Flashcard Set Preview
Side ASide B
Distinguish between magnification and resolution
Magnification is making an image larger than its original sizeResolution is having a clear picture of 2 structures; Clarity
What are the two types of microscopes?
Light and Electron
What is a Light Microscope?
Visible light is passed through the specimen and then through glass lenses. [Refracted]
What is an Electron microscope?
A beam of electrons through the specimen or onto its surface.
Distinguish between prokaryotic and eukaryotic cells
Prokaryotic: No nucleus, DNA is "Naked", No histones, Doesn't form into chromosomes, Contains only one circular DNA molecule, Contains "smaller circlets of DNA" called plasmids, Ribosomes...
Why are there both upper and lower limits to cell size?
A cell has to be large enough to contain the necessary components to live, and it cannot be too big that diffusion would not be able to meet the cell's needs.
Why is compartmentalization important in eukaryotic cells?
A cell's compartments provide different local environments that accommodate specific metabolic processes. This allows for incompatible process to go on simultaneously inside the same...
Describe the structure and function of the nucleus.
Involves the nuclear envelope, nucleolus and chromatin.Regulates all cell activity.
Describe the structure and function of a eukaryotic ribosome.
Made of rRNA and protein. They carry out protein synthesis. Build proteins in two cytoplasmic locales; free and bound ribosomes.
List the components of the endomembrane system.
Nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, various kinds of vacuoles, plasma membrane.
What functions does the nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles and plasma membrane do?
Nuclear envelope: Encloses the nucleus - separates contents from the cytoplasmEndoplasmic reticulum: Contains sacs and tubes - active in membrane synthesis and other synthetic and metabolic...
Describe the types of vacuoles and explain their function differences.
Food, contractile, centralFood vacuoles: Formed by phagocytosis. Responsible for food digestion. Contractile vacuoles: Pump excess water out of the cell, thereby maintaining a...
Describe three examples of intracellular digestion by lysosomes.
Phagocytosis: When smaller organisms or other food particles are eaten Autophagy: A damaged organelle or small amount of cytosol becomes surrounded by a double membrane, which...
Explain the role of peroxisomes in eukaryotic cells.
Peroxisomes; oxidative organelles [not part of endomembrane system]ROLE = Contain enzymes that transfer hydrogen from various substrates to oxygen (producing hydrogen peroxide). Some...
Describe the structure and functions of a mitochondrian.
STRUCTURE = Outer membrane, Inner membrane, Intermembrane space, Matrix, Cristae2 MAIN MEMBRANES; Outer membrane: Phospholipid bilayer with proteins. Smooth. Inner membrane:...
Explain the importance of compartmentalization in mitrochondrial function.
Each perform different functions, each has a greater surface area, "specialized"
A colorless plastid that stores starch and occurs in cells of plant storage.
(No chlorophyll, usually yellow or orange) - Chromoplasts are plastids responsible for pigment synthesis and storage.
plastid containing chlorophyll and other pigments; in plants that carry out photosynthesis. (green)
Identify the three functional compartments of a chloroplast.
Stroma, Intermembrane space, Thylakoid lumenStroma: Fluid outside the thylakoids; contains the chloroplast DNA and ribosomes as well as many enzymes. Intermembrane space: Encloses...
Explain the importance of compartmentalization in chloroplast function.
Enables the chloroplast to convert light energy to chemical energy during photosynthesis.
Describe the functions of the cytoskeleton.
Plays a major role in organizing the structures and activities of the cell.
Describe the structure, monomers and functions of microtubules.
Structure: Thick(est) hollow rods. The wall is constructed from tubulin [a globular protein]. Due to its architecture; its two ends are slightly different - one end can accumulate or...
Describe the structure, monomers and functions of microfilaments.
Structure: Thin(nest) - built from molecules of a actin (globular protein). Twisted double chain of actin subunits. Monomers: ActinFunctions: STRUCTURAL ROLE in cytoskeleton is...
Describe the structure, monomers and functions of intermediate filaments.
Structure: "In between size" - larger than microfilaments but smaller than microtubules. Diverse class of cytoskeletal elementsMonomers: KeratinsFunctions: Bearing tension, may function...
Explain the ultrastructure of cilia and flagella.
Order from "outer to inner": 1. Outer microtubule doublet (both included in microtubules) --> Plasma membrane2. Dynein arms (motor proteins - energy from ATP)3. Cross-linking...
Motion of flagella and cilia.
Flagella; "Undulates" - direction of swimming [snake like]Cilia: "Back-and-Fourth Motion" - direction of organism's movement
Describe the structure of plant cell walls.*Describe FUNCTION, as well.
*extracellular structure - distinguishes them from animal cellsStructure: Made of 3 layer - Primary cell wall (thin and flexible), Middle lamella (between primary walls of adjacent...
