Biochemistry

People need organic compounds

• Compound – two or more elements combined

• Water• Covalently Bonded

• Covalent Bond - Atoms share electrons & bond

Covalent Bond

• Potassium Nitrate

Other Bonds

• Ionic Bond - Atoms transfer electrons & bond

• Hydrogen Bond – The intermolecular force between a hydrogen atom (bonded to oxygen, nitrogen, or fluorine) and a electronegative atom.

Organic Substances

• Parts of cells• Large complex molecules• AKA biomolecules• Four types of

Biomolecules:• Carbohydrates• Lipids• Proteins• Nucleic Acids

Carbohydrates

• Class of molecules that include: sugars, starches, and fibers

• Found in grains, fruits, sugars

• Consist of Carbon, Hydrogen, and Oxygen in 1:2:1 ratio.

Carbs cont…

• Monosaccharide – single sugar

• Example: Glucose

Carbs cont…

• Disaccharide – two linked sugars

• Examples – sucrose (table sugar) and Lactose (milk)

Polysaccharide

• Many linkedGlucoseExample: StarchAnd Glycogen (energy storage for animals and fungi)

Why we need carbohydrates

• Cells use it for energy• Structural Materials• Cellular Id

Functions of Carbohydrates

• Energy Supply-• for many organisms, including humans. Breaking down

glucose creates energy for cell activities

Functions of Carbohydrates• Structural Support-• Chitin is found in the shells of insects and the cell walls

of mushrooms. • Cellulose is found in the cell walls of plants.

Functions of Carbohydrates• Cell Recognition-• In a complex organism, cells recognize neighboring

cells by the short, branched chains of varying sugar units on their outer surface.

Carbohydrates allow the body to recognize invading cells and destroy them

Lipids

• Include fats, phospholipids, steroids, and waxes

• consist of chains of carbon atoms bonded to each other and to hydrogen atoms.

• This structure makes lipids repel water.

Function of Lipids• Storing energy • The main purpose of fats is to store energy.• Fats can store energy even more efficiently than

carbohydrates.

Function of Lipids

• Controlling water movement

• The cell’s boundary is made of phospholipids.

• One end of the structure is attracted to water molecules and the other repels it.

• Waxes (a lipid) ,found on the surfaces of plants and aquatic bird feathers, help prevent evaporation of water from the cells of the organism.

Lipids

Fats are solid at room temperature (saturated) & oils are liquid (unsaturated). Note the double bond on the unsaturated fat.

Carboxyl group (COOH) hydrophilic (loves water)

Hydrocarbon chain hydrophobic(repels water)

Which one of these substances contains lipids. Talk and discuss with a group member and write down your answers.

• Water• Oil• Butter• Pretzels• Potato chip• Muffin• Salad Dressing• Candy• Chocolate

Proteins

• Proteins are chains of amino acids that twist and fold into certain shapes that determine what the proteins do.

• There are many types of proteins that perform many types of functions:

• structure, support, movement, communication, transportation, and carrying out chemical reactions.

Proteins

• A protein is made up of amino acids, building blocks that link to form proteins.

• Every amino acid has an amino group and a carboxyl group. Units of amino acids form links called peptide bonds.

• The side group gives an amino acid its unique properties. Twenty different amino acids are found in proteins.

Amino Acid and Peptide Bonds

Levels of Structure of Proteins • For each type of protein, amino acids are arranged in a

specific order, the protein’s primary structure.

Levels of Structure of Proteins

Levels of Structure of Proteins • For each type of protein, amino acids are arranged in a

specific order, the protein’s primary structure.• The interactions of the various side groups may form coils

and folds, the protein’s secondary structure.

Levels of Structure of Proteins

Levels of Structure of Proteins • For each type of protein, amino acids are arranged in a

specific order, the protein’s primary structure.• The interactions of the various side groups may form coils

and folds, the protein’s secondary structure.• The overall shape of a single chain of amino acids is the

protein’s tertiary structure.

Levels of Structure of Proteins

Levels of Structure of Proteins • For each type of protein, amino acids are arranged in a

specific order, the protein’s primary structure.• The interactions of the various side groups may form coils

and folds, the protein’s secondary structure.• The overall shape of a single chain of amino acids is the

protein’s tertiary structure.• The quaternary structure is the overall shape that results

from combining the chains to form proteins.

Levels of Structure of Proteins

Nucleic Acids• A nucleic acid is a long chain of

nucleotide units.• A nucleotide is a molecule made up of

three parts: a sugar, a base, and a phosphate group.

DNA

Deoxyribonucleic Acid

Contains the sugar deoxyribose

Double Helix

Contains genetic information

RNA

Ribonucleic AcidContains the sugar riboseSingle strandedTranscribes DNA & helps build proteins

Functions of Nucleic Acids

• Heredity Information• Energy Carriers Turn to page 63

and read about each of these functions. Fill in your Guided notes with the information you learned

Functions of Nucleic Acids

• Heredity Information• Nucleic acids store and transmit hereditary

information.• DNA molecules act as “instructions” for the processes

of an organism’s life.• RNA also interacts with DNA to help decode the

information.

Functions of Nucleic Acids

• Energy Carriers• Adenosine triphosphate, or ATP, is a nucleotide that has

three phosphate groups and supplies energy to cells.• Energy is released in the reaction that breaks off the third

phosphate group.

Let’s take a closer look…

Now that you understand the 4 “biomolecules,” you can understand how we use food for energy, but there is one more nutrient we need to discuss – WATER!

FACT

• Humans can survive for a few weeks without food but _____ (how long) without water.

• Only a few days!!!

Why does water mater?

• The processes of life take place in water. Without water’s unique properties, life as we know it could not exist!

pH of water and living things

• In pure water, hydronium & hydroxide ions are present in equal numbers.

• The pH of living things must be stable.• Human blood = pH 7.4• If it goes down to 7 or up to 7.8, an individual will die

within minutes.

pH• In solutions, some substances change the balance of these ions.• Acids form extra hydronium ions when dissolved in water (our

stomach uses an acidic solution to break down food).• Bases form extra hydroxide ions (an example is NaOH which

removes clogs from drains).

Buffers

• For a stable pH to be maintained, the solutions in living things contain buffers.

• A buffer is a substance that reacts to prevent pH changes in a solution.

• Buffers in our blood prevent changes in pH (bicarbonate ion)

Energy & Metabolism

Energy is the ability to move or change matter.

• Changing a substance requires a chemical reaction where bonds are broken and new ones are formed.

• Remember, the arrow means “yields” or “changes to” or “forms.”

Energy

Activation energy

• The minimum amount of energy needed to start a chemical reaction.

Energy

• Chemical reactions release energy by breaking the bonds between molecules.

• This release of energy from food molecules involves many steps & many enzymes.

Enzymes

• A molecule that increases the speed of chemical reactions.

• Enzymes lower the amount of activation energy and assist necessary biochemical reactions

• Without enzymes, chemical reactions would not occur quickly & easily enough for life to go on.

Activation Energy

• Enzymes fit with reactants like a lock & key. The shape of the active site determine which reactants (substrates) will bind to it.

• Each enzyme acts only on specific substrates.

Enzymes

• Shape determines function!

Enzymes are Proteins!

Why is pH important?• Most enzymes need a certain range of temperatures and

pH and changes in pH can change a protein’s shape• If an enzyme changes shape, it won’t work well!

The sum of all chemical processes that occur in an organism.

Metabolism

What it all means…• Your cells get most of the energy needed for metabolism from the

food you eat.• When food is digested, it is broken down into small molecules that

can enter the blood, which delivers them to cells.