Enzyme Review
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Transcript of Enzyme Review
Enzyme ReviewAre you ready?
Define Catalyst.A molecule that allows stable molecules to react quickly.
What is an enzyme?
and what is it made of?
An enzyme is a biological catalyst
It is a protein and made of a
long chain of amino acids
What do enzymes do?They speed up chemical reactions by…….
Lowering Activation Energy needed to start the reaction.
What enzyme did we use in our labs?
Catalase
What reaction does it speed up?
The breakdown of Hydrogen Peroxide into water and oxygen.
H2O2--------) H2O + O2
Why are enzymes necessary?
So that chemical reactions in living things can happen fast enough
Example- In the human body—
Hydrogen Peroxide would break down without catalase, but it would be so slow that H2O2 would build up and become TOXIC!
Name the two kinds of reactions.
Exothermic Endothermic
Which requires energy input
and which gives off heat?
Endothermic RXNS require energy to be
added IN to keep going.
Exothermic RXNS give off energy. Energy
EXITS.
What does it mean to say a reaction is “spontaneous”?
Once it starts it will continue until the end.
No energy input is required after the activation energy.
Define Activation Energy.
The measure of how hard molecules have to collide to get a reaction to begin.
The push to get a reaction started.
Which kind of molecules have high activation energy—Stable or Unstable?
Stable molecules don’t interact easily– they have HIGH activation energy. Need a bigger push to get started.
Unstable molecules react more easily--They are highly reactive, have LOW activation energy.
What is KMT?
Kinetic Molecular Theory
The idea that molecules are always moving and when they collide hard enough with one another, they will react.
What happens when enzymes are exposed
to heat?A little heat can speed up a reaction by
making the molecules move faster----
BUT
What happens when there is too much
heat or the wrong pH?Enzymes DENATURE
They unravel. They no longer keep the same shape so they won’t fit the substrate any more.
They need to be in their OPTIMUM range of temp or pH to function the best!
Explain Lock and Key Model
Enzyme is the
Lock
Substrate is the
Key
The active site is the
Keyhole
What happens at the active site?
The enzyme and the substrate bind together.
What is Induced Fit?
Amino acids in the active site
Attract amino acids on the substrate due to different charges and polarity
They interact and the bonds are broken and new ones form.
Can an enzyme be used in any reaction?
NO
They are very SPECIFIC, SELECTIVE, PICKY
They only work with one substrate.
Are enzymes used up in a reaction?
NO
They can be used over and over again.
What happens when you add more enzyme?
The rate of reaction increases– Happens faster
What happens when you add more substrate?
No change in rate, BUT
You get more product.
Thanks for playing
Enzyme Review
Biochemistry ReviewBiology is the study of living things.
Organic or Biochemistry is the study of the chemical reactions in living things.
What is the smallest unit of matter?
An Atom
Atoms- What area is positive and what area is
negative?The nucleus is positive
The surrounding electron orbitals are negative
Where is the mass?
In the nucleus
Atoms Atomic Number= # of p+
Atomic Mass= p+ + n0
Charge= p+ - e-
First Energy Level= can hold ..
2 electrons
Second Energy level can hold..
8 Electrons
What is a molecule?Atoms bonded together with covalent bonds
How are ions and isotopes same/different?
They are both atoms and the number of protons stays the same, BUT
Ions have different charges (different number of electrons)
Isotopes have different masses (different number of neutrons)
What makes a molecule polar?
Uneven sharing of electrons gives the molecule partially negative areas and partially positive areas
Give an example of a polar molecule.
Water – H20= Oxygen has a partial negative charge, hydrogen has a partial positive charge.
What is a compound?
A substance made of two or more different elements.
Could be bonded by ionic or covalent bonds
What is the most common element in living things?
CarbonIt is present in all four of the biomolecules
Which biomolecule contains nitrogen?
Protein
Let’s talk about bonds!
What are the three types we have covered?
Ionic, Covalent, and Hydrogen bonds
A Bond formed when molecules share
electrons
Covalent Bonds
A Bond between two oppositely charged atoms or molecules (one positive one
negative)Ionic bonds
An intermolecular force between polar
moleculesA Hydrogen Bond
What is the relative strength of these
bonds?
Covalent/ Ionic >>>>>>>Hydrogen Bonds
pH scale 1-14What does it measure?
The acidity or basicity of a solution
7 is neutral
Acids are …
Below 7
Bases are …
Above 7
Four Categories of Biomolecules
Proteins
Carbohydrates
Lipids
Nucleic Acids
These are very large molecules so we call them Macromolecules!
Carbohydrates- What do we know?
