Transcript Agenda
Cell Structure Review Eukaryotic Cells • • Have a nucleus Found in multi-cellular organisms & some unicellular organisms Prokaryotic Cells • • Do not have a nucleus Found in bacteria Cell Membrane • • • • Thin, flexible layer Separates the cell from its surrounding environment Controls movement of materials into and out of the cell Helps maintain the cell’s internal environment Chromatin • • • Coils of DNA and protein that form chromosomes. Can be thought of as chromosomes without shape. Granular-like material found in the nucleus containing genetic information Chromosome • • Worm-like / rodlike structures formed from chromatin during cell reproduction. They become distinct during the reproductive part of the cell cycle as the cell divides. Composed of DNA Cytoplasm • • • Thick, jelly-like substance contained within the cell membrane Most of the work of the cell is carried out here. The majority of the organelles are suspended in the cytoplasm. DNA • • • The genetic material found in all living cells. Contains the information needed for an organism to grow, maintain itself, and reproduce Stands for deoxyribonucleic acid Endoplasmic Reticulum • • • • Network of channels/tubes leading from the nuclear membrane into the cytoplasm Helps transport materials between the nucleus and the cytoplasm Also involved in transporting proteins Two types: - Smooth E.R. = no ribosomes -Rough E.R. = contains ribosomes Golgi Bodies • • • Serve as storage and packaging centers. Look like stacks of flattened sacs Proteins made by the ribosomes are packaged into vesicles (small pockets) These packages are used by the cell and sometimes are released from it. Lysosomes • • Sac-like structures that contain enzymes Where digestion of cell nutrients & food molecules take place Breaks down cellular waste or things that are harmful to the cell • Similar to the job of white blood cells Mitochondria • • • Organelles that cause the release of energy by using oxygen to break down sugars. Usually round or tube shaped Releases food molecules that supply energy to the cell; it is known as the powerhouse of the cell. Usually more than one in a cell Nuclear Envelope • • Has a double-layered membrane that separates the nucleus from the cytoplasm. Contains pores to help facilitate the exchange of materials between the nucleus and the cytoplasm Nucleus • • • • • Control center of the cell Manages all of the cell’s activities Largest organelle Contains the genetic material (chromatin) the cell needs to reproduce and function. Is surrounded by the nuclear envelope and also contains the nucleolus and chromatin. Ribosomes • • Sites of protein manufacturing in the cell Assemble proteins that: • • • Create chemical messages to run a cell. Build cell organelles Line the membrane of the rough endoplasmic reticulum & are found in the cytoplasm