DENNIS BSC 2010 Exam 2 (copy)

nucleus

contains most of the cell's genes and is the most conspicuous organelle

eukaryotic cells

mitochondria are in nearly all

membrane

collage of different proteins embedded in the fluid matrix of the lipid bilayer

non polar, alpha helices

the hydrophobic regions of an integral protein consist of one or more stretches of __ amino acids, coiled into __ that pass through the membrane

transport proteins

allow passage of hydrophilic substances across the membrane

channel proteins

some transport proteins known as __ have a hydrophilic channel that certain molecules or ions can use as a tunnel to cross the membrane

aquaporins

channel proteins called ___ facilitate the diffusion/passage of water across a selectively permeable membrane

carrier proteins

transport proteins that undergo subtle change in shape that translocate the solute binding site across the membrane

diffusion

the tendency for molecules to spread out evenly into the available space, and is a form of passive transport

dynamic equilibrium

equal concentration, equal number of molecules move each direction

concentration gradient

substances diffuse down their ___ which requires no energy

osmosis

diffusion of water across a selectively permeable membrane

lower, higher

Water diffuses across a membrane from the region of ______ solute concentration to the region of ______ solute concentration

tonicity

the ability of a solution to cause a cell to gain or lose water

iso

-tonic solution is one in which solute concentration is the same as that inside the cell, no net water movement across the plasma membrane (non-plant cells)

hyper

__ -tonic solution is one in which solute concentration is greater than that inside the cell, cell loses water

hypo

__ -tonic solution is one in which solute concentration is less than that inside the cell, cell gains water (plant cells)

osmoregulation

the control of water balance

turgid

plant cells in hypotonic solutions swell and become

flaccid

plant cells in isotonic solutions have no net movement of water into the cell making the cell

facilitated diffusion

passive transport aided by proteins, transport proteins speed the passive movement of molecules across the plasma membrane

ion channels

open or close in response to a stimulus (gated channels)

active

__ transport uses energy to in the form of ATP to move solutes/substances against their concentration gradients

ATP

allows cells to maintain concentration gradients that differ from their surroundings

sodium-potassium pump

example of an active transport system, major electrogenic pump of animal cells

membrane potential

the voltage difference across a membrane

voltage

created by differences in the distribution of positive and negative ions across a membrane

proton pump

the main electrogenic pump of plants, fungi, and bacteria

electrogenic pump

a transport protein that generates voltage across a membrane

cotransport

occurs when active transport of a solute indirectly drives transport of other solutes

bulk transport

requires energy, occurs by exocytosis and endocytosis and moves larger molecules across the membrane

vesicles

large molecules cross the membrane in bulk via

exocytosis

out of the cell

endocytosis

into the cell, three types

phagocytosis

solid, cellular eating, cell engulfs a particle in a vacuole

pinocytosis

liquid, cellular drinking, extracellular fluid is gulped into tiny vesicles

receptor-mediated endocytosis

binding of a ligand to a receptor to trigger vesicle formation

metabolic

__pathways begin with a specific molecule and ends with a product, each step is catalyzed by a specific enzyme

catabolic

___ pathways release energy by breaking down complex molecules into simple molecules

anabolic

__ pathways consume energy to build complex molecules from simpler ones

bioenergetics

the study of how organisms manage their energy resources

energy

the capacity to cause change/do work

kinetic energy

energy of motion, heat/thermal energy

potential energy

energy that matter possesses because of its location or structure

chemical energy

potential energy available for release in a chemical reaction

thermodynamics

the study of energy transformations

closed system

isolated from its surroundings, reach equilibrium and then do no work

open system

energy and matter can be transferred between the system and its surroundings (life), cells are not in equilibrium, experience a constant flow of materials

first law of thermodynamics

the principle of conservation of energy

created, destroyed

energy can be transferred/transformed, but it cannot be __ or __

second law of thermodynamics

during every energy transfer or transformation, some energy is unusable and is often lost as heat

entropy

every energy transfer or transformation increases the ___ or disorder of the universe

