Macromolecules

Lesson 4: The Building
Blocks of Life

Essential Question: How can long
term under- or overconsumption of
carbohydrates, proteins, and lipids
affect your health?

Figure 30

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1

Lesson 4 Summary

Students will explore the role of carbon in living organisms and the four
major biological macromolecules. They will learn about the components
and structure of each group of macromolecules and relate the functions of the macromolecules in the body to the structure and function of a cell. This will lead them to understand how having these macromolecules in one’s diet may affect one’s health.

Lesson 4 TEKS

TEKS 5.A Relate the functions of different types of biomolecules, including
carbohydrates, lipids, proteins, and nucleic acids, to the structure and
function of a cell.

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Lesson 4 Vocabulary

• macromolecule
• polymer
• carbohydrate
• protein
• amino acid
• lipid
• nucleic acid
• nucleotide

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Macromolecules

• Life on Earth is considered carbon-based because carbon is an essential element that is part of almost all biological molecules.
• Carbon atoms join with other atoms to form small organic molecules, called monomers.

• Monomers (mono=one) are stored in most cells and serve as building blocks to make large molecules called macromolecules.

• Polymers (poly=many) are made of repeating units of identical or nearly identical monomers that are linked together by a series of covalent bonds.

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Macromolecules

• Water plays an essential role in the chemical reactions that join and break monomers.

• In dehydration synthesis, adding energy to smaller molecules forms bonds which create a larger molecule and remove a water molecule.

• In hydrolysis (meaning “breaking with water”), adding a water molecule to the polymer releases energy when the bonds within larger molecules break to form smaller molecules.

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Carbohydrates

• Carbohydrates are organic molecules composed of carbon, hydrogen, and oxygen in a ratio of one oxygen and two hydrogen atoms for each carbon atom.

• A general formula for carbohydrates is written as (CH₂O)_n.

• The subscript _n indicates the number of CH₂O units in a chain.

• Carbohydrates with values of n ranging from three to seven are called simple sugars, or monosaccharides

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Carbohydrates

• Simple carbohydrates
• The monosaccharide glucose, in Figure 34, plays a central role as an energy source for organisms.
• Two (di=two) monosaccharides can be linked to form a larger disaccharide.
IF IT ENDS IN -OSE IT IS A SUGAR WHICH IS A CARB!!!

Figure 34

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Carbohydrates Uses

• When the body needs energy between meals or during physical activity, glycogen is broken down into glucose.
• Cellulose, a common complex carbohydrate if found in plant cell walls, it provides structural support.
• Cellulose also make the exoskeleton of bugs. Think of the hard outer shell found on Junebugs and locusts.

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10

Multiple Choice

Carbohydrates give you what kind of energy?

• Long term

• Short term

• No energy

• Long and short term

Proteins

• Proteins make up about 15% of your body mass and are involved in nearly every function.

• Your cells contain about 10,000 different proteins.

• Proteins provide structural support, movement, and transport of substances.

• They also increase speed of chemical reactions (ENZYMES) and control cell growth and maintenance.

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Proteins

• Monomer = amino acids
• Polymer = polypeptide
• Your body can synthesize all but nine of the amino acids that make up proteins.


ONLY 20 KNOWN AMINO ACIDS!!

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14

Protein Structures

• Proteins can take on 4 shapes.
THEIR SHAPE DETERMINES THEIR FUNCTION!
IF THEY GET DENATURED (UNFOLD) THEY LOSE THEIR FUNCTION
• Conditions that denature, or modify protein shape, include added heat, excessive salt, and large changes in pH.

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22

Hotspot

Which protein is in the tertiary structure?

Hotspot

Which protein is in the secondary structure?

Hotspot

Which protein is in the quaternary structure?

Lipids

• Lipids are hydrophobic (hate water)
Think of oil and water and how they separate!


Monomer- glycerol backbone and fatty acid tails

• The main groups of lipids are triglycerides (polymer), phospholipids (cell membrane), steroids, and waxes.

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Lipids

• Lipids are made of Carbon, Hydrogen and Oxygen. They are found in fat, oil, and wax.


• Some are single bonded, saturated and solid at room temperature (Crisco)

• Some are double bonded, unsaturated and liquid at room temperature (vegetable oil)

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22

Multiple Choice

What is the monomer of a lipid?

• glycerol and fatty acid

• triglyceride

• amino acid

• glucose

Phospholipids

• A phospholipid is a specialized lipid that is responsible for the structure and function of the cell membrane.

• In a cell, lipids function to create a stable barrier between two watery environments and regulate what substances move in and out of cells.

The head likes water the tails do not!

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22

Match

Match the following.....

• Hydrophobic Tails

• Hydrophilic heads

• Phospholipids

Don't like water

Like water

Double layer that makes cell membrane

• Don't like water

• Like water

• Double layer that makes cell membrane

Steroids

•A steroid is a lipid made from four interconnected carbon rings.
• Steroids include substances such as cholesterol, hormones, and vitamin D.
• Your liver naturally makes cholesterol, and you can also get cholesterol from the foods you eat.
• Cholesterol in cell membranes restricts molecules from passing through the membrane.

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22

Waxes

• Fatty acids combine with hydrocarbons to form wax.
• Waxes are stiff, water-repellent, protective substances.
• Wax is naturally found in feathers, honeycombs, leaves, and inner ears.
• Wax is not an edible lipid.
• Wax is used to package foods and to seal food containers.

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22

Nucleic Acids
Nucleic acids are complex macromolecules that store and transmit genetic information.
• Nucleic acids are made of smaller repeating monomers, called nucleotides.
• Nucleotides are made of three units—a phosphate group, a nitrogenous base, and a sugar.
• In nucleic acids, the sugar of one nucleotide bonds to the phosphate of another.
• The nitrogenous base that sticks out from the nucleic acid chain is available for hydrogen bonding with bases in other nucleic acids.

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Nucleic Acids
• The two types of nucleic acids found in living organisms are deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).

• DNA, which is made of a double helix, stores genetic information that tells cells which amino acids to join to form the proteins that are involved in nearly every cell function.

RNA is single stranded.
• Messenger RNA (mRNA) converts the information in DNA into protein.

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22

Match

Match the following.

• DNA

• RNA

• Protein

Double stranded

Single stranded

Polypeptide chain

• Double stranded

• Single stranded

• Polypeptide chain

Multiple Choice

How many Macromolecules are there?

• 2

• 4

• 1

• 5

Multiple Choice

What biomolecule makes up our genetic information?

• DNA

• RNA

• mRNA

• tRNA