Chapter 3 Biochemistry

Section 1 – Carbon Compounds

Section 2 – Molecules of Life

Objectives

Distinguish between organic and inorganic compounds.

Explain the importance of carbon bonding in biological molecules.

Identify functional groups in biological molecules.

Summarize how large carbon molecules are synthesized and broken down.

Describe how the breaking down of ATP supplies energy to drive chemical reactions.

Carbon Bonding

_______________________________________ are made primarily of carbon atoms.

Most matter in living things is organic

_______________________________________ do not contain carbon atoms.

Water is an example of an inorganic molecule

Carbon has four electrons in its outermost energy level.

o Therefore it can _______________________________________

o Carbon readily binds with other carbon atoms

o Can form _______________________________________

o Can form straight chains, branched chains, or rings.

Carbon Bonds

Functional Groups

A cluster of atoms in many organic compounds is called a

_______________________________________

They influence the characteristics of the molecules they compose and the chemical

reactions the molecules undergo.

_______________________________________ is a functional group that can make a

molecule polar.

o Polar molecules are hydrophilic and therefore soluble in water

Large Carbon Molecules

_______________________________________ are the building blocks of molecules.

_______________________________________ consist of repeated linked units

Large polymers are called macromolecules

Monomers combine to form polymers in a

_______________________________________.

Water is used to break polymers down in a

_______________________________________

Energy Currency

Energy is available to the cells in the form of certain compounds that store a large amount

of energy in their overall structure.

_______________________________________.

o 5 carbon sugar, ribose

o Nitrogen containing compound, adenine

o _______________________________________

ATP

The phosphate groups are attached to each other by covalent bonds.

Relatively unstable bonds

o When the bond between the phosphate groups is broken

_______________________________________.

o This hydrolysis of ATP is used by the cell to provide the energy needed to drive

the chemical reactions that enable an organism to function.

Review Questions

(Complete on a separate sheet a paper. Be sure to include your name and period number.)

1. How do inorganic and organic molecules differ?

2. How do carbon’s bonding properties contribute to the existence of a wide variety of

biological molecules?

3. Name four types of functional groups.

4. What role do functional groups play in the molecules in which they are found?

5. How are monomers, polymers, and macromolecules related to each other?

6. How is a polymer broken down?

7. Why is ATP referred to as the “energy currency” in living things?

3.2 Molecules of Life

Objectives

Distinguish between monosaccharides, disaccharides, and polysaccharides.

Explain the relationship between amino acids and protein structure.

Describe the induced fit model of enzyme action.

Compare the structure and function of each of the different types of lipids.

Compare the nucleic acids – DNA and RNA.

Carbohydrates

_______________________________________ are organic macromolecules that are

made up of carbon, hydrogen, and oxygen atoms. These atoms are combined in a ratio of:

_______________________________________

Some carbohydrates function in storing energy and some provide structural support.

Carbohydrates can exist as monosaccharides, disaccharides, and polysaccharides.

Monosaccharides

_______________________________________are the monomers of carbohydrates.

Also called simple sugars

Glucose, fructose, and galactose are the most common monosaccharides.

o Glucose is the main source _______________________________________.

o Fructose is _______________________________________ (sweetest

monosaccharide)

o Galactose is _______________________________________

Monosaccharides

Glucose, fructose, and galactose have the same molecular formula, C6H12O6, but different

structures.

The difference in structure determines the slightly different properties of the three

compounds.

This is known as _______________________________________-single chemical

formula, but different structural forms

Disaccharides

Two monosaccharides combine in a condensation reaction to form a double sugar, or

_______________________________________.

Fructose and glucose combine to _______________________________________

Polysaccharides

_______________________________________ is a complex molecule composed of

three or more monosaccharides.

_______________________________________ consists of hundreds of glucose

molecules strung together is a highly branched chain.

_______________________________________ is the storage form in animals

_______________________________________ is the storage molecule in plants

o Highly branched chains similar to glycogen

o Long, coiled unbranched chains

_______________________________________is another polysaccharide made by

plants.

o Gives plants strength and rigidity

o 50% of wood is cellulose

o Thousands of glucose monomer linked in long straight chains.

Proteins

_______________________________________ are organic compounds composed

mainly of carbon, hydrogen, oxygen, and nitrogen.

Monomers of proteins are _______________________________________.

Hair, horns, skin, muscles, and enzymes.

Amino Acids

There are 20 different amino acids, and all share a basic structure.

Amino acid contains a central carbon atom covalently bonded to four other atoms or

functional groups.

o A single hydrogen

o A _______________________________________

o An _______________________________________

o A _______________________________________

Amino Acids

The main difference among the different amino acids is in their R group.

