Cellular Respiration Word Search

One list for each stage, from glucose in the cytosol to the ATP made on the cristae.

Name Date

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0 of 20 words found

SSEKREBSCYCLEMN

DCRISTAERTMHAAC

CARBONDIOXIDETH

YAEFXALFGHTGLPE

TCSRYDYELOOLEIM

OAPNGHMRUTCYCOI

PRINEWSMCDHCTEO

LKRENASEOEOORPS

AKACATINSANLOYM

SVTJEEOTEQDYNRO

MSITHRBAIHRSCUS

TDOUAADTPBIIHVI

ELNMATRIXYASFAS

UENERGYOCTRFWTT

AEROBICNENZYMET

This grid is wider and taller than its box. Slide it to see every letter.To drag, hold the first letter for a moment, then slide.Keyboard: Tab to the grid, arrow keys to move, Enter on the first and last letter.

RespirationRESPIRATION
GlucoseGLUCOSE
OxygenOXYGEN
Carbon dioxideCARBON DIOXIDE
WaterWATER
EnergyENERGY
ATPATP
AerobicAEROBIC
EnzymeENZYME
MitochondriaMITOCHONDRIA
GlycolysisGLYCOLYSIS
PyruvatePYRUVATE
CytoplasmCYTOPLASM
NADHNADH
Krebs cycleKREBS CYCLE
MatrixMATRIX
ElectronELECTRON
CristaeCRISTAE
ChemiosmosisCHEMIOSMOSIS
FermentationFERMENTATION

20 words from the Cellular Respiration Key Terms list.

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Answer key: Cellular Respiration Word Search

SSEKREBSCYCLEMN

DCRISTAERTMHAAC

CARBONDIOXIDETH

YAEFXALFGHTGLPE

TCSRYDYELOOLEIM

OAPNGHMRUTCYCOI

PRINEWSMCDHCTEO

LKRENASEOEOORPS

AKACATINSANLOYM

SVTJEEOTEQDYNRO

MSITHRBAIHRSCUS

TDOUAADTPBIIHVI

ELNMATRIXYASFAS

UENERGYOCTRFWTT

AEROBICNENZYMET

RESPIRATION, GLUCOSE, OXYGEN, CARBON DIOXIDE, WATER, ENERGY, ATP, AEROBIC, ENZYME, MITOCHONDRIA, GLYCOLYSIS, PYRUVATE, CYTOPLASM, NADH, KREBS CYCLE, MATRIX, ELECTRON, CRISTAE, CHEMIOSMOSIS, FERMENTATION

Next step Print the airway, lungs and gas exchange Type in the terms from your own respiration notes

All 107 words

Fuel, Oxygen and Energy 25

ADP Adenosine diphosphate, the molecule that is recharged into the cell's currency.
Aerobic Describes a process that uses O2 as its final acceptor.
ATP Adenosine triphosphate, often called the molecular unit of currency of a cell.
Breakdown The taking apart of something large into smaller pieces.
Carbon dioxide The waste gas, CO2, given off in the link step and in the ring of reactions after it.
Catabolism The breaking-down side of a cell's chemistry: large molecules into smaller ones.
Energy The capacity to do work; nutrients store the chemical kind.
Enzyme A biological catalyst, usually a protein, that speeds up a chemical reaction.
Equation Formulas joined by an arrow that sum up a chemical reaction.
Exergonic Describes a reaction that, on balance, gives off free energy.
Fuel A material that reacts to release what it stores, as nutrients do in a cell.
Glucose The six-carbon carbohydrate, C6H12O6, that the first stage starts with.
Heat Thermal energy; the overall reaction is exothermic, so some is given off.
Metabolism All the life-sustaining chemical reactions inside a living thing.
Mitochondria Organelles with a double membrane where, in plant and animal cells, the later stages run.
Oxidize To take electrons away from a substance.

Show all 107 words (91 more)

Fuel, Oxygen and Energy, continued

Oxygen The gas that is the last acceptor at the very end of the chain.
Pathway A run of chemical reactions in a cell, each linked to the next.
Phosphate The group that ADP gains to become the cell's currency molecule, which holds three.
Powerhouse The popular nickname for a mitochondrion: the ___ of the cell.
Product A substance that a chemical reaction leaves at its end.
Reactant A substance that is used up in a chemical reaction.
Respiration How a cell moves the chemical energy of its nutrients into a form it can spend.
Sugar A sweet, soluble carbohydrate; one of the nutrients that cells commonly respire.
Water H2O, formed where the chain finishes, when hydrogen ions join the O2.

