cells

• organisms can be prokaryotes or eukaryotes
• eukaryotic cells are complex and include all animal and plant cells
• prokaryotic cells are smaller and simpler, e.g. bacteria
• there are two main types of eukaryotic cells: animal cells and plant cells
• the different parts of a cell are called subcellular structures
• the nucleus contains genetic material that controls the activities of the cell
• mitochondria are the site where aerobic respiration takes place in the cell
• the cytoplasm is a gel-like substance where most of the chemical reactions happen. it contains enzymes that control chemical reactions
• animal cells have a cell membrane, plant cells have a cell wall
• the cell membrane holds the cell together and controls what goes in and out
• ribosomes are where proteins are made in the cell
• the rigid cell wall is made of cellulose, and supports plant cells
• permanent vacuoles contain cell sap, a weak solution of sugar and salts
• chloroplasts are where photosynthesis occurs in plant cells. they contain a green substance called chlorophyll, which absorbs the light needed for photosynthesis
• bacteria are prokaryotes
• bacteria cells have a single circular strand of DNA
• bacteria cells may also contain one or more small rings of DNA called plasmids
• bacteria don't have chloroplasts or mitochondria