Cells and Cell Organelles

History

Anton Van Leeuwenhoek• The microscope was invented by Anton

Van Leeuwenhoek, a Dutch biologist in the early 1600’s. Leeuwenhoek’s invention allowed him to see tiny living organisms in droplets of water.

Robert Hooke was the first person to name cells.

Hooke was looking at cork under the microscope and thought they looked like the rooms monks lived in called cells.

Matthias Schleiden – stated that all plants are made of cells. (1838)Theodor Schwann – discovered that all animals are made of cells too (1839).Rudolf Virchow – stated that all cells arise from the division of preexisting cells (1855).

Over the next 300 years…

           Three key statements

    i. All organisms are made up of one or more cells.

   ii. The cell is the smallest living organizational unit.

   iii. All cells are produced from previously existing cells.

            

Cell Theory

b.         All cells appear to be descended from the first cell which existed about 4 billion years ago

           For a species to exist, its reproductive cells must be potentially immortal (no aging).

2 type of cells

Prokaryotic cells Eukaryotic Cells

Prokaryotic cells

• Prokaryotic cells are . . .

• (1)Smaller and more primitive.

(2)Have few organelles and their organelles have no membranes. The cell has no nucleus.

• (3)They are bacteria.

Eukaryotic Cells

Eukraryotic Cells are…..(1)       More 1. More advanced, larger, and contain

organelles. These cells have a nucleus. Organisms made of these cells include protists, fungi, plants, and animals (including humans).

                      2.Organelles allow many activities to take place within the same cell other reactions take place on membrane surfaces and eukaryotic cells have much more internal membrane surface that prokaryotic cells

Organization of Organisms

Complex organisms can be organized as follow

Organism

                             Organs and organ systems

                             Tissues

                             Cells

                           Organelles

                             Molecules

b.         All cells appear to be descended from the first cell which existed about 4 billion years ago

           For a species to exist, its reproductive cells must be potentially immortal (no aging).

Cell Membrane

- contains special fat molecules which keep water from passing through

- controls what comes into and goes out of the cell

- also has proteins stuck in it

- very important for homeostasis

- Selectively permeable

Cell Wall

- found in plants, bacteria, and fungi- not living like the cell membrane- because it is not living it requires pores for

things to get in and out.- protects the plant cell and gives it strnegth

and structure- because it is so strong the plant does not

need a skeleton

Cytoplasm

Also known as cytosol

• all the liquid which fills the cell

• mostly water

nucleus

• controls the activities of the cell

• contains the DNA (genetic information)

• DNA is in the form of chromosomes

• surrounded by the nuclear membrane which is similar to the cell membrane

• the nuclear membrane controls what goes in and out of the nucleus

Mitochondria

• release energy from the food we eat

• break down glucose and other molecules for energy

Ribosome

• - make protein for the cell

• - most cells have 1000s of ribosomes

• - some proteins stay inside the cell, some proteins leave the cell

Lysosome

- lysosomes break apart worn out cell parts

- like a little recycling center

- the parts are then reused to make new cell parts

Chloroplasts

- contain a green pigment called chlorophyll

- this pigment absorbs light from the sun

- the chloroplasts make glucose (the main food) for the plant

- this process is called photosynthesis

Vacuole

- the vacuole is used for storing things inside the cell

- plant cells usually have very large vacuoles that they use to store water

- the vacuoles of animal cells are not as large but they have many more