1. 4.1 The Function of the Nucleus within the Cell
Chapter 4 Notes

2. Survey of Animal and Plant Cells
Cell membrane – controls the flow of material into and out of the cell
Cell wall (plants) – tough, rigid structure that provides support
Cytoplasm – jelly like substance that contains organelles (specialized cell parts that carries out specific functions)
Mitochondria – provide energy for cells by changing sugar (glucose) into usable energy
Chloroplasts (plants) – traps the Sun’s energy to make glucose
Ribosomes – either attached to the endoplasmic reticulum or floats in the cytoplasm and produces proteins (essential materials for survival)

3. Survey cont.
Endoplasmic reticulum – membrane covered channels that act as a transport system for materials made in the cell
Vesicles – sacs formed on the ends of the ER that transport new proteins to the Golgi body
Golgi bodies – sorts and packages proteins for transport
Vacuoles – storage containers within cells
Nucleus – controls all the activities of the cell and is surrounded by a nuclear membrane that protects it
Nucleolus – inside the nucleus and makes ribosomes
Nuclear pores – holes in the nuclear membrane that allows material into and out of the nucleus

4. Animal cell

5. Plant cell

6. Nucleus functions Deoxyribonucleic acid (DNA)
Carries all the instructions
Two stranded double helix (twisted ladder)
sides of the ladder are phosphate and sugar
“steps” are 4 nitrogen bases
adenine (A) always joins thymine (T)
guanine (G) always joins cytosine (C)
How the bases are ordered gives us the codes for everything in our bodies

7. Dna diagram Exists as chromatin (DNA is uncoiled) most of the time
When a cell is ready to divide, each chromatin strand coils into a compact X-shaped chromosome
Found in pairs; 23 in humans
In males, the last pair is XY and XX in females

8. Dna cont.
Genes are small segments of DNA located at specific places on a chromosome
Only specific genes are “read’ in each cell to produce specific proteins (specialized)
Specialized proteins called enzymes speed up chemical reactions
Specialized proteins called hormones act as chemical messengers

9. Protein synthesis
1. The nucleus receives a chemical signal to make a specific protein 2. The DNA message for a specific protein is copied into a small molecules called ribonucleic acid (RNA) 3. RNA leaves through a nuclear pore 4. The RNA message is delivered to the ribosome and the ribosome makes the protein (like a factory) 5. The manufactured protein enters the endoplasmic reticulum

10. Protein synthesis cont.
6. A vesicle forms off the end of the ER and carries the protein to the Golgi body
7. The Golgi body repackages the protein for transport out of the cell
8. A vesicle forms off the end of the Golgi body to carry the protein to the cell membrane
9. The vesicle attaches to the cell membrane and its protein contents are released out of the cell

11. Protein synthesis pic