1. SBI 3C SEPTEMBER 2012

2. THE BIG QUESTION HOW DO YOU KNOW IF SOMETHING IS ALIVE??

3. CHARACTERISTICS OF LIVING THINGS:  Stimulus and response  Require energy  Produce waste  Grow and reproduce

4. THE CELL THEORY 1. All living things are made up of cells 2. The cell is the basic functional unit of living things 3. All cells come from pre-existing cells through cell division

5. WHAT DO CELLS DO?  Cellular respiration: In the mitochondria glucose + oxygen  energy + water + carbon dioxide  Absorption: Bring in water and nutrients into cells  Excretion: Remove waste products from cells  Biosynthesis: Make larger molecules out of smaller ones Examples: ○ Amino acids join together to make protein ○ Sugar molecules join together to make carbohydrates

6. GENERAL STRUCTURE OF A CELL:  Inside is a liquid, water-based solution called cytoplasm  Little organs (organelles) sit in the liquid  Cells are surrounded by a membrane that separates them from the outside organelle membrane cytoplasm

7. TYPES OF CELLS:  There are 2 types of cells: Animal Cells Plant Cells

8. ANIMAL CELLS:

9. PLANT CELLS:

10. ORGANELLES:  CELL WALL: Only in plants Firm but porous, surrounds cells giving them rigidity  CELL MEMBRANE: Only in animal cells Surrounds cell and organelles in cell Composed of a bilayer (double layer) of fat (lipid) molecules called phospholipid bilayer

11. NUCLEUS: Control centre of the cell Contains DNA Surrounded by a porous double membrane (nuclear envelope) Filled with nucleoplasm (like cytoplasm)

12. DNA AND RNA: DNA: double stranded, found in nucleus RNA: single stranded, found in cytoplasm Chemical storage of information needed to keep the cell alive and functioning properly RNADNA

13. RIBOSOMES: Used to produce protein Either free floating in cytoplasm or attached to membranes Very small

14. ENDOPLASMIC RETICULUM: System of tubes and canals that attach to the nuclear envelope Two types: ○ Rough ER (RER) has ribosomes and is the site of protein manufacturing ○ Smooth ER (SER) no ribosomes and is where fat molecules are produced

15. GOLGI APPARATUS:  Stacks of membraneous tubes  Takes proteins from the ER and changes them  Packages them into vesicles to be released outside the cells

16. LYSOSOMES: Found only in animal cells Contain protein that help to digest food or kill invading bacteria or viruses Also kills dead or dying cells, called the suicide sac

17. MITOCHONDRIA:  Shaped like a kidney bean  Float in the cytoplasm  Site of chemical reactions that produce energy for the cell  Powerhouse of the cell

18. PLASTIDS:  Only in plant cells  Fairly large  Different types have different functions: storage (amyloplast - stores starch) energy production(chloroplast-site of photosynthesis)

19. VACUOLES:  Common in plant cells  Large, membrane bound sac  Filled with watery solution containing dissolved sugars, proteins, minerals  Pressure from water (turgor pressure) prevents plants from wilting