Use the magnifying lens in front of you to --------- Let’s have some fun… Use the magnifying lens in front of you to --------- the specimens in front of you. Start with number 1 Specimen 1 cork Specimen 2 blood smear or animal cell Specimen 3 plant cell slide What do you see?

Use the _________ in front of you to observe the specimens in front of you. Start with number 1 What do you see?

What is a Cell?

Cell theory Activity

Year of Discovery Scientist Contribution 1595 Hans and Zacharias Janssen produced the first compound microscope by combining two convex lenses within a tube 1665 Robert Hooke Discovered the cellular composition of cork and introduced the word cell to science 1674 Anton van Leeuwenhoek Improved magnification of microscopes by polishing lenses 1676 "animacules" were discovered 1683 discovered bacteria from a sample of saliva from his mouth 1838 Matthias Schleiden discovered the plants were made up of cells 1839 Theodor Schwann discovered that animals were made up of cells 1855 Rudolph Virchow stated that all living things come from other living things

1. State the 3 main ideas of the cell theory. 2. Explain one of these ideas.

C E L T H O R y

Questioning the cell theory using atypical cells as: striated muscles, giant algae and fungal hyphae)

Questioning the cell theory using atypical cells as: striated muscles, giant algae and fungal hyphae)

Questioning the cell theory using atypical cells as: striated muscles, giant algae and fungal hyphae)

What is a L.O?

MR H GREN Metabolism Response Homeostasis Growth Reproduction Excretion Nutrition

Do we have different types of L.O? What is the difference between unicellular and multicellular organisms?

Let’s get to know unicellular organisms and their activities to stay alive Paramecium Chlorella Draw a table to compare between both organisms and how they maintain different life processes

Paramecium

Paramecium Chlorella Draw a table to compare between both organisms and how they maintain different life processes

Characteristics of life Paramecium Chlorella Metabolism Burning food that is ingested Photosynthesis making sugar and burning it Response (sensitivity) Responds to food in water and moves towards it Responds to lack of sunlight and starts to divide to reach it Homeostasis Contractile vacuole control the water content of the cell to maintain a stable environment Growth The grows in size then divides into 2 cells The cell grows then the cell divides into spores Reproduction Nucleus divides then cytoplasm and cell membrane The cell gives 4 autospores that form a cell wall around them and then mother cell wall disappears Excretion Loss the wastes from the cell surface Nutrition Ingests microorganisms in the water Photosynthesis

Cell size Why does it matter? Which is better to be made up of one big cell or many cells? NOTE: Gases and food molecules dissolved in water must be absorbed and waste products must be eliminated. For most cells, this passage of all materials in and out of the cell must occur through the plasma membrane 

The cell is very small so we use micrometers (or micron)to measure the size of a cell 1 Micron = 10-3 mm = 0.001mm

Elephant weighs 5000 Kgs Food intake 150-300 Kgs /day Mouse weighs 35 gms Food intake 54 gms/day

Egypt and over population Resources? Wastes? Services?

Surface area- volume ratio Activity 3 Surface area- volume ratio activity

Each internal region of the cell has to be served by part of the cell surface. As a cell grows bigger, its internal volume enlarges and the cell membrane expands. Unfortunately, the volume increases more rapidly than does the surface area, and so the relative amount of surface area available to pass materials to a unit volume of the cell steadily decreases.

The surface area to the volume ratio gets smaller as the cell gets larger. Thus, if the cell grows beyond a certain limit, not enough material will be able to cross the membrane fast enough to accommodate the increased cellular volume. When this happens, the cell must divide into smaller cells with favorable surface area/volume ratios, or cease to function.

How can cells overcome this problem? 1. Cells divide 2. Compartments within cells 3. Cells have folds to increase SA:V 4. Cells have organelles with their own membranes

Homework

If cells are so small then how can we see them? microscopes

Mention the differences..

Microscope Vocabulary Magnification VS Resolution Magnification: increase of an object’s apparent size Resolution: power to show details clearly Both are needed to see a clear image

1. Compound Light Microscope 1st type of microscope, most widely used Types of Microscopes 1. Compound Light Microscope 1st type of microscope, most widely used light passes through 2 lenses Can magnify up to 2000x

Types of Microscopes 2. Electron Microscopes Used to observe VERY small objects: viruses, DNA, parts of cells Uses beams of electrons rather than light Much more powerful

Types of Electron Microscopes Scanning Electron Microscope (SEM) Can magnify up to 100,000x

Types of Electron Microscopes Transmission Electron Microscope (TEM) Can magnify up to 250,000x

Mention the differences..

Three advantages of using light microscopes include: Colour images instead of monochrome, A larger field of view, Easily prepared sample material with the possibility of examining living material and observing movement. Advantages of Electron microscopes (Scanning and transmission electron microscopes) Higher resolution and magnifications