Microscopy And Characterization Of Cells Biology Essay

Jekathjenani Ratnakumaran

Class: Biology 2070 H

Lab Group: Tuesday 1-3:50 pm

Due Date: February 5th, 2013

Expt. # 1

MICROSCOPY AND CHARACTERIZATION OF CELLS

Questions and Answers:

What is the field size at each magnification for the microscope you’re using? Show your calculations and give your answer in millimetres.

Full size at each magnification for the given microscope is calculated by multiplying the objective lens with the magnification of the ocular lens. The eyepiece of the magnification used in this experiment is 10X and the magnification of the given microscope are 10X, 25X, 40X and 100X. The diameter of the field size can be calculated by using the following formula,

=

Under the objective 10X:

=

1000x = 100 x 1.5mm

X =

X = 0.15mm

Under the objective 25X:

=

1000x = 250 x 1.5mm

X =

X = 0.375mm

Under the objective 40X:

=

1000x = 400 x 1.5mm

X =

X = 0.6mm

Under the objective 100X:

=

1000x = 1000 x 1.5mm

X =

X = 1.5mm

Briefly summarize the observations you made during the lab, using a comparative approach. You may use a table. Using these observations to formulate a specific question regarding some aspect of cells that you would like to explore. State your question and the method of how you would go about answering it. Include one primary reference that uses the technique you are proposing to use and very briefly describe what they were investigating and the primary result.

Type of cells

Cell movement

Colour

shape

Cell arrangement

Cow blood cells

Slight vibration

Red colour

spherical like shape

all cells packed tightly together and has nucleus.

Bacterial cell

Not defined

After stain it appears pink colour.

Rod and oval shape

Cells were transparent and lined together.

Algae

Has vibration

colourless

Oval shape

Had nucleus and cell membranes.

Cyanobacteria cells

Slight movement

Colourless , not stained

spherical shape

Colonized and very small.

Yeast cells

No movement

Colourless

Round shape

Had nucleus and aligned as chain

Cheek cells

Movement

colourless

Rounded shape

Cell had nucleus, vacuoles, cell membranes and cytoplasm.

In the above table, only few information are listed . Eukaryotes cell are plant and animal cell and prokaryotic cells are eubacteria and archae bacteria. Eukaryotic cell have nucleus, cytoskeleton and membrane bound organelles. Prokaryotic cell have no nucleus and no membrane bound organelles. In above table, listed cell types are eukaryotic cells as they have nucleus. Moreover, as they are all eukaryotic, they must have membrane bound organelles. When all cells are viewed under microscope, membrane bound organelles are not determined clearly. Therefore, the question is how to view the cell clearly under microscopic view and what method has to used to differentiate the cell from prokaryotes. Cellular staining method can be used to visualize the cells and its components under microscope. Cell staining can be prepared by following some techniques such as permeabilization, fixation, mounting and staining. Monica Z. Brukner states in the article that visualizing cell components can be done by staining procedures- Permeabilization include treatment of cells with a mild surfactant, which dissolves cell membranes in order to allow larger dye molecules to enter inside the cell. Fixation process can be done by adding a chemical fixative such as formaldehyde, ethanol, and methanol which creates chemical bonds between proteins to increase their rigidity. Mounting process involves by attaching samples to a glass microscope slide for observation of cells. Staining process will determine color cells, tissues, components, or metabolic processes. This process has done by immersing the sample in a dye solution and then rinsing and observing the sample under a microscope (Monica.Z Brukner)

Rank the cells you have observed in order of size, stating the specific size you have calculated for each. Show how you carried out the calculation. Include the cell suspensions and the cheek cell samples (A to E).

In order to rank the observed cells, the cell size can be calculated using the calculation below,

0.85% NaCl suspension washed red cells:

