Onion Root Tips Mitosis WebQuest

ONION ROOT TIPS AND THE CELL CYCLE


In this activity, you will calculate the lengths of the various phases of the cell cycle in an onion root tip. First you will view some slides and graphics of onion root tips provided by the Molecular Expressions Photo Gallery. Then you will complete the online activity provided by the Biology Project at the University of Arizona.

Part 1.

Use your browser to go to Molecular Expressions Photo Gallery: Mitosis

http://www.microscopy.fsu.edu/micro/gallery/mitosis/mitosis.html

Notice in the micrograph at the top of the page that there are cells in a variety of stages. View the onion slides in this section, then click on "mitosis" in the sentence "Learn the steps in mitosis ... " This will take you to a Java tutorial.  Keep in mind what you have learned here as you proceed to the second part of the activity.

Part 2.

Use your browser to go to Online Onion Root Tips at

http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/assignment.html
Begin by reading the description of the five major cell phases. You will need to keep this information in mind during the activity.

Make a copy of the data sheet that appears on the second page. You will need it to answer the questions.

Proceed through the activity, identifying the phase for each cell you are shown. Pay attention to the hints if you misidentify a cell at first.

When you have completed the activity, answer the following questions:

1. What percent of cells were in interphase?
20%2. What percent were in mitosis?
100% All of the cells are in different stages of mitosis.3. Which phase of mitosis takes the longest?
Interphase
4. During which stage is the nucleolus visible as a dark spot?
Prophase5. How can you recognize a cell in metaphase?
It doesn't seem as dark as prophase; It's much lighter and looks like it's beginning to separate.6. How might you figure out how long (in minutes and/or seconds) each phase of the cell cycle takes based on the data from these onion root cells? Explain your logic and show your calculations and results below.

7. Produce a pie chart in Create-a-Graph that shows the relative lengths of each stage of the cell cycle in these cells including interphase and each stage of mitosis. You can embed the graph here.

	Interphase	Prophase	Metaphase	Anaphase	Telophase
Number of Cells	20	10	3	2	1	36
Percentage	55.55%	28%	8.33%	5.56%	2.78%	100%

Cancer Cells

Cells go through a cycle which includes many processes. These are:
1. Interphase
2. Prophase
3. Metaphase
4. Anaphase
5. Telophase

How do cancers...happen??
When cancers develop, it is because proteins don't work the same way because cells don't go from one stage to the next properly in their cycle. The cancer cells reproduce at a far faster rate than normal cells do. But those cells all seem to have a loss of function. This happens because the cell division does not happen properly. In most cases, cancer takes many years to develop.

So...give an example of a cancer and how it happens...
Let's use breast cancer as an example!
So breast cancer is a type of cancer that will form in any part of the breast. It's more commonly seen in women, but men are also at risk of getting this cancer, too. When cancer begins to occur, cells begin to go through a change which rapidly spreads through the body (as previously stated). Women release a hormone, estrogen, which stimulates cell division, but may effect cells and DNA to be damaged or permanently effected. Women who have not been through a first term of pregnancy still have immature cells and can be more easily effected by this because their cells contain carcinogens that are not as strong or able to repair damaged cells as easily.

How can one treat this?
Through cell technology and radiation techniques, scientists have found new ways to practically zap away the bad! Treatment programs can be created to help the side effects of the cancer be reduces and can even eliminate the cancer altogether!

Sources:
Scitable by Nature Education

The Biology of Breast Cancer

Breast Cancer

As it is the new year, I would like to present to you this month's end-of blog-picture topic! The snake! Happy 2013, the year of the snake!

Microscopy

Your supplies:
2 Artifacts
1 Test Tube

Now let's do this!


The main objective in this project is to test the ability to use a microscope. Objectives will be tested.

Start off on lowest magnification possible, find the desired area, and magnify!

There is a part just below the microscope call the condenser. It has an iris under microscope. If no light is coming through, the iris must be twisted. So of course, this is a sign that there's a little bit of microscope anatomy we need to touch up on first!

There!

First, we tested hair! The outcome was very interesting. It looked like the following:

JUST KIDDING!

It REALLY looked like...

Next, we checked out some infected pork! That one was very interesting to see up close! It looked somewhat like the following...

Notice the three chunked spots. That, we concluded, is the infection. Pretty nasty, but neat, right??

Microscopes are awesome! Just with one little peek through, one's world can be completely magnified! Very nifty tool that everyone should have to experience in playing with!

"By the help of Microscopes, there is nothing so small, as to escape our inquiry; hence there is a new visible World discovered to the understanding."-Robert Hooke

Diffusion and Osmosis Lab

     Diffusion and Osmosis are very similar and different. In this experiment, we will observe the strengths in their differences.
     As the lab analysis paper says, "molecules only move from regions of higher concentration to lower concentration during diffusion and osmosis. Cells often need to absorb molecules from regions in which concentration of the molecules may be lower than the concentration already inside the cell. The absorption of glucose from blood frequently occurs under these circumstances. Cells use the process of active transport to move substances through the cell membrane against a concentration gradient. Active transport involves proteins in the cell membrane and energy derived from ATP. Diffusion and osmosis do not require any added energy."
     A solution of glucose and starch will be placed inside a bag of dialysis tubing, and we will pour water into the beaker, outside the dialysis bag. We'll let it sit for about 30 minutes, and the solution inside the bialys is tubing and in the beaker were tested for glucose and starch. To test for glucose, we use indicator strips. To test for starch, we use Lugol's solution (iodine and potassium iodide) Starch appears to be a bluish-purple complex with iodine, and glucose does not.

