Metabolic Processes (Unit 2) Flashcards
ability to do work
ENERGY
Living organisms must ______, _______ and _______ energy
capture, store and use
is produced by mitochondria in eukaryotes
ATP
the sum of the chemical reactions taking place—sums up anabolic and catabolic reactions
Metabolism
Type of energy that occurs as a result of motion
Kinetic Energy
Type of energy stored within an object; depends on location and/or chemical structure
Potential Energy
Two types of potential energy
Chemical potential
Gravitational potential
Chemical potential is caused by
(electrons and protons)
Gravitational potential is caused by
(distance from Earth)
“Energy cannot be created nor destroyed; it can only be changed from one form to another” is what law?
First Law of Thermodynamics
a.k.a. “Law of Energy Conservation”:
Energy conversion depends on
breaking and re-forming chemical bonds
Can electrons be attracted to multiple nuclei at the same time?
yes! = chemical bond!
Electrons have more potential energy the ________ they are from the nucleus
farther
For bonds to break, energy is _______ so it can be used to pull an electron away
absorbed
When new bonds are formed, energy is ________
released
A measure of the strength or stability of a covalent bond
Bond Energy
amount of energy released per mole when bonds form
Bond energy
Every reaction requires energy to begin the reaction, even if it ultimately produces energy true or false?
true
the energy required to begin a reaction
activation energy (Ea)
When bonds are broken, and new ones are ready to be formed, this is known as the
transition state
Endothermic rxn: net ________ of E
absorption
Ea = (give formula)
Epot (transition) – Epot (reactants)
Exothermic rxn: net _______ of E
release
“Every time energy is converted to another form, some of the useful energy becomes unusable and increases the entropy of the universe” what law?
Second Law of Thermodynamics
All systems in the universe tend towards _______
entropy
refers to the degree of disorder in a system
Entropy
Entropy increases when
product molecules > # reactant molecules
Living cells can create order by ________ energy
expending
Change that will continue to occur on its own once it has started
Spontaneous Changes
example of Spontaneous Changes
E.g. a match will continue to burn once it’s started; a diver will continue to fall once they have jumped
requires continual energy input
Non-spontaneous
Since rxns aren’t 100% efficient, whatever energy remains to do work is known as free energy (whats this called?)
Gibbs Free Energy
example of non-spontaneous changes
E.g. keeping a pot of water boiling
If ΔG is negative, energy is _________ (_________) 🡪 _______
released (exergonic) 🡪 spontaneous
If ΔG is positive, energy is _________ (_________) 🡪 _______
absorbed (endergonic) 🡪 non-spontaneous
_________ rxns release free energy, which can be used to make _________ rxns happen
Exergonic
endergonic
Rxns tend to be part of a
metabolic pathway
complex molecules broken down, releasing energy (e.g. cellular respiration) ΔG -ve
Catabolic
All living things perform activities that increase the _________ available
free energy
simple molecules combined, consuming energy (e.g. photosynthesis) ΔG +ve
Anabolic
ATP – (stands for)
Adenosine Triphosphate
a continual supply of energy is required for (4 things)
The energy comes from
Movement, growth, repair, reproduction
ATP!
