Chapter 2 - Basic Chemistry

THESE NOTES FOLLOWS A SERIES OF ONLINE VIDEOS. If you feel rusty with chemistry, or just insecure, you might want to spend the time to go through those videos, which will allow you to move more

slowly.

I. CONCEPTS OF MATTER AND ENERGY

- universe has 3 things that exist: • matter - has mass (weight) and volume

can be solid, liquid or gas. See later section "States of Matter"

• force (attractions/repulsions) . 3 Types (for us): Gravity Electromagnetism Friction

• energy (ability to do work). Four types of energy. See later section "Types of Energy"

- energy and forces are invisible. Aren’t they all the same thing? Isn’t energy a kind of matter? No…but they are all related, which is why you think of them “together”:

Force gives matter energy. Let's see how: A. Energy and Force: 1. Relationship between the 2: - energy = ability to do work, because of force (attractions/repulsions) * electromagnetic, gravity & friction = the 3 important forces for us.

*the attractions/repulsions CAUSE ability to do work. EXAMPLE: Electromagnetic force: opposite charges attract like forces repel As they move, work can be done. A lot of work will be done using this force

EXAMPLE: Gravity is the attraction between mass

EXAMPLE: Friction is the attraction between molecules

this is work! 2. Forms of Energy

* energy can be kinetic (in-action or moving) or potential (stored).

3. Types of Energy (i) Mechanical Energy : mass (matter) moving - man pedaling bike, water falling over cliff (waterfall), windmill (ii) Electrical Energy : movement of charged particles (see later)

(iii) Radiant Energy : electromagnetic waves. These waves form a spectrum.

X-rays, light, infrared (heat), radio, UV are waves of different length. Heat = special case. “Energy lost to the environment"

(iv) Chemical Energy : bonds = connections between matter (see later)

- like a handshake is a bond. 2 things "connected". - RECALL: Energy is always something moving * In Chemical Energy, chemical bonds are moving. See later * Chemical bonds = little “packets” of energy. -RECALL: all types can be potential or kinetic * food, dynamite, etc. are potential chemical energy * battery contains potential electrical energy

4. Energy from Conversions : - First Law Of Thermodynamics – energy can’t be created or destroyed, but it can be converted - However, easily goes from 1 form to another. * Machine: something that converts energy But...inefficient...some always lost as heat.

A light bulb is a machine that converts electrical energy into light energy.

So…you eventually run out of energy, As it all becomes heat. Main problem = friction

Your body's cells are machines that turn chemical energy (glucose and O2) into mechanical (movement), electrical (nervous system), and other chemical energy (growth, repair, hormones, etc.)

B. Matter : anything with mass that occupies space. - Matter has energy, because of internal forces.

- Made of atoms.

OVERVIEW:

Atoms form bonds when they collide, because they have energy (internal kinetic energy). Then, these bonds can reform when they collide again. These are "chemical reactions". Chemistry = study of how matter interacts when it collides ("how it behaves").

1. COMPOSITION OF MATTER (i) Nucleus with subatomic particles: protons (+) & neutrons (no charge) (ii) Orbitals with electrons (-).

Electrons move around the nucleus, at the speed of light. They are small, have (for all intents and purposes) no mass. What makes them move? Electromagnetic force!

They are smaller, so they move, not the protons. But…why don’t the electrons simply move to the nucleus, and attach to it??? They repel each other!

So they end up in these circulating electron clouds!

Main point: Electrons move, give the atom internal kinetic energy. Therefore, atoms move!

It is these electrons that will bond later.

2. Elements and Atoms. Atoms are fundamental, indivisible units of matter. Nothing is smaller. And yet, they are made of still smaller units. How can this be?

The parts they are made out of can't exist by themselves. They must exist together.

So atoms can differ from each other in the number of protons, electrons and neutron.

(i) element = different # protons.

(ii) Isotopes = different # neutrons. (iii) Ions = different # electrons.

Anions vs. cations Don't atoms need the same # electrons and protons, since the +s are attracted to the –’s?

Normally, #p = # e so they are electronegatively neutral, and there is a strong tendency towards that. However, there is another tendency, which is sometime stronger: THE NEED TO NOT BE “Wobbly”

If outer valence shell is not filled, the electrons are not evenly spaced. So when they “whiz” around, they give the atom an imbalance.

