Transcript protein

Enzyme Review
 Are 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 Review
 Biology 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?
Carbon
It 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 molecules
 A Hydrogen Bond
What is the relative strength of
these bonds?
 Covalent/ Ionic >>>>>>>Hydrogen Bonds
pH scale
1-14
 What 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
Lipids
 Monomers 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)
Proteins
 Monomer 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
Polar
 Size
 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 TransportRemember-- no additional energy
required
 Diffusion
 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 input
 Endocytosis– 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 REVIEW
aka.. 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
Anaphase
 Duplicated
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 End
 Good luck!
Photosynthesis
 Is 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.
ATP
 How 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 Lab
 What 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 Equations
Photosynthesis: 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 fermentation
 There 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.
Cycles
 Photosynthesis 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.
Review
 Cellular 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.
Review
 Two 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 End
 Good Luck!