negative, increase

only processes with a __ delta G are spontaneous, occur without energy input, and __ the stability of a system

free energy

the ___ change of a reaction tells us whether or not the reaction occurs spontaneously, can do work when temperatures and pressures are in uniform

positive, decrease

only processes with a __ delta G are non-spontaneous, occur with addition of energy, and __ the stability of a system

equilibrium

state of maximum stability

exergonic reaction

proceeds with a net release of free energy and is spontaneous

endergonic reaction

absorbs free energy from its surroundings and is non spontaneous

atp

___ powers cellular work by coupling exergonic reactions to endergonic reactions, cell's energy shuttle

energy coupling

to do work, cells manage energy resources by ____, the use of an exergonic process to drive an endergonic one, mediated by ATP

ribose, adenine (nitrogenous base), 3 phosphate sugars

ATP is composed of

hydrolysis

the bonds between the phosphate groups of ATP's tail can be broken by____, energy is released from ATP when the bond is broken

mechanical, transport, and chemical

the three types of cellular work, powered by the hydrolysis of ATP

renewable, phosphate

ATP is a _____ resource that is regenerated by the addition of a ___ to adenosine diphosphate (ADP)

lowering energy barriers

enzymes catalyze or speed up metabolic reactions by ___

activation energy/free energy of activation

the initial energy needed to start a chemical reaction is called

enzymatic reactions

in ___ the substrate binds to the active site of the enzyme = catalytic site

enzyme-substrate complex

the enzyme binds to its substrate forming

active site

the region on the enzyme where the substrate binds (catalytic site)

cofactors

nonprotein enzyme helpers

coenzyme

organic cofactor (vitamin)

competitive inhibitors

bind to the active site of an enzyme, competing with the substrate

noncompetitive inhibitors

bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective

allosteric regulation

occurs when a regulatory molecule binds to a protein at one site and affects the proteins function at another site, can inhibit or stimulate enzyme activity

cooperativity

a form of allosteric regulation that can amplify enzyme activity by binding substrate to one active site stabilizing favorable conformational changes at all other subunits

feedback inhibition

in _____, the end product of a metabolic pathway shuts down the pathway, this process prevents a cell from wasting chemical resources by synthesizing more product than is needed

FAD & NAD+ (dinucleotides)

electron carriers of cellular respiration

CO2 + H2O + energy

products of cellular respiration

glucose + O2

reactants of cellular respiration

oxidation

loss of electrons from a substance

reduction

gain of electrons to a substance

mitochondria

major organelle of respiration

glucose

electron source for cellular respiration

redox reactions

occur when the transfer of electrons is not complete but involves a change in the degree of electron sharing covalent bonds, requires both a donor and an acceptor

CO2

the most oxidized form of carbon is

glucose, enzymes

the process of glycolysis breaking down __ is catalyzed by __

oxidized, reduced

in a series of reactions, glucose is __ and oxygen is __

dehydrogenase

enzyme that takes away a hydrogen (oxidation reaction)

phosphatase

protein __ remove the phosphates from proteins, a process called dephosphorylation (enzyme)

kinase

protein __ transfer phosphates from ATP to protein, a process called phosphorylation (enzyme)

isomerase

enzyme that rearranges molecule and makes isomers

synthetase

enzyme that builds

Glycolysis, transfer to mitochondria, citric acid cycle, oxidation phosphorylation

steps of cellular respiration

NAD+

as an electron acceptor, __ functions as an oxidizing agent during respiration

dehydrogenase enzymes, NADH

__ enzymes transfer hydrogen atoms (electrons) from substrates to NAD+ forming ___

2, 4, 2, 2

glycolysis uses __ ATP, forms __ ATP and __ NADH which brings a net output of __ ATP

substrate-level phosphorylation

makes direct ATP

oxidative phosphorylation

makes indirect ATP

glycolysis

harvests chemical energy by oxidizing glucose to pyruvate

dinucleotides

the electron carriers, such as NAD+