These atoms tend to exchange electrons until their outer valence shell is “full”…that is, they have 8 (in most of the shells) and therefore the electrons are evenly spaced.

3. Identifying Elements - The Periodic Table up close Periodic table and atomic symbols. See table of elements important to human body. (i) Atomic Number : # of protons. H = 1, He = 2, etc. (ii) Atomic Mass Number : sum of protons + neutrons (electrons have basically no mass) - H = 1, He = 4, etc (iii) Atomic Weight and Isotopes : isotopes = different # neutrons. Weight = average of all the isotopes.

- H has isotope with 1,2 & 3. It's AW = 1.0079

II. CHEMICAL BONDS

A. Bond Formation

1. Role of Electrons - electrons move around nucleus in electron shells, which are energy levels (valence shells). - Therefore, atoms move. They collide, and electrons re-configure to make them more stable. Different kinds of bond depending on how they re-configure.

B. Types of Chemical Bonds

1. Ionic Bonds : atoms/molecules collide, one completely loses an e-, one completely gains e-. They take on charges, forming ions. RECALL: - Some molecules do this readily, such as H2CO3- In Review: (see images on previous page of notes) Ionic Bonds : atoms/molecules collide, one completely loses an e-, one completely gains e-. THIS IS BECAUSE ONE IS MUCH LARGER THAN THE OTHER - They take on charges, forming ions. A CATION AND AN ANION. THE BOND IS THE ATTRACTION BETWEEN THE 2.

* Weak bonds, not a lot of potential energy in the bond, dissolve easily in water, because water is charged, so the anion and cation are pulled apart! * Solutions of water conduct electricity.

- in body, used to:

* transport things (things stick to them)

EXAMPLE: Oxygen is carried by Fe++ (iron) *conduct electricity. Electrolytic solutions

- Not used for: * Structure (dissolves in water) * Storing energy (not enough in bonds)

- synonyms: Salts, electrolytes or ionic compounds.

- Some elements do this readily. Common ones in your body: H+, Na+, Cl-, K+, Mg++ Know the common ones described in your author’s book!

2. Covalent Bonds :

- atoms/molecules collide. One is not powerful enough to completely remove the electron(s) from the other. - They "share" an electron. No ions formed.

- One is not powerful enough to completely remove the electron(s) from the other because they are equal or similar sized. - Some elements do this readily

O, C, H, N, P

- We’re going to see a lot of molecules with these elements bonded together:

All carbohydrates, all lipids, all proteins, all nucleic acids … and there are a lot of these in your body!

- This bond will ALWAYS form if it is a reaction (collision) between 2 atoms of the same element

EXAMPLE: O (element) + O (element) -------> O2 (elemental molecule)

Others we’ll see in A&P: H2, N2

- Charcteristics of Covalent bonds: * Strong bonds, lots of potential energy ("explode" if broke). * Do not dissolve easily in water. - uses in body: store energy and building structures.

- Types of covalent bonds:

(i) They can be non-polar, if they are the same sized atoms. No partial charge. Neutral.

(ii) or, can be polar with a partial charge

- Also, they can be single or double:

(i) single: only 1 e- shared.

(ii) double: 2 e-’s shared. Hold more potential energy, and are stronger

There are triple covalent bonds, but we aren't going to see many.

3. Hydrogen Bonds : the only "intra-molecular" bond we will discuss.

- occur between polar molecules with hydrogen take on a strong attraction to each other because of their shape.

- Water is important example. Water molecules form H-bonds between each other...this gives water many of it's special properties for life (see later).

C. Compounds & Mixtures - most things are not pure (only 1 atom), but are mixtures. - mixtures can happen at the molecular level (involve bonds) or at the physical level (do not involve bonds between molecules)

1. Physical Mixtures - Can be solid, liquid or gas. We are only going to concern ourselves with mixtures of a solid in a liquid:

* Solution: liquid mixture * Solvent: liquid medium of solution. What we use to dissolve the other "stuff", which may be another liquid (example: water and oil), solid (example: water and table salt), or gas (example: water and CO2). For us, the solvent will always be water!! * Solute: the stuff we dissolve into the liquid.

2. Chemical Mixtures (involve chemical bonds): MOLECULES vs. COMPOUNDS

- Compound = more than 1 element involved.

