Marjolein

__Comparing Cells and Tissues__ By Marjolein and Sunny Lab Sci 9 J. Happer


 * Relevance:** Our experiment is relevant because the structures of animal cells from different body parts may define how that body part works. We first wanted to do an investigation concerning the lens of an eye, but this didn’t work due to problems with the availability of a fresh eye.


 * Goals**: Some specific goals of the first part of our investigation were too study optics in mammal’s eyes. Since this didn’t work, we set up a second investigation concerning cells and our new goalsare to compare and contrast cells from different body parts of different animals, and examine their structures.

For the first part of the investigation we took it for granted that the lens was clear enough to be able to see through, and we expected to be able to stretch it out somehow and study the focus of a lens.
 * General Expectations and Models**:

Generally, we expect to be able to properly see the cells, and by cells we mean the cell membrane and hopefully the nucleus, and we expect to be able to compare these cells properly.


 * Variables**: I am unable to conclude what the variables in this type of experiment could be.

-microscope -different animal cells and tissues (cows eye, frog...) -alcohol to prepare the cells and tissues
 * Materials**:

- scrape the organ with a toothpick/q-tip to get the cell - put the scrapings on a slide - examine wiht microscope --- or --- - take a piece of tissue - put it in said alcohol for several hours - take the hardened tissue out and examine under the microscope
 * Procedure**:

Failed Investigation I: In this experiment we expected to study the optics and focus of eyes.
 * Expectations:**

For part two, our general expectations are that we can accurately compare cells from different types of tissues, including eye tissue, skin tissue, and blood tissue, and note their differences.

The results for part one weren’t what we expected and caused that part of the experiment to fail.
 * Results:**

On to part two, here are some pictures taken through the microscope of the tissues that we examined. It was particularly difficult to see the cells and we rarely got a chance to see them properly.

image 1

image 2

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image 9

The results of part one were that when we eventually found the lens in the eye, it had already turned opaque and we were unable to use it effectively for our first experiment. Perhaps we should’ve planned to get our hands on a cows eye that was more…recent, so that we could successively carry out our first investigation. However, we thought of what else we could do and came up with another experiment concerning tissues and cells, and so we carried that out. As a result we got lots of interesting images of tissues from cows eye, and some tissue from frogs. Although we couldn’t successively see individual cells in the tissues, we managed to examine the differences in tissues from different body parts, and the difference before and after they’d been soaked in alcohol.
 * Discussion of Results:**


 * Appendix I**


 * Aqueous humor**: A clear fluid that helps the cornea keep its rounded shape.
 * Blind spot**: The place where the optic nerve leaves the retina. Each eye has a blind spot where there are no light-sensitive cells.
 * Cell**: A collection of living matter enclosed by a barrier that separates the cell from its surroundings. The basic unit of all forms of life.
 * Cornea**: A tough, clear covering over the iris and the pupil that helps protect the eye. Light bends as it passes through the cornea.
 * Dissection**: The act of cutting apart (an animal body part, plant, etc.) to examine the structure, relation of parts, or the like.
 * Iris**: The muscle that controls how much light enters the eye. It is suspended between the cornea and the lens.
 * Lens**: A clear, flexible structure that makes an image on the eye’s retina. The lens is flexible so that it can change shape, focusing on objects that are close up and objects that are far away.
 * Pupil**: The dark circle in the center of the iris. It’s a hole that lets light into the inner eye.
 * Retina**: The layer of light-sensitive cells at the back of the eye. The retina detects images focused by the cornea and the lens.
 * Sclera**: The thick, tough, white outer covering of the eye.
 * Tapetum**: The colorful, shiny material located behind the retina. Found in animals with good night vision, the tapetum reflects light back through the retina.
 * Tissue**: A group of similar cells that perform a particular function
 * Vitreous humor**: The thick, clear jelly that helps give the eyeball its shape.


 * Appendix II (Big Ideas)**

-A cow's eye is very similar to a human eye. The anatomy of basically all mammal's eyes are alike.

-All animal cells have GENERALLY the same type of structure.

-How do you prepare tissues in a slide?


 * References:**
 * -**Miller KR, Levine JS. //Biology.// Upper Saddle River, New Jersey: Prentice Hall; 2006: 1087-1105

- [|www.exploratorium.edu/learning_studio/cow_eye/index.html]