteins

http://www.visualphotos.com/photo/2x4142081/hiv_virus_particles_computer_artwork_hiv_human_f0013163.jpg

The full notes are on Moodle. The video we watched featured influenza, the flu, and was basically a review of the notes.

Homework: review viruses, moodle notes, work on group project script, work on textbook notes sheet

NEXT SCRIBE: Yvette

October 6th, 2011

Today in class we did day 2 for the egg demo. Since our egg broke yesterday we redid the experiment for day 2 and our results were:

• still the same shape


• that the egg was soft


• bubbles on the shell


• the shell was getting thinner so you could see the yolk a little bit


• the egg was slightly yellow as a result of the thin shell
  http://www.greensim.com/lemonade/egg1.JPG
  
  
  

We also went over the Mitosis notes from last night's homework.
-To find the notes log onto moodle and go to the biology page, then scroll down to Unit 2- Cells R us and click on the folder called class notes unit 2 and then click CH 7mitosis notes

In class we started the Mitosis lab in the UP packet on pages 53-56. We will finish the lab later in class.

Homework:

• Study for unit test on Tuesday


• work on lab UP pages 53-56


• Internet activities on pg. 4 (review)

Up next is Lydia

October 5th, 2011

In class today we first checked our Egg Mitosis DEMO. The egg was soaked in vinegar and we had to draw a picture and describe it. The shell was being eaten away by the vinegar so it did not make a noise when it was touched. It was soft instead of hard. There were bubbles all over it because the shell was being eaten away and there was no color change.

Next in class we did a lab about osmosis and diffusion on pages 41-42. Under a microscope, we looked at elodea leaves with regular tap water and 6% salt water. The plant cells looked normal in the tap water. The chloroplasts were all on the outside of the cell, the cell membrane was close to the wall, the vacuole was visible and the nucleus was seen. In the 6% salt water, though, the cell membrane condensed and the vacuole shrunk. Here is a cartoon showing what happened from http://waynesword.palomar.edu/images/elcell7a.jpg:

As can be seen, the water left the vacuole and it could not be seen, but is still present.

We also drew a picture (similar to these pictures) of what we saw in each type pf water. We also labeled what we saw. We then answered questions from the lab on page 42 by ourselves, and then went over them in class together.

We filled out page 43, which was about osmosis and different water concentrations inside and outside of cells.

At the end of class we watched an intro movie to mitosis.

Homework: Read Chapter 8 (pages 121-129), Mitosis notes from Moodle, and read mitosis labs from pages 53-60.

Next Scribe: Maddy

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

Oct. 3, 2011

Today we finished the notes on the cytoskeleton and began notes on the cell membrane. There is a quiz tomorrow on everything we've learned so far in the section. There is also a lab tomorrow. The homework is to read pages 37-39 in our UP and draw a picture of the lab.

Here are some basic overviews of what we learned.

Intermediate Filaments

• ropelike protiens
• anchor organelles

Microtubules

• straight, hollow tubes made of protiens called tubulins
• provide rigity and shape to the cell
• tracks for organelle movement
• guide chromosome movement in cell division
• move cilia and flagella

Cilia-propel protists

Flagella-propel some types of cells, long "tail"

Microtubule structure

• form a 9+2 arrangementto
• to move cilia or flagella, dyniens grap onto an adjacent microtubule doublet
• basal bodies and centrioles have identical structures

Plasma Membrane

membranes of a cell

• plasma membrane-outer membrane
• endomembranes-smooth and rough ER, golgi, vacuole,lysosome
• membraneous envelope-nucleus chloroplast mitochondria

membrane features

• semi-permeable, allow some substances to pass through, but not others

membrane structure

• two layer membrane called phospholipid bilayer, composed of protien and lipids
• lipids called phospholipids
• contain 2 fatty acids, not 3, fatty acids are hydrophobic
• contain phosphate groub in place of 3rd fatty acid

flexibility

• membranes not flexible, rigid
• protiens move freely in membrane plane
• called fluid mosaic

diffusion and osmosis

diffusion-the tendency of molecules to move from a higher concentration to a low concentration until equilibreum is reached