- Recall that a molecule = atoms collide, form bonds. We use FORMULAS as a shorthand: reactant + reactant -------> product

O (element) + O (element) -------> O2 (elemental molecule) C (element) + 4 H (element) --------> CH4 (molecule, compound) C (element) + O2 (molecule)-----------> CO2 (molecule, compound) 3. Measuring relative amounts in a mixture (physical or chemical) - Concentration ([ ]): the relative amounts of the components of a solution. "Percent" is a type of concentration, but it doesn’t lways work well, as it doesn’t take into account the relative mass (only the relative number)

This crowd is 2% “elephants” by number, but 50% “elephant” by weight!

Therefore, we use a different measurement: Molarity (M) – measure of relative mass, based on atomic weight. I will not make you figure it out. But do not think it is %. For example, a saline solution (water and sodium) in the hospital may be labeled "15M". This IS NOT 15 %!!!!

The [ ] always denote concentration. The relative size of the brackets represents relative amounts of the substances involved.

[A] = concentration of A

[A] > [B] means there is more of A than B

D. Changes in Matter

1. Physical Level - do not alter basic nature (ice melting, cutting up food) - no chemical bonds broken/switched

2. 2. Chemical Level - alter the composition (see next section). Digestion of food. Chemical bonds broken/switched

1. Physical States : Same chemically, no bonds broken/switched. But the states differ in amount of internal kinetic energy.

1. Solids 2. Liquids 3. Gases.

Example: water (H20) - increase IKE, changes physical states. Can use heat (or other energy) to increase IKE (light, pressure, etc. will evaporate water, too!)

2. Changes in Chemical States: Patterns of Chemical Reactions

They collide, sometimes they unite, sometimes they split apart, sometimes they rearrange. a. Categorized based on what happens to the bonds……..

(i) Synthesis Reactions : 2 or more atoms/molecules combine when collide.

- Bonds are formed. - Increase energy: energy absorbing. - Anabolic reactions.

(ii) Decomposition Reactions : Molecule is broken down. Bonds are broken, which releases energy. Catabolic reactions. In body. often involve water (= hydrolysis)

(iii) Exchange Reactions : bonds are made & broken. Switching bonds.

b. Categorized based on what happens to the ENERGY

(i) Endothermic Reactions: Some reactions take in energy (need energy to get them to happen. Body uses the energy in ATP molecule...see later).

These are all SYNTHETIC Polymer = a long chain molecule. Repeating units. a polymer They take energy to make. Think of boxcars in a train.

(ii) Exothermic Reactions: Some release energy (these will happen by themselves, although the body will often control when and where they happen, in order to get the body's work done)

These are all DECOMPOSITION

(See next section on catalysts)

(iii) Catalyzed reactions. (Not here in book) - any reaction that releases energy (exothermic) will happen by itself eventually. * However, the cell may not be able to “wait around” * A catalyst speeds up reactions.

Let’s put this all together. Cellular Metabolism. To get work done, cell does this reaction:

ATP ------> ADP + P (plus a release of energy, which can be used to do work) ATP: the energy source for (vast majority) of the cell’s metabolism EXAMPLE: Storing and using glucose (see first image below) 1. Glucose enters cell ----> stored as glycogen via dehydration synthesis

This uses ATP ATP ------> ADP + P * ATP contributes energy used to make glycogen, which is energy storage. VERY WASTEFUL! * but now have a molecule with more potential energy (bonds)

2. Now, the cell wants to use glucose:

Glycogen ------> individual glucose through hydrolysis If the cell needs to use glucose, Individual glucose molecules are released because glucose will now be used in AEROBIC cellular respiration: O2 + glucose ------> ATP and CO2 and water (H2O) Now...we have made ATP again! But we used ATP making it! We lost energy SEVERAL TIMES in the process. Inefficient as heck! Notice "energy arrows" leaving are smaller than the "energy arrows" going in! Why do it? So we can have energy when and where we need it! Catalysts make sure all these reactions happen when and where we need them to! (see second image below)

Handout found on website

c. Speed of reactions (not here in book)

- anything that increases movement of molecules increases the speed at which they collide...therefore they speed up chemical reactions.

* temperature

* pressure

* concentration: the relative amount of substance (see later)

* catalysts (enzymes)

d. Chemical equilibrium (not here in book) - If chemical reactions = collisions, then when the reaction is over are the collisions over?

