1. Cell Structure - Part I
Chapter 3 – Unit A

2. Cytology – the science of studying the cell, became possible with the invention of the compound/light microscope.

3. Cytology reached new levels with the invention and use of the Electron Microscope.

4. You do not need to do math conversions, but it is important that you have some idea of the units used to measure cells and cell structures. Scientists often measure in micrometers, there are 1000 micrometers in a single millimeter. Sometimes micrometers are too large, so scientists measure in nanometers. There are 1000 nanometers in a single micrometer.

5. Cells are limited in their size
Cells are limited in their size. They need to maintain themselves by getting rid of wastes and taking in nutrients throught their cell membrane. As a cell gets bigger, its volume goes up much faster than its surface area, the cell membrane would no longer be able to keep up with the demands of the cell; and the cell would die.

6. Prokaryotic vs Eukaryotic

7. Prokaryotic VS. Eukaryotic
Prokaryotic = “Before Nucleus”
Much smaller cell ( X smaller)
No membrane bound organelles
No true nucleus
Use different ribosomes
Only life forms that use this cell are bacteria
Eukaryotic = “True Nucleus”
Much larger size
Various membrane-bound organelles
A true membrane-bound Nucleus
Much more metabolically efficient
Used by all other life forms, Protists,
Fungi, Plants and Animals.

8. Plant Cell vs. Animal Cell

9. 1. Cell Wall 2. Large Central Vacuole 3. Chloroplasts
This can be identified as being a Plant Cell in that it possesses the following:
1. Cell Wall 2. Large Central Vacuole 3. Chloroplasts

10. Fig. 3.2a
ANIMAL
CELL

11. THE CELL MEMBRANE
Consists primarily of a double layer of phospholipids. Acts as a gate-keeper to determine what will enter and exit the cell.

12. Fig. 3.2b

13. THE NUCLEUS
Acts as the control center for the cell. Stores the DNA in the form of Chromatin. This DNA has all the blue prints to build all the crucial structural and functional proteins of the cell. These proteins build the cell and run the cell.

14. Recall that membrane consists of a double layer of phospholipids
Recall that membrane consists of a double layer of phospholipids. The nucleus is enclosed with a double membrane (Nuclear Envelope), therefore having four layers of phospholipids. Nuclear pores tunnel through.

15. Endoplasmic Reticulum
Branching out from the nuclear envelope is a series of membranous folds that form a network of channels (Endoplasmic Reticulum). These membranous channels act like roadways to transport materials.

16. Rough E.R. vs. Smooth E.R.
Rough E.R. – Is studded with Ribosomes. These Ribosomes translate mRNA to make proteins which then enter the inside of the Rough E.R.
Smooth E.R. – Lacks ribosomes. It is responsible for producing sterol lipid hormones (Ex. Testosterone) and for housing detoxifying enzymes.

17. ROUGH ER Function: To build and transport proteins.

18. SMOOTH ER SMOOTH ER Function:
To help form Sterol Lipids as well as key Detoxifying Enzymes and then transport them.