Passive transport

• diffusion across a membrane
• cell uses no energy
• selectively permeable membrane
• osmosis-passive transport of water across a semipermeable membrane
• in osmosis water moves across membrane not the solute

Hyper tonic-solution with a higher concentration of solute and a lower concentration of water

hypotonic- solution wit ha lower concentration of solute and a higher water concentration

isotonic-solution with equal solute concentration

Effect on living animal cells

• osmoregulation-control of water balance
• animals must use this when exposed to hypertonic or hypotonic environments
• fish use gills and kidneys to keep too much water out

Effect on living plant cells

• most plants thrive in a hypotonic environment when there is more water
• plants become wiltedin isotonic environment

next-Dana

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

Today in Biology the class participated in a cell structure and function lab. This lab included a microscope to observe the cells. The cells came from different substances and objects such as tomato skin, potato skin, frog blood, streptococcus lactis, onions, algae, elodea leaves and the inside of human cheeks. The cells were observed in a slide. Substances such as iodine, water and methylene were put on the slide as well to help make the cells visible. The lab did not include a true experiment involving control and independent variables but was more of observations and the study of cells. The lab was divided into two different parts; part two was considerably longer with the observation of six different cells. There was also a prelab and homework.


Prelab (pgs. 23-26)

Before students could participate in the lab they had to complete a prelab that was divided into two different parts. Part one dealt with prokaryotic cells and their organelles/structures. There was a picture of a prokaryotic and five different structures students had to label and describe their functions. On the second page of part one there was two pictures of eukaryotic cells; one was of a plant cell, the other,an animal cell. Once again the students had to label eighteen different structures and describe their functions. Part two was the comparison of plant and animal cells. There was a chart that had to be filled out with organelles that were unique in only one of the cell types, plant or animal. This was followed by pre lab questions that dealt with previewing the lab and answering questions about the materials and connecting them to the previous activity.

Part I (pg. 27-28)

Part one of the lab dealt with the observation of the prokaryotic cells from streptococcus lactis and eukaryotic cells from the skin of an onion. The streptococcus lactic was put on a slide with a cover slip and observed under 400x power of a microscope. The students than had to draw what they observed. The students than had to peel off the transparent membrane of an onion and place it on a slide with one drop of iodine and a cover slip. Once the slide was prepared the slide was observed under the microscope at 400x power. Once again what was seen under the microscope was drawn out on the designated area in the packet.


Part II (pgs. 28-30)

Part two of the lab was the observation of eukaryotic cells, both plant and animal. Students had to first pull off an elodea leaf with tweezers and place it on a wet mount slide with a cover slip. This leaf was than observed under the microscope at low power and high power. The observations were than drawn on the packet, the students could choose whether to draw the image at low power or the 400x power (high). The elodea leaf was than observed in a slide that now had iodine. The iodine stain maid the organelles more visible. The students than had to sketch what the elodea leaf looked like under high power. The students than had to take a toothpick and rub the inside of their cheek and mix the cells on the toothpick on to a wet mount slide with methylene blue stain. After placing a cover slip over the slip the slide was to be placed under the microscope and the cells observed under low than high power. The students than had to sketch their observations of the cheek cell under high power and label the parts of the cheek cell. The next substance to be observed was frog blood. Students had to take a pre prepared slide of frog blood. The students must than title the magnification they chose to observe the frog blood cells under. The students than had to cut off a piece of potato skin and place it on a wet mount slide with a cover slip. The potato skin was than observed under the microscope power of choosing and the observations sketched out on the designated area on the packet. The students than had to cut off a piece of tomato skin and place it on a wet mount slide with a cover slip. The slide was than to be placed under the microscope and observed under the power of choosing, the observations were than to be sketched in the packet. The last substance to be observed was a piece of algae. The algae was placed on a wet mount slide and observed under the microscope and the observations were sketched out.

Post lab/ homework (pgs. 31-32)

The homework for this lab was to answer analysis questions on pg. 31 and to label the parts of the cell pictures on pg. 32. Also to finish up any unfinished questions on pgs. 27-30.