Cells need energy to carry out many important functions such as:
-Mechanical work (beating cilia, muscle movement)
-Transport Work (pumping substances across membranes)
-Chemical Work (providing energy to build complex molecules)
ATP can be used to attach _________ to another molecule (phosphorylation) to supply it with ______
The _______ may make the molecule more reactive and more likely to undergo a spontaneous reaction
a phosphate group
ENERGY
phosphate
ATP consits of
-3 phosphate groups
-ribose sugar
-adenine
using energy released from one reaction to drive another reaction
Energy Coupling
ATP contains large amounts of _________ (energy that can do useful work)
FREE ENERGY
In ATP Specifically the crowded, __________ repel one another and weaken the bonds holding them together
These bonds can be ______ broken by ________ to release energy
-negatively charged phosphate groups
-easily
-by Hydrolysis
Cells must regenerate _______ in order to continue functioning (like recharging batteries)
ATP
Cells make ATP by combining ________ (Adenosine diphosphate) with a Phosphate group
ADP
ATP is generated through
the breakdown of more complex molecules in the food we eat (fats, carbohydrates, proteins)
The Universal Energy Currency
ATP
provides a manageable amount of energy for cell reactions (just the right amount)
ATP
ATP Can be assembled using the energy from a variety of different _____ molecules and can therefore be reliably utilized (no shortage of ATP)
food
Enzymes help chemical reactions
take place at ________ energy levels
LOWER
what allows your body to use less energy to drive reactions
Enzymes
enzymes DO or DO NOT supply energy for reactions
DO NOT supply energy for reactions
Help speed up the rate of reactions
Enzymes
Enzymes as Catalysts are Almost always ________
PROTEINS
the amount of energy required to start a reaction
Activation Energy
A __________ of energy is needed to help break the bonds of chemicals
certain amount
temporary state between
reactants and products (before new bonds are formed)
Transition State
Transition state occurs when __________ is required to begin reaction
enough energy
lower or higher activation energy when using a catalyst
lower
What Provides Activation Energy?
Thermal Energy
Catalyst (Enzymes)
Thermal Energy often causes more and more reactions to take place as more and more energy is ________
released
Lighting gasoline on fire
using a match is example of what
Thermal Energy
is thermal energy easy or hard to regulate
Hard to regulate
Allows reactions to occur using less energy
Catalyst (Enzymes)
Can be regulated to control rates of reaction
Catalyst (Enzymes)
In exothermic reactions do products have more or less energy then reactants
LESS energy
In endothermic reactions do products have more or less energy then reactants
MORE energy
How can Enzymes lower Activation Energy? (3)
- BRINGS REACTANTS TOGETHER
Orients molecules into position so they can bind
- CHARGED ENZYMES HELP BREAK BONDS
Charged functional groups help to attract reactants and break bonds
- ENZYME CHANGES SHAPE OF SUBSTRATE
Enzyme changes shape to change the shape of the
substrate and break bonds
What do gasoline and glucose have in common? (2)
Both have an abundance of Carbon-Hydrogen Bonds
These bonds hold a large amount of Potential Energy
The closer or farther away an electron is from the nucleus of an atom the MORE POTENTIAL ENERGY IT HAS?
farther
Energy is _________ as electrons move closer to the nucleus
released
Energy is ________ as electrons move farther away from the nucleus
absorbed
How is energy released?
As the electrons in the C-H bonds are pulled toward larger, more ________ nuclei
(from other atoms) energy is ______ and the electrons move to a ______ energy level
electronegative
released
lower
Oxygen atoms are very ________ and will pull the electrons closer towards their
nuclei. As they do so the electrons ______
electronegative
release energy
Reduction occurs when an atom or molecule _______ ELECTRONS from another
atom
GAINS
Oxidation occurs when an atom or molecule _______ ELECTRONS to another
atom
LOSES
As electrons are exchanged they may be shared in ___________ which
results in the ________
different arrangements
release of energy
______ combustion which would be disastrous for
living organisms because we would _______
rapid
spontaneously combust
Reactions within the body need to be ________ and so undergo a number of different steps
controlled
The body can _________ at each step and (increase or decrease?) the efficiency of the reaction (so we release less wasted _______)
STORE ENERGY
increase
heat energy
Enzymes help to _______ each of the steps needed in controlled _______
CATALYZE
oxidation
Energy is absorbed by _________ molecules and can be used to ________ or to make ________
Energy-carrier
power other reactions
ATP
Molecules that help to store energy released by reactions and help to power other reactions
Energy Carriers
energy carriers are Also called _________ – help remove
hydrogen atoms and transfer electrons
Dehydrogenases
Ex. of Dehydrogenases:
NAD+ is reduced (gains_______) to form NADH.
