Bell Work
• What are carbohydrates, lipids, and proteins?
• Where can you find each one?
• What is their function?
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 linked
Glucose
Example: Starch
And Glycogen (energy
storage for animals and
fungi)
Why we need carbohydrates
• Cells use it for energy
• Structural Materials
• Cellular Id
Eat too much and don’t work them
off? You get this!
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)
Hydrocar
bon chain
hydropho
bic
(repels
Which one of these substances
contains lipids. Talk and discuss with a
group member and write down your
answers.
• Water
•
•
•
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•
•
•
•
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 Acid
Contains the sugar ribose
Single stranded
Transcribes 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.
Energy
• 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.”
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
• 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.
• 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!
Metabolism
The sum of all chemical processes that occur in an
organism.
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.