Ratio of C:H:O is
1:2:1
Monomers are:
saccharides-simple sugars
Polymers are:
polysaccharides- starches
LipidsMonomers are glycerol and fatty acids
Polymers are Trigycerides- a glycerol with three fatty acid chains
Lipids can be fats or oils,
They are nonpolar- don’t mix with water
Saturated fats are solid (butter, lard)
Unsaturated are oils (olive, vegetable)
ProteinsMonomer is an amino acid (20 types), each amino acid has an R group on its central carbon.
Polymers are polypeptides, two or more amino acids bonded together
What is the process that builds polymers
from monomers?Dehydration Synthesis (synthesize is to make)
Remember this process gives off a molecule of ……
H20
Breaking down polymers into
monomers is called
Hydrolysis- “Lysis” is to break
What molecule is needed for this to happen?
H20 must be present and breaks into its parts to replace the H’s and O
In our lab, we tested for different biomolecules:
Iodine- What does it test for and what’s a positive reaction?
Iodine tests for starch- If starch is present it turns..
Blue-Black
What tests for simple sugars (Glucose)?
Benedicts plus heat (it starts out blue)
Positive reaction is a change to green, yellow or red depending on how much glucose is present
What does Biuret test for?
Proteins
What color change do you see if protein is present?
It changes from blue to a purple-lavender to violet.
How did we check for Lipids?
Paper towel test
Translucent (can see through it) when lipids were present.
This is the end.Best of Luck!
CELL Parts and CELL Membrane REVIEW
Name the cell part that corresponds to
the function
Control Center (Brain of the Cell)
The Nucleus
Makes Ribosomes and is found inside the
Nucleus
The Nucleolus
Where proteins are made?
On the Ribosomes
Packages, stores, and distributes proteins; pancake-shaped layers
Golgi Apparatus
Thick fluid inside cells
CYTOPLASM
Hair-like extensions that help cells sense their surroundings
Cilia
Has a double membrane called the “nuclear
envelope”
The Nucleus
Folded membrane that transports proteins throughout the cell
The Endoplasmic Reticulum
Contains chlorophyll, found only in plant
cells
Chloroplast
The “powerhouse” of the cell, site where
ATP is made
Mitochondria
Boundary of the cell, found in both plant and animal
cells
The cell membrane
Digests (breaks down) wastes and old cell parts, kills bacteria and viruses
Lysosome
Tail-like extension that helps move some cells
through watery environments
Flagella
Stores water, wastes, and nutrients for plants
Central Vacuole
Rigid outside boundary for plant cells
Cell Wall
Now let’s examine the Membrane!
What does selective permeability mean?
Selective= choosy, picky, doesn’t let just anything in.
Permeable= allow substances to enter and exit.
Selective permeability= the ability of the membrane to let some things in and keep others out.
The membrane is made of these!
Phospholipid Molecules
They have the following parts:
Phosphate and Glycerol Head (polar)
Fatty Acid Tails (nonpolar)
Why is the membrane so fluid?
Fatty acid tails are unsaturated (kinked) so they don’t compress
Cholesterol is embedded (stuck in) between the tails
What other components make the membrane a
mozaic?
transport proteins
What are three examples of transport proteins?
1. gated proteins
2. channel proteins
3. receptor proteins
Why are transport proteins needed?
They allow substances that are too…
Big, charged or polar to cross the membrane.
What substances can or cannot pass easily across
the membrane?CAN CANNOT
Polarity
Nonpolar PolarSize
Small Large Charge
Uncharged Charged
What is a concentration
gradient?Different concentrations of molecules between two areas.
If there is no difference, there is no gradient—
You have equilibrium!
When is there equilibrium?
When there is an equal concentration of molecules on both sides of a membrane or throughout the space.
Why is it called “Dynamic” Equilibrium?
The molecules are always moving (dynamic), but the concentration stays equal.
Movement of molecules from high concentration to low
concentration
Diffusion
Diffusion of Water Molecules
Osmosis
Two types of Transport:
Active Transport
Passive Transport
Name kinds of Passive Transport-Remember-- no
additional energy requiredDiffusion
Osmosis
Facilitated Diffusion=movement down a gradient for substances that cannot easily cross the membrane– they
need to be helped or assisted by a …….
Transport protein
Name two kinds of Active Transport– these require
energy inputEndocytosis– Endo= IN
Exocytosis- Exo = Exit
Solutions:
Hypertonic
Hypotonic
Isotonic
Which has more dissolved solutes?
Hyper
Which has more H2O?