2 electrons and a
Hydrogen
NADH
_____ can be used
to power ATP synthesis
NADH
Aerobic Cellular Respiration:
The process that extracts _______
Used to make _____
Takes place in most _______ and some ________
energy from food
ATP
Eukaryotes, some prokaryotes
a process that uses oxygen to harvest energy from organic compounds
Aerobic Cellular Respiration
an organism that must have
oxygen to live
Obligate Aerobe
ex of Obligate Aerobe organisms
Humans, plants, tiny turtles etc. all need oxygen to live and carry out cellular respiration
an organism that cannot
survive in an environment with oxygen
Obligate Anaerobe
ex of Obligate Anaerobe organisms
Some species of bacteria/microorganisms cannot live in the presence of oxygen
4 main steps in Cellular Respiration
Glycolysis
Pyruvate Oxidation
Citric Acid Cycle
Electron Transport Chain/Oxidative Phosphorylation –
Glycolysis – splits ________ into __________ and
releases _______ (used to make ATP)
Pyruvate Oxidation – pyruvate is ________ to form ______
Citric Acid Cycle - a cycle of reactions that produces _____
and _________ molecules
Electron Transport Chain/Oxidative Phosphorylation –
uses energy ________ to make ATP
glucose, 2 pyruvate molecules, energy
oxidized, Acetyl CoA
ATP, energy carrier
carrier molecules
what part of the cellilar respiration creates the most ATP
ETC/Oxidative Phosphorylation
Where do the 4 steps of cellular respiration occur
Glycolysis - Occurs in the
Cytosol
Pyruvate Oxidation, Citric
Acid Cycle and ETC/Oxidative
Phosphorylation - Occurs in the
Mitochondria
cell organelle involved in the
production of ATP
Mitochondria
______ and ________
take place within
the inner
membrane of the mitochondira
ETC and Oxidative
Phosphorylation
_________ and
________ take
place within the Matrix
(fluid inside inner
membrane)
Citric Acid Cycle, Pyruvate Oxidation
true or false Energy can also be extracted from food
molecules using Anaerobic Respiration
TRUE
harvesting energy from
food molecules without using oxygen
Anaerobic Respiration
Anaerobic Respiration
Use _______ as oxidizing agents
Produce ______ energy then aerobic respiration
Ex. _______ yeast feed on sugar
molecules and produce ethanol as a by-product
other molecules
less
Alcohol Fermentation
Glycolysis overview:
Splits ______ Molecule into _________
Produces __ ATP
Produces __ NADH (energy carrier molecule)
Cytosol (cytoplasm)
1 Glucose, 2 Pyruvate Molecules
2 ATP
2 NADH
______ and ______ - Nicotinamide adenine
dinucleotide
_____ can be reduced to form _______
_____ can be oxidized to ______ electrons
NAD+ and NADH
NAD+, NADH
NADH
donate
_____ and _____ - Flavin adenine dinucleotide
______ can be reduced to form _______
____-can be oxidized to donate electrons
FAD and FADH2
FAD, FADH2
FADH2
_______ - Guanosine triphosphate
Can be used to generate ____
GTP –
ATP
What to do with Pyruvate?
The 2 molecules of Pyruvate that are synthesized by ______ still contain about 75% of the energy stored in ______
Pyruvate oxidation and the Citric Acid Cycle help to harvest ________
Glycolysis
Glucose
harvest the remaining available energy
Pyruvate Oxidation
- ________ is removed – creates _____
- _____ steals electrons from remaining molecule to
become ____ - ________ attaches to molecule to form _____
Carboxyl Group, CO2
NAD+, NADH
Coenzyme A, Acetyl CoA
The Citric Acid Cycle:
Consists of __ enzyme catalyzed
reactions
Used to create ________ (give 2 example)
Creates __ ATP (1 per pyruvate)
Converts the remaining carbon from pyruvate into ___
8
Energy Carrier Molecules (NADH and FADH2)
2
CO2
__ Carbon atoms Enter Cycle and __ Carbon atoms Released as CO2
2
2
The Citric Acid Cycle Important Points to Remember:
The cycle keeps moving because ______ (the first reactant) is ______
Every step is _______ by reactions
________ is used to make ATP
NADH and ____ will be used later to make ATP
oxaloacetate, regenerated
catalyzed
GTP (guanosine triphosphate)
FADH2
What enters the ETC?
