1. HOW do Enzymes Work? WHAT are ENZYMES??? Enzymes…
Name: ___________________ Unit 5: Enzymes and Cell Energy Per. __________
WHAT are ENZYMES???
Enzymes…
Are CATALYSTS: that speed up chemical reactions that would otherwise happen too slowly to support life. Catalysts DO NOT make reactions happen that couldn’t happen by themselves.
Are PROTEINS. Their amino acid sequences determines their shapes, which are important for their functions.
Are not consumed during the reaction—the same enzyme can be used repeatedly
AND, BECAUSE of its shape, an Enzyme…
SUBSTRATES
ENZYME
PRODUCTS
ACTIVE SITE
ENZYME-SUBSTRATE COMPLEX
Is specific to the reaction it catalyzes. The reactants (called substrates) fit perfectly into a place on the enzyme called the active site.
The shape of the enzyme active site makes it substrate-specific.
Where the enzyme and the substrate fit together is called the enzyme-substrate complex.
Finally, the products are released from the active site, and the enzyme can be reused over and over again for more reactions.
Said to be like a lock and key b/c the shape is so specific.
Only functions in narrow pH and temperature ranges, where it has the proper shape.
changing the temperature or pH (acidity) may change an enzyme’s shape
It may no longer stick to its substrates, and therefore not function.
An enzyme that has lost its proper shape and does not function is said to be denatured.
HOW do Enzymes Work?
TEMPERATURE
PRODUCTS MADE (ENZYME FUNCTION)
37°C
ENZYME WORKS BEST AT THIS CONDITION
DENATURED ENZYME
An enzyme lowers the activation energy of a reaction
Make the reaction happen faster/easier
What biomolecule group do enzymes belong to?
What does activation energy mean?
What happens to the enzyme if you raise the pH or the temperature?
An Enzyme is like a lock and key, what does that mean?
What is A? ______________________________
What is B? ______________________________
What is C?_______________________________
What is D?_______________________________
What is E?_______________________________

2. CHEMICAL ENERGY AND LIFE
Enzymes work by lowering the activation energy of a reaction. A chemical reaction that might otherwise occur once every thousand years can happen in milliseconds with the help of the proper enzyme.
CHEMICAL ENERGY AND LIFE
ENERGY is the ability to do work.
Cells require energy for metabolic reactions, active transport, cell division, and maintaining homeostasis.
Heterotrophs (consumers): obtain energy from food.
Autotrophs (producers): obtain energy from the sun, through the process known as Photosynthesis.
Which occurs in the chloroplast
The Equation for photosynthesis: CO2 + H2O + energy → C6 H12 O6 + O2
Glucose (C6 H12 O6 ) is the preferred energy source, but we can obtain it from other carbs, lipids and even proteins
CHEMICAL ENERGY in food is stored in chemical bonds as potential energy.
When bonds are broken, the energy of electrons is released. Some energy is lost as heat, but some portion of it can be converted into a usable form in the bonds of ATP.
We use ATP energy to “pay for” reactions
ATP is a better form of energy because it contains smaller packets of energy than glucose
If we released the energy from food molecules (like glucose) all at once, it would be wasteful and destructive
What is cell energy? ________________________________________________________________
What do cells use the energy for? __________________________________________________________ ____________________________________________________________________________________________
How do humans get energy? ____________________
How do plants get energy? _________
What is the preferred energy source? ________________
Where is chemical energy stored? __________________________________________________________
When bonds are broken is all the energy converted into ATP? _________ What is it lost as? ________________
What would happen if our bodies released all of the energy found in glucose at once? __________________________________________________________________________________________

3. ATP- Adenosine TriPhosphate: Cell Energy
ATP, Adenosine TriPhosphate is a nucleotide composed of:
Adenine, a nitrogen base
Ribose, a 5 carbon sugar
Three phosphate groups
Potential energy is stored in the phosphate-phosphate bonds
ATP is like a rechargeable battery
ATP = “charged” (3 phosphates), high Potential Energy
ADP (Adenosine DiPhosphate, 2 phosphates)= “uncharged”, low Potential Energy
Adenosine means: Adenine nitrogen base (Aden__ine) + Ribose Sugar (os)
Tri- 3
Phosphate- Phosphate groups attached
What does Adenosine mean? ________________________________________________________________
What does Triphosphate mean? ______________________________
How is the energy release from ATP? ______________________________________________
When energy is released ATP is turned into? _________
How is energy “recharged”, what has to be added back? ________________
When it is “recharged” ADP turns into ______________
Where is chemical energy in ATP stored? ___________________________________________________
Why is ATP used instead of glucose directly? __________________________________________________________________________________________
What cell organelle makes energy (where does this process occur in the cell)? ______________________________

