GenBio1: Cell Theory-Types of Cells

Cell Theory - Prokaryotes & Eukaryotes

robert hooke (1665)

• The first person to see cells under the microscope and give them a name.

• Coined the term cells (by a piece of a cork) from the Latin word cellula (little room)

anton van leeuwenhoek (1670)

• First to see living microscopic organisms, he called them animalcules.

• He was also able to observe blood and sperm cells

robert brown (1831)

• Discovered the nucleus in plant cells.

matthias jaokob schleiden (1838)

• Proposed that all animals have cells

• Stated that cells are the basic building blocks of all plants

theodor schwann (1839)

Concluded that all plant and animal tissue was made of cells.

rudolf vrchow (1855)

• Concluded that cells arose only from pre-existing cells (omnis cellula e cellula).

1. All living organisms are composed of cells.

2. The cell is the basic unit of life.

3. Cells come from pre-existing cells.

3 Classical Cell Theories

spontaneous generation

• proposed by aristotle

• a disproved process where life/cells arose from nonliving matter.

1. Transmission Electron Microscope (TEM)

2. Scanning Electron Microscope (SEM)

2 types of microscope

Transmission Electron Microscope (TEM)

- electrons go through a very thin slice of the specimen. (200,000x)

Scanning Electron Microscope (SEM)

- a beam of electrons across a whole specimen (sprayed with a final metal coating). (100,000x)

1. Cells contain DNA that is passed on by cell division

2. All cells are similar in chemical composition (biomolecules)

3. Energy flow occurs within the cell

4. All cells arise from pre-existing cells

5. The basic unit of life

6. Metabolic pathways

• Anabolic - energy required

• Catabolic  - energy released

Modern Cell Theory

• RBCs do not have a nucleus and do not divide

• Skeletal muscles have multiple nuclei despite being surrounded by a single, continuous plasma membrane.

exceptions to the cell theory

1. external covering

2. cytoplasm

3. nucleus

3 major parts

cell or plasma membrane

• Acts as a protective barrier in a way that prevents toxins from entering the cell.

• regulates the entrance and exit of the cell

• semi-permeable

cell wall

- Maintains all shape for protection

• Rigid structure made of chitin or cellulose.

• permeable

organelle

• called a little organ because it serves specific functions within the cell.

cytoplasm

• Holds everything and prevents it from damage.

• Also known as Cell / Cellular Sap

• gel-like interior

mitochandria

- The powerhouse of the cells, in which ATP is produced and gives energy to the cell

• contains cristae

- It contains its DNA, and it is a double-walled organelle

endoplasmic reticulum

- SER: production of lipids

- RER: production of proteins

- Flattened sheets of sacs and tubes

Golgi Apparatus

- For modification, sorting, and packaging of substances

- Flattened membrane-bound sacs

lysosome

- Contains lysozyme, a digestive enzyme that breaks down molecules and cellular components that are not working properly

- Phospholipid bilayer

vacuole

- For the storage of substances

vesicle

- Carry or transport molecules and packed substances

Cytoskeleton

- Give support and structure to the cell

- Filamentous or fiber-like

chloroplast

- Site for photosynthesis

- Has its own DNA & Ribosome

centriole

- produces spindle fibers during cell division

• 9+0

- Filamentous or Fiber-like

ribosome

• contains 2 subunits and creates protein

- Protein & RNA

nucleus

• Control center of the cell.

• A double membrane that sends out instructions

• Bordered by a porous membrane–nuclear envelope

• Contains the fiber of DNA and protein called chromatin.

nucleoplasm

- Contains thin fibers of DNA & protein

-Semifluid medium separated from the cytoplasm

nuclear envelope

- Control material flow into and out of the nucleus

- Double membrane perforated with nuclear pores

nucleolus

- For the synthesis of ribosomes

- Mass of fibers and granules

cilia

• moves like a car wiper

• 9 +2

flagella / flagellum

• moves like a motion

• used for locomotion

• propeller

prokaryotes

• faster to reproduce, all the same, and simple, easy to go.

eukaryotes

can build large bodies, making them more complex, and can specialize.

animal cell

excess glucose = glycogen

plant cell

excess glucose = starch

peroxisome

• contains oxidative enzymes