Describe the structure of intercellular junctions found in plant cells. Also, describe the functions of these structures.
Plasmodesmata - Perforates plant cell walls, creating channels between adjacent plant cells*Cytosol passes through the plasmodesmata and connects the chemical environments of adjacent...
Describe the structure of intercellular junctions found in animal cells. Also, describe the function of these structures.
Tight junctions, Desmosomes, Gap junctions (all 3 are especially common in epithelial tissue [lines external/internal surfaces of the body]) Tight junctions = tightly pressed against...
Describe the functions of the plasma membrane. What are the 3 ingredients of membranes?(Also know, a phospholipid is amphipathic - and know what it means)*
(ALL cells have one) Protection, isolation ["physical barrier"], communication, regulated transport ["selectively permeable" = allows some substances to cross it more easily than others],...
Describe the functions of the fluid properties of the cell membrane.
Considered a "fluid mosaic" because the components [phospholipids] can move laterally [sideways] through the membrane; the membrane isn't completely solid*Though fluidity can be affected...
Describe how membrane fluidity is influenced by membrane composition and temperature.
Membrane composition; Membranes must be fluid to work properly. Saturated fats make it "stiff" - because they are solid at room temperature. Unsaturated fats helps it "bend" which helps...
Explain how hydrophobic interactions determine membrane structure and function.
Holds the membrane in place and what orients them so the phospholipid bilayer forms. Also - affects what can/can't pass through
Distinguish between integral and peripheral proteins. Also know what their functions are.
INTEGRAL; Penetrate the hydrophobic core of the lipid bilayer -permanently attached (many are transmembrane proteins; which span the membrane - others extend only partway) The hydrophobic...
Distinguish between channel and carrier proteins.
Channel; (Some are open or gated) - Provide a patheway for small ions to move directly through the cell membrane's hydrophobic core [Allow certain ions]Carrier; transport a specific...
List the major functions of membrane proteins.
Transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to the cytoskeleton and extracellular matrix [ECM]
Describe factors that affect selective permeability of membranes.
Hormones, temperature, electrical charge of membrane, sizeElectrical charge = charged ions can't pass freelyTemperature = increase temperature makes less transmittableSize = smaller...
Define diffusion [also include what causes it and why its a spontaneous process]
Diffusion; the movement of molecules of any substance so that they spread out evenly into the available space. From a region where it is more concentrated to a region that is less concentrated....
Explain why a concentration gradient of a substance across a membrane represents potential energy.
POTENTIAL energy is STORED energy; "it drives diffusion" - in general requires no energy
Define hypertonic solution.
Cell LOSES water to its environment - it "shrivels" and more than likely dies
Define hypotonic solution.
Cell GAINS water [too much] - therefore the cell will "burst" like an overfilled water balloon
Define isotonic solution.
NO net movement of water across the plasma membrane. At the same rate, water enters the cell and exits. Therefore it looks "normal"
Define osmosis. [Also predict the direction of water movement based upon differences in solute concentration]
Osmosis; The diffusion of water across a selectively permeable membrane*Involves tonicity; ability of a solution to cause a cell to gain or lose waterNonpenetrating solutes = cannot...
Explain how bound water affects the osmotic behavior of dilute biological fluids.
(Doesn't affect it a lot) - Tight clustering of water molecules around the hydrophilic solute molecules makes some of the water unavailable to cross the membrane. "It is the difference...
Describe how living cells with and without walls regulate water balance.
With walls; "the cell wall will expand only so much before it exerts a back pressure on the cell that opposes further water uptake" Without walls; can tolerate neither excessive...
Distinguish among osmosis, facilitated diffusion and active transport.
Osmosis; diffusion of water across a selectively permeable membraneFacilitated diffusion; NO energy - uses integral channel proteins to transport hydrophilic substances (molecules/ions)Active...
What is the "Cell Theory"?
Theory that cells form the fundamental structural and functional units of all living organisms
What is exocytosis?
When the cell secretes certain biological molecules by the fusion of vesicles with the plasma membrane
Explain how potential energy generated by transmembrane solute gradients can be harvested by the cell and used to transport substances across the membrane.
This is the electrochemical gradient. Electrochemical Gradient = Variation of both electrical potential and chemical concentration across a membrane. (due to ion gradients) - and...
Explain how large molecules are transported across a cell membrane.
In some instances, [receptor-mediated] Endocytosis ("pockets") and Proteins help by recognizing the molecules to be passed through
Type of endocytosis - cell ingests extracellular fluid and its dissolve solutes
Define receptor-mediated endocytosis.
Movement of specific molecules into a cell by the inward budding - enables cell to acquire bulk quantities of specific substances even if not concentrated in fluid (proteins are involved)