Cell Types and Structure

• Cells are the basic building blocks of life and are the smallest unit of life that can replicate independently.
• Animal and plant cells are examples of eukaryotic cells, while bacterial cells are prokaryotic cells.
• Cells contain various subcellular structures known as organelles.
• Both animal and plant cells are surrounded by cell membranes that control which substances can pass in and out of the cell.
• Both types of cells have a nucleus which contains the genetic material or DNA of the cell and controls the activities of the cell.
• Both animal and plant cells are filled with a gel-like substance called cytoplasm where all the other subcellular structures sit and where the chemical reactions take place.
• Both types of cells contain mitochondria whose job is to provide the cells with the energy they need to function.
• Mitochondria break down sugars like glucose in a process called aerobic respiration which releases energy.
• The cell can use ribosomes, which are the site of protein synthesis, and both cell types contain loads of ribosomes.
• Plant cells have a rigid cell wall around the entire cell, made up of material called cellulose, which provides support and structure to the cell.
• Plant cells also have a permanent vacuole, a big sac that contains cell sap, which is a mixture of sugars, salts, and water that the cell can use when it needs to.
• Plant cells have chloroplasts, where photosynthesis happens, and contain a green substance called chlorophyll, which absorbs the light energy needed for photosynthesis and makes plants leaves green.
• Bacteria are prokaryotes and consist of a single prokaryotic cell, making them unicellular organisms like the eukaryotic cells we've seen so far.
• Bacteria have a cell membrane, a cell wall, ribosomes, and cytoplasm, but they don't have mitochondria or chloroplasts and they don't keep their genetic material in a nucleus.
• Bacteria have a single circular strand of dna that's free to float around the cytoplasm and contains all the genes they need to survive and reproduce, which is also labeled the circular chromosome or nucleoid.
• Some bacteria also have additional small rings of dna called plasmids, which carry extra genes like antibiotic resistance, and flagella, thread-like structures that protrude out from the bacteria and rotate to propel the bacteria along, allowing the bacteria to move around.