4. Name: _____________________________ Per.__________
METABOLIC PATHWAYS: CELLULAR RESPIRATION AND PHOTOSYNTHESIS
METABOLISM: Breaks down or builds up materials the cell needs.
The chemical processes occurring within a living cell, Necessary for maintaining life
Uses enzymes
METABOLIC PATHWAYS: a series of sequential reactions in which the product of one reaction is the reactant for the following reaction.
TWO major metabolic pathways in life:
PHOTOSYNTHESIS
Light energy from sun is converted to chemical energy in the form of glucose
CELLULAR RESPIRATION
Organic molecules (like glucose) broken down to release energy for cell use
The relationship between these two pathways results in the continual flow of energy within an organism as well as within an ecosystem.
Plants and other organisms that can make their own food are known as autotrophs (producers)
Humans and other organisms that have to obtain food are known as heterotrophs (consumers)
Are things only broken down during metabolism? _______________
What is a metabolic pathway? ___________________________________________________________
_______________________________________________________________________________________
2. What are the 2 major metabolic pathways of life? __________________________________________
3. Looking at the picture, what is produced during photosynthesis? ___________________________
4. Looking at the picture, what is produced during cellular respiration? ________________________
What is an autotroph? ____________________________________________________________________
What is a heterotroph? ____________________________________________________________________
Is cellular respiration needed to run photosynthesis? _______________ Why? _________________ ____________________________________________________________________________________________
Is photosynthesis needed to run cellular respiration? ______________ Why? __________________ ____________________________________________________________________________________________

5. STEPS OF PHOTOSYNTHESIS:
Photosynthesis is the metabolic pathway that provides energy for most ecosystems
Occurs in the chloroplasts of plants and other photosynthetic eukaryotes like algae
Occurs in cyaneobacteria—photosynthetic bacteria
Overall Equation:
___________________________________________
CHLOROPLASTS: Abundant in the leaf cells of most plants
PIGMENTS: light-absorbing colored molecules act like antennas for absorbing energy
Different pigments absorb different wavelengths of light
Chlorophyll—most abundant pigments, absorb violet-blue the strongest, reflect green
STEPS OF PHOTOSYNTHESIS:
LIGHT-DEPENDENT REACTIONS: requires light
Chlorophyll absorbs light energy and uses it to excite, and strip away electrons from H2O
Water broken apart, forming O2 gas
High energy electrons are passed along an electron transport chain (ETC) used to make ATP
Waste product of Light-Dependent reaction is O2 gas
CALVIN CYCLE (Light-independent rxns)—does not require light,
CO2 gas is used as a source of carbon and oxygen atoms to make glucose.
ATP is used as a source of energy
Waste product of Calvin Cycle is Glucose
FACTORS AFFECTING PHOTOSYNTHESIS:
Light —more light, more photosynthetic activity
Water —needed to supply electrons. Not enough water, slow or no photosynthesis
Temperature —photosynthesis depends on enzymes that functions best at 0-32 C
What energy does photosynthesis provide? _____________________________________________
What are the 3 things needed to go into photosynthesis? __________________________________
What are the products of photosynthesis? __________________________________________________
What is the waste produce of the Light dependent reaction? _______________________________
What is the waste product of the Calvin cycle reaction? ____________________________________
What is the most abundant light absorbing pigment that performs photosynthesis? _________
What type of organisms can perform photosynthesis? ______________________________________

6. CELLULAR RESPIRATION Glycolysis
CELLULAR RESPIRATION - AEROBIC (requires O2) ENERGY PRODUCTION (pp )
Cellular respiration is the breakdown of glucose in the presence of oxygen to “make” ATP.
The oxygen required for cellular respiration is inhaled into the lungs, diffuses into the blood, and is delivered to the mitochondria of the body cells by red blood cells.
The glucose needed is obtained through digestion. The glucose is transported in the blood and enter the body cells via facilitated diffusion by protein channels.
Remember that this happens even in autotrophs like plants, too! (Plants DO require oxygen, but they produce more than they need)
OVERALL EQUATION: ____________________________________________________________________
Major parts:
Glycolysis
Krebs Cycle
Electron Transport Chain
KEY PLAYERS:
ATP, the final energy molecule
Glucose, a six-carbon monosaccharide
O2 gas, the final electron acceptor of the ETC
Pyruvic acid, a three-carbon product of glycolysis
CO2 gas and H2O
Electron Carriers: carry high-energy electrons
What does Aerobic mean? ___________________________________________________________________________
What has to be broken down during cellular respiration? ___________________________________
What is made during cellular respiration? ____________________________________
The glucose needed to run cellular respiration is obtained through _____________________________
How is the glucose transported into the body cell? __________________________________________________
What type of organisms perform cellular respiration? ________________________________________________
What are the 3 steps for cellular respiration? _______________________________________________________
What are the reactants for cellular respiration? ______________________________________________________
What are the products for cellular respiration? _______________________________________________________
How do we get the oxygen that is needed for cellular respiration? __________________________________
How is the oxygen transported into the blood cells? _______________________________
Where in the cell does cellular respiration occur? (what organelle) __________________________________