Hypo
Water always moves from ……
Hypo to Hyper
Hypotonic solutions-- (mo H2O)
To Hypertonic solutions-- more solutes, but less H2O
Plant cells need water to maintain upright structure.
What is this pressure called?
Turgor Pressure
When a plant loses turgor pressure, it loses water from osmosis. That’s called……
Plasmolysis
Thank you and Good-Luck!
Cell Cycle REVIEWaka.. The story of the life of a cell.
What phase does a cell spend most of its time in?
Interphase– subphase=G1
What happens in G1?
The cell is metabolically active=
Performing the chemical reactions needed for the cell to do all the jobs in needs to do
In G1, What is DNA called and what does it look like?Chromatin
A thin, tangled mass (good for directing protein making to catalyze chemical rxns).
What is the G1 checkpoint checking for:
Is the cell healthy enough and large enough to divide?
What happens in S phase?
Synthesis of, Replication of, Duplication of:
DNA
Need two copies of the DNA if the cell is going to divide and make two identical cells from the original
What happens in G2?The DNA coils and condenses.
Each strand joins to its duplicate at the centromere- now called duplicated chromosome made of two sister chromatids.
Centriole is duplicated, too
What does the G2 checkpoint check for?
It checks the DNA to make sure it was copied accurately. If not, repairs can be made or cell can die.
Now for Mitosis!What will divide in Mitosis?
The Nucleus!
How many subphases are there in Mitosis?
4= PMAT
Prophase, Metaphase, Anaphase, Telophase
Describe Prophase.
Nuclear membrane dissolves
Centrioles move to opposite poles
Spindle fibers attach to chromosomes
What happens in Metaphase?
Spindles move the duplicated chromosomes to the equator (midline)
They line up head to toe in a row
AnaphaseDuplicated chromosomes are pulled apart
They are now unduplicated
They move to opposite sides (poles)
Telophase- the last phase of Mitosis
Two nuclei form
The membranes around them form
Spindles break down
Cytokinesis
The cytoplasm is divided and the two separate cells form. They are identical.
In plant cells, a cell plate forms (see above)
In animal cells, the cytoplasm pinches or furrows in (see right).
Identify the following: chromosomes, chromatids,
centromere, centriole, spindle
What does the DNA instruct the cell to make?
Protein
Specifically, enzymes that:
Catayze reactions including the process of cell division
Types of DNA (genes) that start or stop cell
division:Proto-onco genes= accelerator- they tell the cell to go ahead and divide (reproduce)
Tumor suppressor genes= brakes that stop the process of cell division
What is contact inhibition?
Under normal DNA instructions, contact inhibition stops a cell from dividing when it is touching other cells.
But sometimes, things go terribly wrong!
Mutations- What are they?
Changes in DNA caused by:
Mutagens- factors in the environment-
chemicals (tobacco, drugs, cleaning products, pesticides),
energy (radiation, x-rays)
Random mistakes in DNA copied or inherited
These can cause cancer, AKA
Uncontrolled cell growth= the cells divide because there are failures in tumor suppressor and proto-onco genes
The cell is in contact with other cells, but proto-onco genes are turned on and the suppressor genes are turned off.
How is cancer treated?1. Surgery– remove the tumor or group of cells that is dividing rapidly
2. radiation- using concentrated radiation to kill cancer cells
3. chemotherapy- chemicals (powerful drugs) that kill cancer cells
The EndGood luck!
PhotosynthesisIs defined as…
A process by which light energy is converted into chemical energy
Where does this take place?
In the chloroplasts of plant cells
The Basics: Reactants and
Products
The main source of energy for all life is….
The SUN
Photosynthesis is the process of converting sunlight into ATP then into organic molecules that store energy.
ATPHow is ATP like money?
It is: Energy currency -- the only form of energy living things can use (spend).
How does ATP release energy?
By breaking the bond between the 2nd and 3rd phosphate and becoming ADP.
Autotrophs are…
Plants or other organisms that make their own energy from the sun or inorganic compounds (they are producers)
Heterotrophs are consumers that…
Get energy from food by eating plants and animals that eat plants
Where are the stroma and thylakoid space relative to the thylakoid
membrane?
The chloroplast contains thylakoids in a fluid-filled space called the stroma.
The thylakoid space is inside the thylakoid and the membrane surrounds it.
Where is chlorophyll located?
On the thylakoid membrane
What is chlorophyll?
A pigment that absorbs and reflects light
What frequencies of light are absorbed and reflected by
chlorophyll?
Red and blue are absorbed
Green is reflected
What happens to chlorophyll when it absorbs light energy?
It loses excited electrons to the electron transport chain.
How are these electrons replaced?