Glycolysis 19

Aldolase The enzyme that cuts fructose bisphosphate into two three-carbon phosphates.
Cytoplasm All the material inside the cell membrane apart from the nucleus.
Cytosol The liquid part of a cell, around the organelles, where the first stage happens.
Enolase The enzyme of the ninth step, the last but one.
Fructose Fruit sugar; the pathway handles it with phosphate groups attached.
Glyceraldehyde The three-carbon sugar whose 3-phosphate, G3P, is an intermediate of the pathway.
Glycolysis The first stage, whose name means sugar splitting: ten reactions, with or without O2.
Hexokinase The enzyme of step one: it moves a phosphate group from ATP onto glucose.
Hexose Any simple sugar built on six carbon atoms.
Investment A name for the opening phase, which spends two ATP to prepare the glucose.
Isomerase An enzyme that rearranges a molecule into another with the same formula.
Mutase An enzyme that moves a functional group from one place to another in the same molecule.
NADH The reduced form of the coenzyme NAD; it feeds the first protein complex of the chain.
Payoff The closing phase, which makes four ATP for the two that were spent.
Pyruvate The three-carbon molecule the first stage ends with; each six-carbon sugar gives two.
Pyruvic acid CH3COCOOH, an alpha-keto compound that the first stage makes from glucose.
Split What happens to the six-carbon chain midway, leaving two three-carbon pieces.
Substrate The molecule that an enzyme acts on.
Triose Any simple sugar built on three carbon atoms.

Citric Acid Cycle 21

Acetyl CoA The carrier molecule, made from pyruvate, that delivers two carbons to the ring.
Acetyl group A two-carbon unit, a methyl bonded to a carbonyl, that the ring oxidizes.
Aconitase The enzyme that changes citrate into its isomer.
Citric acid The six-carbon compound, often called citrate, that the ring uses up and then remakes.
Coenzyme A A helper molecule, built in humans with vitamin B5, that carries two-carbon units.
Decarboxylate To remove a carboxyl group from a molecule, which releases CO2.
Dehydrogenase An enzyme that oxidizes its substrate by passing electrons to an acceptor such as NAD.
FAD Flavin adenine dinucleotide, a redox coenzyme; each lap of the ring reduces one.
Fumarate A four-carbon intermediate whose acid, found widely in nature, has a fruit-like taste.
GTP Guanosine triphosphate; one lap of the ring makes one, which can be traded for ATP.
Isocitrate The more reactive six-carbon isomer that citrate is rearranged into.
Ketoglutarate With alpha in front, the five-carbon molecule that follows the six-carbon ones.
Krebs cycle The ring of reactions named for one of the two men who identified it in 1937.
Link reaction The step between the first stage and the ring: pyruvate loses one carbon as CO2.
Malate The intermediate just before the ring closes; its acid helps make fruits taste sour.
Matrix The innermost space of a mitochondrion, inside both of its membranes.
Oxaloacetate The four-carbon molecule that takes in two carbons to open the ring and is remade at its end.
Regenerate To make again: the ring ends by doing this to its own four-carbon starter.
Succinate A four-carbon intermediate; the enzyme that oxidizes it is also complex II of the chain.
Tricarboxylic Describes an acid with three carboxyl groups; it gives the ring its short name, TCA.
Turn One lap of the ring; a glucose needs two, one for each pyruvate.

Electron Transport Chain 22

Acceptor A substance that takes up electrons; oxygen is the last one in aerobic respiration.
ATP synthase The enzyme that joins ADP to a phosphate as hydrogen ions flow through it.
Carrier A molecule that picks something up in one place and hands it on in another.
Chemiosmosis Ions moving through a membrane protein from the crowded side to the other.
Complex One of the four numbered protein groups, I to IV, that pass electrons along.
Cristae The folds inside a mitochondrion, which give a large surface for the reactions.
Cytochrome A redox protein with an iron atom at its core; the kind called c ferries electrons.
Electron A negatively charged particle; a coenzyme hands these to the first protein complex.
Gradient A difference in concentration from one side of a membrane to the other.
Heme A ring-shaped molecule that holds an iron atom.
Inner membrane The folded layer of a mitochondrion that separates the matrix from the space outside it.
Intermembrane Describes the narrow space between the two layers of a mitochondrion.
Outer membrane The layer that wraps the whole mitochondrion.
Oxidation The loss of electrons.
Oxidative With phosphorylation, the name of the last stage, which makes most of the ATP.
Proton A hydrogen ion, H+; the chain moves these out of the matrix.
Pump To push ions across a membrane, building up more on one side.
Redox A reaction in which one substance loses electrons and another gains them.
Reduction The gain of electrons.
Rotor The part of ATP synthase that turns as hydrogen ions pass.
Shuttle A system that carries the electrons of NADH across a membrane NADH cannot cross.
Ubiquinone A small molecule in the membrane, also called coenzyme Q, that ferries electrons.

