1. Cells Final Review
Chavez & Marrero

2. Cells & Living Organisms
All cells must contain certain cellular structures which help maintain homeostasis.
Living organisms can be classified as eukaryotes and Prokaryotes.
Eukaryotes: cells contain a nucleus, include animals, plants, fungus, protists
Prokaryotes: NO NUCLEUS includes bacteria ( eubacteria and archaebacteria)
Homeostasis: the relatively constant internal physical conditions of an organism.
Living organisms need energy to survive. They either make their own energy/food or take in energy/food.
Autotrophs: organisms that make their own food.
Heterotrophs: organisms that must consume their food.

3. Animal vs Plant Cells
Animal and plant cells have similar organelles, however Plant cells have a cell wall, chloroplasts and one large vacuole.

4. Bacterial Cells
Bacterial cells are unicellular and are very simplistic. They only contain DNA, ribosomes, cell membranes , cytoplasm, and some contain cell walls.

5. Cell Parts
1. nucleus: stores DNA, control center of the cell, directs all the cell activities
2. nucleolus: manufactures ribosome parts ( proteins and RNA)
3. DNA: hereditary material that carries the genetic code
4. Chromatin: strands within the nucleus which form chromosomes
5. Nuclear membrane: encloses the cell’s genetic material
6. Ribosomes: factories for building proteins, makes proteins using coded instructions that come from the nucleus.
7. Cytoplasm: the jellylike interior of the cell, sticky, semi – fluid material inside a living cell in which other cell organelles are suspended.

6. Cell Parts
8. Endoplasmic Reticulum: roadways for moving materials throughout the cell. Serves as a transport system within the cell.
9. Rough Endoplasmic Reticulum: internal membrane system with tiny bumps ( ribosomes) all over its surface. ( J Lo)
10. Golgi Apparatus / Body: serves to process, package and export proteins, prepares and packages proteins either for use within the cell or shipment out of the cell, packages useful materials and secrete them to the outside of the cell.
11. Lysosome: responsible for breaking down and digesting things, destroys worn out cell parts, contain digestive enzymes.

7. Cell Parts 12.vacuoles: storehouse for excess water, food, wastes
13. mitochondria: involved in energy conversions, release energy for cell functions, powerhouse of the cell, involved in energy production
14. chloroplasts: involved in energy conversions, green organelle of plant cells where photosynthesis takes place, found in plant cells but not animal cells, that carries out the process of photosynthesis.
15. cell membrane: controls what enters and leaves the cell, holds the contents of the cell together, regulates the movement of materials into and out of the cell.
16. cell wall: provide strength for plant cells, thick surface structure that gives shape, support, and protection to plant cells.

8. Cell Organelles

9. Cell Membrane
Substances are moved into and out of cells through the cell membrane.
Some methods such as active transport, pinocytosis , phagocytosis , endocytosis, and exocytosis require energy to take place. The substance is being moved from a lower concentration to a higher concentration.
Endocytosis: the process in which a cell takes in ( engulfs) particles into the cell.

10. Cell Membrane
Other methods of transport which do not require energy are known as passive transport. These include osmosis, diffusion and facilitated diffusion.
Osmosis: the movement of water from and area of high to low concentration across the cell membrane.
Diffusion: the movement of substances from and area of high to low concentration across the cell membrane. The cell membrane contains channels made of proteins that help move materials from one side to the other.
During diffusion, when the concentration of molecules on both sides of the membrane is the same, the molecules will continue to move across the membrane in both direction.