2/10 – Wednesday – “B” Day –period 7B, 8B– I 7(B) 8(B,D) AP BIOLOGY – (double period Lab)
-period 7B, 8B -R 7(B) 8(B,D) AP BIOLOGY – REMOTE INSTR
2. Complete the worksheet below and Review with the Key:
I had the wrong worksheet posted! Thanks Patricija!
3. READ my notes below: Connections!
Acidic solutions (pH that is lower than 7) and basic (pH that is higher than 7) solutions
can potentially be harmful to enzymes due to the fact that these tertiary proteins have R groups that will change according to pH of the solution.
Acidic R groups have -COOH endings that will become -COO– (have a negative charge) because the H+ will be taken by the base in a basic solution. So proteins that have amino acid that have R groups that are acidic will become negatively charged and they will attract other R groups that are positively charged. If the R groups change their attractive partners then THEIR SHAPE and thus THEIR FUNCTION changes. (Basic R – groups will also become charged (+) in the higher pH solutions.)
So R – groups that have ionic attractions will be be affected by slight changes in pH because there will more ions in the solution that these R could attract too. This means that changes in the pH will cause changes in the amount of H+ and OH- in the cell which will cause the R groups of amino acids to attract the H+ (if the R group is negative) and attracts the OH- (if the R group is positive) AND thus change the shape of the tertiary folded protein. Changing the shape is called denaturing and denaturing changes the function of the protein when the active site is changed.
Form and Function!
So Arginine, Histidine, Lysine have positive R groups that will be affected by OH– (Bases)
Aspartic Acid and Glutamic Acid have negative R groups that will be affected by H+ (acids)
Proteins (enzymes) that have less of these amino acids with these R groups will be more resistant to pH changes and will denature at lower or higher pH’s as compared to enzymes that have more of these amino acids.
Remember the 4 types of attractive forces that occur in folded tertiary proteins:
Remember that tertiary proteins are long chain polypeptides (amino acid linked together) that take an active form (shape) by the R groups attracting each other. There are 4 types:
a) Ionic – positives attract negatives
–H+ and OH– compete with these!
b) H – bonding – electron deficient Hydrogens
– Strongest attractive force
c) Disulphide Bridges – Sulfur bonding to Sulfur
– Strongest force (chemical bond)
that keeps R groups together
d) Hydrophobic – LDF’s – (non-polar attractions)
– weakest attraction
A permanent change in the shape of the protein is called DENATURING. A denatured protein or enzyme will have no enzymatic properties as the active site will no longer have the shape to interact with the substrate.
Enzymes can become denatured if the temperature is too high as this high energy state will cause R group attractions to break and unfold the protein. “How did the Boiled enzyme do in our lab?“
Remember the Taq polymerase in our PCR – Taster Lab? Taq polymerase is an enzyme that has a higher temperature tolerance that most enzymes do not have . It is an example of the heat tolerant bacteria (Thermostable)that is in the graph below. They have a lot more disulphide bridges R group connections which are actually chemical bonds, and much less hydrophobic R – attractions in our folded proteins.
All enzymes have optimum pH ranges and optimum temperatures that they work most effectively:
SO DNA does not just code for the amino acids that make certain shapes they also code for certain amino acid combinations that can make them more or less stable in certain environment.
4. Complete the Form Below: You will only have 1 submission to the form tonight.
Please look over the data from Sintia and Will to answer questions regarding Catalase activity for some questions.
2/11 – Thursday – “C” Day – period 7C, 8C -I 7(C) 8(A,C) AP BIOLOGY – (double period Lab)
– period 7C, 8C –R 7(C) 8(A,C) AP BIOLOGY – REMOTE INSTR
The RED team is Remote today!
Catalase Lab – REVIEW:
– Quick review of pH!!
1. Complete the catalase lab in terms of the graphs!
The reaction from the lab : H2O2 –> O2 + H2O + Heat was moving toward Equilibrium!