Estimation of cells can fit across the field size = 20 cells

The magnification of the lens = magnification x eye piece

= 40 x 10 = 400x

Field size = 0.6 mm

Size of the cell = =

Blood cell size = 0.03mm

Suspension of yeast cells

Estimation of cells can fit across the field size = 28 cells

The magnification of the lens = 40 x 10 = 400

Field size = 0.6mm

Size of the cell =

=

Yeast cell size = 0.021 mm

Suspension of bacteria

Estimation of cells can fit across the field size = 13 cells

The magnification of the lens = 40x 10 = 400

Field size = 0.6 mm

Size of the cell =

=

Bacteria cell size = 0.046mm

Suspension of algae

Estimation of cells can fit across the field size = 27cells

The magnification of the lens = 40 x 10 = 400

Field size = 0.6 mm

Size of the cell =

=

Algae cell size = 0.022 mm

Cheek cells

Estimation of cells can fit across the field size = 4 cells

The magnification of the lens = 40 x 10 = 1000

Field size = 0.6 mm

Size of the cell =

=

Cheek cell size = 0.15 mm

The animal cells (baby monkey kidney cells)

Estimation of cells can fit across the field size = 25 cells

The magnification of the lens = 40 x 10 = 400

Field size = 0.6 mm

Size of the cell =

=

Baby monkey kidney cell size = 0.0224 mm

Therefore, the cell size from smaller to larger size is as follows,

Yeast cell < animal cell < blood cell < bacteria < algae < cheek cells

Choose one cell type that you found interesting and submit a drawing of it. Refer to the section on how to do a scientific drawing. Title each drawing, label the cells properly and include a scale bar. Choose the magnification and conditions (unstained, stained) that you feel are best to illustrate the cells, and in a separate paragraph (i.e. NOT on your drawing) give your reasons for choosing this particular cell and conditions.

Cheek cells (figure 1) are found to be more interesting and had chosen for drawing. As they were collected from our own body, they were found interested to view under given microscope in order to view how they were look like. They were slightly round shape and colourless cell with cell membrane, nucleus, vacuoles and cytoplasm. They are in larger in size compared to other cell types. Cheek ells are not stained and are living cells as they are collected directly from our body. These are the reasons found to be more interesting compared to other cell types.

Choose one primary reference that uses cultured cells as an experimental model. Describe briefly the type of cell used, why these particular cells were useful for the study and how they were used. List two ways in which the cells used in the study would resemble cells that are growing within a body, and two ways in which they would differ.

The cultured baby monkey's kidney cell was used in this experiment as model. The cell type of baby monkey's kidney is epithelial cell. Epithelial cells are structural surface cells with limited intercellular space between them and has only small amount of intercellular substances. These cells are tightly packed cells and are three basic types such as Squamous, cuboidal, and columnar cells. Function of the epithelial cells are mainly secretion, selective absorbance, protection, and intercellular transport. As they are consists of rich protein complexes, provide cell contact between cells and lining the cell membranes, epithelial cell culture is used for studying host- pathogen dynamics in infectious diseases. Animal cells are used for many medical purposes. Usage of cultured cells for treatment are result in major successes in controlling viral diseases such as polio, measles, mumps and rubella (World Health Organisation (WHO), 1998). The WHO reports states that cultured Monkey's kidney cells are used for "the production of inactivated and oral poliomyelitis vaccines" for many years and it continues for the vaccine production. The cultured cells are known as primary cell cultures which are grow in bioreactors using micro-carrier method. Moreover, WHO report states that continuous cell line (Epithelial cells) from African green monkey kidney cells are used as substrate for the production of many biological substrates. On the other hand, disadvantage of using continuous cell lines from monkey will also result in risk of tumorigenicity which is associated with residual cellular DNA which may encode transforming protein (WHO, 1998).

Using your textbook or other sources, briefly describe two types of microscopes other than light microscopes, and explain for what purposes they would be used.

There are two types of microscopes other than light microscopes used for laboratory purposes. They are as follows,

The stereo microscope:

This type of microscope is also known as dissecting microscopes which provide an erect, three dimensional viewpoints. This microscope has a low magnification power and two separate eyepieces with two objectives, which builds the visual effect of depth perception. This dissecting microscope is used mainly for viewing large and solid surfaces or specimens. This microscope is also used for detailed work purposes such as microsurgery, watch making and circuit board inspection.

Digital microscope : The digital microscope is one of the modern microscopes which has optic and charged-coupled device camera which output the image to monitor. Also, it has incorporated light sensitive pixels to capture images. It has ability to measure samples in 2D and 3D. It consists of step motor in system which take images from lower focal plane to higher focal plane in the field of view . Also, these microscopes are used to create 3D images and used of magnified viewing of samples and specimens. As they have high resolution cameras, they can produce high qualified images than other microscopes.