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 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