7. RESPIRATION STEP 1: GLYCOLYSIS RESPIRATION STEP 2: KREBS CYCLE
Glycolysis – Means “sugar-breaking”.
Occurs in the cytosol of the cell.
does not require oxygen.
The splitting of glucose, or glycolysis, occurs very quickly with the aid of enzymes, producing two 3-C molecules known as pyruvic acid.
In addition, when the bonds of glucose are broken, some high energy electrons are produced.
Glycolysis requires 2 ATP to occur, but results in the formation of 4 ATP, for a net gain of 2 ATP.
Reaction: C6 H12 O ATP → 2 pyruvic acid ATP + 2 high energy electrons
Net Energy Gain = 2 ATP + 2 high energy electrons
Series of reactions that occur in the mitochondria, in which the energy stored in pyruvic acid is released in the form of high-energy electrons when bonds are broken and pyruvic acid is completely broken down to CO2.
What’s made:
2 ATP produced
High energy electron
CO2
Wastes Generated = CO2
start
PAYDAY
Krebs Cycle + 4 2
STEP 3: ELECTRON TRANSPORT CHAIN (“PAY DAY”)
the electron carriers, “dump” their High energy electrons. These electrons are passed along a series of molecules embedded in the inner membrane of the mitochondria of eukaryotic cells.
This same process occurs in the cell membrane of prokaryotic cells.
As the electrons “fall” down the ETC, the energy they release is used to power an enzyme known as ATP synthase, which attaches phosphate groups to ADP to produce ATP.
This process is known as oxidative phosphorylation because oxygen must be present. It is the electronegativity of oxygen that “pulls” the electrons down the ETC. As the electrons are collected by oxygen, water is produced from oxygen.
Net Energy Gain = __~ ATP_______
Waste Product: Water

8. xx Total ATP= ______ STAGE WHERE # ATP Needs O2? Wastes
GLYCOYSIS xx
KREBS
CYCLE
ELECTRON
TRANSPORT CHAIN
Total ATP= ______
Look on the previous page to find the answers to the following questions:
What is the 1st step in Cellular respiration? ________________________________
What is needed to start the 1st step of Cellular Respiration? _____________
What is broken down during the 1st step? _________________ which is turned into _____________ acid and ___________________________ electron with a net gain of _______ ATPs.
Where in the cell does the 1st step occur? ______________________________
What is the 2nd step in Cellular Respiration? ____________________________________
During the 2nd step ______ ATP are produced along with a ____________________________________ and the waste product is ________________
Where in the cell does the 2nd step occur? ______________________________
What is the 3rd step in cellular Respiration? ________________________________________
During the 3rd step the enzyme ________________________ is responsible for adding the 3rd P to ADP and turning it into __________.
At the bottom of the 3rd step ________________ has to be present to collect the high energy electron and it is then turned into ___________________ (the waste product).
Where in the cell does the 3rd step occur? ______________________________
The total ATP produced during the 3rd step is _____________
The total amount of ATP produced in all 3 steps is ____________________

9. ALTERNATIVE PATHWAY : ANAEROBIC (WITHOUT OXYGEN) FERMENTATION
The Krebs Cycle and ETC depend on oxygen (they are aerobic) to take electrons from the electron carriers. If no oxygen is present, the high energy electron carriers will all fill up with high energy electrons and have no where to put them, and cellular respiration comes to a halt.
A backup mechanism exists called anaerobic fermentation.
In anaerobic conditions, the cell still uses glycolysis and generates 2 ATP and 2 pyruvic acid, along with 2 high energy electron .
The cell can empty the electron carriers by converting the 2 pyruvic acids into other chemicals. Either Lactic Acid OR Alcohol
LACTIC ACID FERMENTATION: In human muscle cells, pyruvic acid is converted to lactic acid
Lactic acid buildup contributes to the muscle soreness experienced during intense exercise
Some bacteria and fungi do this and are important in producing the lactic acid in cheeses and yogurt
ALCOHOLIC FERMENTATION: In yeast and some bacteria, the pyruvic acid are converted to alcohol. This is important in commercial brewing and baking. (bread, beer & wine)
Overall, much less energy (only 2 ATP compared to 32) is produced by fermentation
What does Anaerobic mean? _______________________________________________________________
What part of Cellular Respiration can continue to occur if there is NO oxygen? _____________________
What two steps would stop? _______________________________________________________________________
When Oxygen is NOT present what process does cellular respiration switch to? ______________________
Those ATP produced during fermentation are then used to keep what part of cellular respiration going? __________________________________
What type of fermentation do humans, go through? _________________________ and it causes ________________________________________________________________________
What type of fermentation do some bacteria and fungi go through? ______________________ and it makes __________________________________________
What type of fermentation does Yeast & Bacteria go through? ______________________________ and it makes ______________________________________________________________
How many ATPs are produced during Fermentation? ________________, SO… if you start with 2 molecules of glucose and the body switches to fermentation how much ATP is produced? _________
How many ATPs are produced during cellular respiration? ______________ So… if you start with 2 molecules of glucose and the body goes through cellular respiration, how many ATPs are made _______