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Daily Science
• In forming a protein, why is it important that every amino
acid has the same structure of a carboxyl group on one
side and amino group on another?
• Answer: so that when the carboxyl and amino groups
combine to form a peptide bond a water molecule can be
dehydrated (an OH combines from one side and a H from
the other)
• What properties emerge as the structural level of a
protein increase from primary to quaternary?
• Answer: properties increase in complexity from simple
and linear to twists, folds, and multiple chains twisted
together for strength purposes
Daily Science
• Share Top Chef Activity
Daily Science
• What 2 components make up a lipid (not
the elements)?
• What 2 elements make up a lipid? What 3
elements make up a carbohydrate?
• Is dehydration or hydrolysis used to put a
lipid together?
• What is one reason why fats are good for
us?
Proteins
Biology I
Who cares about Proteins?!
Build
Muscle
Repair
damaged
cells and
tissues
Form
Nails
Form
Haircurly or
straight
Proteins
• Proteins contain nitrogen in addition to
carbon, hydrogen, and oxygen.
• The proteins that your body makes are
controlled by DNA.
• The shape of a protein is very
important because it determines the
function of that protein.
Proteins
• Proteins are polymers of amino acid
molecules.
– Amino acids – compounds with an amino
group (-NH2) on one end and a carboxyl group
(-COOH) on the other end
– There are 20 different R/functional groups.
Proteins
Label this
on your
note
sheet!
• Amino Acid Structure
R/Functional Group
R
Carboxyl Group
Cx
O
Central Carbon
H
Amino Group
N
C
H
O
H
Proteins
• The amino group and carboxyl group on
each amino acid is identical.
• Amino acids are bonded together at the
carboxyl group of one amino acid and the
amino group of a second amino acid.
– Bonded together using dehydration
synthesis!
– These are called peptide bonds.
Proteins
• Peptide Bonds
R
R
Cx
H
O
N
C
H
O
Cx
H
dehydration synthesis
H
O
N
C
H
O
H
Peptide Bonds
Proteins
• What do proteins do?
– Proteins carry out the instructions given by
your DNA.
– Examples:
•
•
•
•
•
•
Control the rate of reactions.
Regulate cellular processes.
Form bone and muscles.
Transport substances in and out of cells.
Help fight disease.
Many, many more!
•
Proteins
Protein Structure
– Primary – sequence of amino acids in a protein.
– Ordered specific to each protein like the letters
of the alphabet
– Secondary – the sequence of amino acids can
be twisted or folded.
Silk protein of a spider’s
web
Makes the structure of
hair
Proteins
• Protein Structure
– Tertiary – the secondary
chain is folded to give protein shape.
– Quaternary – arrangement of a protein
with multiple chains.
Tertiary Structure
Collagen is twisted for
connective tissue in skin,
muscle, bone, etc.
Quaternary Structure
Hemoglobin is shaped
to better bind with
oxygen
•
Proteins
The most important thing to remember
about proteins is:
SHAPE = FUNCTION