All of the Carbon from Glucose
has already been turned into
_________
______ and ______ are now
used to power the ETC
Carbon Dioxide
NADH and FADH2
a series of membrane bound molecules that transfers electrons
Electron Transport Chain
The ETC:
Uses energy from _______ to pump _______
across the cell membrane to create a ________ ___________
Accepts electrons from ________
Consists of __ protein complexes and shuttle molecules
electrons to pump protons, concentration gradient
energy carriers
4
ETC: Complex I (NADH Dehydrogenase)
Oxidizes ______ (loses electrons)
into _______
______ atoms are pumped
across the membrane as
electrons move through the
complex
NADH, NAD+
Hydrogen
ETC: Complex II (Succinate Dehydrogenase)
_______ is oxidized by complex II
and donates electrons
Energy from electrons is used to pump protons across the
membrane
FADH2
is used to move
electrons from complex I and
complex II to Complex III
Ubiquinone (UQ)
Ubiquinone is a ________
molecule found within the ______ mitochondrial membrane
hydrophobic, inner
Complex III (Cytochrome Complex)
Electrons transferred from
Ubiquinone move to Complex III
Complex III transfers the electrons to _______ (another electron
shuttle) which can then move
electrons to Complex IV
Cytochrome C
Complex IV (Cytochrome Oxidase)
Electrons are transferred from
Cytochrome c to ______
Electrons combine with _____ ions
and an ______ to form water
Movement of ______ drives the pumping of more Hydrogen across the cell membrane
complex IV
Hydrogen, oxygen atom
electrons
Increasing Electronegativity
The electrons move through the ETC because each complex is _______ than the last
________ is the final electron acceptor and has the (highest or lowest?) electronegativity
(thus it drives the process)
more electronegative
Oxygen, highest
Chain Reaction
_____ causes complex IV to steal electrons from complex III which then steals electrons from complex II which then steals electrons from complex I which then steals electrons from NADH
This _________ is what ultimately drives the ETC
Oxygen
chain reaction
Chemiosmosis
Proton gradient created by the
ETC drives ________
ATP synthesis
Protons flow through ________ (a membrane
protein) which phosphorylates
ADP
ATP Synthase
Uncoupling Electron Transport and Chemiosmosis
Special _________ are used as an alternative route for protons to flow back into the matrix of the mitochondria
Instead of producing ATP these proteins help convert the energy into _______ to keep animals warm
Uncoupling Proteins
thermal energy
ATP from Cellular Respiration
Glycolysis –
Citric Acid Cycle –
Electron Transport/Chemiosmosis –
________________________________
Total ATP Produced =
per Glucose Molecule
Glycolysis – 2 ATP
Citric Acid Cycle – 2 ATP
Electron Transport/Chemiosmosis – 34
ATP
__________________________________
Total ATP Produced = 38 ATP per Glucose
Molecule
The maximum amount of ATP that can be produced is 38, however, this value
may change due to other circumstances: (2)
Uncoupled proteins (H+ not powering ATP synthase)
Using different electron shuttling
molecules may yield less ATP
Energy Efficiency
____ of the energy from Glucose is converted into ATP
41%
The rest of the potential energy from glucose is released as
thermal energy
the amount of energy that is expended per unit time in an organism
Metabolic Rate
the metabolic rate of an organism at rest
Basal Metabolic Rate (BMR) –
The BMR:
Varies from individual to individual (T/F?)
Higher fat content increases BMR (T/F?)
