Biology Notes PDF

Chapter 7.1 Cell Structure and Function A. Discovery of the Cell 1. Scientist who contributed to cell discovery a. Robert Hooke - Discovered tiny chambers in a cork - Named chambers cell b/c reminded of cells in monast...

Chapter 7.1 Cell Structure and Function A. Discovery of the Cell 1. Scientist who contributed to cell discovery a. Robert Hooke - Discovered tiny chambers in a cork - Named chambers cell b/c reminded of cells in monastery 3 Principles of Cells 1. Cells are basic unit of structure and organization of all living things 2. All living things composed of one or more cells 3. New cells produced from existing cells, with cells passing on copies of their genetic material to their daughter cells Microscope Types Optical Microscope - compound light microscope or visible light magnification limited by the magnification TEM - Transmission Electron Microscope - focuses electron (e-) through a fluorescent background, yielding a black & white image- Non living samples up to 500,000x SEM - Scanning Electron Microscope - scans electrons on the surface of the object to give topical 3D black and white pictures of nonliving samples that can be colorized. Scanning Probe Microscopy (SPM) is a branch of microscopy that forms images of surfaces using a physical probe that scans the specimen. AFM - Atomic Force Microscope measures forces between the tip of the probe and the surface to create 3D images Microscope Table Microscope Power Magnification Limitations Advantages Compound Light TEM Sem Chapter 7.2 Cells 1. All Cells have: Two types of cells prokaryote and eukaryote: A) Membrane enclose structure called a plasma membrane Controls what enters and leaves the cell B) Genetic Material (DNA) That provides instructions for making Controls cells activities C) Break down molecules for energy Prokaryotes Eg: bacteria - Prokaryote does not have a nucleus to enclose genetic material (DNA found with the cell) - Does not contain membrane bound organelles - Simple structure, no specialized structures - Unicellular, must perform all characteristics of life with one cell PROKARYOTES = Cells without specialized internal structures Eukaryotes Eukaryotic cells = constrain cell organelles - Contains nucleus separated by membrane from rest of cell - Specialized organelles surrounded by a membrane: plasma membrane - Unicellular or multicellular - Larger, more complex cell type A. Cell Membrane 1. Regulates what enter/leaves the cell = selectively permeability 2. Protection/support 3. Found in plant and animal 4. Lipid bilayer Chapter 7.3 B. Nucleus: Control Center/ Director 1. Contains cell’s DNA instructions for making proteins 2. surrounded by nuclear envelope w/ pores - Material can move in/out 3. Contains DNA bound to protein in long strands 4. Nucleolus a. Dense region inside nucleus b. Beginning of ribosome production/assembly C. Ribosomes 1. Small particles of RNA and protein 2. Produces proteins following DNA instructions from nucleus 3. Smallest Organelle 4. TWO Types - Free in cytoplasm - Attached to ER D. Endoplasmic Reticulum (ER) 2 types make proteins and enzymes 1. Rough ER - Studded w/ ribosomes - Site of protein synthesis - Modifies changes proteins exports proteins 2. Smooth ER - No ribosome attachment - Contains enzymes w/ specific functions - Makes cell membrane lipids - Vesicles E. Golgi Apparatus 1. Shipping facility 2. Modifies, sorts, packages proteins in ER 3. Proteins are stored or secreted F. Lysosomes Organelles filled w/ enzymes Breaks down or digest unwanted materials Breaks down organelles which have their usefulness ANIMAL CELLS ONLY “Clean-up Crew” Tay-Sachs Disease a. Lysosomes don't function properly b. ‘junk ‘ builds up in cell c. Fatal G. Vacuoles 1. Sac-like structures 2. Storage of water, salts, carbohydrates, proteins 3. Plants a. Large, single vacuole b. Supports stems/leaves - Wilting 4. Animal or a single-celled organism a. Several small vacuoles H. Energy Producing Organelles 1. Mitochondria a. Converts stored food energy unusable form b. “Powerhouse of cell” c. Double-membrane (outer/inner membrane) 2. Chloroplast a. Plants only b. Captures sunlight energy and converts into chemical energy (photosynthesis) c. double membrane d. Contains chlorophyll I.Cilia and Flagella 1. Cillia - Short, numerous projections that look like hairs 2. Flagella - Longer and less numerous than cilia - Create movement with a whip like motion  Chapter 7.4 Diffusion Diffusion = the net movement of particles from an area of high concentration to an area of low concentration 3 Main Factors That Affect the Rates of Diffusion - Concentration - Temperature - Pressure  Particles diffuse quicker when concentration, temperature, and pressure is high Collisions are more likely to occur when the size of the particles are bigger Similar charges of particles decrease rates of diffusion and different charges increase the rates of diffusion Particles go from regions of higher concentration to low concentration PASSIVE TRANSPORT PASSIVE TRANSPORT = Does not require additional energy Facilitated Diffusions = uses transport proteins to move other ions and small molecules across the plasma membrane. Uses Carrier proteins and Channel Proteins (Passive transport) Osmosis = Water passing freely through the membrane (Passive transport) ○ Water can diffuse across the plasma membrane but most other substances cannot The carrier protein is blocked off on one side and the channel protein has both sides open PASSIVE TRANSPORT = Does not require additional energy ACTIVE TRANSPORT ACTIVE TRANSPORT = The movement of substances across the plasma membrane against a concentration gradient requires energy - Can also occur with the aid of carrier proteins (Pumps) - Active transport is about Homeostasis Concentration = the amount of solute dissolved in a solvent Cell are most happy when they are at dynamic equilibrium things inside and outside the cell are the same What are the 2 Ions that are actively transported in and out of the cell?  ○ Sodium and Potassium HIGH to LOW Concentration does not require energy LOW to HIGH Concentration requires energy ATPase Pump ○ Found in the plasma membrane of animal cells ○ Maintains the level of sodium and potassium ions inside and outside the cell ○ For transporting 3 sodium ions outside the cell 2 potassium ions enter the cell ○ Coupled Transport = When sodium leaves the cell it has a opportunity to couple with a sugar and go back in the cell SOLUTION TYPES 1. Isotonic Solution = when a cell is in a solution that has the same concentration of water and solutes- ions, sugars, proteins, and other substances- as its cytoplasm 2. Hypotonic Solution = if a cell is in a solution that has a lower concentration of solute 3. Hypertonic Solution = the concentration of the solute outside of the cell is higher than it is on the inside Endocytosis Endocytosis = the process by which a cell surrounds a substance in the outside environment, enclosing the substance in a portion of the plasma membrane. Exocytosis Exocytosis = the secretion of materials at the plasma