1. Cells

2. What is a cell?
The smallest living unit and basic building block of life.
The human body has about 100 trillion cells!!!
Different cells in the body are specialized to carry out special jobs…just like the organs in our body!
All cells digest nutrients, excrete waste, synthesize (make) needed chemicals, and reproduce.

3. Cells…
Scientists believe life began somewhere between 3.9 – 3.5 billion years ago.
Cells are the basic unit of life, basic building block of organisms.
Different cells in the body perform various tasks. (Examples: muscle cells are capable of rapid contraction; nerve cells transmit special chemicals to the body about our environment and help us be able to respond).

4. Brain nerve cells
Muscle Cells at rest
Muscle Cells contracting
Muscle Cells

5. What are the two big groups into which cells are classified?
Eukaryotic - type of cell that does have its chromosomes surrounded by a nuclear membrane. (has a nucleus)
Animal and plant cells
Prokaryotic - A type of cell that does not have its chromosomes surrounded by a nuclear membrane (no nucleus)

6. Eukaryotic Cells… More advanced then prokaryotic
Appeared about 1 million years ago!
Dinoflagellates – found on the ocean floor

7. Are there living beings without cells?
Viruses are considered the only living beings that do not have cells. Viruses are constituted by genetic material (DNA or RNA) enwrapped by a protein capsule. They do not have membranes and cell organelles.

8. The Cell Theory All living things are composed of one or more cells.
The cell is the smallest entity that retains the properties of life.
New cells arise only from cells that already exist.

9. Lets look at the Animal Cell
But first…can you tell me:
Is it a prokaryotic or eukaryotic cell? How do you know?

24. Microfilament

25. Microfilament

26. Cytoplasm
Microfilament

27. Plasma (Cell) Membrane
Holds cell together
regulates the movement of materials into and out of the cell
Cell membrane is made up of proteins and a double layer of lipid (fat) molecules.
Border/City Wall

28. The Cell Membrane

29. Mitochondrion Tiny oval shaped organelles
Mitochondria provide the cell with the needed energy.
Glucose (sugar) molecules are transported to the mitochondria where it can be broken down and made into energy (ATP).
Cellular Respiration: sugar molecules combine with oxgyen to form carbon dioxide and water. Energy is also released and stored in a compound called ATP. Power Plant of the cell

30. Nucleus
The control center of the cell (just like your brain is the centre for your body).
It directs all cell activities including reproduction and metabolism.
It contains the genetic material (DNA)
In a city it would act like City Hall

31. Nuclear Membrane (Envelope)
The outer lining of the nucleus (kind of like its skin)
Regulates materials into and out of the nucleus
In a city it would act like the security gaurds or a fence for City Hall…only allowing certain molecules in.

32. Chromatids/ Chromatin
Chromatin is the combination of DNA and proteins that make up the contents of the nucleus of a cell.
Two chromatid make up a chromosome.
Mayor/Councilors

33. Nuclear Pore
Openings in the nuclear membrane that permit passage of substances into nucleus
City Hall gates/doors

34. Ribosomes The organelles that make proteins!
The smallest organelle found in the cytoplasm.
In order for cell growth and reproduction to happen…ribosomes need to be making proteins.
Lumberyard/steel factory (raw materials for building)
Ribosomes can attach to Endoplasmic Reticulum depending on the type of cell.

35. Nucleolus
Produces ribosomes
Contractor or forest

36. Lysosome Organelles formed by the golgi apparatus.
Contain digestive enzymes for breaking down old organelles and bacteria.
They are only found in animal cells.
They play a big role in the human body’s defense mechanism to fight harmful substances. (White Blood Cells)
Garbage truck/landfill

37. Centrioles
Every animal-like cell has two small organelles called centrioles. They are there to help the cell when it comes time to divide.
Aid in cell reproduction
Maternity ward/midwife

38. Vacuole
An organelle that stores food and wastes left over by chemical processes inside the cell.
In a city it would be like a Warehouse

39. Golgi Complex
Stores, modifies, and packages proteins from the rough endoplasmic reticulum.
The Golgi apparatus also creates vesicles which help take contents outside the cell.
Factory

40. Microtubule/Microfilament
Microtubule - Long, hollow, cylindrical tubes that help transport materials throughout the cytoplasm.
Microfilament – long, solid, threadlike strands found in the cytoplasm that help provide shape and movement cells.

41. Endoplasmic Reticulum
Fluid-filled canals transport materials throughout the cell
Smooth = no ribosomes; Rough = ribosomes
Trucking/Railway/Metro Transit

42. Cytoplasm Watery material containing substances for cell metabolism
Everything else in the city

43. Good Link!