Transcript Egg Protein PowerPoint

Interactive Properties of Matter

Density = mass per unit volume
 d=m/v
standard units = g/mL

Solubility = the amount of solute that will
dissolve in a solvent to produce a homogeneous
mixture

Buoyancy = the ability of one substance to float
in another substance

All of these can be affected by the structure of
matter
Engage
Investigation #1

Ice and water: which is more dense and why?
 take the mass of your water balloon (currently filled
with ice)
 measure the volume by displacement
○ does this float (buoyant) or sink (non-buoyant) or
neither in water?
 record results in your lab notebook
 We will return to this later
Explore 1
Investigation #2

How many ways can you “cook” an egg?

Work in pairs

Follow the handout and record
results/observations in your lab notebook.
Extend/Elaborate
What’s In An Egg?
~ 75% water
 ~12.5% proteins
 ~ 11% fat
 ~1.5% other

Explain 2
© 2006 W. W. Norton & Co. and Sumanas, Inc.
http://www.sumanasinc.com/webcontent/animations/content/proteinstructure.html
Leading Questions

How do proteins relate to living organisms? How
does the structure of a protein (the shape/ way it
is molded) affect the density and buoyancy of
that protein?
○ Explore the importance of proteins to life
○ Explore things that can change the structure of a
protein
○ Observe how changing protein structure can affect life
Explain 2
Review

What is a protein?
 A macromolecule made up of amino acids joined by peptide
bonds
 DNA translation = coding for .....PROTEINS

What is an amino acid?
 special organic (carbon containing) molecules
 Contain:
○
○
○
○
central -carbon
amino group
carboxyl group
Distinct Side chain (R group)
© Pearson Education 2009
 20 possible, distinguish 20 amino acids from each other

The ABCs of atoms and molecules: (malleable to your
needs)
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
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atom = letter of alphabet
molecule = a word
macromolecule = a sentence
DNA/Genetic code = a paragraph
Organ = a chapter in a book
Organism = book
Explain 2
Explanation
pH can change protein structure (“denature”
proteins)
 Structure affects the way molecules interact with
other molecules

 Changing structure changes the function/functionability
of a protein
 Some changes can be seen
 Some changes can be observed in other ways (smell,
taste, texture, etc).
Explain 2
Why pH matters

What is pH?
 measure of hydrogen ion concentration
○ [H+]

What is special about H+ ions?
 H+ + OH- = H2O
 charged particles have a stronger pull than
hydrogen bonds/intermolecular bonds
(disulfide bonds) of tertiary structure
 Acids have many H+ ions to “donate”
○ donated H+ ions bond to other molecules and
change their shape/break them apart = change
density
 Bases “steal” H+ ions from other molecules
○ stolen H+ ions result in a change in the shape of
the molecule/molecule breaks apart = changes(c) Pearson Education
density
Explain 2
Investigation #3

Now lets explore the effects of electrolyte
concentration on eggs.
Work in pairs.
 Record your observations in your notebook

Extend 3
Why Electrolytes Matter
The term electrolyte is a medical term for salts
 Salt is an ionic compound

 specifically, electrolytes are the free ions that comprise
salts
○ Charged particles magnetically attracted to each other
 Salt ionizes in water: NaCl(s) + H2O(l) = Na+(aq) + Cl-(aq)
 Charged particles cause proteins to denature because
they have a stronger pull than hydrogen
bonds/intermolecular bonds (disulfide bonds)

Common Electrolytes:
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Sodium (Na+)
Potassium (K+)
Chloride (Cl-)
Bicarbonate (HCO3-)
Explain 3
Linking Concepts

Proteins are essential to life because they provide
support, protection, and energy to living things
 Proteins are macromolecules
○ molecules joined by chemical bonds
(c) Sheppard 2005
 Chemical bonds contain....
○ ENERGY
 All functions of living and life require energy

Many proteins need to be transportable so they can
be shuttled from one location to another inside a cell
or by the blood stream (or vascular system of plants)

Transportability is dependant on buoyancy (blood is
45% water)
Explain 3
Back to Investigation #1

Your balloons should have thawed by
now
 take the mass of your water balloon (now
filled with water)
 measure the volume by displacement
○ does this float (buoyant) or sink (non-buoyant)
or neither in water?
 What changed from when this was ice?
○ mass?, volume?, density?, buoyancy?
 record results in your lab notebook
Extend 4
Linking Concepts

Transportability is dependant on buoyancy

Buoyancy is dependant on density

Density is dependant on shape/structure

Protein structure can be affected by temperature,
pH, and electrolyte concentration

Change protein structure  change
buoyancy  can affect normal functions important
to life!
Explain 4
Additional Information
The following slides contain additional
information for you to use as you see fit
What Contains Proteins?

