AIM: All Living Organisms Are Made of Cells

THE CELL

AIM: All living organisms are made of cells.

1. Organisms composed of one cell are

unicellular

a. includes Kingdoms Monera and

Protista

b. ex. bacteria and amoeba

2. Organisms composed of many cells are

multicellular

a. Kingdoms: Fungi, Plant, Animal

b. cells ->tissues ->organs ->organ

systems

c. in multicellular organisms cells have

specific functions and shapes,

ex. white blood cells, red blood cells,

nerve cells (neurons)

3. Viruses do not have cellular organization

and are not considered living

4 . There are many similarities in the cells

of different organisms (= cell theory)

a. cells are usually microscopic in size

-exception: egg yolk

-the making and use of the microscope

since 1590 led to its discovery

b. Every cell carries on all the life functions

- nutrition, respiration, excretion,

reproduction, transport, growth,

regulation

c. Cells take in nutrients

- to provide energy for the cell and

organism which is released during

respiration

- nutrients are used to make

(synthesize) materials that the cell

or organism needs

d. Cells grow and divide, making more

of the same type of cells

-  this involves asexual reproduction

(mitosis)

e. Cells provide structure for the organism

AIM: Every cell has three main parts:

1. cytoplasm:

a. watery, gel-like material in which

specialized structures called

organelles are found/”float”

b. transports material in cell

c. many chemical reactions occur

here

2. cell membrane: (plasma membrane)

a. separates the interior of the cell from

the surrounding environment,

offers protection to the cell

b. regulates and controls movement of material into and out of the

cell

c. gives support and shape to the cell

3. nucleus:

a. “control center” for life processes

and reproduction

b. controls all life processes

(metabolism) of the cell

b. contains genetic material (DNA)

- “instructions” for cell functions

- “instructions” for cell reproduction

- pass on traits to offspring

AIM: Cell organelles are suspended in the

cytoplasm, each has a “job” or life function

in the cell

1. mitochondria: “powerhouse” of the cell

a. release of energy during cell respiration

b. most organisms are aerobic (use

oxygen)

2. lysosomes: contains digestive

enzymes for cell digestion

a. digests nutrients

b. breaks down and recycles old cell

parts

3. ribosomes:

a. makes (synthesizes) proteins;

proteins are needed for growth and

repair and all cell processes

4. endoplasmic reticulum (ER)

network of “tubes” for transport

within the cell transport (“highway”)

5. vacuoles: storage space in cell for

a. water

b. wastes that are later excreted; this

could include toxins especially in plant cells

c. storage of food that is later

digested and used

d. plant cells have very large vacuoles

6. golgi bodies:

a. packages and distributes materials

for the cell

b. may help in excretion and egestion

AIM. Plant cells have a few specialized

organelles which animal cells do not have

1. Cell Wall: rigid wall composed of

cellulose outside the cell membrane;

non-living ; ex wood, roughage (corn,

lettuce)

a. provides shape for the cell

b. provides support for the cell

c. contains many small openings that allow material to pass into and out of the cell, protection for cell

2. Chloroplasts:

a. contain the green pigment

chlorophyll which absorbs sunlight

so plants can make “food”

b. site of photosynthesis (food making

process in autotrophic plants

CO2 + H2O -> O2 + C6H12O6

3. one or two large vacuoles

a. plant support and structure

b. stores water for the plant

AIM. The Microscope enabled us the discover

the cell and its functions.

1. The microscope is used for observation of:

a. cells and cell organelles

b. microorganisms: very small organisms which can only be seen with a microscope.

Ex. Monera, Protists

2. Compound microscope

a. first made and used in 1590

b. resulted in discovery of the living cell

c. has two lenses, each magnifies the

image by bending the reflected light

a. eyepiece lens (you look through)

b. objective lens (closest to the

specimen)

d. amount of enlargement = magnification =

power of eyepiece X power of the objective

-  highest magnification for compound

microscope is 1000 X

-  electron microscopes will magnify

300,000 times but can not observe a living organism/cell with it

3. When you look through a microscope:

a. Image seen in microscope is:

- enlarged

- backward (reversed)

- upside down

b. If you move specimen to right it appears

to move to left and v.v.

4. Parts of the microscope include:

a. arm and base : carry the microscope

by these

b. eyepieces (ocular): first lens you look

through

c. nosepiece with the objective lenses:

low and high power

-  always use the lowest power first to

focus the object

-  when turning to a higher power watch

as you change the objective

d. coarse and fine adjustment

-use coarse ONLY with low power

- if object is focused under low then it

will be focused under high, may need

to use the fine adjustment slightly

e. stage and clips

f. light source and diaphragm to control light

intensity

5. You see a circle of light (field of view) and

the specimen should be in this circle.

a. field of view = the diameter in mm

of this circle of light

b. If you know the field of view you can

estimate the size of the cell or

specimen you are observing through

the microscope.