Carbohydrates

• Carbohydrates are sugars and are the key to metabolism.

• Identify sugars by their ending in –ose.• Metabolism is the break down of food

into sugar for energy.• Basics sugars are called

monosaccharides and are made of a single monomer of carbon, hydrogen and oxygen in a 1:2:1 ratio.

• Linked sugars are polysaccharides and are found in starches and cellulose.

Carbohydrates (and beyond …)

• Glucose is the preferred energy source for the brain. Brain function drops off sharply if glucose is in short supply.

• PET scans can detect areas of glucose usage and can show brain damage following trauma or drug use.

• The breakdown of glucose for energy can be traced all the way through glycolysis, Kreb’s cycle and electron transport chain.

Lipids

• Lipids include fats, waxes, and steroids.

• Lipids are non-polar and do not dissolve in water.

• Lipids store energy and are the basis for steroid hormone synthesis.

• Phosphoplipids make up all cell membranes.

Lipids (and beyond …)

• Phospholipids make up all cell membranes and play a large role in determining what gets in and out of the cell.

• Hydrophilic and hydrophobic regions give phosopholipids their unique properties.

Proteins

• Proteins are the cell’s molecular machinery.

• Most catalysts are made of protein.• Proteins are linked chains of amino

acids.• Proteins are synthesized by the

ribosome from a code made of RNA.

Proteins (and beyond …)

• Proteins gain their function from the way they fold.

• Proteins act as catalysts by lowering activation energy.

• Hemoglobin transports oxygen to all tissues and is made of 4 dimers.

• Many proteins use minerals such as calcium or iron to aid in their function.

Nucleic Acids

• Nucleic Acids are polymers consisting of many nucleotides monomers that serve as a blueprint for proteins.

• There are two types of nucleic acids: Deoxyribonucleic acid (DNA) and Ribonucleic Acids (RNA).

• DNA gains its function from its structure, the double helix.

Nucleic Acids

• The helical backbone is made up of sugar and phosphates.

• Each pair is made of one of the four nitrogenous bases: adenine, guanine, cytosine and thymine.

• In order to maintain the integrity of the genome, each base can only pair with one other base through hydrogen bonding.

Organic Nomenclature and

StructureExamples of functional groups:

Type Generic Example

Alcohol 2-propanol

Carboxylic Acid

Acetic Acid(ethanoic Acid)

Alkyl Halide 1-chlorobutane

Ketone 2-propanone

Aldehyde 1-ethanal

R OHOH

OHR

O

OH

O

ClR Cl

R'R

O O

HR

O

H

O

Organic Nomenclature and

Structure• When double or triple bonds are

added the suffix changes.Bond Order

Suffix

Example

Single -ane Pentane

Double -ene 1-pentene

Triple -yne 2-pentyne

Organic Nomenclature and

Structure• Aromatic compounds are

derivatives of benzene (shown below).

• These compounds are named for their strong aroma (benzene is put gasoline so you can smell it).

Enzymes

• Enzymes are proteins that catalyze biochemical reactions by lowering the activation energy of reactions that would normally happen anyway.

• Identify enzymes by the suffix –ase: helicase (splits DNA), lactase (breaks down lactose), polymerase (inhibits HIV).

Enzymes

• This reaction normally happens (black), but is catalyzed by the enzyme (red). Free energy change (ΔG) is constant, but lowers activation energy (EA).

Enzymes

• Enzymes bind substrates (enzyme reactant) into active sites (pocket or groove on enzyme).

• While the enzyme and the substrate are joined, the enzyme catalyzes the reaction and converts the substrate to the product(s).

Enzymes

• The most classic example an enzymatic reaction is the hydrolysis of sucrose (table sugar) into glucose and fructose.

Enzymes

• Another look…

Effects on Enzyme Activity

• Rate of Enzyme Activity is influenced by:– Substrate concentration (more substrate = more

activity until saturation)– Temperature (higher temperature = more activity

until the enzyme’s protein denatures)

Effects on Enzyme Activity

• Rate of Enzyme Activity is influenced by:– pH (usually in range of 6-8 for humans)

– Inhibitors (reduce activity by binding or changing shape of active sites)

Alkaline IntestineAcidic

Stomach

Enzymes(and beyond …)

• Inhibitors—reduce the productivity of enzymes as seen to the right with herbicides.

• The body uses enzymes to control metabolic pathways.

Enzymes(Challenges/

Misconceptions)

• Students may struggle with exactly how the enzyme transforms the substrate (by putting more pressure on bonds and creating microenvironments at the active site).

Enzymes (Teaching Hints)

• Enzymes work quickly—about 1000 substrates are taken in and converted every second.

• Consider having students kinetically walk through the process with students play the roles of enzymes, substrates, and inhibitors.

Nucleic Acids

• A only pairs with T, C only pairs G.

• This specificity allows the genome to replication itself with few errors.

Nucleic Acids

Nucleic AcidsA

den

ine

Nucleic AcidsC

yto

sin

e

Nucleic AcidsG

uan

ine

Nucleic Acids

Nucleic Acids (and beyond …)

• RNA is single stranded and DNA is double stranded.

• RNA folds back on itself into hairpin turns and loop structures. These RNAs can catalyze reactions such as RNA splicing and translation .

• The RNA world hypothesis suggests that RNA is the progenitor of both DNA and protein.

Nucleic Acids (Summary)

• DNA codes for proteins using four bases: Adenine, Guanine, Cytosine and Thiamine.

• DNA gains its unique properties based on its structure, the double helix.

DNA (Challenges/Misconception

s)

• Differentiate clearly between DNA and RNA. RNA uses Uracil instead of Thymine and is single stranded.

• One molecule of DNA is very long (1.3 m) but is tightly coiled to fit every cell in the body.

DNA (Teaching Hints)

• Making 3-D models of DNA helps tactile learners see how the parts of DNA fit together.

• The Human Genome Project is a great way for students to understand how relevant DNA research is to medicine.

Amino Acids

• Amino acids are the building blocks of proteins.

• Only twenty amino acids account for the amazing variety of proteins.

• Amino acids are linked by peptide bonds.

• Each amino acid has a hydroxyl, amino, hydrogen and a variable functional group.

Amino Acids

• Amino acids range from a simple hydrogen side chain to hydrophobic side chains like tryptophan.

Amino Acids (Summary)

• Amino acids are monomers which link together to form proteins.

• Their variety comes from different combination of the 20 different types of amino acids.

• Amino acids have a repeating structure with a variable side chain.

Amino Acids (and beyond …)

• Amino acids are zwitterion, they have both a negative and positive charge.

• Amino acids are also amphoteric; they can act as both acids or bases depending on pH.

• Amino acids strongly influence how proteins fold depending on their polarity and hydrophobic regions.

Amino Acids (Challenges/Misconception

s)

• Connect amino acids with polymers. Help students understand that proteins are polymers and amino acids are monomers.

• Amino acids can be confusing if students are unclear about functional groups, hydrophobic regions and polarity.

Table

of

Codons

Amino Acids (AA formed by 3 letter mRNA

codons)

Amino Acids (Teaching Hints)

• Use the analogy of the alphabet to introduce the incredible variety of proteins from only 20 amino acids. Even though there are only 26 letters in the alphabet, millions of words with different meanings can be created.

Proteins (Protein Synthesis)

Proteins (Protein Synthesis)