Fermentation and Anaerobic Respiration 20

Acetaldehyde The compound, also called ethanal, that a yeast enzyme turns into the alcohol.
Anaerobic Describes a process that goes on without oxygen.
Anoxic Describes water that holds no dissolved oxygen.
Bacteria Microscopic one-celled organisms; some ferment and some respire without oxygen.
Bubbles What carbon dioxide forms inside a rising loaf.
Cori cycle The loop in which the liver turns lactate from the muscles back into glucose.
Dough A paste of flour and water that rises as carbon dioxide collects in it.
Ethanol The alcohol, C2H5OH, that forms along with carbon dioxide in one kind of fermentation.
Facultative With anaerobe, an organism that respires with oxygen when it can and ferments when it cannot.
Fermentation A way to live on sugar without O2: organic molecules are both the donor and the acceptor.
Lactate What pyruvate is turned into when an animal cell ferments.
Lactic acid C3H6O3, formed when bacteria ferment the sugars of milk or cabbage.
Methanogen One of the archaea that give off methane as they make their ATP.
Muscle The tissue whose cells ferment when their demand for ATP outruns the oxygen supply.
Nitrate NO3-, an ion that some microbes use in place of oxygen as the last electron taker.
Obligate With anaerobe, a microbe that the normal amount of oxygen in air kills.
Sauerkraut Finely cut cabbage soured by bacteria; the name is German for sour cabbage.
Sulfate SO4 2-, an ion that some microbes use in place of oxygen as the last electron taker.
Yeast A fungus that grows as single cells; bakers and brewers use one that ferments sugar.
Yogurt Milk that bacteria have fermented; the acid they make gives its tart flavor.

How it works

A review sheet for the unit: the first grid of this cellular respiration word search holds the reactants Glucose and Oxygen, the products Carbon dioxide, Water and ATP, and the places, Cytoplasm, Mitochondria, Matrix and Cristae, among its 20 terms.

Read the full guide

A sheet for each stage

Under Start from a list, Glycolysis has 19 words, such as Hexokinase, Aldolase, Investment and Payoff. Citric Acid Cycle has 21, with the intermediates from Oxaloacetate round to Malate. Electron Transport Chain has 22: Ubiquinone, Cytochrome, ATP synthase, Rotor.

With oxygen and without

Fuel, Oxygen and Energy has 25 words for the overall reaction. Fermentation and Anaerobic Respiration has 20, from Lactate and Ethanol to Methanogen and Cori cycle, for the lesson on what cells do when oxygen runs short.

Carbon dioxide, Krebs cycle, ATP synthase and 10 more two-word entries hide closed up: KREBSCYCLE.

Questions and answers

What are the stages of cellular respiration?

Glycolysis in the cytosol, then three steps inside the mitochondria: pyruvate is oxidized to acetyl-CoA, the citric acid cycle runs in the matrix, and oxidative phosphorylation, the electron transport chain with ATP synthase, runs on the cristae.

How many ATP does cellular respiration make?

Textbooks often give 38 for one glucose: glycolysis makes 2, the Krebs cycle 2 more and the electron transport chain about 34. That maximum is never quite reached, and current estimates are around 29 to 30.

What is the difference between aerobic and anaerobic respiration?

Aerobic respiration hands its electrons to oxygen at the end of the chain. Anaerobic respiration ends with another acceptor, such as nitrate or sulfate. Fermentation is neither: it uses no outside acceptor and yields 2 ATP for each glucose.

What is the word equation for cellular respiration?

Glucose + oxygen → carbon dioxide + water + energy. The energy is used to make ATP, and the reaction is exothermic. Glucose is the usual example, but cells also respire amino acids and fatty acids.

Does the cellular respiration word search have an answer key?

Yes: the key prints as a second page, Letter or A4, with all 20 words ringed. For a harder review, tick Show clues, not words, and Pyruvate becomes "The three-carbon molecule the first stage ends with; each six-carbon sugar gives two."

All 107 words

Fuel, Oxygen and Energy 25

Fuel, Oxygen and Energy, continued

Glycolysis 19

Citric Acid Cycle 21

Electron Transport Chain 22

Fermentation and Anaerobic Respiration 20

How it works

A sheet for each stage

With oxygen and without

Questions and answers

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