Cells

CellsCells

The Building Blocks of LifeThe Building Blocks of Life

Cells• Cell: The smallest unit of an organism that

can carry on life functions.

• They are organized, grow, reproduce, use energy, and respond to stimuli.

Blood cellsNerve cells

Muscle cells

I. History of Cells

• Robert Hooke was the first to see and name cells in 1665.

A thin slice of cork showing cells

• 10 years later in 1675, Anton van Leeuwenhoek was the first to observe living cells (bacteria and protozoa)

Microscope he invented

• The nucleus was not described until 1833

• DNA was not described until the 1950s.

Timeline of Cell Discoveries

1665 cells named

Today19001600 1700 1800

1950s DNA described

1833 nucleus observed

1675 bacteria observed

Why did it take so long to make these discoveries?

The technology did not exist!

http://www.mos.org/sln/SEM/sem.html

Scratch and sniff paper x1000

Mascara brush x35

Staple in paper x35 Mosquito head x200

II. Cell TheoryA collection of ideas that forms the foundation

for all biology.

Equivalent to the Theory of Gravity (Physics), Atomic Theory (Chemistry), and Theory of Evolution (Evolutionary Biology)

1. All living things are made of one or more cells.

2. Cells are the basic units of structure and function in living things. (The building blocks of life)

3. Living cells only come from other living cells.

http://ed.ted.com/lessons/the-wacky-history-of-cell-theory

III. Types of Cells

• Prokaryotic-cells that have no membrane (“skin”) bound nucleus

• DNA floats freely inside the cell

• Seen in the Monera Kingdom (bacteria)

• Eukaryotic-cells with membrane (“skin”) bound nucleus

• Seen in the protist, fungi, plant, and animal kingdoms

“Nucleus”

• New-clee-us

NOT

• new-cue-lus

• “nu-cue-ler bombs”

Which cell is which?

Prokaryotic

or

Eukaryotic?

Prokaryotic vs. Eukaryotic

IV. Single or Multicelluar

• Some organisms are only one cell big. (unicellular)

diatoms

protozoa

paramecium

• Some organisms are made of millions or billions of cells working together. (multicellular)

• In a single celled organism, the cell has to do all of the life characteristics by itself.

Division (reproduction)

Eating (using energy)

• In a multicellular organism, each cell is assigned a specific job. Together, they make the organism complete.

Blood, nerve, and muscle cells working together make our heart

complete.

http://www.teachersdomain.org/resource/tdc02.sci.life.stru.singlecell/

  Monera Protista Fungi Plant Animal

Unicellular          

Multicellular          

Prokaryotic          

Eukaryotic          

The 5 Kingdoms and their Cell Types

X

X

X

X

XX

XX

X

X X

The more cells, the more complex the organism

V. Cell Organization

• Within each cell, there are small structures that help the cell do its job, they are called organelles. (tiny organ)

• Cell Membrane: Protective outer covering for plant and animal cells. It controls what moves into and out of the cell. (revolving door)

• Cytoplasm: Supportive, gelatin-like structure found inside plant and animal cells. Helps maintain cell shape. (jell-o)

• Nucleus: Directs all cell activities in plant and animal cells. It also holds a copy of the chromosomes for the organism. (coach)

• Chromosomes: Found inside the nucleus, they contain the DNA which holds all of your hereditary information. (play-book)

• Nucleolus: Found inside the nucleus, it manufactures ribosomes. (ribosome factory)

• Ribosomes: Makes proteins for cells. (protein factory)

• Endoplasmic Reticulum (ER): Helps transport materials around the cell. (hallway)

• Golgi Apparatus/Bodies: Sorts, packages, and mails proteins around the cell. (post office)

• Lysosomes: Contains digestive enzymes (acids) to help break down food, wastes, and worn out cell parts. (recycler)

Lysosomes “eat” the tadpole tail.

• Mitochondria: breaks down food into energy for the organism. (batteries)

Which type of cell would have more mitochondria? Why?

• Muscle cells or fat cells?

• Vacuole: Storage containers for food, water, or waste. Plant cells have one large vacuole. (lunchbox)

Plants with empty vacuoles have limp leaves and stems

• Cell Wall: Outermost covering of a plant cell. Provides protection and support for the plant. (brick wall)

Humans do not have the right digestive enzymes to break down the

cellulose in cell walls

• Chloroplasts: In plants cells only, it converts sunlight into food. Chlorophyll inside the chloroplasts gives plants their green color. (solar panel)

Organelles all work together to make a cell function

Organelle review video: http://www.watchknowlearn.org/Video.aspx?VideoID=39968&CategoryID=579

Cells work together to make the whole organism function

VI. Levels of Organization in Biology

O rga n ism

O rg an S ys tem

O rg a ns

T issu e

C e lls1

2

3

4

5

These levels continue through ecology

5. Organism

6. Population

7. Community

8. Ecosystem

9. Biome

10. Biosphere

Modeling the levels using building blocks

Level 1 - Cell

Level 2 - Tissue

Level 3 - Organ

Level 4- Organ System

• Circulatory system

Level 5 - Organism

Organ systems combine to

form an organism

Level 6 - Population

• A group of alike organisms

Level 7 - CommunityGroups of different

populations

Level 8 - Ecosystem

• All the living and non-living things in an area

Level 9 - BiomeAreas of similar

climate (weather)

Grassland Biome

Level 10 - Biosphere

• Earth