* During the reaction, [reactants] decreases, [products] increases

* occasionally, the products break up, but more are “moving to the right” than are “moving to the left”

At CHEMICAL EQUILIBRIUM, just as many move to the right as to the left. There are still collisions, but they equal out and the

[ ] of products and reactants doesn’t change. The reaction is “over”.

We call this a DYNAMIC EQUILIBRIUM because collisions keep happening!

II. BIOCHEMISTRY: THE CHEMICAL COMPOSITION OF LIVING MATTER

- these do not contain carbon and hydrogen together. A. Inorganic Compounds

1. Water (H2O or HOH): - most abundant molecule, 2/3 of body weight. NOTE: life is mostly INORGANIC! - 2 H’s covalently bonded to a central O - Recall this about covalent bonds:

* Strong bonds, lots of potential energy ("explode" if broke). * They can be non-polar or they can be polar with a partial charge

- End up with a very stable molecule that is partially charged at its ends

So what??? Let’s see…..

- Due to its shape, charge, and the H-bonds between molecules, water has several characteristics that make it perfect for life’s metabolic (i.e., chemical) needs:

- the polarity of the HOH molecule sets up H-bonds between individual water molecules, making them very stable (they don’t move readily)

- also, the partial polarity at the ends of the molecule affects other surrounding molecules.

a. water is the "universal solvent" -terms

* solution: liquid mixture * solvent: liquid medium of solution. What we use to dissolve the other "stuff", which may be another liquid (example: water and oil), solid (example: water and table salt), or gas (example: water and CO2). For us, the solvent will always be water!! * Solute: the stuff we dissolve into the liquid.

-Water is the “universal solvent” .... salts, acids, bases dissolve easily.

* polarity of molecule "pulls" ionic bonds apart!

- NOTE: this is so pronounced, we have special terms for a substance’s solubility in water.

Hydrophilic : Anything that is charged (ionic bonds and polar covalent bonds) is soluble in water.

Hydrophobic: Anything non-charged (non-polar covalent bonds) is insoluble in water.

Soaps, oils, fats, grease = Non-polar covalent bonds! however, they are soluble in each other!!

- water is good for transport (ex: blood plasma)

b. High Heat Capacity : Polarity of molecule and H-bonds makes water absorb a lot of heat. * Example: if you heat water, it is good for cooking, because the water "holds the heat". * We us water for cooling things down (radiator of car, etc.). Body will use water in the same way. c. Chemical Reactivity : chemical reactions happen well in water (NaCl will break down...but you put it in water to speed it up!). Water will even break covalent bonds, speeding up their reactions! d. Cushioning : polar bonds & H-Bonds means water also absorbs a lot of mechanical energy! A "water pad" makes a great cushion! * Your body uses the hardness of water to protect your internal organs e. Capillary action. Water’s adhesion (they stick to other molecules) and cohesion (they stick to each other) allows it to go against gravity in a narrow tube (capillary).

2. Salts : ionize in water. - Solutions are good for conducting electricity (electrolytic solutions).

- Salts are good for transporting other substances (iron will be used in Hemoglobin molecule to transport O2 gas), etc.

3. Acids and Bases : a. Acids = H+ donor in water - Special case of salts.

a salt/electrolyte that releases H+ in water (a salt with H+ as the cation) * They are only "acids" or "bases in water! *increases [H+]!

- Why special? Those Extra H+’s are VERY reactive! Break other bonds. - Example: Hydrochloric acid (strong acid ... completely breaks down): HCl ----- (water) ----> H+ + Cl- - Example: carbonic acid (weak acid ... doesn't completely break down): H2CO3 ----- (water) -----> H+ + HCO3- + H2CO3

- Characteristics of Acids :

* Breaks other bonds. Breaks things down. * taste "sour“ * conducts electricity

b. Bases (Alkalines) "Hydrogen acceptors" or "Proton acceptors". -When in water, “sucks up” (i.e., attaches to) the H+’s

- Also a salt. Also must be in water. - any compound that binds to H+, thereby removing them from the solution. - common base: anything that contains Hydroxide ion (OH-)

OH- + H+ à H2O - example: sodium hydroxide (lye)

NaOH ---- (water) ----> Na+ + OH- ---- (if H+ are present) -----> Na+ + H2O

- Characteristics of Bases * Also a salt. Also must be in water. * bitter taste, "slippery" feel. * also electrolytic solutions. There are alkaline batteries. * also very destructive. Bleach is a base!