Also because group placed 3 ml of hydrogen peroxide with 7 ml of catalase there was an initial very fast reaction rate but it decreased quick as most of the substrate was reacted and used up. The forward reaction was becoming less spontaneous and the reverse was becoming more spontaneous!
-Another concept that you need to understand is that if you increase the substrate too much you could reach the limit of the enzyme. That means you could be reaching the substrate saturation point where the enzyme is at its fastest and having more of the substrate will not make the reaction go any faster.
Catalyzed reaction – (what biological enzymes would do)
Catalyzed reaction – (what biological enzymes would do)
A catalase demo:
Todays Demo: 2H2O2 -> 2H2O + O2
Very small rate of reaction until a catalyst was added.
Just lowering the Ea (activation) but not increasing the ΔG .
Green Monster Demo:
This was a catalyzed reaction that lowered the activation energy and increased the rate of the reaction.
2. Reviewed Cell Respiration basics – Proton motor force with videos of ATP -synthase
Cellular Respiration Overview – Note taking started!!
Complete oxidation formula: when you combine all 3 parts of cellular combustion
Complete Cellular Respiration Formula:
C6H12O6 (s) + 6O2 —–> 6CO2(g) + 6H2O (l)
glucose –> Electron Carriers (NAD+, FAD) –> Electron transport System (Oxygen bonds with H+ to make H2O)
High Energy oxidize glucose high energy electrons used to pump H+ ions against gradient
Electrons these H+ rush out of membrane giving atp synthase energy
2/11 – Thursday – “C” Day Homework:
1. Complete the Catalase Lab – NOT DUE Friday!
I will give more time when we come back from break!
On the back of the lab please
a) list each independent variable that was tested
b) Explain the outcomes based on your knowledge of enzymes, collision theory, or
energy why each variable caused each outcome.
2. Make another submission on the Connections Form from last night. I have graded it and emailed your grade.
2/12 – Friday – “D” Day – period 7D,8D – I 7(D) AP BIO ACADEMIC STUDY / 7(B) 8(B,D) AP BIOLOGY
– period 7D,8D – R 7(D) REMOTE INS / 7(B) 8(B,D) AP BIOLOGY REMOTE INSTR
The Blue team is Remote Today.
1. Continue with note -taking
A) with Glycolysis
B) Kreb’s Citric Acid Cycle –
C) Electron Transport System, Oxidative Phosphorylation
REDOX Reactions – Gaining and losing or electrons-
1. REDOX : Who is getting oxidized and and reduced: Slide 9 – 17 in Cell Respiration presentation
NAD+ + H+ + 2e– —-> NADH
FAD + 2e– + 2H+ —> FADH2
Yesterday we learned that the energy that we harness from glucose (from the food we eat) is due to high energy electrons that exist in C – H bonds. These electrons are shared equally because the Carbon and the Hydrogen have almost the same attraction for electrons which allows electrons to have the most freedom. Electrons with the most freedom have the greatest potential energy. When they are held closer to one or another atom the electrons “feel” the nucleus more thus have less potential energy.
The “slow” burn of glucose occurs as we take the high energy of the C-H electrons and convert them into lower energy electrons. This is accomplished by slowly taking these electrons away from the glucose in each stage of cellular respiration ( Glycolysis, Pyruvate oxidation, Citric Acid Cycle, Oxidative Phosphorylation) and combining with the final electron acceptor, oxygen and water is made. In water the electrons are held more tightly or are pulled more to the oxygen (who loves to grab electrons) These electrons are held closer to one of the atoms in a bond and have less freedom leading to a release of energy which is used to make ATP.
Do not forget there is whole host of enzymes that catalyze the many steps needed to slowly grab the high energy electrons. There are also co-enzymes (vitamins!) that help carry these electrons into electron transport system. They include NADH (Vitamin – Niacin), FAD (Vitamin – Vitamin B2 – riboflavin).
Do some vitamins give us energy? No but they help get the free energy!!! to create 34 ATP