Speeds up as we age (T/F?)
True
False
False
Regulating Cellular Respiration
Your body needs to regulate cellular processes to keep our ________ under control
Your body only needs a certain
amount of ATP to function properly and so it must control its production (T/F?)
metabolism
TRUE
When there is an excess amount of ATP present then ATP can bind to phosphofructokinase (an enzyme in glycolysis) to stop ATP production (WHAT IS IT CALLED?)
Negative Feedback Loops
Similarly Citrate (from the citric acid
cycle) can also inhibit
phosphofructokinase and prevent a build
up of ___________
unneeded molecules
Converting Food into Energy
Proteins – converted into _________ which can
be converted into pyruvate, acetyl CoA or
fumarate
Complex Carbs – broken down into usable
________ subunits
Fats – can be converted into _______ and
Acetyl CoA
amino acids
glucose
G3P (glycolysis)
Fats and Sugars
When you eat a gram of pure sugar (hydrophilic)
you also have to _____
When you eat a gram of fat (hydrophobic) you only
_____
This is why many animals (yourself included) will
_________ in order to store them (as this
is lighter)
consume a gram of water to make up for the amount of water that binds to the sugar
molecules
gain the mass of the fat.
convert sugars to fats
an organism that
makes its own food using sunlight energy.
Photoautotroph
Plants convert ________ energy into chemical energy in the form of _____
Plants can then convert _____ into other cellular parts or into ATP
sunlight, sugar
sugars
Overall Formula for Photosynthesis
CO2 + H2O 🡪 C6H12O6 + O2
this reaction is the reverse
of ____________
Cellular Respiration
first stage of photosynthesis which requires light
Light-Dependant Reactions
Steps in Light-Dependant Reactions
Splits _______ molecule
Absorbs _____ energy
_____/______ are generated
_______ used to capture light energy
Occurs in ________
Splits water molecule
Absorbs light energy
ATP/NADPH* are generated
Chlorophyll used to capture light energy
Occurs in Chloroplast
*NADPH – nicotinamide adenine dinucleotide phosphate
Calvin Cycle:
Uses ____ and _____ to convert CO2 into Sugars
Can also convert fixed carbon into other molecules
Uses ATP and NADPH to convert CO2 into Sugars
second stage of photosynthesis that does not require
light
Calvin Cycle (Light-Independent
Reactions)
plant cell organelle that is the site of photosynthesis
Chloroplast
chloroplasts:
Contains how many membranes?
Contains _________
3
chlorophyll
fluid that surrounds thylakoids
Stroma
pancake shaped membranes inside chloroplast (site of light absorption, electron transfer, ATP Synthesis)
Thylakoid
Capturing Light Energy
Absorption of a photon by _______
(pigment molecule) excites an electron
chlorophyll
The “excited” electron moves to a higher or lower energy level?
higher
As the electron falls back down towards the nucleus it releases or absorbs? energy
releases
The electron may also be transferred to an ______ molecule
energy carrier
- Energy from electrons can be
transferred from one atom to the next
- ___________ can be
transferred to other molecules
These electrons can then be used to power reactions
High Energy Electrons
photosynthetic pigments found in plants
Chlorophylls
transfers energy to chlorophyll a
Chlorophyll b
Chlorophyll a or b?
accepts energy from other
pigments and transfers electrons to Primary
Electron Acceptors (molecules that accept
electrons)
a
other plant pigments which transfer
energy to chlorophyll molecules
Carotenoids
a cluster of light
absorbing pigments in the thylakoid
membrane
Antenna Complex
Antenna Complex:
Captures and transfers light energy to _______
________ then transfers an electron to the Primary Electron Acceptor
chlorophyll a
the amount of
light energy that a substance absorbs
Absorption Spectrum
Absorption Spectrum:
Chlorophyll a – absorbs
blue and red
light
Chlorophyll b – absorbs
absorbs blue-green and
orange light
Carotenoids – absorbs
absorbs purple to green
light
all plants reflect what colour?