HCl + NaOH (water)-----> H + + Cl- + OH- + Na ------> H2O + NaCl

- Some bases are dangerous, some are good for you. Some acids are dangerous, some are good for you. What is the difference?? [H+] or [OH-] after the salt has dissolved

strong acid = high [H+] weak acid = low [H+] (not many dissolve) strong base = high [OH-] weak base = low [OH-] (not many dissolve)

c. pH: Measuring Acid-Base Concentrations

- Scale measuring the [H+] and [OH-] in water - strong versus weak acid or base - pH stands for “potential of Hydrogen” - neutrality = 7.0

* A glass of pure water always has H+& OH- in it…so neutral is not “none”. There is no such thing as “no H+” * lower number = acidic (6, 5, 4, etc…). Something very acidic, like lemon juice, has a low pH on this scale. * higher number = basic (7.5, 8, 9, etc…). Something very basic, like bleach, has a very high pH on this scale.

pH blood must stay between 7.35 – 7.45.

However, you are always putting things into your body that change the pH. For example…look at the pH of coffee, tomato juice, and egg white. You put these into your body all the time. How does your pH not change enough to kill you? In other words, how do you maintain homeostasis of blood pH? .....see next section d. Buffers – anything that protects against a change in pH *often = a weak acid-base pair, which: -acts like an acid if a base is added (neutralizing it), or -a base if an acid is applied (neutralizing it).

EXAMPLE: carbonic acid & bicarbonate

B. Organic Compounds

1. Common Characteristics, & Overview of Function - Organic: anything with C & H

* Carbon forms four evenly-spaced covalent bond. Perfect for building things.

Also…..good amount of potential energy in these bonds. Not too much, not too little.

- CHNOPS: These elements form all the important organic molecules for life * in our body, they also contain NOPS.

- They combine to form the "building block" molecules. The building blocks then join to form the organic macromolecules ("Big molecules")

*RECALL: Any molecule that is a linkage of several repeating smaller molecules is called a POLYMER. *So…we make macromolecules out of BUILDING BLOCK MOLECULES by making POLYMERS using DEHYDRATION SYNTHESIS

* This makes them less soluble in water!

* And, they have a 3-D shape that can be used in a function!

* And they make great energy storage molecules!

* We can split up the polymer using hydrolysis! * We do this if we want the smaller molecules again. For example, to transport them, or to build another macromolecule.

- Overview of Roles in body of the organic macromolecules: (i) Carbohydrates: short-term energy storage (ii) Lipids (fats): long term energy storage, insulation, cell membranes (plasma membranes) (iii) Proteins: the only molecules that can "do" a job in the body. In a sense, your body's cells are machines that make proteins; the proteins then do your "physiology" (metabolism) -cellular machinery: do all the physiological "jobs" -structure (iv) Nucleic acids: Genetic material. Store instructions on how to make the proteins. (v) ATP: direct-use energy of the body's cells (the power to run the proteins).

Now, we’ll do them individually. For each know:

1. Name 2. Function in the body 3. What its building block molecules are called

2. Carbohydrates : sugar & starches. Have C, H & O, in combination of CH2O ("carbonated water"). -Energy Storage - Building blocks are the "monosaccharides". a. Building blocks are the "monosaccharides“ = Simple sugars.

- Ring-shaped molecules. - They are all in ratio 1C : 2H : 1O

* Difference between them = the number of carbons. if 5 C’s, 10 H’s, 5 O’s if 6 C’s, 12 H’s, 6 O’s etc….

- Names end in “-ose” (glucose, fructose, ribose, etc…)

Some important examples:

Glucose = main energy sugar

Ribose & deoxyribose are used to make the genetic material (later). Fructose = fruit sugar. Galactose = milk sugar.

b. Disaccharides "two sugars" - first step to making a bigger molecule! - Attach 2 monosaccharides: Monosaccharide + monosaccharide ---- (dehydration synthesis) ------> disaccharide - too big to be absorbed by the body. To use, must be broken down:

disaccharide ---------(hydrolysis)-----> monosaccharide -2 to know: * Sucrose: Table sugar, white refined sugar, sugar beets and sugar cane plants * Lactose: milk sugar

SIDE NOTE: Remember that we often use ENZYMES to catalyze these reactions? The catalyst for the breakdown of lactose into its component monosaccharides is lactase. Some people can’t make it…they are lactose intolerant. They get diarrhea when they drink milk because it can’t be broken down. Instead it stays in their gut.

c. Polysaccharides - COMPLEX CARBOHYRATES . Attach disaccharides into a long chain. Long, branching storage forms. - starch = plant storage. - glycogen = animal storage. Stored in liver. Animals can't store carbohydrates very long-term....we use lipids (see later).

