Cell Structure

Your body is made up of billions of individual living structures called cells. All cells are different, but most cells have certain common structures called organelles. We will study the anatomy of these structures in this chapter. More detail on the anatomy and physiology is given in your textbook.

Exercise 3.1

Figure 3-1 shows a generalized human cell and its basic parts. Using your textbook as a guide, fill in the labels on the figure.

Exercise 3.2

Examine the models of the cell. Be able to identify these parts on the model: cell membrane, Golgi apparatus, lysosome, mitochondrion, nuclear envelope (membrane), nucleolus, nucleus, pinocytosis, RER, ribosomes, SER, and vacuole.

Exercise 3-3 Materials:

microscope slide with a small drop of iodine in the center cover slip toothpick microscope

Using a toothpick scrape off a few cells from the inside of your cheek. Do not draw blood!

Float the cells off the toothpick into the drop of iodine.

(The iodine will stain the cell and allow you to see them more clearly. Iodine also kills the cells.)

Put the coverslip on the drop and mount the slide on the microscope.

View the cells. Remember to start with the low power objective. Switch to high power when you are in focus. Readjust the light when you change lenses.

Generalized Human Cell DiagramGeneralized Cell Labeled

Figure 3.1 Generalized Human Cell

Cell membrane (plasma membrane, plasmalemma) Centriole Golgi complex Lysosome Mitochondrion Nuclear membrane (envelope) Nucleus Nucleolus Phagocytosis Pinocytosis Ribosome Rough endoplasmic reticulum (RER) Smooth endoplasmic reticulum (SER) Vacuole

Color each part of the cell a different color using crayons or colored pencils.

Sketch three cells in the space below. Label the nucleus, nucleolus (if visible), and cell membrane. All other organelles are too small to be seen with a light microscope. An electron microscope must be used.

Exercise 3 A

Clean your slide and coverslip with a lens paper. Place a small drop of pond water on the slide. Replace the cover slip.

Observe the organisms. Look for nuclei, nucleoli, cell membranes, cilia, flagella, and vacuoles. Generally the green organisms are algae, the blue-green ones are photosynthetic bacteria, and the colorless ones are one-celled animals. Sometimes the animals eat the other organisms and therefore appear colored. Discard your slide and coverslip when you are finished. Remember to turn off the light and return the low power objective into the down position. Return the microscope to its storage area.

The "control center" of the cell is the (1) .

Inside the nucleus there are one or two (2).

The outer boundary of the cell is a sack called the (3) .

Between the nucleus and the cell membrane there is a jelly-like substance called (4) which contains many submicroscopic organelles.

The organelle called a "suicide sac" or "digestive vacuole" is the (5).

Which organelle produces most of the energy for the cells and is thus known as the "powerhouse"?

Small, hairlike, moveable protrusions of the cell membrane which allow the cell to move material past its surface are called (7).

Small extensions of the plasma membrane which do not move but which do increase surface area for absorption are (8).

Proteins and other substances can be packaged for export by the (9) .

Movement through the cell is conducted in the tubes which make up the rough (10) and the (11) endoplasmic reticulum.

The rough endoplasmic reticulum is rough because of the presence of (12) on its surface.

Ribosomes are the site of (13) synthesis in the cell.

The (14) plays a role in nuclear division.

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Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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