Biology study guide for first exam
Biology study guide for first exam Biology 1105
Popular in Principles of Biology
Popular in Biology
This 11 page Study Guide was uploaded by Meghan Babington on Saturday September 10, 2016. The Study Guide belongs to Biology 1105 at Virginia Polytechnic Institute and State University taught by Dr. Jonathan I. Watkinson in Fall 2016. Since its upload, it has received 23 views. For similar materials see Principles of Biology in Biology at Virginia Polytechnic Institute and State University.
Reviews for Biology study guide for first exam
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 09/10/16
MACROMOLECULES IN THE CELL proteins = provide functionality within membranes carbohydrates = only located on the outer surface of the membrane which helps the cell attach to the extracellular matrix, and these external sugar molecules provide ID markers for cellular recognition lipids = phospholipids are the main structure of the membrane; hydrophobic Phospholipids are made of fatty acids and glycerol Cholesterol helps maintain the cells fluidity Fatty acids (aka acyl) are long hydrocarbon chains with a carboxyl group on the end of it glycerol is a 3 carbon polyalcohol with 3 hydroxyl groups. glycerol with 3 fatty acid tails are called triglycerides SATURATED FATS: lipids with 1 double bond are termed monounsaturated. Examples are saturated fatty acids. Because they only contain one double bond, the structure is linear and clean (solid at room temperature) UNSATURATED FATS: lipids with more than one double bond are termed polyunsaturated fatty acids. Because they have more than one double bond, their structure becomes competitive for space and creates not as clean of a structure, making it appear clustered (liquid at room temperature) TYPES OF LIPIDS terepens: pigment lipids steroids: hormones in animals MAIN LIPIDS: phospholipids hydrophilic heads (polar) hydrophobic tails (nonpolar), having both hydrophilic and hydrophobic properties means it is amphiphilic CELL TO CELL INTERACTIONS MAIN JOBS: CELL IDENTITY AND MARKERS Cell Identity Cells acquire identity through the expression (turning off and on) of certain genes that code for certain functions within the cell or between cells. Most of the functions are done by different proteins. This is important because cells must be able to recognize which cells are part of your body, and which are intruders/viruses/bacteria etc. Types of markers Glycolipids: lipids with carbohydrate heads on the membranes of cells that identify/label the cell Cell junctions and types Goal of junctions: to serve as the cement and foundation for the house that is the cell Adhesive junctions: found in external skin and muscle tissue, attaches the cytoskeletons of neighboring cells Adherens junctions: based on the protein cadherin, this is a transmembrane protein that acts with the extracellular domains of cells along with actin (muscle protein) to create flexible connections between cells Desmosomes: unique to vertebrates, and interact with intermediate filaments of the cytoskeletons rather than bonding with the microfilaments of actin, and help support against mechanical stress on the cell Hemidesmosomes and focal adhesions: Proteins called integrins that connect cells to the extracellular matrix via the cytoskeleton. o In hemidesmosomes, the junctions connect to intermediate filaments o In focal adhesions, the junctions connect to actin Septate junctions: more modern of the two (septate vs tight), found in both vertebrates and nonvertebrates, and have the ability to form a barrier around a sheet of cells that helps protect from leakage within extracellular space Tight junctions: unique to vertebrates, these junctions act as a wall, or airtight seal to keep items on one side of a cell, with the aid of proteins called claudins Communicating junctions: Junctions that can be found in singlecelled organisms that allow things to diffuse freely between cells (**think of diffusion, or water passing through a porous object like a sponge) in animals, these junctions are called gap junctions formed by porous proteins called pannexins, and is formed when the pannexins in two cells line up with one another and allow small molecules like sugars and amino acids to pass through. in plants they’re called plasmodesmata, and they are cytoplasmic connections that join cell walls together; more complex than gap junctions MEMBRANES: Establish space, act as a barrier to protect what goes into and out of the cell (however it is malleable, it does not have a set shape like cell walls). In eukaryotes, cell membranes are composed of our major parts: WHAT CAN PASS INTO THE MEMBRANE? EASILY: small nonpolar molecules like gases SEMIEASILY: small polar molecules like water DIFFICULT: larger polar molecules IMPOSSIBLE: ions, anything charged A phospholipid bilayer WHAT IS IT: a semipermeable membrane that looks like a zipper WHAT IS IT MADE OF: lipids with a hydrophilic head, and a hydrophobic tail WHAT DOES IT DO: selectively allows certain substances in and out of the cell, they also form spontaneously due to their opposite polar/nonpolar “magnetic” attraction Transmembrane proteins WHAT IS IT: receptors and carrier channels WHAT IS IT MADE OF: proteins WHAT DO THEY DO: float freely within the bilayer orchestrating communication across the membrane Interior protein network WHAT IS IT: a foundational structure WHAT IS IT MADE OF: sets of proteins that are more rigid WHAT DOES IT DO: provide a scaffold or mold for the membrane Cellsurface markers WHAT ARE THEY: markers that help the cell selfrecognize WHAT ARE THEY MADE OF: glycoproteins and glycolipids WHAT DO THEY DO: indicate to the cell that certain tissues and molecules are part of the cell (separates familiar from foreign substances) PROTEIN FUNCTIONS WITHIN THE MEMBRANE TRANSPORTERS: Selectively pick and carry solutions in and out of the cell via channels or carriers using active or passive transport ENZYMES: carry out biochemical reactions in and on the membrane CELLSURFACE RECEPTORS: markers that serve as “ID tags” that allow the cell to recognize its individual parts CELLTOCELL ADHESION PROTEINS: specialized proteins that are used to stick cells to one another, whether it be temporarily or permanently ATTACHMENTS TO THE CYTOSKELETON: proteins on the surface of the cell that interact with other cells by attaching themselves to the cytoskeleton of other cells via linking proteins Transmembrane proteins = proteins completely embedded inside the membrane Peripheral proteins = sit on the edge of the proteins TYPES OF TRANSPORT ACROSS THE CELL MEMBRANE PASSIVE TRANSPORT: no energy required, WITH the concentration gradient ACTIVE TRANSPORT: energy required, AGAINST the concentration gradient DIFFUSION Direct Molecules float freely from high to low concentrations, no energy and no channel to pass through other than the membrane itself FACILITATED DIFFUSION channel proteins The movement of polar ions/molecule through an open protein channel in (think open the membrane (rather than just through the membrane itself) from high to tunnel) low concentration carrier proteins A molecule binds with a protein inside the protein channel that then carries (think tunnel the item through the channel and into the cell; moving from high to low with taxi) concentration (down/with the concentration gradient) OSMOSIS Aquaporins Diffusion of water only, via an osmotic gradient (high to low concentration) PROTEIN CARRIERS particles are moved against their concentration gradients using the Sodium potassium exchange of sodium and potassium in order to open a pump that pump allows molecules inside the cell (potassium gets pumped out, and glucose binds with the free sodium outside and then is able to be let into the cell) ENDOCYTOSIS (transporting items INTO the cell) Phagocytosis mainly solid particles; membrane “eats” the particle and surrounds it like a bubble, forming a vesicle that takes the particle inside the cell Pinocytosis Mainly liquid particles; fluid is “eaten” by the membrane, forming a bubble vesicle that takes the liquid inside the cell Receptormediated Endocytosis activates a receptor that creates a clathrincoated vesicle endocytosis that brings particles inside the cell EXOCYTOSIS (EXpelling items OUT OF the cell) Membrane vesicle Vesicles inside the cell reach the cell membrane, fuse with it, and thrust particles outside of the cell
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'