The differences among the amino acid R groups gives different proteins very

_______________________________________.

Different shapes allow proteins to carry out many different activities.

Dipeptides and Polypeptides

Two amino acids bond to form a dipeptide through a condensation reaction.

Held together by _______________________________________

Very long chains of amino acids are called

_______________________________________.

Proteins are composed of one or more polypeptides

Some contain hundreds of amino acids

Proteins may be bent and folded in shape

_______________________________________ a proteins changes its shape

o Heat and pH.

o Ex. Cooking eggs

Enzymes

_______________________________________molecules that act as biological catalysts.

Are essential for the functioning of any cell.

Work by the _______________________________________

Enzyme reactions depend on a physical fit between the enzyme molecule and its specific

_______________________________________ (reactant being catalyzed)

Enzymes have fold, or an active site the substrate fits into.

Enzymes can be denatured-which causes them to change shape and they will no longer

function

Lipids

_______________________________________ are large, nonpolar organic molecules.

they do not dissolve in water

Triglycerides, phospholipids, steroids, waxes, and pigments.

Higher ration of carbon and hydrogen atoms to oxygen atoms that carbohydrates do.

Three most important lipids to living things:

o _______________________________________

o _______________________________________

o _______________________________________

Fatty Acids

_______________________________________ are unbranched carbon chains that make

up most lipids

long carbon chains with a _______________________________________, -COOH,

attached at one end.

The two ends have different properties

o The carboxyl end is polar and is thus

_______________________________________ or attracted to water

o The hydrocarbon end is in nonpolar and therefore

_______________________________________ or “water fearing”

Fatty Acids

The fatty acids in _______________________________________s do not contain any

double bonds between the CH2 units

o Saturated fats are found in butter, cheese, chocolate, beef, and coconut oil.

The fatty acids in _______________________________________contain some carbon-

carbon double bonds.

o Unsaturated fats are found in olives and olive oil, peanuts and peanut oil, fish, and

mayonnaise.

Triglycerides

_______________________________________ are composed of three fatty acids joined

to one molecule of alcohol glycerol

o Saturated triglycerides are composed of saturated fatty acids

High melting points

Hard at room temp

Butter and fats in red meat

o Unsaturated triglycerides are composed of unsaturated fatty acids

Soft or liquid at room temp

Plant seeds – serve as energy and carbon source for germinating seeds.

Phospholipids

_______________________________________ have two fatty acid tails attached to a

molecule of glycerol-phosphate group attached to the third carbon of the glycerol.

Make up the phospholipid bilayer of the cell membrane.

Waxes

_______________________________________ is a type of structural lipid consisting of

a long fatty-acid chain joined to a long alcohol chain.

Waxes are waterproof

o provide a protective coating on the outer surface of plants.

o Form protective layer in animals

Ear wax-stops microorganism from entering the ear canal.

Steroids

Steroids are composed of four fused carbon rings with various functional groups attached

to them.

o _______________________________________

Nucleic Acids

Nucleic acids are formed from _______________________________________

monomers.

Nucleotides are chemical compounds that are primarily comprised of the elements

carbon, hydrogen, oxygen, nitrogen, and phosphorus.

They consist of a five-carbon sugar, a nitrogenous base, and one or more phosphate

groups.

There are two main types of nucleic acids - ribonucleic acids (RNA) and

deoxyribonucleic acids (DNA).

These nucleic acids are different because their five-carbon sugars are different. RNA

contains ribose, and DNA contains deoxyribose

Nucleic Acids

DNA and RNA also have different functions.

DNA stores genetic information and encodes the sequences of all the cell's proteins.

RNA is involved in the direct production of the proteins.

Nucleic acids are also different because the sequence of nitrogenous bases that they

contain are different.

There are five nitrogenous bases found in nucleic acids. Adenine (A), cytosine (C), and

guanine (G) are found in both DNA and RNA. Thymine (T) is only found in DNA, and

uracil (U) is only found in RNA.

RNA vs. DNA

Review Questions

(Complete on a separate sheet a paper. Be sure to include your name and period number.)

1. Compare the structure of monosaccharides, disaccharides, and polysaccharides.

2. How are proteins constructed from amino acids?

3. How do amino acids differ from one another?

4. Describe a model of enzyme action.

5. Why do phospholipids orient in a bilayer when in a watery environment, such as a cell?

6. Describe how the three major types of lipids differ in structure from one another.

7. What are the functions of the two types of nucleic acids.