Download Proteins - Sewanhaka Central High School District

Thursday 12/11/14
• AIM: Why do we eat proteins
• DO NOW: What are biomolecules? Why
are biomolecules organic compounds?
• HW:Read page 63. Answer the following
questions:
• 1- What is a nucleotide?
• 2- what does DNA stand for?
• 3- what does RNA stand for?
• 4- what is the function of ATP?
Take out a clean sheet of loose
leaf Put your heading on top
• For each of the 5 lipids discussed, list and
give its function
Review
What are the 4 categories of biomolecules?
• Why are biomolecules called polymers?
• How do you build polymers?
• How do you break down polymers?
Synthesis of polymers
• Monomers form larger molecules by
condensation reactions called dehydration
reactions
HO
1
3
2
H
Unlinked monomer
Short polymer
Dehydration removes a water
molecule, forming a new bond
HO
Figure 5.2A
1
2
H
HO
3
H2O
4
H
Longer polymer
(a) Dehydration reaction in the synthesis of a polymer
The Breakdown of Polymers
Hydrolysis
HO
1
2
3
4
Hydrolysis adds a water
molecule, breaking a bond
HO
Figure 5.2B
1
2
3
(b) Hydrolysis of a polymer
H
H2O
H
HO
H
Which biomolecules can be found
in the food sources below?
Protein
• Carbon, Hydrogen,
oxygen, nitrogen,
sulfur
• Structure for tissues
and organs
• Hormones
• Metabolism
• Transport
• Receptors
• Catalysts
Structural Support
• Collagen and elastin
Hormones: chemical messengers
• Human Growth Hormone, Insulin,
Glucagon
Transport across the cell
membrane
• In and out of cell
Transport through the body
• Hemoglobin
Receptors
Enzymes are protein catalysts
How do we build large proteins?
Amino Acid
• Amino acids build
protiens
• All amino acids have
the same
fundamental structure
• The R group gives the
amino acid it’s unique
properties
• Size, water solubility,
electrical charge
Friday 12/12/14
• AIM: How is the shape of a protein related
to the proteins function?
• DO NOW: What are proteins built from?
• Why are proteins polymers?
What are the functions of
proteins?
How are amino acids related
to proteins?
• There are only 20
amino acids which
account for all of the
proteins in all
organisms
Structure of an amino acid
• The general structure
of all amino acids is
the same
• A central carbon is
bonded to:
–
–
–
–
1- an amino group
2- a carboxyl group
3- a hydrogen
4- a functional group
or side chain ®
Dehydration synthesis of amino
acids forms peptide bonds
• The amino group of
one amino acid and
the carboxyl group of
a second amino acid
loose a water
molecule
• This forms a new
bond
Proteins
•
•
•
Polymers made of
subunits called amino
acids
Protein or polypeptide:
50 or more amino acids
bonded together
Peptide: shorter chains
Amino acids: form 1 or
more chains which fold
extensively to form a
functional protein
Tuesday 12/16/14
• AIM: how does the shape of a protein effect
its function?
• DO NOW: draw the structure of an amino
acid. Choose 5 different colors and create a
key for your drawing
• Part of amino acid
Color
• Central Carbon
• Hydrogen
• Functional group
• Amino group
Homework: we will be adding to
this table all week
• Create and complete the following table
Organic Compound Elements that build it
Shape of protein correlates to it’s
function
•
•
•
•
Shape of protein is determined by exact type,
position and number of it’s amino acids
In many cases 2 or more amino acid chains
join
Amino acid chain undergoes a series of folds
If the shape of protein is denatured, the
protein may no longer be able to function
properly
Proteins
• ProteinsProtein structure
• ProteinsProtein structure Primary
structure
•
Primary structure: Polypeptide
chain
Secondary structure:
• ProteinsProtein structure Secondary
structure
folding of polypeptide chain
Tertiary structure
• ProteinsProtein structure Tertiary
structure
•
Disulfide bridges
Quaternary structure
• ProteinsProtein structure Quaternary
structure
•
Functional protein
Hemoglobin protein
Protein Structure
Denaturing a protein
• If the shape of the protein changes, it may
work at a slower rate or not at all
• Factors that effect denaturization:
– pH (acidic or basic)
– temperature
Assessment
• Create a table listing and describing each
step in the development of a functional
protein
Enzymes are proteins
• Built from amino acids
Enzymes are catalysts
Enzymes are organic catalysts
• Speed up chemical
reactions without being
consumed by the
reaction
• Enzymes lower the
activation energy
• Lower activation
energy: the amount of
energy needed for a
chemical reaction to
occur
QuickTime™ and a
decompressor
are needed to see this picture.