Photolysis= light splitting water with an enzyme.
What are the three products of photolysis?
1 Oxygen to the atmosphere
2 H+ ions inside the thylakoid membrane
3 Electrons to chlorophyll to replace those lost to the ETC
Describe the ETC:electron transport
chain.
A series of protein molecules embedded on the membrane where each one has a higher attraction for electrons than the previous one.
What happens as the energy is released in each redox reaction?This energy is used to actively transport H+ ions into the thylakoid space against the gradient.
This builds up a higher concentration of H+ in the thylakoid space.
Are H+ freely permeable to the thylakoid membrane? (can they cross easily?)
No-- they are charged!
How do H+ ions diffuse out of the thylakoid space into the stroma?
Through a transport protein called…
ATP Synthetase
Is the flow of H+ ions through ATP Synthase “energy requiring” or
“energy releasing”?
Energy releasing
This energy is used to form ATP
Is the formation of ATP energy requiring or energy releasing?
Energy requiring
Energy is needed to create the bond between the 2nd and 3rd phosphate making ATP from ADP + P
What serves as the final electron acceptor at the end of the electron
transport chain?
NADP+
What happens to create NADPH?
NADP+ combines with the final e- and H+ from the stroma to make NADPH.
NADPH is used in the next phase.
What three things are needed for the light reactions? What three things are produced
in the light reactions?
Needed--Light, water, chlorophyll
Produced--oxygen (to atmosphere), ATP, and NADPH (to dark reactions)
The dark reactions, AKA -- the light independent reactions, are also
known as…
The Calvin Cycle
What is carbon fixation and where does the carbon come from?
CO2 from the air is added to a 5 Carbon sugar = this is “carbon fixation”
Glucose is produced
What is NADPH used for?
It carries electrons and H+ ions to the Calvin Cycle.
These are used to build glucose molecules.
What enzyme is key to this process?
Rubisco
Explain the results of the Photosynthesis LabWhat light treatments had the highest and the lowest rate of reaction?
What role did DPIP (blue stuff) play in the photosynthesis reaction?
Now that you know all about photosynthesis..Don’t forget to hug a tree!
Without photosynthesis, we would not have air to breath or food to eat.
THE END ?
Define Cellular Respiration.
The process in which biomolecules, like sugar, are converted into an energy form that living things can use (ATP).
How many types of Cellular Respiration are
there?
Two Types: Aerobic or Anaerobic
Distinguish between these.
With or without oxygen
How much ATP does each yield?
Aerobic yields 36 or 38 ATP
Anaerobic yields only 2, but gives NAD back to glycolysis to keep the process going.
What do cells do with the energy they get from
food?Store it as ATP or
Release as heat
Chemical EquationsPhotosynthesis: light energy converted to chemical energy
CO2 + H2O + light O2 + glucose
Cellular Respiration: biomolecules converted to ATP
O2 + glucose CO2 + H2O + ATP
Where is the energy stored in biomolecules like sugars, carbs,
lipids, etc.?
In the bonds between the atoms
Where in the bonds is energy stored in ATP?
In the bond between the second and third phosphate
How do living things access and convert the energy stored in
biomolecules?
Break existing bonds and form new ones
What is the name for the series of reactions that converts the stored
energy in biomolecules into molecules of ATP?
Cellular Respiration
What is the first stage of cellular respiration called?
Glycolysis
Where does this step occur?
In the Cytoplasm
Is this aerobic or anaerobic?
Anaerobic
What are the products of this step?
ATP, NADH, and 2 3-C Pyruvate molecules
What is the net production of ATP in this step?
2 ATP’s
If oxygen is available where do the pyruvates
go?
To the Mitochondria
What type of Cellular Respiration is this?
Aerobic
What happens in the Prep Step?
The pyruvates are transported into the mitochondria.
They lose a carbon (CO2 given off)
2 carbon acetates are formed—they use NAD and Co enzyme A to become…
acetyl Co A
Diagram and describe the events of the prep step (pyruvate conversion)
2 3-C pyruvate molecules are converted to…
2 2-C acetate molecules with the production of…
2 molecules of NADH and 2 molecules of CO2
Diagram the events of the Kreb’s Cycle indicating the number of NADH, FADH2, ATP,
and CO2 molecules produced
The Krebs Cycle produces electron carriers a CO2 is released leaving…
6 NADH, 2 FADH2, 2 ATP, 4 CO2
What is the significance of the 6 CO2 molecules produced in the Prep Step and
Kreb’s Cycle?
The four carbons in the four CO2 molecules plus the two carbons in the two CO2 molecules from the prep step are evidence that the initial six carbon sugar molecule is completely broken down
Describe what the electron transport chain is and where it is located in the
mitochondria.