green
collection of pigment
molecules and chlorophyll a that absorbs light at
the 700nm wavelength
Photosystem I
Pigments and Photosystems
_______ are bound to other molecules in the
thylakoid membrane which are collectively called Photosystems
Pigments
collection of pigment
molecules and chlorophyll a that absorbs light at
the 680 nm wavelength
Photosystem II
In Photosytem ll -
______ is used to excite and transfer an electron to the primary electron acceptor
Light energy
Electrons are replaced by splitting ____
water
____ and ______ are formed as a result
Oxygen and Hydrogen
An electron is then transferred to
_______
Plastoquinone (PQ)
Plastoquinone (PQ) -
Moves an Electron to the
________
Cytochrome Complex
PQ Also helps to move _____
atoms across the membrane as it
transports an electron
Hydrogen
Cytochrome Complex and Plastocyanin -
Accepts e- from PQ and
transfers it to _______
Plastocyanin
Plastocyanin transfers the
electron to ______
photosystem I
Photosystem I -
_____ is used to excite an electron
Light energy
This electron is then accepted by an _______
electron acceptor
The electron acceptor passes the electron on to ____
Ferredoxin
Ferredoxin passes the electron onto NADP+ Reductase which helps form ____
NADPH
Chemiosmosis in Photosynthesis
A proton gradient is established in three main
ways:
1) Protons are moved into the thylakoid lumen
by plastoquinone (PQ)
2) The concentration of Protons in the lumen
increases as water is split to provide
electrons for photosystem II
3) Removal of Hydrogen to form NADPH in the
stroma decreases the concentration of
hydrogen
Chemiosmosis in Photosynthesis:
The establishment of a proton
____ across the membrane
allows protons to flow through ATP
Synthase which drives ATP synthesis
gradient
Protons flow from the thylakoid
lumen into the ______
stroma
The Role of Sunlight Energy -
In Cellular Respiration _____ energy electrons
from NADH/FADH2 are transferred to _____
energy molecules to form _____
high
lower
Water
In photosynthesis electrons move from ___
energy water to a ____ energy level in
NADPH
low
higher
This is accomplished through the addition of
_____ energy which “energizes” electrons to a
higher energy level
light
when
electrons move through both
photosystems to form NADPH
Linear Electron Transport –
Splits ______ into Oxygen, Hydrogen ions,
and free electrons
water
Called linear because
electrons move in a
straight line to NADPH
________ uses photosystem I
to transfer electrons to plastoquinone to pump
protons across the membrane
Uses ________ to reduce plastoquinone
Electrons move in a ______
Used to create the extra ATP needed in the
Calvin Cycle (More ATP is needed than
NADPH)
Cyclic Electron Transport
ferredoxin
cycle
is (Calvin Cycle) The Light Independent or dependent Reactions
Light Independent Reactions
Calvin cycle -
Occurs in the _____ of the chloroplast through cyclic reactions
stroma
Converts ____ into carbohydrate molecules
CO 2
Uses __ molecules of ATP and __ molecules of NADPH
6
Carbon Fixation
CO 2 reacts with _____ (5 carbon molecule) to form 2 molecules of 3-phosphglycerate
The enzyme _____ is required for this reaction
This is known as C 3 metabolism from the two 3-carbon molecules formed
RuBP
Rubisco
Calvin cycle can be divided into three phases:
o Carbon Fixation
o Reduction
o Regeneration
Reduction
Each molecule of 3-phosphglycerate is phosphorylated by the hydrolysis of ATP
This molecule is then reduced by ____ producing G3P (glyceraldehydes-3-
phosphate) which is a sugar
One molecule of ___ exists as a final product which can then be used to synthesize larger sugars such as glucose or other carbohydrates
NADPH
G3P
Regeneration
The remaining G3P are combined and rearranged to regenerate the _____ that is
required to start the cycle over again
RuBP