Wednesday 12/17/14
• AIM: How do enzymes catalyze metabolic
reactions?
• DO NOW: Explain why enzymes are
catalysts
• Why are enzymes proteins?
DO NOW ANSWER
• Enzymes are catalysts because they
speed up chemical reactions without being
consumed by it
• Enzymes are proteins because they are
built from amino acids
Homework
• Add and complete the following column on
last nights table:
– Monomer subunit
Naming enzymes
• Enzyme names end with the -ase suffix,
• the -ase suffix is added to the substrate name.
• For example, sucrase is the enzyme that breaks
down the substrate sucrose, a disaccharide,
into the monosaccharides glucose and
fructose.
• Protease: the enzyme that catalyzes the break
down of proteins into amino acids
• Lactase: the protein enzyme that catalyzes the
breakdown of lactose: the sugar in milk
How Do Enzymes Work?
How do enzymes work?
• Enzymes are
substrate specific
• Substrate is the
reactant
• Active site: part of
the enzyme capable
of recognizing and
binding to substrate
2 methods in which enzymes work
• Induced Fit Model
• Lock and key model
Induced fit model
• Actually the "fit" of the substrate and the active
site is not a "perfect fit”
• enzyme slightly changes shape to fit the
substrate
Lock and key model
• Active site of the enzyme fits perfectly to
only one type of substrate
Enzyme-substrate complex
• Lowers the activation
energy causing the
chemical reaction to
happen
Assessment
• In one complete sentence,explain why the
shape of enzyme is important to its
function.
• AIM: What factors effect the rate of
enzyme activity?
• DO NOW: What is activation energy?
• Enzyme Quiz Monday
DO NOW Answer
• Activation energy: The amount of energy it
takes for a chemical reaction to occur
• How do enzymes catalyze chemical
reactions?
• By lowering the activation energy
• When do enzymes lower activation
energy?
• Enzyme substrate complex
• Enzymes lower
activation energy
• At the enzyme
substrate complex
• This causes a
chemical reaction to
take place which
leads to the
production of
products
Factors that affect enzyme
activity
1. Amount of enzyme
2. Amount of substrate
3. pH
4. Temperature
Concentration of Enzyme
If the amount of substrate
remains
the same:
 As increase amount of
enzyme,
 the rate of an enzyme
action also increase
 UNTIL…
 All enzymes become
saturated
 At this point all enzymes
are working at maximum
capacity
Thursday 12/18/14
• AIM: how do enzymes work?
• DO NOW: 1- Enzymes are catalysts
because
• 2- how do enzymes catalyze chemical
reactions?
• HW: Text read pages 66-67 Answer the
reading check question on page 67 and
questions 3 and 5
DO NOW Questions
• Enzymes are catalysts because they
speed up chemical reactions without being
consumed by the reaction
Monday 1/5/15
• AIM: what factors effect enzyme activity?
• DO NOW: 1-Explain the difference
between a substrate and a product.
• 2- what is the active site of an enzyme?
• HOMEWORK: text read pages 64-65.
answer Reading check question page 65
and question 1 page 67
Enzymes- a fun introduction YouTube
• Substrate: the
molecule acted on by
the enzyme
• Active site; the part
of the enzyme
capable of
recognizing and
binding the substrate
• Product: the
molecule produced by
the reaction
Which substrate would work with
this enzyme?