The ETC is a series of protein molecules embedded on the inner membrane of the mitochondria that each have a higher attraction for electrons than the previous one.
What is the source of electrons to the electron transport chain?
The co-enzymes NADH and FADH2
Every time an electron is accepted and released by a protein in the electron transport chain –
a redox reaction releases a small amount of energy used to do what?
Actively transport a H+ ion from the matrix into the outer compartment
What happens when a molecule is reduced?
It accepts electrons.
What happens when a molecule is oxidized?
It loses electrons.
What is this reaction called?
A Redox Reaction.
Mnemonic Strategy
LEO the lion says GER
Lose Electrons=Oxidize
Gain Electrons=Reduce
Where do H+ ions become highly concentrated?
In the Outer compartment
Are these ions freely permeable to the membrane?
No, so…how can they diffuse through the membrane into the inner compartment?
Through ATP Synthetase transport proteins.
Is the diffusion of H+ ions energy releasing or energy requiring?
Releasing
Is the formation of ATP from ADP energy releasing or energy requiring?
Requiring
Link these two statements in explaining the formation of ATP.
The energy released in the diffusion of H+ is required to form ATP.
How many ATP molecules can be created from the electrons delivered by NADH?
3/NADH
How many ATP molecules can be created from the electrons delivered by FADH2?
2/FADH2
What serves as the final electron acceptor in aerobic
respiration?
Oxygen
What happens to pyruvates if oxygen is not available?
Pyruvates stay in the cytoplasm and participate in Lactic Acid Fermentation pathways.
Diagram the lactic acid anaerobic respiration pathway that occurs in animals
2 3-C Pyruvates-->2 3-C Lactic Acid
2 NAD+ molecules are produced in this step
What products from lactic acid fermentation are re-cycled in
the respiration pathways?NAD+ to re-start glycolysis
How many ATP molecules per glucose are formed in lactic
acid fermentation?2 ATP’s/glucose
Why do you “feel the burn” when you are
exercising strenuously?
Lactic acid fermentationThere is a build up of lactic acid in the muscles due to anaerobic lactic acid fermentation.
Give two reasons why muscles can’t contract well when fatigued during strenuous
exercise.
1. Only get 2 ATP per glucose due to anaerobic respiration.
2. Lactic acid molecules build up in muscles and interfere with muscle contractions.
Why is it valuable that animals can respire
anaerobically?It allows animals to exert energy at a high intensity for a short period of time– times of stress for fighting or fleeing.
If we were not able to do anaerobic respiration, we would pass out when we had a decrease of oxygen
What kind of fermentation do yeasts and bacteria
undergo?Alcoholic fermentation
Diagram the ethyl alcohol anaerobic respiration pathway
2 3-C Pyruvates-->2 2-C Ethyl Alcohol + 2 CO2
2 NAD+ molecules are produced in this step
Compare: Photosynthesis and Cellular Respiration
Location: Where does each take place?
Photosynthesis happens on the chloroplast.
Aerobic Cellular respiration happens in the the mitochondria.
Both build up a concentration of hydrogen to power the transformation of ADP into ATP.
Compare -- Photosynthesis vs. Cellular respiration
Source of electrons:
Photosynthesis gets electrons from—breakdown of water molecules (photolysis).
Cellular respiration gets electrons from—breakdown of biomolecules in the Kreb’s cycle source of FADH2 and NADH.
Final electron acceptors=
NADP+ in photosynthesis
Oxygen in aerobic respiration.
CyclesPhotosynthesis has Calvin cycle….
adds carbon to make sugar.
Cellular Respiration has the….
Krebs cycle– breaks down biomolecules creates source of electrons and ATP for larger production of ATP
Compare--- Organisms that do photosynthesis and cellular
respiration.
Photosynthesis happens …only in plants.
Cellular respiration in both plants and animals.
ReviewCellular respiration –Three basic stages:
Glycolysis, Krebs Cycle, ETC.
Glycolysis yields 2 ATP
Aerobic respiration (Krebs and ETC) yields:
36 or 38 ATP
If no oxygen is available..
Fermentation begins and NAD+ is recycled back into..
Glycolysis which continues until…
Oxygen is available.
ReviewTwo kinds of fermentation:
Alcoholic and Lactic Acid
Alcoholic fermentation is done by:
Yeast, bacteria, fungus and creates foods like
Beer, wine, cheese, bread
Lactic acid fermentation happens in
animals and some bacteria. It causes..
Sore muscles after anaerobic exercise.
The EndGood Luck!