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Biology 1110 Principles of Biology Biology 1110 Laboratory Laboratory # 2 Beginning Cytology Support/Review Materials All of the micrographs in this presentation were photographed in the MnWest Biology Laboratory unless otherwise noted. The microscope symbol that you see indicates a change in microscope power. Clicking on the microscope most often increases the viewing magnification. Give it a try.

Beginning Cytology Cytology – the study of the cell. In this exercise you will study a cell obtained from the animal kingdom as well as a plant cell. The representative animal cell is a starfish unfertilized egg. The cell has been stained so as to assist in the viewing and study of certain cellular structures (organelles). The plant cell viewed is a living plant cell taken from an aquatic plant. The compound(light) microscope is used in these investigations.

Cytology - Study of a representative animal cell Cytology - Study of a representative animal cell. The Starfish Unfertilized Egg The specimen is placed on the microscope stage and brought into clear focus. For most specimens we will shift to high power for our more detailed observations.

Cytology – A representative animal cell You are viewing this cell using the high power objective on a compound microscope. The total magnification varies some between microscopes, but will be around 400 times. Can You identify the cellular structures (organelles) in the micrograph?

The cell or plasma membrane This area of the cell contains the living substance outside the nucleus. This living substance is the cytoplasm. Nuclear membrane This is the nucleus of the cell. The living substance of the nucleus is called nucleoplasm. Nucleolus

CeLl Structures The cell or plasma membrane – the surface membrane that encloses the cell contents and regulates the passage of material in and out of the cell. The Cytoplasm – the living substance of the cell found outside of the cell’s nucleus. Many cellular organelles are found within the cytoplasm. The Nucleus – this is the control center of the cell. The living substance of the nucleus is called nucleoplasm. The nucleoplasm contains most of the cell’s deoxyribonucleic acid (DNA). The nuclear membrane – the membrane separating the nucleoplasm and cytoplasm. This membrane regulates communication between the nucleus and the rest of the cell.

Cytology A representative animal cell A – the plasma or cell membrane B – the cytoplasm C – the nuclear membrane D - the nucleoplasm E – the nucleolus

Cytology A cell from the plant kingdom The micrograph you are looking at demonstrates a portion of a leaf taken from an aquatic plant. The micrograph demonstrates a low power view. This is a living plant and no biological stain has been applied. On high power we will focus in on a single plant cell and identify certain structures.

Cytology A cell from the plant kingdom. No biological stain has been applied to this tissue. As a consequence only a few structures are clearly identifiable. On the next slide we will identify the plant cell wall, chloroplasts, and the general cytoplasmic area.

The cytoplasm The plant cell wall – a rigid structure found outside the cell membrane. This structure is not found in animal cells. Cloroplasts – these green spherical stuctures are the site of the photosynthetic process.

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