The Induced Fit Model of
Enzyme Catalysis - YouTube
Enzymes lower activation
energy
Dehydration synthesis
reactants
Lowers activation
energy: causes
chemical reaction to
happen
Hydrolysis (digestion)
Activation energy is lowered
Chemical reaction takes
place
Enzymes are shape specific
• The active site of each enzyme has a
specific shape to fit only one type of
substrate
• If the shape of the active site changes, the
enzyme-substrate complex cannot form so
activation energy is not lowered so
chemical reaction does NOT happen
The enzyme substrate complex
2 different ways enzymes work
• Lock and key; the active site of an enzyme
does not change at all and only fits a
specific shape substrate
• Induced fit model: active site can slightly
change shape to fit a substrate but after
the reaction goes back to its original shape
• REGARDLESS of the model of enzyme
activity, at the enzyme-substrate complex,
the activation energy is lowered causing
the chemical reaction to happen
Factors that effect the rate of
enzyme activity
• Concentration of substrate
• pH
• temperature
Concentration of substrate
If the amount of enzyme
remains the same:
a)
at low concentrations,
of substrate,
 Enzyme activity is low
 Because all enzymes are
NOT working
 As you increase the amount
of substrate, you increase
enzyme activity until all
substrates are bound to
enzymes

At this point, enzyme activity
is steady
pH
1. Each enzyme works
best at a certain pH
2. At optimal (best) pH:
enzyme has the right
shape
to fit substrate
3. Changes in pH change
the shape of enzymes
and their ability to fit
with substrates
4. Most enzymes work best
at pH’s near 7 (neutral)
Temperature
1. Enzymes work best at a
certain temperature
2. Optimum (best) temp. for
human enzymes is near
normal body temp. (37C)
3. Changes in temp. alter
shape of enzyme
4. At extreme temp’s
enzyme can ‘t fit with
substrate
5. high temperatures
denature the enzyme
• If I changed the shape of the active site, how
would the enzyme activity change?
• In this picture, name the products.
• When is the activation energy lowered?
• The most likely result of mixing both enzymes with their substrates in a
single test tube is that:
• A- only gastric protease would be active if the pH of the mixture was
basic
• B- gastric protease would be more active than intestinal protease at
pH 6
• C-both enzymes would exhibit some activity at pH 5
• Which enzyme shows the greatest change
in its rate of action with the least change in
pH?
Practice questions
• The picture below represents which type
of organic compound?
Practice question
• What type of chemical
reaction is this and
how do you know?
What builds nucleic acids?
nucleotides
• AIM: How do amino acids form peptide
bonds?
• DO NOW: What is the optimal pH for each
enzyme?
• MOTIVATION: Draw the structure of an
amino acid using the following colors
• Central Carbon: green
• Amino group: Pink
• Carboxylic acid group: Blue
• Functional group: Red
Amino acids
• A central carbon forms 4 covalent bonds
(share electrons)
• Bond 1: with a single hydrogen atom
• Bond 2: with an amino group (NH2)
• Bond 3; with a carboxylic acid group
(COOH)
• Bond 4: with a functional group
represented by the letter R
How do amino acids bond
together to form a chain of
amino acids?
Dehydration synthesis: loss of
water to form a bond
Peptide bonds
• Always formed between the Nitrogen of an
amino group of one amino acid bonded to
the Carbon of the carboxylic acid in a
second amino acid
• THE CENTRAL CARBON IS NEVER part
of the peptide bond!!!!!!!!!!!!!!!!!!!!!
Wednesday 1/7/15
• AIM: How do nucleic acids help build living
things?
• DO NOW: Why are nucleic acids organic
compounds?
• Why are nucleic acids polymers?
• What are the building blocks of nucleic
acids?
• HOMEWORK: Read pages 66-67.
Reading check on page 67 question 3
pg67
Nucleic Acids
• Hereditary
Information
– Passed down from
parent to offspring
• DNA and RNA
• Deoxyribose Nucleic
Acid
• Ribose Nucleic acid
Nucleic acids are built from
nucleotides
• Nucleotides
– Phosphate group
– 5 carbon sugar
– Nitrogen base
DNA: deoxyribose nucleic acid
• James Watson and Francis
Crick
• DNA is a double helix
• Sugar-phosphate backbone
• 2 strands of nucleotides
connected at nitrogen bases
• Weak Hydrogen Bonds hold
Nitrogen bases together
• A-T
• G-C
Nitrogen Base Pair Rules
• Hydrogen bonds hold
nitrogen bases
together
• A-T
• C-G
RNA
• Ribonucleic acid
• Single strand
• Ribose- 5 Carbon
sugar
• AUCG
How do Nitrogen bases specify
protein production?
• The sequence of Nitrogen bases A,T,C,G
are what build a gene.
How are genes related to DNA?
• Genes: sequences of
nitrogen bases that hold
the code to build a protein
• DNA carries genes
• Chromosomes are
condensed forms of DNA
• Many genes are found on
1 chromosome
Chromosomes are made up of
DNA
• Specific sequences of nuleotides form genes
• Genes code for proteins
• EVERY SINGLE chromosome is copied before
the cell divides
• ALL cells contain the same genes
• So how then are cells different
• Cells are different because they express
different genes
• Therefore different cells build different proteins
Assessment
• In your own words explain the difference
between a DNA and RNA nucleotide