Chapter 2.1 The study of cells

Question 1

The structural and functional unit of all organisms, including humans

Answer 1

Cells

Question 2

An adult human body contains about how many cells?

Answer 2

75 trillion cells

Question 3

Most cells are composed of characteristic parts that work together to allow them to

Answer 3

Perform specific body functions

Question 4

How many different type of cells are there in the human body

Answer 4

Approximately 200 different types of cells in the human body

Question 5

Even though there are hundreds of different types of cells they all share certain common characteristics

Answer 5

• General “housekeeping functions”
• Must obtain nutrients and other materials essential for survival from its surrounding fluids
• Dispose of wastes they produce
• Shape and integrity is maintained by its internal contents and its surrounding membrane
• Most are capable of undergoing division to make more cells of the same type

Question 6

The total of all the chemical reactions that occur in cells is called

Answer 6

Metabolism

Question 7

If a cell didn’t remove its wastes products what would happen?

Answer 7

The waste would build up in the cell and ultimately lead to the cells death

Question 8

The study of cells is called

Answer 8

Cytology

Question 9

What is the greatest obstacle in obtaining the nature of a cell

Answer 9

Their small size

Question 10

Cells were discovered after what was invented?

Answer 10

Microscopes

Question 11

What are required to see the smallest human body cell?

Answer 11

High-magnification microscopes

Question 12

What is often used to measure cell size?

Answer 12

The dimensional unit, the micrometer (um)

Question 13

One micrometer is equal to how many centimeters?

Answer 13

1/10,000 of a centimeter

Question 14

A red blood cell has a diameter of about

Answer 14

7-8 um

Question 15

One of the largest human cells, the oocyte, has a diameter of about

Answer 15

120 um

Question 16

The use of the microscope is called

Answer 16

Microscopy

Question 17

This has become a valuable asset in anatomic investigations

Answer 17

The microscope

Question 18

What are the most commonly used microscopes

Answer 18

1) Light microscope (LM)
2) Transmission electron microscope (TEM)
3) Scanning electron microscope (SEM)

Question 19

Because specimen samples have no inherent contrast, they cannot be seen clearly under the microscope unless

Answer 19

Contrast is added

Question 20

Colored-dye stains are used in what type of microscope

Answer 20

Light microscopy

Question 21

Heavy metal stain preparations are used in

Answer 21

Electron microscopy, which includes both TEM and SEM

Question 22

This type of microscope produces a two-dimensional image for study by passing visible light through the specimen. Glass lenses focus and magnify the image as it is projected toward the eye.

Answer 22

The Light microscopy (LM)

Question 23

Uses a beam of electrons to “illuminate” the specimen. Easily exceed the magnification obtained by light microscopy, they improve the resolution by more than a thousandfold. Directs an electron beam through a thin-cut section of the specimen. The resultant two-dimensional image is focused onto a screen for viewing or onto photogenic film to record the image. Can show a close up

Answer 23

Transmission electron microscope (TEM)

Question 24

Detailed three-dimensional study of the surface of the specimen. The electron beam is moved across the surface of the specimen, and reflected electrons generate a surface-topography image captured on a television screen

Answer 24

Scanning electron microscope (SEM)

Question 25

In what ways do cells vary?

Answer 25

Size and shape

Question 26

What are the different cell shapes?

Answer 26

Flat, cylindrical, oval, or quite irregular

Question 27

Often cells functions are reflected on what?

Answer 27

Their size or shape

Question 28

What are the general function of cells?

Answer 28

1) Covering
2) Lining
3) Storage
4) Movement
5) Connection
6) Defense
7) Communication
8) Reproduction

Question 29

Describe how cells are used for covering

Answer 29

Epithelial cells form a sheet to cover surfaces. For example, skin cells cover the external body surface

Question 30

Describe how cells are used for lining

Answer 30

Epithelial cells line the internal surfaces of our organs, such as the small intestine

Question 31

Describe how cells are used for storage

Answer 31

Some body cells, such as hepatocytes (liver cells) and adipocytes (fat cells), store nutrients or energy reserves for the body

Question 32

Describe how cells are used for movement

Answer 32

Muscle cells are composed of contractile proteins that cause the muscle to shorten (contract), thereby allowing movement to occur. Skeletal muscle cells attach to the skeleton so that when these cells contract, they move the skeleton. In contrast, when the muscle cells in the heart wall contract, they are able to pump blood throughout the body

Question 33

Describe how cells are used for connection

Answer 33

Multiple cell types are found in connective tissues, which help connect and support other tissues. For example, fibroblast cells produce protein fibers that are found in ligaments, the connective tissue that binds bone to bone