What makes something living,…

living?

Does it have to…

consume oxygen??

Does it have to…

be able to move??

Does it have to…

be able to think??

Does it have to…

grow??

Does it have to…

consume food??

Does it have to…

have a heart??

Does it have to…

reproduce??

Does it have to…

be able to die??

Hmmm…?????

Use these questions and work with your neighbor to compile a

list of the

Characteristics of Life(Hint: There are six

total!)

1. Contain Cells• All living things are composed of cells that

contain hereditary information (DNA)• In multicellular organisms, cells are specialized

for the job that they perform• Cells are the smallest unit of life…so each cell

contains the characteristics of life

Nerve Cell

Skin Cell

2. Organization

• All living things are highly organized.• Cell structures carry out particular functions.

**Structure equals function!**• Multicellular Organisms: cells are grouped by

their function• Cells Tissues Organs Organ systems

Click here for how it works!

3. Energy Use

• All living things use energy in order to:– Maintain their organization– Grow– Reproduce

• Metabolism: chemical process of breaking down materials for energy

4. Maintain Internal Conditions

• All living things, even single cells, work to maintain a steady internal environment

• Homeostasis: process of maintaining these conditions– Water level in cells– Temperature

Click to see how!

5. Growth and Development

• All living things grow as a result of cell division and cell enlargement.

• Unicellular (single-celled organisms): Simply an increase in size

• Multicellular (many-celled organisms): Develop from one cell into many through cell division (differentiation and different functions)

6. Reproduction

• Reproduction (transmitting hereditary information to offspring) is not essential to the survival of an individual organism-it is essential for the continuation of the species.

• Two types:– Sexual: cells from two different parents unite to

form a new cell– Asexual: new cell formed from

a single cell

Scientific Method

1. Observe2. Ask a Question3. Collect Data (background information)4. Form a Hypothesis5. Experiment6. Draw Conclusion7. Communicate

Variables

• Independent Variable- manipulated, the variable that is changed

• Dependent Variable- responding, the variable that changes in response to the independent variable

Microscope and Measurement

• Compound Light Microscope

• Magnification:– Increase of the image’s

apparent size

• Resolution:– The power to show

details clearly

Parts of Microscope

Objective lenses

Diaphragm/Condenser

Lamp

Base

Fine Adjustment

Course Adjustment

Stage/Stage Clips

Revolving Nosepiece

Eyepiece/Ocular Lens

Arm

High=40X; Low=10X; Scanning=4X

Changes objective lenses

Directs light into microscope

Focuses the light

Amount of light entering the microscope

Look through; lens inside is 10X

Brings objective into slow focus

Carry and support (2 items)

Supports the slide; positions the slide

Brings object into rapid focus

So How Do We Use It??

Click on the scientist to see

Now let’s do the lab!

Working Space on a Light Microscope

• Depth of Field: Area between lens and stage• Field of View: Area seen through the

microscope– Calculated by the equation:

Total Mag A X Diameter A = Diameter BTotal Mag B

Practice Problems

• Calculate…

Total magnification at:-High Power-Low Power-Scanning

Ocular x Objective

• High = 10x40 = 400• Low = 10x10 = 100• Scanning = 10x4 = 40

Practice Problems

• Calculate…..

If a cell measures 20 um at 100X, what is the length of the cell at 200X?

100 X 20 um =200

10 um

Practice Problems

• Calculate…

If the field diameter at scanning power measures 5 um, what is the field diameter at low and high power?

Low 40 X 5 um = 2 um 100

High 40 X 5 um = 1 um200

Electron Microscope

• A beam of electrons produces an enlarged image of the specimen.

• Types:– TEM: Transmission Electron Microscope– SEM: Scanning Electron Microscope

TEM• Can view the

internal structure of an organism

• Magnifies up to 200,000 times

Images under TEM

Lung Spinach Chloroplast

Rat Nerve Mouse Kidney

• Sperm and Egg

Under an SEM

Pollen Lung

SEM• View the

surface of an object

• Magnifies up to 100,000 times

Under an SEM

Leaf Vein Staple through paper

Under an SEM

Toilet paper Hypodermic needle

Under an SEM

Mascara brush with flakes of skin and bacteria

Under an SEM

Sperm and Egg

Comparisons

TEM SEM

Disadvantages of an electron miscroscope:• Very expensive

• Cannot be used to view to a living specimen• Can be large in size