Science Notes Four

Cell Notes:

• The Earth was formed 4.5 billion years ago. The first cells showed up 3.5 billion years ago.
• First seen in 1665 (first microscope) by Hooke who looked at cork. He first used word "cell."
• Cell Theory
• proposed by: (in 1838) (first two worked together)
• Schliden - botanist
• Schwam - zoologist
• Virchow - 20 years later
• Parts
• All organisms are made of one or more cells
• A cell is the smallest unit able to carry out life processes
• Cells can only come from other cells
• Cells --> Tissue --> Organ --> Organ System --> Organism
• Cytoplasm - All living material in cell except nucleus
• Protoplasm - All living material in cell
• Organelles - a structure inside a cell
• Cell Membrane - controls what enters/exits a cell
• Nucleus - Structure that directs activities of cell
• Nucleic acid - Large organic compound that stores info that helps cell make proteins.
• Endoplasmic reticulum - tubular passageway in cell; for transport
• Chloroplast - Photosynthesis structure
• Lysosome - Small round digestive structure
• Chlorophyll - Pigment that converts sunlight to food
• Mitochondria - Place where cellular respiration takes place
• Diffusion - process by which substances move from a higher concentration to a lower concentration
• Active Transport - Movement of materials that requires energy.
• Passive Transport - Movement of materials that doesn't require energy.
• Nuclear Membrane - Double-layered membrane encasing cell nucleus
• Golgi bodies - stack of smooth membrane saccules that has to do with transport and modification of proteins.

I'm sure that there's more, but that's all I'm going to type for now.