Biochemistry Test Review

A review of some of the harder/ confusing/ or brushed over concepts

QOD:

1. How would there be potential and kinetic energy in bonds of molecules?

2. What property of ATP makes it an energy carrier?

How would there be potential and kinetic energy in bonds of molecules?

Energy = the ability to do workKinetic Energy (energy of motion)

Potential Energy (stored energy)

Potential energy is store in the bonds as they formKinetic energy occurs as the bonds break and can be used to do work

What property of ATP makes it an energy carrier?

The last phosphate bond is considered high energy bond, when hydrolyzed, it releases releases energy.

P

ADP

2 Phosphate groups

Chemistry in Biology

activation energy: the minimum amount of energy needed for a reaction.

Enzymes lower the activation energy

What is activation energy and what does it have to do with enzymes?

Exothermic vs endothermic?

Explain the Bicarbonate Buffer system:

H2O + CO2 H2CO3 HCO3 -+ H+

HCO3- = Bicarbonate (weak base)H2CO3 = Carbonic acid (weak acid)

Major buffer system in bloodMaintains blood pH between 7.38 and 7.42 reservoir of H+

donate H+ when [H+] fallsabsorb H+ when [H+] rises

What elements make up most of life?

• C, H, N, O, P, S make up 98% of living things. • C, H, O and N make up about 96%

Explain how the properties of water are important:

1. High Specific Heat: The temperature of liquid water rises and falls more slowly than that of most other liquids. protects organisms from rapid temperature changes and helps them maintain normal temperatures.

2. Water has a high heat of vaporization: Hydrogen bonds between water molecules require a large amount of heat to break.b. This moderates earth's surface temperature; evaporation of the sweat takes away body heat, thus cooling the animal.

3. Water is universal solvent: facilitates chemical reactions: because it dissolves a great number of solutes. - Solvents dissolve other substances (solutes) and do not lose their own

properties.

4. Liquid water is cohesive & adhesive: causes higher surface tension; Transport H2O against gravity in plants= capillary action

5. Ice floats: water is less dense in it’s solid form, so it floats, allowing for life under the ice

Explain what alkane, alkene, and alkyne carbons chains are.

ALKANE

 consists of only carbon to carbon single bonds

C- C- C -C -CALKENE  

consists of at least one carbon to carbon double bond  

C = C - CALKYNE

consists of at least one carbon to carbon triple bond

They are alphabetical: a, e, y 1, 2, 3

bonds

Careful, those words are so similar!

• Isotopes: – atoms with same protons but different neutrons

ex: Carbon-12 and Carbon-13• Ion:

– charges atom- lost or gained an electron• Isomer:

– same molecular formula, different structure

MATCHINGa.  carbohydrate     b.  lipidsc.  protein               d.  nucleic acids

1. contains adenine and thymine2. cholesterol3. Lactose4. chains of amino acids5. plant cell walls6. long term energy storage7. chains of fatty acids and glycerol 

Saturated or Unsaturated?

a b c

• Which is better to have in your diet?Unsaturated: mostly plant origin, saturated (animal origin) fats are associated with circulatory disease.

1. Bond in which the sharing of electrons between atoms is unequal

2. Charged particles that carries a negative or positive charge are attracted to each other

3. Molecules share electrons equally4. Attraction between slight negative and slightly

positive charges of a molecule

Name the bond!

Polar covalent

IonicCovalent (nonpolar)

hydrogen

Acid or Base?

Dissociate in hydroxide (OH-) ionspH greater than 7Stomach fluidDissociates into H+ hydroxide ions pH less than 7Sodium hydroxidepH of 7

basebase

base

acidacid

acid

Neutral

What are the Properties of Enzymes:

•Enzymes are made of proteins.

•They speed up chemical reactions inside the cytoplasm.

•They are needed only in small amounts

•They remain unchanged after each reaction and can therefore be reused

•Each enzyme is specific for a substrate

1. The only atom that has a nucleus with no neutrons is _________.

A) argonB) carbonC) oxygenD) hydrogen

2. Which of the following elements is NOT one of the six that make up 98% of most organisms' body weight?

A) hydrogenB) nitrogenC) carbonD) iron

More Ch 2 stuff

Which of the following statements is true?A) All isotopes give off subatomic particles.B) All isotopes are radioactive.C) All isotopes have the same number of

protons.D) All isotopes have the same number of

neutrons.

What type of bond is formed when atoms share electrons?

A) ionicB) covalentC) hydrogen

If an atom has an atomic number of 17 and an atomic mass of 35, the number of neutrons in its nucleus equals _____.

A) 17B) 18C) 52

Which bond is most easily broken?A) a hydrogen bondB) a triple covalent bondC) a single covalent bond

Hydrophobic molecules tend to be _________.A) nonpolarB) inorganic mineralsC) ionicD) water soluble

The calcium ion (Ca2+) _____.A) has accepted two protonsB) has given away two electronsC) will form a covalent bond with the chlorine ion (Cl-)D) All of these

The three isotopes of carbon 12C, 13C and 14C have different numbers of _______?

A) electronsB) protonsC) neutrons

The combined number of ___________ will determine the number of electrons in orbital(s) around a neutral atom.

A) orbitalsB) neutronsC) bondsD) protons

Which of the following statements is true?A) There are two polar covalent bonds in

water.B) There are two ionic bonds in water.C) There is one ionic and one covalent bond

in water.D) Electrons are less attracted to oxygen

than hydrogen.

The two parallel strands of DNA are held together by _______ bonds.

A) nonpolarB) hydrogenC) ionicD) covalent

The calcium ion (Ca2+) _____.A) has accepted two protonsB) has given away two electronsC) will form a covalent bond with the

chlorine ion (Cl-)D) All of these

Hydrogen bonds form when ___________.A) atoms share electronsB) a slightly negative atom is attracted to a slightly positive atomC) atoms gain electronsD) atoms lose protons

Which of the following has a basic pH?A) lemon juiceB) milk of magnesiaC) tomatoesD) hydrochloric acid

Aquatic living things are able to survive the winter thanks to which property of water?

A) It is less dense as a solid than as a liquid.B) It is cohesive and adhesive.C) It is the universal solvent.D) It resists changes of state (from liquid

to ice or liquid to steam).