1. The Human Body: A Nutrition Perspective
Chapter 3
BIOL1400
Dr. Mohamad H. Termos

2. Chapter 3 objectives
Following this lecture, you should be able to describe:
The Cell
Basic functions
Cell organelles
Cell membrane
Body systems as they relate to human nutrition

3. Human physiology
- Production and break down of substances constantly occurs in every cell
- Cells require constant supply of nutrients
- Cells also require oxygen
- A healthy diet is required to supply the body with these substances

4. The Cell The basic unit of a living organism.
Only seen using microscopes
Differ in shape, size, and function.

5. The Cell Functions
Organisms contain organs that do individual jobs for the survival of the organism; cells have “mini organs”, called organelles to do their basic jobs!
An Idealized Animal Cell

6. Major parts of a Cell

7. Major parts of a Cell

8. Organelles: The nucleus
Cellular Anatomy
The largest cell structure
Usually a sphere in the center of the cell
Considered as the cell control center.
Houses the heredity molecules (DNA)
We’ll start by seeing what role these parts play in making and moving proteins.

9. The Nucleus Anatomy of the nucleus:
Nuclear envelope (Outer and inner nuclear membranes)
Nuclear pores (permit molecule movements)
Nucleolus

10. The Endoplasmic Reticulum (ER)
The Cytoskeleton in Action
Made up of many fattened membrane sacs
Part of it is dotted with ribosomes for protein synthesis, the rough ER (RER).
The part that has no ribosomes, is called smooth ER.
The smooth ER is a site of lipid synthesis
Smoker’s cough is due to destruction of cilia linking the airways.

11. The Golgi Apparatus Analogous to postal service for the cell
After rough ER protein is sent to Golgi
Protein will be modified, packaged, and sent to various destinations (outer membrane of the cell or secreted outside of the cell entirely)

12. Mitochondria The powerhouses of the cell Major energy source
Surrounded by outer and inner membrane
Cells may have varying number of mitochondria, according to their energy requirements.

13. Lysosomes and Peroxisomes
The cell “stomach”
Houses acidic environment and digestive enzymes
Site of molecules break down.
Peroxisomes:
Degrade lipids and alcohol
Degradation of these produce hydrogen peroxide (toxic byproduct).
Luckily, peroxisomes degrade this toxic molecule too.

14. The Cell Membrane
Plasma membrane of the cell is the outer wall of the cell.
Separates the inside fluids and organelles (that are found in the cytoplasm) from the outside environment (the interstitial fluid)

15. The Cell Membrane The cell membrane is made up of phospholipids.
These phospholipids are arranged in a bilayer and they act as an excellent barrier for the cell.
The cell membrane is also “equipped” with protein channels that regulate the passage of molecules in and out of the cell.

16. Types of Tissue
1- Epithelial tissues: cover surfaces inside and outside the body. Function in substance secretion, nutrient absorption, and waste excretion.
2- Connective tissues: support and protect the body. store fat and produce blood cells
3- Muscle tissues: designed for movement
4- Nervous tissues: designed for communication. Found in the brain and spinal cord