Human Biology Unit 1 Summary Sheet PDF

Cells are present in every single living organism and are the building blocks of life. Cell Theory: - Come from preexisting cells - All organisms are made from cells - Cells are the smallest structure that can perform life's functions. Cell Membrane: - Fatty, membrane. - Controls wh...

Cells are present in every single living organism and are the building blocks of life. Cell Theory: - Come from preexisting cells - All organisms are made from cells - Cells are the smallest structure that can perform life's functions. Cell Membrane: - Fatty, membrane. - Controls what comes in and out of cell. - Adds structure to cell - Acts as a barrier to separate cytoplasm from exterior substances. - Contains proteins Cytoplasm: - Watery material that fills all space between organelles and the organelles with the cell. - Cytosol is the name of the liquid part of the cytoplasm. It is 75% to 90% water, with extra dissolved substances like salts and carbs. There are other compounds that just float around in it, like proteins. Where metabolic reactions occur. Organelles: - Organelles are the structures with the cell that all have specific functions. - Nucleus: Almost all cells have a nucleus, some have more the one, and a few have none (like mature red blood cells). Has double membrane to separate from cytosol. Contains DNA and the nucleolus, which helps make ribosomes (proteins). - Ribosomes: Small circle organelles. Joins amino acids together to make proteins. Found free in cytoplasm or attached to membranes. - Endoplasmic Reticulum: Pairs of parallel membranes that create channels from cell membrane to nuclear membrane. Store, package and transport proteins, carbohydrates and lipids. Rough ER = ribosomes are attached to membrane, so it has a ribosome focus. Smooth ER = no ribosomes, so it is carb and lipid focused. - Golgi Body: Series of stacked, flattened membranes. Usually near nucleus. Modifies proteins and packages them for secretion from cell. Final checks after ER (or straight to Golgi body) before excretion. - Lysosomes: Small sphere formed from Golgi body. Contain digestive enzymes. - Mitochondria: Spread throughout cytoplasm. Double membrane. Some chemical reactions of cellular respiration occur here. These reactions generate energy for the rest of the cell to function. - Cilia: Short and numerous hair-like membrane that is outside the cell. that beat back and forth to move the cell or other substances over it. - Flagella: Longer and fewer membranes. - Cytoskeleton: Framework of protein fibres. Gives cell shape and assists cell movements. Microtubes -- hollow rods to keep organelles in place or move them. Microfilaments -- move material around cytoplasm or move whole cell. - Inclusions: Chemical substances. Not part of cell. Found in cytoplasm. - Centrioles: In animal cells. Involved in formation of the spindle during nuclear division. - Cell Membrane: - Fluid Mosaic Model Structure of a cell membrane. - Phospholipid bilayer made up of phospholipid molecules each molecule has two parts: - Hydrophilic head water loving - Hydrophobic tail water hating - In bilayer is protein and cholesterol molecules: - Cholesterol support structure - Proteins extends from in to out of cell: - Carrier proteins - Channel proteins - Cell identity - Receptor proteins - Function of membrane: - Physical barrier - Regulation of what passes through - Sensitive to changes (such as temp) - Supports the cell (connected to cytoskeleton) - Functions on Proteins: - Channel proteins Transports molecules through membrane quickly without using energy (passive) - Carrier proteins Binds to materials and transports across membrane (active/uses energy) - Cell identity markers allows identification and analysis of specific types of cells. - Receptor Proteins receive and interpret changes in the cell and report it to the rest of the body. - Function on Cholesterol: - Helps stabilize the cell. - Helps regulate the membrane fluidity during changes of temperature. - They are wedged in between the phospholipid molecules. - Membrane Transport: - Semi-Permeable/ differentially permeable (some move freely, others are restricted/controlled) - Active transport requires energy - Passive transport requires no energy - 3 main modes of transport: - Simple diffusion: - Spreading of particles until evenly distributed - Particles will flow from an area of high concentration to area of low concentration. - Cell uses oxygen up more o2 on outside of cell o2 spread through membrane to the area of low concentration. - Also works other way (co2) - Higher concentration gradient = higher rate of diffusion. - Osmosis diffusion of water across membrane: - Water is a solvent. - Substances such as sugar are solutes. - Water will move to areas with higher solute concentration. - Even if there is same amount of water on each side. - Facilitated Transport: - Proteins in cell allow substances to cross. - Protein channels: - Pathways for hydrophilic molecules to move without touching hydrophobic tails. - Pathways are small, so ions and water move through easily. - Passive transport. - Protein carriers: - Control exit and entry of large molecules - Specific and only binds to specific molecules. - Can become saturated - Controlled by hormones increase/decrease movement. - Active process - Grabs the substances and dumps them in. - Vesicular transport: - Movement across membrane in a vesicle. - Active process - Moves in both directions - Endocytosis moving into cell: - Folds around substance and pinches around until contained. - Pinocytosis taking in of a liquid - Phagocytosis taking in of solids - Exocytosis exiting cell - Same process - Pushing out content of vesicle into extra-cellular fluid.