Characteristics of Life:
Homeostasis: maintenance of internal stability, body responds to internal and external changes
Metabolism: combinations of all the chemical reactions that occur in an organism.
Life Functions
| Respiration | the ability to convert food into energy |
| Regulation | the ability to maintain a stable internal environment (maintain homeostasis) |
| Reproduction | the ability to produce more of their own kind (not needed for the individual organism to survive) |
| Growth | the ability to increase in size |
| Excrete | the ability to remove metabolic wastes (Carbon Dioxide, Water & Urea) |
| Nutrition | the ability to obtain and process food (Autotrophic or Heterotrophic) |
| Transport | the ability to move materials into, out of and throughout an organism |
| Synthesis | the ability to manufacture materials not able to be gotten from the environment |
Cell Structure
Cytoplasm- liquid in cell
Nucleus- contains genetic information
Vacuoles- stores food, wastes
Mitochondria- cell energy, respiration, ATP
Chloroplast- photosynthesis (plant cell only)
Cell wall- plant cell only
Cell membrane- controls what enters and leaves the cell
Cell membrane consists of;
- Double layer of lipids (phospholipids)
- Proteins imbedded in lipids
- Carbohydrates chains project from proteins.
Carbohydrates part of membranehelps with cell communication. Lipid part of membrane allows small molecules to pass through easily. For examples; water carbon dioxide, and oxygen. Protein portion of cell membrane allows glucose and amino acids into and out of the cell.
Types of Transport
1. Passive Transport
- Movement of material without energy
- Molecules move from high concentration to low concentration.
- Types of passive: diffusion & osmosis
Diffusion- spread of molecules from higher to lower concentration. (small molecules: CO2, O2)
Osmosis – diffusion of water through a membrane.
2. Active Transport
- Movement of materials that requires energy (ATP)
- Only move through proteins
- Moves from low concentration to high concentration.
- Types of active: endocytosis (pinocytosis, phagocytosis), and exocytosis
Photosynthesis:
Photosynthesis takes place in the chloroplast of plant cells and makes food for the cell. This process produces both oxygen and gluse as show in the diagram. The formula of photosynthesisis as follows: cabron dioxide + water –> glucose + oxygen. The glucose will be used as food for the plant and the oxygen is released into the atmosphere.
Respiration:
Respiration on the other hand occurs in the mitochondria of both autotrophic and heterotrophic cells. This formula is the reverse of the earlier mentioned photsynthesis formula. Respiration formula: oxygen + glucose –> carbon dioxide +ATP