Which of the following contain/s proteins?
 rocks
(c) Genentec Inc. 2009
 sunlight
 cells
 leaves
 pure water
 you (human beings)

What do these things have in common?
 all are biological
 biological organisms/biproducts of biological
organisms contain proteins
Proteins and Life
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Protein Functions: (energy, structure, protection)
 Catalysis (enzymes): speed up/facilitate chemical
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reactions
Transport: hemoglobin transports oxygen in blood
Storage: Calcium & iron = bound to proteins for
storage
Support: fibrin is important in forming blood clots;
collagen is important in skin, tendons, ligaments,
bones
Motion: actin and myosin = 2 protein filaments that
function in muscle movement
Cell to cell communication/recognition: defense;
regulation (hormones)
Acquiring Proteins

Sources of protein
 Food
○ milk, eggs, cheese, yogurt, peanut
butter, fish, poultry, beans, tofu,
grains, nuts and seeds
 Body cells (recycled)
○ Broken down cells
○ Normal cell processing (metabolism)
 endocytosis (taking in) of amino
acids/proteins
- manufactured (put together) in cell by
linking amino acids
 exocytosis (releasing) of proteins
- transported to other cells
(c) PSC 2007
The Fate Of Proteins

Proteins are consumed
 not usually “instantly” usable, need to be broken down
○ need to change structure

Proteins are digested
 makes proteins transportable/usable
○ changes structure by breaking chemical bonds

Proteins are metabolized
 catabolism
○ breaking down of macromolecules/molecules into smaller
pieces (protein  amino acids)
○ changes structure by breaking chemical bonds
 anabolism
○ building up of molecules/macromolecules
(amino acids  protein)
○ uses energy to make chemical bonds
 new protein = new structure
 remember, DNA translation codes for proteins!
Mobile Proteins

Many proteins are manufactured by cells
 intercellular fluid is aqueous (contains water)

Others are mostly transported by the blood stream
 Blood:
○ 55% plasma
 90% water = blood is 45% water
 Includes proteins necessary for
- blood clotting
- fighting infection
- regulating fluid movement into/out of blood
○ 45% formed cells (red and white blood cells) and platelets
 hemoglobin = protein in RBCs that transports oxygen through
body
 How does this relate to protein structure?
○ Density affects buoyancy
○ Structure (shape) affects density
○ If it can’t float, it can’t move!
Protein Structure

Changing structure changes how one
molecule interacts with another
 Primary structure:
○ amino acid sequence of a protein
○ strong chemical bonds (like snaps)
 Secondary structure:
○ twisting due to hydrogen bonding between
peptide groups
 hydrogen bonds are weak like static electricity
 Tertiary structure:
○ folding to hide hydrophobic regions results in
ionic/disulfide bonds between R groups (mid:
like 2 attracted magnets)
○ DETERMINES PROTEIN FUNCTION!
 Quaternary structure:
○ 2 or more polypeptide chains come together to
form a functional protein
○ not all proteins have a quaternary structure
©McGraw-Hill
2008
unknown author
Protein Structure (repeat, pictures removed for printing)
May be helpful to demonstrate by folding a paper airplane (doesn’t fly until folded
into an airplane)

Changing structure changes how one molecule interacts
with another
 Primary structure:
○ amino acid sequence of a protein
○ strong chemical bonds (like snaps)
 Secondary structure:
○ twisting due to hydrogen bonding between peptide groups
 hydrogen bonds are weak like static electricity
 Tertiary structure:
○ folding to hide hydrophobic regions results in ionic/disulfide bonds
between R groups (mid: like 2 attracted magnets)
○ DETERMINES PROTEIN FUNCTION!
 Quaternary structure:
○ 2 or more polypeptide chains come together to form a functional
protein
○ not all proteins have a quaternary structure
Things That Affect Protein Structure

Temperature
 cold decreases mobility, doesn’t really change structure
 Excess heat: denatures protein (breaks hydrogen/disulfide bonds)

pH
 too high (basic) denatures protein, changes density
 too low (acidic) denatures protein, changes density
 working range depends on protein

Electrolyte (salt) concentration
 too high may denature protein, changes density
○ steals water = dehydrates protein
 not often a “too low” that will denature protein
 working range depends on protein
A Bit More Detail About Eggs
© 2006 W. W. Norton & Co. and Sumanas, Inc.
http://www.sumanasinc.com/webcontent/animations/content/proteinstructure.html