Unit 2 Ch. 5 Flashcards
Fluid-mosaic-model-
fluid phospholipid bilayer with embedded protein molecules
- phospholipids are arranged so that the hydrophilic heads face the intracellular and extracellular fluids and hydrophobic tails face each other in the middle
Glycolipids-
- similar to phospholipid but hydrophilic head is a variety of sugars
Glyco- sugar
lipid-protein
Cholesterol-
- found in animal plasma membranes
- reduces permeability of membrane (rate liquid can pass through)
Glycoproteins-
proteins with sugars attached (protecting the outside of the cell)
What would happen if the membrane was stiff/hard?
the cell membrane is fluid, would limit mobility
Proteins of the plasma membrane: (5)
Channel proteins- allows a particular molecule or ion to cross the plasma membrane freely.
Carrier protein- selectively interact with a specific molecule or ion so that it can cross the plasma membrane.
Cell recognition protein- allow the cells of an organism to identify other cells of that organism as well as invading cells
Receptor protein- is shaped in such a way that a specific molecule can bind to it.
Enzymatic proteins- catalyzes a specific reaction ( cause to speed up or happen faster)
Permeability of the plasma membrane:
Selectively permeable membrane
Allows some substances to pass but not others
Based on size and charge
- large molecules and molecules with charges do not cross cell membranes without help of a transport protein
- non-charged molecules and water can pass
- follow concentration gradient: a change in the concentration of a substance over a distance
- substances move from high to low concentration
Diffusion:
Solution:
Diffusion: movement of molecules from a higher concentration to a lower concentration (down a concentration gradient) until equilibrium is reached
Solution: contains both solute and solvent
Solute:
Solvent:
Solute: substance dissolved in a solvent
Solvent: liquid portion of a solution
Osmosis:
Osmotic pressure:
Osmosis: the diffusion of water across a selectively permeable membrane
Osmotic pressure: pressure that develops in a system due to osmosis
- The greater the osmotic pressure, the more likely water will diffuse in that direction
Tonicity:
what happens when you put a cell in hypo, hyper, and iso solutions?
Tonicity: the relative concentration of solutes in two fluids
Isotonic solution:
Hypotonic solution:
hyper tonic solution:
Isotonic solution: solute concentrations are the same
- No net movement
Hypotonic solution: lower concentration of solutes and a higher concentration of water
Net movement of h2o into cell
Creates turgor pressure in plants
hyper tonic solution: higher concentration of solutes and a higher concentration of water
Net movement of h2o out of cell
Causes crenation-shrinking of animal cell or, plasmolysis-shrinking of plant cell cytoplasm
Name the two laws of thermodynamics:
- energy cannot be created or destroyed (can change forms. Ex. when you drop an object, potential to kinetic energy)
- when energy is converted/transformed from one form of quality to another, some of the useful energy is always lost in the form of (heat)
Metabolism:
Reactant:
Product:
the sum of all the reactions that occur in a cell
substances that participate in a reaction
substances that form as a result of a reaction
carrier proteins
combines with and transports a molecule or ion across the plasma membrane
passive transport
movement of molecules or ions down a concentration gradient through transport proteins in a cell membrane
no outside energy is required for the process
example is facilitated diffusion (transport)
active transport
movement of molecules or ions against a concentration gradient
causes solute to become more concentrated on one side
requires outside energy
examples include sodium potassium pump in nerve and muscle cells, iodine collecting in thyroid, sodium being withdrawn urine by kidneys
Membrane assisted transport:
Exocytosis:
exo=
cyto=
vesicles (sacks with stuff in it) formed by golgi bodys (packages things with a phospholipid bilayer aka plasma membrane) and carrying a specific molecule fuse with the plasma membrane resulting in secreting (what happens when chemicals made inside the cell get dumped outside of the cell)
exo=outside
cyto=cell
Endocytosis:
endo=
cyto=
cells take in substances by vesicle formation due to plasma membrane invagination ( folding inward, a fold of something= vag)
endo= inside
cyto= cell
Phagocytosis:
Pinocytosis:
Phagocytosis: “cell eating”
Large food molecules taken in by endocytosis- forms a food vacuole
Pinocytosis: “cell drinking”
Vesicles form around a liquid or very small particles
Receptor-mediated endocytosis:
Receptor-mediated endocytosis: selective uptake of molecules into a cell by vacuole formation after they bind to specific receptor proteins in the plasma membrane
Junctions between cells:
Plasmodesmata:
Adhesion junction:
Tight junction:
Gap junction:
Plasmodesmata: channels that pass through plant cell walls and connect cytoplasm of neighboring cells
energy:
kinetic energy:
potential energy:
chemical energy:
ability to do work, cause change, or transfer heat
energy of motion
stored energy/energy of position
interactions between atoms in a molecule
Exergonic reactions:
Endergonic reactions:
Exergonic reactions: energy is released
Endergonic reactions: products have more free energy than the reactants, require energy input (photosynthesis)
What is ATP composed of, what’s it broken down into? What is required for ATP to break down?
ATP- adenosine triphosphate
Nucleotide composed of adenosine (adenine + ribose) and 3 phosphate groups
Energy for cells
Broken down into ADP (adenosine diphosphate)
Metabolic Pathways And Enzymes:
Metabolic pathway:
Enzyme:
Metabolic pathway: a series of linked reactions
Begin with reactants (substrates) and terminate with end products
Enzyme: made of amino acids, order determined by DNA. protein moleulce that functions as an organic catalyst to speed a chemical reaction
Four features of enzymes:
- Enzymes do not make anything happen that wouldn’t happen on its own
- Aren’t permanently altered or used up in a chemical reaction- we can use the same enzymes over and over again
- Usually work in both forward and reverse directions of a reaction
- Are highly selective about their substances
Factors affecting enzymatic speed: (5)
- Substrate concentration: enzyme activity increases as substrate concentration increases
- Temp and ph: as temp increases enzyme activity increases (more collisions)
Enzyme can become denatured if temp increases too much and will no longer work
Each enzyme has an optimum pH- a change in ph can also cause denaturation - Enzyme concentration:
- Enzyme cofactors- non proteins which allow enzyme to work (co=together)
- enzyme inhibition: occurs when the active site on an enzyme becomes altered because too much of an end product was made, or when an active enzyme is prevented from combining with its substrate
- Enzyme cofactors- non proteins which allow enzyme to work (co=together)
Active site-
Region on an enzyme where the substrate binds and the reaction occurs
what occurs when an enzyme is induced to undergo a slight alteration to achieve optimum fit
Change in shape of active site facilitates the reaction
After reaction has been completed the products are released and the active site returns to its original state.
Electron transport system:
Passage of electrons along a series of membrane-bound carrier molecules releasing energy used to synthesize ATP
Coenzymes:
what ae they derived from
Coenzymes: complex organic enzyme helpers
Many are derived from vitamins
Ex. NAD and FAD (accept hydrogens and electrons) known as dumptrucks, move ions from different locations
- vitamins necessary for this
ATP production:
ATP production:
H+ (protons) are pumped to one side of membrane, which establishes an electrochemical gradient
H+ flow back across membrane through ATP synthase complexes and this provides energy for ATP production
the production of ATP due to a hydrogen ion gradient across a membrane
Electron transport system:
Passage of electrons along a series of membrane-bound carrier molecules releasing energy used to synthesize ATP
