Unit 3 Cell Structure and Function PDF

Unit 3: Cell Structure and Function Cell Theory Why is it called cell theory: Theory means strongly proven. It’s strongly proven that cell makes up the body - Robert Hook first described cell in 1665: Cell is small - Schleiden: cell is fundamental to plant - Schwann: animal is compos...

Unit 3: Cell Structure and Function Cell Theory Why is it called cell theory: Theory means strongly proven. It’s strongly proven that cell makes up the body - Robert Hook first described cell in 1665: Cell is small - Schleiden: cell is fundamental to plant - Schwann: animal is composed of cells - Modification: Cell has special structure to increase surface area o More surface, more absorption Prokaryotic and Eukaryotic Cells Two major types of Cells Prokaryotic Eukaryotic - No nucleus and internal - Has nucleus and internal membrane-bound organelles membrane-bound organelles - All eubacteria and archaea - All organism other than bacteria bacteria - Oldest and Simplest - Larger - Peptidoglycan: A cell wall that - Complex give inflexible structure - Chitin: Fungi’s cell wall - Unicellular - Cellulose: plant and some Simple Organization: protist’ cell wall - Cytoplasm - Chloroplast: photosynthesis - Ribosomes (site of protein - Multi or unicellular synthesis) - Nucleoid region (where DNA is located, not a true nucleus because it's not membrane bound)  ❖ Test Hint: Know labels of the cells. Know the organelles and which one they are (be able to label the cell diagram) Organelles of the Cell ❖ For Organelles: know what it looks like, function and why care Nucleus - Nuclear Envelope: double membrane that bounds nucleus surface - Nuclear pores: allows protein and RNA to come in and out - Nucleolus: has gene to code for rRNA - Chromatin: Chromosomes turn into chromatin, its loosely uncoiled, protein synthesis occurs when in this form Endoplasmic Reticulum (ER) - Has space than is enclosed by Vesicles o There are different types of vesicles, and each has specific function Ex: Transport Vesicle transports - Rough ER: dedicated to protein synthesis o Rough because of implanted ribosomes - Smooth ER: help carb and lipid production o Smooth because it has no ribosomes Golgi Bodies - After synthesis in ER, made molecules are passed to here - Function: collect, package and distribute molecules Mitochondria - Site for oxidative metabolism: chemical rxn - Like prokaryotic organism - Function: makes ATP, powerhouse Ribosomes - Composed of rRNA and protein - Not membrane-bound  - Site of protein synthesis reads mRNA sequence and translates into amino acids o Ribosome is the only organelle that also exists in prokaryotic cells Lysosomes - “Digestive system of the cell” - Produced by Golgi complex - Contains enzymes to breakdown macromolecules - Function: recycle, digest, waste are packaged and excreted Peroxisomes - Function: Breaks down long chains of fatty acids that are used in mitochondria for ATP production. Breaks down toxic substances o Those fatty acids are used to produce Myelin in the brain Centrioles - Only in animal cell - Function: Produces spindle fibers (microtubules): separates chromosomes during cell division Plasma Membrane - Filled with Cytoplasm inside - Controls what goes in and out of cell - Amphipathic: polar and nonpolar - Bilayer structure: phospholipids - Function: protection Terminology ❖ Know the terminology Intracellular: Within the cell Intracellular protein - Cytoskeleton: keeps organelle in fixed location, support the shape of cell, made up of intra proteins Ex: Microtubule, actin filament intermediate filament  o It is always rearranging itself Extracellular: Outside of the cell Extracellular protein - Collagen and Elastin forms protective layer over the cell surface - Fibronectin: connects outside of the cell to the plasma membrane o Also connects to integrin that extends into the cytoplasm – this connection allows the outside to influence cellular behavior - Cell junction: Structure that connects cells together and allows communication between bells. There are different types: o Tight: holds cell together, prevents molecules from moving between cells o Adhering: secures cell to the outside of the cell o Gap: forms channels that directly connect cells together and allows communication Intercellular: between cell/tissue Movement Across the Cell Membrane - Large or charged molecules must cross using membrane proteins Types of Movement No energy required Energy required Diffusion: higher concentration to Active: again, the concentration lower concentration area. gradient, uses membrane protein - O, CO2, N, Glycerol, water and ATP - Ions, polar, and large - Ends with high or low molecules need to use concentration membrane protein Na-K Pump: Uses ATP Factors: concentration - 3 Na+ out and 2 K+ in gradient, temp, size of - Result: to have more Na molecule, surface area, out, maintains electrical diffusion distance (if far away, charge (resting potential) less likely) Proton Pump: use energy to move - Ends with equilibrium H+ against concentration gradient concentration  - Ex: in breathing, o2 goes Coupled Transport: single carrier in, co2 goes out protein moving 2 substances at the same time Osmosis: diffusion of only water Symport: substance move in - Water can also use same direction aquaporins: a membrane Antiport: opposite direction protein - Common way to get sugar and Factor: dependent on the amino acids concentration of the solute in Endo and Exocytosis: Uses vesicles the solution (greater# of for molecules that are too big for solute, less water to move) membrane protein: encapsules Tonicity: molecules Hypertonic: water - Endo: moves cells inside, in moves out vesicle Hypotonic: water moves - Exo: Moves cell outside from in vesicle at the inner surface of Isotonic: no movement the cell Facilitated Diffusion: Moves specific molecules down the concentration gradient with help of membrane protein. - Can move polar, charged molecules Channel Protein: openings to specific type of ions Ex: Na or K channel - Ion transport Carrier Protein: binds to specific molecule and changes its shape - Amino acids, glucose and fatty acids Capacity limited: if not enough carriers, no more movement