	Initial Contents	Initial	Final	Initial	Final
Bag	15% Glucose $ 1% Starch	Clear	Clear and Black	+	+
Beaker	H2O + IKI	Yellow and Brown	Clear	+	+

1. How would you explain the results you obtained? Which substances are entering the bag and which are leaving the bag?

    I believe that the water from the outside of the bag started to seep into the bag. I believe this because a color change, or chemical reaction, took place. I know that such a thing wouldn't happen unless the solution was mixed with another.

2. What evidence could have been collected to show quantitatively that water diffused into the dialysis bag?

    The amount of water outside the bag, and inside the bag. These measurements could have been taken before and after the experiment.

3. What results would you expect if the experiment started with a glucose and IKI solution inside the bag and only starch and water outside?

    The results would be different because the IKI would have mixed differently with the glucose solution than the simple water and iodine mixture did.

Cell Membrane Notes

The plasma membrane is common to all cells
Separates:
  Internal living cytoplasmic from
  External environment of cell
Phospholipid bilayer:
  External surface lined with hydrophilic polar heads
  Cytoplasmic surface lined with hydrophilic polar heads
  Non polar, hydrophobic, fatty-acid tails sandwiched between

MEMBRANE MODELS
Fluid-Mosaic Model
Three components:
  Basic membrane referred to as phospholipid bilayer
  protein molecules
    float around like icebergs on a sea
    Membrane proteins may be peripheral or integral
      Peripheral proteins are found on the inner membrane surface
      Integral proteins are partially or wholly embedded (transmembrane) in the membrane
    Some have carbohydrate chains attached
  Cholesterol

How does it do its job?
How does it let stuff through?

It's like a perfume being sprayed. Once the particles get into the air, they spread out more. That's why people across the room can smell just one spray of perfume!

Diffusion: Movement from high concentration to low concentration

Osmosis: diffusion of water across a membrane

What CAN go across a cell membrane WILL go across!

When it is warmer, the molecules move faster. So when it's colder, they must move slower and it's tougher for them to move around.

My Macromolecules in Cells Web Activity

Web Activity: Macromolecules in Cells

Open your web browser and navigate to:

http://www.sci.uidaho.edu/bionet/biol115/t2_basics_of_life/lesson2.htm

Read the introduction to Macromolecules and answer these questions:

1. What is a macromolecule?

Macromolecules usually refer to a large group of molecules.

2. What is a monomer?

A monomer is something (one) that can be combined with other monomers to create polymers.

3. What is a polymer?

A polymer (multiple) is many monomers joined together.

4. List the four main types of macromolecules.

The four main types of macromolecules are proteins, lipids, carbohydrates, and nucleic acids.


In the learning materials box click the link for the activity “making and breaking polymers.”  Use this activity to help answer the following questions:

5. What are the types of reactions that macromolecules are shown to undergo?

Dehydration synthesis (condensation), and hydrolysis reaction (breaking down covalent bonds).

6. Describe how monomers are joined together.

Monomers might be made of sugars or like substances, allowing them to become linked together by the dehydration process.

7. Describe how polymers are broken down.

An addition of a water molecule breaks

8. What is the specific name for the bond between simple sugar monomers?

Dehydration synthesis (condensation).

9. Which kind of enzyme joins monomers together?

Covalent bond


Back on the previous macromolecules page, scroll down to the section on carbohydrates. In the learning materials box for carbohydrates click the link to the “build a carbohydrate” activity.

10. Describe how you had to arrange the sugar monomers in order to build a polysaccharide.

I had to move a monomer to match up with the certain elements on the other monomers to bond together and create the polysaccharide. A little water drop formed (probably meaning condensation), and the two bonded. Very neat!

11. Which building blocks of macromolecules are not used in building carbohydrates?

Nucleotide, Fatty Acid, and Amino Acid.

Back on the previous carbohydrates page, click on the link on the bottom of the page labeled “More on Carbohydrates.”  Read the article and answer these questions:

12. Why is sugar stored as glycogen in the human body?

Sugar is stored as glycogen in the human body for it to break down and absorb energy from.

13. Why are plant foods essential to animal life?

Those plant foods have sugar in them, which are also pretty good for giving energy.

14. Describe how starch is digested by animals.

Begins in the mouth with salivary amylase (spit), continuing in the small intestine with pancreatic amylase (stomach acid).

15. What is “fiber” and why is it important in your diet?

Carbohydrate polymers. It's important to your diet because it helps in absorption or neutralization of toxicity or other foods. Pretty much, it saves you from frying because of what you ate. AND it's great for the bowels! Keeps from getting bowel/colon cancer.

16. What causes you to pass gas (fart) according to the article?

Undigested protein and putrefaction cause this to happen. Protein-carbohydrate balance is important here. Stinky gas means you're eating bad. But if your farts don't stink (but there's no way they're gonna come out smelling like roses, so don't expect that!), then you can know that you're eating good and should keep it up!

Scroll back up to the top of the carbohydrates article and click on the link in the text to “Low Carbo Madness” and read the linked article. (or click here)

17. What are some disadvantages of a low-carb diet?

Your body must have approximately 45% to 65% of what it eats to be calories from carbohydrates in order to maintain function.



Return to the original carbohydrates lesson page and click on the link on the bottom “Carbohydrates and Cavities” and read the linked page.

18. Describe the role that sugars play in cavity formation in your teeth.

acid-producing bugs, carbohydrates, and teeth. These add up to cavities. Some preople don't have enough acid in their mouth produced in order to break down certain foods, so they sit in their teeth and rot, making cavities form.