biology unit 2

homeostasis

chemical reactions need certain conditions to occur, so living things maintain ______

phospholipid bilayer

the main barrier between internal and external environments

the phospholipid bilayer is

selectively permeable

selective permeability means

only certain compounds with certain characteristics can cross it

phospholipids

the most abundant compounds in the cell membrane

phospholipids are

amphipathic

amphipathic means

one end is hydrophobic and the other is hydrophilic

the phospholipid bilayer is _______ and ________ not ________ and ____________

fluid and dynamic, static and still

the fluid mosaic model

describes the phospholipid bilayers' movements and behaviors

the two major proteins in the bilayer are

integral proteins and peripheral proteins

integral proteins

penetrate into the hydrophobic bilayer

integral proteins are also known as

transmembrane proteins

peripheral proteins

bound to the surface of the membrane by integral proteins, they are simpler than integral/transmembrane proteins

glycolipids and glycoproteins

facilitate the many things a cell may interact with

hydrophobic

can cross the interior of the membrane with relative ease

hydrophilic

struggle more to cross the membrane and rely on other parts of the membrane to expedite exchange

transport proteins

facilitate the movement, allows hydrophilic substances to avoid the hydrophobic interior of the membrane

channel proteins

have a hydrophilic channel that certain molecules use as a tunnel

carrier proteins

change their shape and actually move/transport things across the membrane

concentration gradient

difference in the concentration of a substance from one area to another (when two areas have equal number of molecules, they're in equilibrium)

passive transport

diffusing a substance across biological membrane, it requires no energy

osmosis

diffusion (movement) of water across a selectively permeable membrane

tonicity

a difference in tonic environments, it determines how the surrounding solution will influence the movement of the solvent (water)

isotonic environment

the concentration of solutes is the same inside and outside the cell

result of isotonic environment

no net change in solute concentration

hypertonic environment

higher concentration of solutes outside the cell than inside

result of a hypertonic environment

shrivel-when the solvent moves out of the cell to balance the concentration

hypotonic environment

higher concentration of solutes inside the cell than outside

result of a hypotonic environment

swell-when the solvent moves into the cell to balance the concentration

facilitated diffusion

the passage of certain hydrophilic compounds through the membrane along the osmotic gradient

active transport

requires some energy input and exclusively relies on carrier proteins to move substances across the concentration gradient

electrochemical gradient

combination of things that can be used to form a variety of functions and how we generate ATP depends on it

cotransport

coupled transport by a membrane protein

exocytosis

substances within the cell vacuole are exiting

endocytosis

substances are entering to form the cell vacuole

hormones

influence behaviors or work by causing cells to change which genes they're expressing

cell signaling

reception, transduction, response

reception

receives, the detection of some signaling molecule originating from outside the cell

reception is dependent on

ligands

ligands

molecules that specifically bind to other molecules

transduction

conveys the signal to modify patterns of gene expression, process by which signals are converted to a form that can bring about a specific response

response

what we get as a consequence of the signaling

everything is a

chemical reaction

metabolism

the totality of an organism's chemical reactions

metabolic pathway

the series of steps involved in transitioning one compound to another form, a series of reactions

the two types of metabolic pathway:

anabolic reactions and catabolic reactions

anabolic reactions

typically consume energy to build larger compounds, takes smaller molecules and builds them into larger, more complicated molecules

catabolic reactions

breaks compounds down, generally relating energy, takes larger molecules and breaks them into smaller ones

photosynthesis is an example of

anabolic reactions

aerobic respiration is an example of

catabolic reactions

energy

the capacity to cause change

thermodynamics

the study of how energy transportation occurs in relation to matter, examines energy in the context of different systems

the first law of thermodynamics

states that the amount of energy in the universe is constant, and so cannot be created or destroyed (but can change form)

the second law of thermodynamics

states that energy transfer or transformation of energy increases the entropy of the universe (things want to fall apart, so the universe wants to increase entropy and disorder)

entropy

measure of molecular disorder

we require inputs of ________ to maintain, when you don't get that ________ takes over and you start to ____________________ and eventually ______

energy, entropy, fall apart, die

biological systems are driven by

chemical reactions

free energy

defined as the amount of energy available to perform work in systems

formula to measure the change of free energy

ΔG= G final state- G initial state

some reactions occur spontaneously(moves energy towards a state of equilibrium), meaning they're

energetically favorable and will occur with no energy input

exergonic reactions

reactions which proceed with a net realize of free energy =, resulting in -ΔG values

exergonic reactions are

catabolic

endergonic reactions

absorb free energy from the surrounding system, resulting in +ΔG values

endergonic reactions are

anabolic

open system

organisms receive inputs from the external environment and make outputs to the external environment

chemical work

pushing of endergonic tractions that would not occur spontaneously- the formation of new chemical bonds

transport work

pumping substances across membranes against the direction of spontaneous movement

mechanical work

the physical movement of the organism and cellular components

mechanical work needs

energy

energy coupling

an exergonic process is used to drive an endergonic one

what is the primary coupling molecule?

ATP

ATP

adenosine triphosphate

ATP has a chain of ___ phosphate groups attached to the __________

three, sugar

what does hydrolysis of the phosphate group do during ATP?

releases a lot of energy

phosphorylation

how ATP energy is transferred, through the coupling of the phosphate group to another molecule

T/F- human consume/ues a lot of energy daily

true

catalysts

speed up chemical reactions (the best way)

catalysts speed up chemical reactions w/o

being consumed themselves

enzymes

a type of catalysts that work to lower the activation energy of chemical reactions

activation energy

the initial investment of energy required to contort the reactant molecules so the bonds can break

substrates

reactants whose reactants are accelerated by enzymatic catalysts

enzyme-substrate complex

when enzymes bond to substrates at the active site

cofactors

influence the behavior of an enzyme and help facilitate processes such as electron transfer

coenzymes

organic cofactors

competitive inhibitors

block the active site of an enzyme so that it cannot bind the substrate

noncompetitive inhibitors

changes the shape of the enzyme so that it cannot bind the substrate

enzymes end in

"ase"

enzymes need to be

controlled/told what to do

allosteric regulation

a proteins function at one site is affected by the binding of a regulatory molecule to a separate site

feedback inhibition

a metabolic pathway which is halted by the inhibitory binding of its end product to an enzyme that acts early in the pathway

what do all living things/cells require?

energy

the source of energy is

organic compounds

energy creates ____ and _____ powers ______

ATP, ATP, work

the breakdown of organic molecules is

exergonic

anaerobic respiration

does not use oxygen

fermentation is an example of

anaerobic respiration

aerobic respiration

requires oxygen and is more important than anaerobic

cellular respiration

includes both aerobic and anaerobic respiration but is usually used to refer to aerobic respiration

glucose formula

C6H12O6

redox reactions

chemical reactions that transfer electrons between reactants