Cells: Basic Unit of LifePart 1

Moss Cells

Blood Cell

Cheek Cells

Onion Cells

I. Discovery of Cells• First Sighting of Cells

in late 1600’sa. Robert Hooke (1665)-

i. built one of the first compound microscopes

ii. Discovered cork cells

b. Anton van Leeuwenhoek (1673)-

i. discovered creatures swimming in pond scumii. First person to see

bacteria and discovered that yeast makes bread rise

Cork Cells

MS-LS1-1: Conduct an investigation to provide evidence that living things are made of cells: either one cell or many different numbers and types of cells.

Discovery of Cells (cont.)c. Matthias Schleiden-

i.stated all plants are made of cells (1838)

d. Theodor Schwann- i. stated all animals are made of cells (1839)

e. Rudolf Virchow- i. saw cells could not develop from anything but cells (1858)– Both scientists

contributed to cell theory

Cell Theory

f. Cell Theory:1. All organisms are

composed of one or more cells.

2. The cell is the basic unit of life in all living things.

3. All cells come from existing cells.

Question

Explain the cell theory:

a. ____________________________

b. ____________________________

c. ____________________________

Question

Explain the cell theory:

a. all organisms are made of one or more cells.

b. the cell is the basic unit of life.

c. all cells come from other cells.

g. Microscopes

a. Compound Microscope- i. uses light to pass

through specimenii. Lenses magnify the

image making it appear larger

Microscopes (cont.)

b. Electron Microscopes

i. Beam of electrons are used to magnify images instead of light

ii. Living specimens can not be examined

iii. Higher resolution (clearer image)

iv. Ex. Transmission Electron Microscope (flat image) and Scanning Electron Microscope (3D Image)

Transmission Microscope

Mite

Electron Scanning Microscope

Ant

Questions

1. Which microscope uses light passing through the image? ________________

2. What do scientists use microscopes for?

___________________________________

3. How did the discovery of the microscope help scientists learn more about cells?

___________________________________

Questions

1. Which microscope uses light passing through the image? Compound light microscope

2. What do scientists use microscopes for?

Observe organisms that are smaller than unaided eye.

3. How did the discovery of the microscope help scientists learn more about cells?

Helped to see inside the cell and to discover things like bacteria.

II. Living or Non Living:

a. 6 characteristics of living things:•Made of cells•Have DNA•Respond to stimulus: homeostasis – process of maintaining a stable internal environment •Use Energy: metabolism- the total of all of the chemical activities that an organism performs.•Grow & Develop•Reproduce

b. Basic Needs of Living Things

•Place to Live•Air [oxygen or carbon dioxide]•Water•Food

– Autotroph/ Producers: makes own food (plant, protist)

– Heterotroph/ Consumers: get food from other sources (animal, fungi, protist)

III. Two Types of Cella.Prokaryote-

i. No nucleusii. No membrane

covered organellesiii. Circular DNA found

in cytoplasmiv. Smallest cellv. Ex. Bacteria

b. Eukaryote- i. Nucleusii. Membrane-covered

organellesiii. Linear DNA found

in nucleus (chromatin)

iv. 10 times larger than bacteria cells

v. Ex. Plants, animals, fungi, and protists

Questions1. Is a dolphin living or non-living? Explain ______________________________________________________________________________________________

2. What do organisms need to survive? ______________________________________________________________________________________________

3. What are the two types of cells?– ___________________________– ___________________________

4. Which type of cell has a nucleus? ______________

 

5. Give an example of a eukaryote: _______________

Questions1. Is a dolphin living or non-living? Explain A dolphin is considered living because meet all 6 characteristics ot living things

2. What do organisms need to survive? Organisms need air (oxygen for animals and carbon dioxide for plants), living space, water and food

3. What are the two types of cells?– Prokaryote– Eukaryote

4. Which type of cell has a nucleus? Eukaryote  

5. Give an example of a eukaryote: dolphin

IV. Organisms Independent LivingLiving things are made of cells a single cell or many different cells working together.a.Unicellular: •one celled organism living on its own•Can survive on its own•Example- amoeba, bacteria, paramecium

b. Multicellular: •many cells that work together.•Multicellular organisms can grow larger and have cells that are specialized for different tasks. Must remain part of the organism to survive.•Example: flower, dog, human, insect,mushroom

Questions1.How do the cells of unicellular organisms differ

from the cells of multicellular organisms?____________________________________________________________________________

2. Explain the advantage of being multicellular. ____________________________________________________________________________

Questions1.How do unicellular organisms differ from the

multicellular organisms?Unicellular organisms are one cell which must do

all the jobs for the cell, they can survive on their own. Multicellular are many celled, and must remain part of the organism to survive.

2. Explain the advantage of being multicellular. ____________________________________________________________________________