1. If all living things need water to survive…
Why do you think the runner reacted so negatively when given water during her marathon?

2. 7.1 Life is Cellular
The key to how organisms live and function is found in cells.
Let’s see what you remember or already know about cells…

3. Pre-Test … What do you know?
The smallest unit considered “alive” is…
T / F: All cells contain genetic material called DNA
DNA is found in this centralized structure within a cell called the ______________
All cells are surrounded by a thin, flexible barrier called __________________________
Scientists didn’t know about cells until (THIS) was invented in the late 1500’s.

4. 6. T / F: All cells have the same basic structure and function 7
6. T / F: All cells have the same basic structure and function 7. T / F: Most plants and animals are multi-cellular (made of many cells) 8. An example of a unicellular (one-celled) organism is _________________.

5. Pre-Test Answers Anyone get 100% ? A cell True Nucleus Cell membrane
Microscope
False
Bacteria
Anyone get 100% ?

6. CELLS The building blocks of living things
Some organisms are made of 1 cell
Unicellular (bacteria)
Some organisms are made of many cells
Multi-cellular (plants, animals)

7. Discovery of the Cell
Invention of microscope led to discovery of cells!
1665 – Robert Hooke, Englishman – used microscope to observe piece of cork
Made of many tiny compartments, like rooms in a monastery called “cells”
Anton van Leeuwenhoek - using a microscope, found organisms in pond water, drinking water, and even his mouth

8. Types of Microscopes (p.192)
Light microscopes – can see cells and cell structures – use stains
Can be magnified up to 500x
Electron microscopes (2 types)
Scanning electron microscope – produces dramatic 3D images
- Have 3750x magnification
2. Transmission electron microscope – samples are cut in thin slices, making a flat 2D image
- Have 4375x magnification

9. Transmission Electron Microscope (TEM)
Light Microscope
Transmission Electron Microscope (TEM)
Scanning Electron Microscope (SEM)
Light microscopes use stains to add color to cells
Electron microscopes use the computer to add color

10. What do all cells have in common?
Cells are many different shapes and sizes
But all cells have a _______________ – thin, flexible barrier that surrounds the cell -
All living things are made of cells
Cells are the basic unit of structure and function of living things
New cells are produced from existing cells
cell membrane
The Cell Theory

11. How are cells different?
Cells fall into 2 broad categories,
based on the presence or absence of a _________
_________ = large, membrane-enclosed structure that contains genetic material called DNA
Prokaryotes (bacteria)
Eukaryotes (animals, plants)
nucleus
Nucleus

12. 2 Categories of Cell Types
Prokaryotes
Eukaryotes
No nucleus (DNA floats freely)
Unicellular
Small and simple
Some swim or glide along surfaces
Nucleus (contains DNA)
Multi-cellular
Large and complex

13. Is a virus a cell? Is it alive?
No, it is not a cell, and it is not alive
Viruses are nonliving particles
Made of proteins, nucleic acids (DNA or RNA), and sometimes lipids (fats)
Can ONLY reproduce by infecting living cells (remember cell theory?)

14. Structure of Viruses
Many shapes and sizes – All very small – need what type of microscope …?
Viruses have a protein coat called a capsid
Bacteriophages – virus that infects bacteria
Once inside bacteria, it makes many copies of itself
Breaks open and infects other cells