These molecules are cycled. You eat a polysaccharide: Break it down using hydrolysis into the monosaccharides

Then, you build COMPLEX CARBOHYRATES using dehydration synthesis:

monosaccharide + monosaccharide ---- (dehydration synthesis) ----> polysaccharide

3. Lipids (fats & oils). Long-term energy storage. a. building blocks: - 2 Building block molecules: glycerol and fatty acids.

- Lots of Non-polar bonds = insoluble in water.

*Covalent bonds hold a lot of energy. For the most part, must be converted into glucose to be used by body's cells.

b. Classifying fats based on their covalent bonds. You can classify fats based on the presences of certain types of covalent bonds in the fatty acid chain!

(i) Saturated fats: no double covalent bonds. Hard at room temperature. Animal fats have a lot. (ii) Unsaturated fats: contain double covalent bonds. Might have one, might have more! Liquid at room temperature. Plants have a lot. (a) Monounsaturated -1 double covalent bond. (b) Polyunsaturated - more than one. 2 or 3.

c. Classifying fats based on the amount of fatty acid.

(i) Neutral Fats (triglycerides) Storage in animals. Can be used by cells to make ATP (provide energy needs) Handout online covering the similarities between carbos and neutral fats, and their interconversion (ii) Phospholipids - 2 fatty acid chains attaced, as above. However, now a phosphate attaches to the 3rd site.

- Not used for energy. Used to make the membrane surrounding our cells (plasma membrane)

(iii) Steroids (includes cholesterol & sex hormones)

4. Proteins a. building blocks: Amino Acids. 22 types.

b. The macromolecule: polypeptides

- Through dehydration synthesis, forms a polymer.

- Forms a macromolecule called Polypeptides or PROTEINS. Because of the interactions between the AA's,the polypeptide takes on a 3-D shape!

- What this protein does in your body depends on it’s SHAPE.

* Example: enzymes:

c. Types of proteins: Fibrous and Globular Proteins - For the most part, fibrous proteins build things, globular proteins perform physiological functions.

fibrous globular

- What determines their shape in the first place? You’re genetic information:

(see later) d. Denaturization: loss of shape, and therefore function heat & pH

Shape depends on hydrogen bonds between amino acids. Heat, acids and bases interfere with these bonds, changing their shape.

e. One special case: Enzymes and Enzyme Activity Enzymes = biologic catalysts. Names end in -ase Catalyst is a chemistry term, meaning any substance that causes a chemical reaction to happen faster. Enzymes do this by attaching to a binding site.

Denaturization through heat or pH destroys enzyme function 5. Nucleic Acids - macromolecule. - Carries the GENETIC INFORMATION, which is the instructions on how to place the amino acids in the correct order, so you get good functioning proteins. - RECALL:

- A GENE is a piece of genetic info that codes (gives the information for) 1 polypeptide!! a. Building block: nucleotide bases - Do not worry about molecular shape. Use this shorthand:

*There are 5 of them. *We use the first letter in their name to talk about them. - Their sequence in the macromolecule (see below) = the GENETIC INFO b. The Macromolecule: Nucleic Acids (DNA & RNA) - The nucleotide bases polymerize into a chain. Within that chain, they have a sequence (order)

- The sequences of the bases determines the sequence of the Amino Acids in the polypeptide. * Genes are sequences of these bases found along the length of the DNA molecule * There will be a something in the cell that “reads” the sequence of bases on the DNA, and use that “info” to put the amino acids in the correct order to give it the correct shape to do it’s job! - Of course, a change in the genetic info can led to a misshapen protein. A change in the genetic sequence is called a MUTATION!

6. Adenosine Triphosphate (ATP)

Building blocks = a ribose (adenine) and phosphates. Through hydrolysis, releases the energy needed for cellular metabolism