Chapter 3- Cell Structure and Function Flashcards
Flexible outer boundary. Selectively permeable. Act as an active barrier separating intracellular fluid (ICF) from extracellular Fluid (ECF). Also known as the cell membrane provides a surface for chemical reaction. Generally described as phospholipid Bilayer.
Plasma membrane
Intracellular fluid containing organelles
Cytoplasm
DNA containing Control Center
Nucleus
Serve as a general barrier
Phospholipids
integral- for transport
peripheral-for receiving chemical sign
Proteins
Used for attachment to other cells or to surfaces
Carbohydrates
Holds membrane together while promoting flexibility
Cholesterol
Firmly inserted into the membrane. Most are transmembrane protein, have both hydrophobic and hydrophilic regions. Function as transport proteins (channels and carriers) enzymes or receptors
Integral proteins
Loosely attached to integral proteins. Include filaments on intracellular surface used for plasma membrane support. Function as enzymes, motor proteins for shape change during cell division and muscle contraction. Cell to cell connections.
Peripheral proteins
Consist of sugars (carbohydrates) sticking out of cell surface. Some sugars are attached to lipids and some to proteins. Functions as specific biological markers for cell to cell recognition. Allows immune system to recognize self versus non-self.
glycocalyx
Some cells are bound together to form tissues and organs.
Cell junctions
Integral proteins on adjacent cells fuse to form an impermeable junction that encircles whole cell. Prevent fluids and most molecules form moving in between cells.
Tight junctions
Rivet like cell junction formed when Linker proteins of neighboring cells interlock like the teeth of a zipper. Linker protein is anchored to its cell through thicken button like areas on inside of plasma membrane called plaques. Allow “give” between cells reducing the possibility of tearing under tension.
Desmosomes
Trans membrane proteins form, tunnels, that allows small molecules to pass from cell to cell. Used to spread ions, simple sugars, or other small molecules between cells.
Gap junction
Protein matrix running through the cytoplasm
Cytoskeleton
Thin strips of the protein actin, used in cell movement
Microfilaments (cytoskeleton)
Consist of rope like fibers of the protein keratin, protects a cell against stress and trauma.
Intermediate filaments (cytoskeleton)
Hollow tubes of the protein tubule, used in cell division.
Microtubules (cytoskeleton)
A pair exist right outside nucleus. Composed of microtubules used in separating DNA during cell division.
Centrioles
Region of cytoplasm where centrioles sit.
Centrosome
Extensions from cells that allow for the cell to move or allow for fluids to move along the surface of cells
Cilia and Flagella
Long whip like tails.
-sperm cells
-protozoan cells
Flagella
Short hair like extensions that move like stiff oars.
-paramecium
-cells lining respiratory tract
Cilia
Finger like extensions of plasma membrane that project from surface of select cells. Used to increase surface area for absorption.
Microvilli
Tiniest of all cell structures, site of protein synthesis.
Ribosomes
System of membranous channels with compartments that form vesicles
Endoplasmic reticulum
Has ribosomes attached. Processes and packages protein.
Rough endoplasmic reticulum
Has no ribosomes, site of lipid synthesis, stores calcium, and performs detoxification
Smooth endoplasmic reticulum
Stack of membrane bound flatten sacs. Packaging and distribution center. Receives vesicles from endoplasmic reticulum and repackages substances into vesicles for transport to their final destination.
GOLGI apparatus
Spherical membranous bags containing digestive enzymes. (acid hydrolase)
-digest, ingested, bacteria, viruses, and toxins.
-degrade non-functional organelles
Intracellular release in injured cells causes cells to digest themselves (autolysis).
Lysosome
Membranous sacs containing powerful detoxify substances that neutralize toxins. Two main detoxifiers: oxidase uses oxygen to convert toxins to hydrogen peroxide (h2o2), which is itself toxic: however, peroxisome also contains catalase, which converts H2O to harmless water.
Peroxisomes
Powerhouse of the cell. An organelle that is the site of cellular respiration (process that converts glucose into ATP).
Mitochondria
Control center of the cell.
Holds DNA
Nucleus
Fluid and the nucleus
Nucleaoplasm
Double membrane covering over nucleus.
Nuclear envelope
Produces ribosomes
Nucleolus
-Movement of salute particles from an area of high concentration to an area of low concentration.
Solute moves along the concentration gradient.
Salute particles will continue to move until they are equally spread out and have reach equilibrium.
Occurs through force in the plasma membrane between phospholipid molecules
Simple diffusion (passive process)
Requires no energy- ATP
Passive processes
Requires energy – ATP.
Active processes
Nonpolar lipid-soluble substances diffuse directly through phospholipid bilayer.
Hydrophobic
The greater the difference of concentration between two areas, the faster diffusion occurs
Concentration (factors affecting the rate of diffusion)
Smaller molecules, diffuse faster
Molecular size (factors affecting the rate of diffusion)
High temps increase kinetic energy, which result in faster diffusion
Temperature (factors affecting the rate of diffusion)
Channel and carrier proteins.
Facilitated diffusion (passive process)
Substances bind to protein carriers.
Trans membrane integral proteins.
Transport specific polar molecules, such as sugars and amino acids that are too large for membrane channels.
Binding is limited by number of carriers present.
Carrier mediated (facilitated diffusion)
Substances move through water fill channels.
Aqueous filled cores are formed by transmembrane proteins. Transport molecule, such as ions or water down their concentration gradient. Specifically based on pore size and/or charge.
Channel mediated (facilitated diffusion)
Water channels
Aquaporins
Always open
Leakage channels
Controlled by chemical or electrical signals.
Gated channels.
The comparison of salute concentrations
Tonicity
Describes a solution that has a higher salute concentration
Hypertonic
Describes a solution that has a lower solute concentration
Hypotonic
Describes a solution that has an equal solute concentration
Isotonic
The movement of water molecules across a selectively permeable membrane from an area of low solute concentration to an area of high solute concentration.
Osmosis (passive process)
Requires carrier proteins (solute pumps)
-Bind specifically and reversibly with substance being moved.
-moves solutes against their concentration gradient (low to high)
Active transport (active process)
Most studied pump.
Basically is an enzyme that pumps Na out of cell and K back into cell.
Located in all plasma membranes, but especially active in nerves and muscles
Sodium potassium pump
Transport into cell
Endocytosis
Transport into across and then out of cell
Transcytosis
Type of endocytosis that is referred to as cell eating. Membrane projections called pseudopod form and flow around solid particles that are being engulfed forming a vesicle, which is pulled into cell. Is used by microphages and certain other white blood cell.
Phagocytosis
Formed vesicle
Phagosome
Type of endocytosis that is referred to as “cell drinking” or fluid phase endocytosis.
Plasma membrane infolds, bringing intracellular fluid and dissolves solute inside cell.
Main way in which nutrient absorption occurs in the small intestine.
Pinocytosis
Involves endocytosis and transcytosis of specific molecules.
Many cells have receptors embedded in clathrin-coated pits.
Receptor mediated endocytosis.
Process where material is ejected from cell
Exocytosis
Substance being ejected is enclosed in
Secretary vesicle.
