bio exam 2 chap 5-7

integral proteins

embedded in the plasma membrane

peripheral proteins

embedded in cytoplasm

fluid mosaic model

describes the interactions of phospholipids, cholesterol, and proteins

glycolipid

attached carbohydrate chains in phospholipids

glycoproteins

attached carbohydrate chain in proteins

channel proteins

form channel to allow particular molecules or ions to cross the plasma membrane

carrier proteins

receive substrate and change shape which moves substrate across membrane

cell recognition proteins

glycoproteins that help body recognize when it is being attacked so immune response can occur

receptor proteins

shape only allows specific molecules to bind to it, causes protein to change shape and therefore bring about cell response

enzymatic proteins

carry out metabolic reactions directly

junction proteins

form various junctions between animal cells

concentration gradient

gradient change in chemical concentration between 2 areas of different concentrations

diffusion

movement of molecules from high to low concentration (down concentration gradient)

solution

solute (usually solid) being dissolved by solvent (usually liquid)

osmosis

diffusion of water across selectively permeable membrane from high to low water concentration

isotonic solution

equal in solute concentration to cytoplasm of cell

tonicity

strength of solution

hypotonic solution

lower solute/high water concentration than cytoplasm, cells gain water

hypertonic solution

high solute/low water concentration than cytoplasm, cells lose water

crenation

refers to RBCs that shrink if in hypertonic solution

plasmolysis

cytoplasm shrinks because of osmosis

facilitated transport

passive transport of substance in or out of cell with carrier protein

active transport

moves molecules against concentration gradient, requires energy (ATP) and carrier proteins

sodium potassium pump

Na+ out of cell, K+ in cell

exocytosis

intracellular vesicle fuses with plasma membrane as secretion occurs, contents are released

endocytosis

cells bring substances into cell by forming vesicles around material

phagocytosis

transports large substances

pinocytosis

vesicles form around liquid or small particles

receptor mediated endocytosis

specific form of pinocytosis that uses receptor proteins to recognize compatible molecules and take them into cell

extracellular matrix

meshwork of proteins and polysaccharides in close association with cell that made them

adhesion junction

mechanically attaches adjacent cells

desmosome

internal cytoplasm plaques firmly attach to intermediate filament cytoskeleton within each cell

tight junction

connect plasma membrane of adjacent cells like a zipper, closer than desmosome

gap junction

allows cells to communicate, formed when two identical plasma membrane channels join

energy

ability to do work and bring about change

kinetic energy

energy of motion

potential energy

stored energy, capacity to do work but is not currently being used

chemical energy

composed of organic molecules

mechanical energy

energy possessed by object as a result of motion or position

heat

type of KE associated with random motion of molecules

1st law of thermodynamics

law of conservation of energy, energy can’t be created or destroyed but can be changed

2nd law of thermodynamics

energy can’t be changed without the loss of usable energy

metabolism

sum of all chemical reactions that occur in cell

exergonic reactions

spontaneous, releases energy

endergonic reactions

nonspontaneous, requires energy input

free energy (delta G)

amount of energy left to do work after chemical reaction occurred (negative means spontaneous, positive means nonspontaneous)

ribozymes

enzymes made of RNA, involved in the synthesis of RNA and proteins at ribosomes

metabolic pathway

linked reactions, begin with particular reaction and ends with end product

active site

region of enzyme where substrate binds and where chemical reaction occurs

induced fit model

enzyme undergoes slight alteration to achieve optimum fit for substrate

energy of activation

energy that must be added to cause molecules to react with one another

cofactors

inorganic ion that helps enzyme speed up reactions

coenzyme

organic molecule that helps enzyme speed up reactions

enzyme inhibition

occurs when molecule binds to enzyme and decreases activity

noncompetitive (allosteric) inhibition

inhibitor binds to enzyme at location other than active site (allosteric site)

competitive inhibition

inhibitor and substrate compete to bind to active site of enzyme

photosynthesis

converts solar energy to chemical energy of carbohydrate

stomata

small openings between two guard cells which gas passes through

chloroplasts

where water and CO2 diffuse to, carry out photosynthesis

thylakoids

flat sacs where light reactions occur

chlorophyll

pigment capable of absorbing solar energy to drive photosynthesis

light reactions

occur only when sun is out, captures solar energy and produces ATP and NADPH

calvin cycle reactions

can occur in dark or light, uses light reaction products to reduce CO2 to glucose

absorption spectrum

graph of how much solar radiation is absorbed vs wavelength

carotenoids

play accessory role, typically yellow or orange

photosystem

consists of pigment complex and electron acceptor molecules within thylakoid membrane

noncyclic pathway

light dependent, used to generate ATP/NADPH, electrons have to b replaced by splitting water, electrons are moved from water to NADP+

photosystem II

water is the reactant/O2 the product, uses light energy to oxidize water molecules and fuel ATP synthesis, P680

photosystem I

uses light energy to to reduce NADP+ to NADPH, P700

ATP synthase complex

enzyme joins ADP+P

chemiosmosis

allows ATP synthase to make ATP from ADP+P, tied to establishment of H+ gradient

carbon dioxide fixation

1st step of calvin cycle, molecule of CO2 from atmosphere is attached to RuBP resulting in 6 carbon molecule that splits in half

RuBP carboxylase

enzyme that speeds CO2 to RuBP attachment, makes up 20-50% of roteins of chloroplasts

carbon dioxide reduction

3PG is reduced to BPG using ATP, then to G3P using NADPH

regeneration of RuBP

takes 3 turns of calvin cycle to allow 1 G3P to exit, 5 molecules G3P are used to reform 3 molecules of RuBP every 3 turns

C3 plants

majority of plants, use RuBP carboxylase to fix CO2 to RuBP, best at moderate temperatures

photorespiration

O2 rises in C3 plants because stomata closes to conserve water, causes RuBP carboxylase to combine with RuBP instead of CO2

c4 plants

fix CO2 to PEP (c3 molecule) using enzyme carboxylase, creates oxaloacetate

CAM

form of photosynthesis in succulents that separates light dependent and calvin reactions by time