1. Features and Functions of Cells

2. Cell Structure
(Page 10)
One of the first structures to be seen clearly through a microscope
was the nucleus.
The nucleus is the organelle that controls the cell’s activities.
Organelles are specialized structures within a cell.
Copyright © 2010 McGraw-Hill Ryerson Ltd.

3. The Cell Theory 2. The cell is the basic organizational unit of life.
(Page 11)
The Cell Theory was proposed by German scientists in the late 1830s.
Theodor Schwann and Matthias Schleiden used their studies of plants and animals to formulate the first two ideas. In 1855 Rudolph Virchow added the final one.
The theory states that:
1. All living organisms are made of one or more cells.
2. The cell is the basic organizational unit of life.
3. All cells come from pre-existing cells.
Copyright © 2010 McGraw-Hill Ryerson Ltd.

4. Cell Size Typically less than a tenth of a mm in diameter
Must be small so that nutrients, water, oxygen, carbon dioxide, and waste products enter or leave the cell efficiently.
Rule breakers include an ostrich egg that weighs up to 1.4 kg and the human sciatic nerve which can be 1.5 m long but its very skinny!

5. Animal and Plant Cell Organelles
(Pages 12-13)
The cytosol (the fluid material between the cell membrane and the nucleus which contains many specialized cells and other life-supporting materials, such as sugar and water)
Each organelle has specific functions that it performs in the cell. Together the organelles and fluid are called the cytoplasm.
There are some important differences between the organelles found in plant and animal cells.
Copyright © 2010 McGraw-Hill Ryerson Ltd.

6. Animal Cell nucleus rough endoplasmic reticulum nucleolus
Golgi apparatus
nuclear membrane
Golgi
vesicle
nucleus
chromatin
smooth endoplasmic reticulum
nucleoplasm
ribosome
lysosome
vacuole
mitochondrion
cell membrane
centrioles
cytoplasm

7. Plant Cell vacuole chloroplast cell wall rough endoplasmic reticulum
mitochondrion
ribosome
chromatin
cell membrane
nucleoplasm
cytoplasm
nucleolus

8. Cell Organelles
Cell membrane – separates the inside of the cell from the external environment; controls the flow of materials into and out of the cell (“gatekeeper”)
Nucleus – controls the cells’ activities (“the brain”)
Mitochondria – (singular: mitochondrion) where energy is released from glucose to fuel cell activities (“factory”)
Ribosomes – help to produce proteins, which make up much of a cell’s structure and are required for activities necessary for the cell’s survival; some ribosomes float in the cytoplasm, and others are attached to the endoplasmic reticulum

9. Cell Organelles
Endoplasmic reticulum – a network of membrane-covered channels that transport materials made in the cell; is connected to the nucleus
Golgi body – sorts and packages proteins and other molecules for transport out of the cell
Vacuoles – contain water and other materials and are used to store or transport small molecules; plant cells tend to have one large vacuole; animal cells may have several smaller vacuoles

10. Cell Organelles
Lysosome - contains enzymes (type of proteins) that can break down molecules (food, bacteria, wastes, the cell itself)
Cytoskeleton – filaments and tubules that provide a framework for the cell, helping it maintain its structure and providing “tracks” along which vesicles and organelles can move
Cell wall – a tough, rigid structure lying just outside a plant cell’s membrane; provides support for the cell
Chloroplasts – found only in plant cells; trap energy from the Sun to make glucose, which is broken down in the mitochondria to power cell activities (animals must get glucose from the food they eat)