1. Cells and Their Functions
Chapter 3

2. Objectives List 3 types of microscopes
Describe the function and composition of the plasma membrane
Describe the cytoplasm and the organelles
Describe the composition, location, and function of DNA
Compare the 3 functions of RNA
Explain briefly how cells make proteins
Name and briefly describe mitosis
Define 8 methods by which substances enter and leave the cell
Explain what happens if cells are placed in solutions with the same concentration as the cell fluid and different as the cell fluid
Define cancer
List several risk factors for cancer

3. Basic unit of all life.
The study of cells is cytology.

4. Cell Structure
Plasma Membrane

5. Cell Structure
Nucleus

6. Cell Structure
Cytoplasm

7. Cell Structure
Organelles – ER,ribosomes,mitochondria,Golgi apparatus,lysosomes,vesicles

8. Protein Synthesis Carries genetic message Located in nucleus
DNA
Carries genetic message
Located in nucleus
Composed of nucleotides
Double-stranded
- They are segments that make up our chromosomes

9. Cell Division Serves for growth, repair, and reproduction
Meiosis : Chromosome number divided in half
(forms the sex cells)
Mitosis : Cell division that results in 2 identical
daughter cells (exactly like parent cell)

10. Meiosis
First, cuts the chromosome number in half to prepare for the union of the sperm and egg
You need the reduction in chromosome number to have offspring with the right number.

11. Mitosis Continuous process, but distinct stages can be identified:
All our somatic (body) cells divide this way.

12. Movement of Substances across the Plasma Membrane
Some substances can enter the cell, others can not. The plasma membrane serves as a barrier between the cell and its environment.
Separated into:
movement that requires energy
movement that does not require energy

13. Movements cont….
- Does NOT require energy
Diffusion – constant mvmt of particles from higher concentration to lower
Osmosis – special type of diffusion for water (move from an area where there are fewer solutes to one where there are more solutes)
Filtration – passage of water through membrane due to a force
Facilitated Diffusion – movement across membrane from higher to lower using transporters
- DOES require energy
Active transport – plasma membrane moves particles in or out in opposite direction
Endocytosis – moves into cell (Phagocytosis, Pinocytosis)
Exocytosis – moves out in vesicles

14. Solutions you need to know….

15. Cancer
is defined as a tumor that spreads to other tissues. Also known as a malignant neoplasm.

16. Risk Factors for Cancer
Heredity
Chemicals
Ionizing Radiation
Physical Irritation
Diet
Viruses

17. Understanding…
Your understanding of cell structure and function will help you to understand tissues, organs, systems and the whole human body!