ALL DONE :0)
Key questions
1. How do enzymes catalyze decomposition and synthesis reactions, and in doing so illustrate how the shape of a protein is crucial to its function? DONE (I re-wrote the ending to help)
Polymers, in the human body, don't have enough energy to break the bonds between its monomers. This is where the enzyme comes into place. The enzyme is shaped similar to a Pac Man where the mouth (the active site) is specifically sized and shaped for a specific substrate (reactants). So when that specific substrate gets caught in the enzyme the enzyme starts to pull and twist the substrate by attracting the charges on the substrate to the opposite charges on the r-groups that make up the active site. This weakens the bond between the parts of the substrate enough, so that the energy of the impact when the enzyme collides with something (another enzyme, wall, ect.) the bond breaks and two smaller pieces. The reason this works is because the activation energy, the energy needed to break the bond, is decreased by the bend and twist on the bond. The activated complex forms when the enzyme combines with its substrate. It is during this time when the activation energy is lowered, either by applying stress on the bonds, or by aligning reactants during synthesis reactions. During synthesis reactions the shape of the active site is important because the shape forces the two different monomers to fit into the active site in a specific way allowing them to bond easier. An example of this is when two amino acids get bonded together in a synthesis reaction and create a dipeptide. The amino acids must line up with the carboxyl group of one next to the amino group of the other.
2. How would a change in pH alter the shape of enzymes? (Include in this answer an explanation of how the charges of carboxyl and amino groups are affected by the addition of acid and base.) DONE
Changes in the pH would alter an enzyme’s shape because of the change in charge of the carboxyl and amino groups. For example if a base like OH- is added it will cause a reaction with carboxyl groups. OH- ions will bump into the carboxyl groups and remove H+ protons from the carboxyl group. All carboxyl groups that have lost an H+ are now negatively charged. When OH- reacts with an amino group a H+ proton is removed making the amino group neutral. When an acid is added the opposite occurs. In an amino group when an acid is added the proton H+ is attached to the amino group, now NH3+. Similarly adding acid causes the carboxyl to gain an H+ now making it neutral.
When changes of charges on the R groups occur, this then causes the active site to alter its shape. The like charges on, say 2 amino groups that have become positively charges, are repelled from each other in an acidic environment, meaning H+ has been added, causing the 2 groups to repel each other and alter the shape of the enzyme. The same process occurs for 2 negatively charged carboxyl groups in a base environment, meaning OH- was added, causing the groups to repel. If there is a positive amino group and negative carboxyl group, then these 2 will attract, also causing a change in the shape of the enzyme. The reason this affects the shape of an enzyme is because the change in the charge of the R groups changes the ionic bonding between them. If the ionic bonding is changed the entire 3-D structure of the enzyme will be changed because of the different ways that the R groups will attract and repel each other.
3. How does the carbonic acid buffer system keep the pH of the blood constant when small amounts of acid and base are added to the blood? How does your breathing help you adjust to larger amounts. DONE
This is separate from the one above) Through the equation CO2 + H20→H2CO3→HCO3- + H(+), since all of these are present simultaneously, they can collide to create different things, therefore, making the equation move to the right or left. When CO2 and H20 bond, it makes the compound H2CO3, which is carbonic acid. Carbonic acid is a toxin to humans, and when there is too much carbonic acid in our bodies, it creates more H+ ions. A mass buildup of H+ ions (adding acid to your blood) can denature the protein, so when more H+ ions are present, the equation shifts to the left, in order to raise your pH to a healthy level. For example, when you hold your breath CO2 builds up in your blood due to cellular respiration. The CO2 build up causes more collisions to take place between CO2 and H20, so that means there are fewer collisions between the HCO3- and H+ since the CO2 is getting in the way of the HCO3 finding the H+ ions. In order to compensate for this our bodies use the “carbonic acid buffer system,” which is a chemical system that allows it to either absorb acid or base in order to keep the pH constant. The pH of human blood is 7.4, so in order to maintain a pH of 7.4, the body controls the rate of breathing which can either lower or raise the pH in order to achieve 7.4. Our brain tells our body to breathe more deeply in order to make the pH go up, so there is not an accumulation of H+ ions. They do not accumulate because the H+ ions are able to bond to the hydrogen in H2CO3 or H20 (the equation goes in reverse). We also deep breathe to get the H+ ions to go down because there is too much acid and we need to let out more CO2 faster. Our brain also tells our body to breathe shallow when there is not enough acid in the body, so there is a buildup of CO2 in your lungs at this time. For example, if you have less H+ ions, meaning there is a high pH, you need to breathe shallow slow breaths in order to get the pH levels to 7.4 The mass build up of CO2 in the body shifts the equation to the right BECAUSE THERE ARE MORE COLLISIONS BETWEEN H20 and CO2 BECAUSE there are more of them which causes them to collide more frequently AND FEWER COLLISIONS BETWEEN HCO3- and H+ BECAUSE the CO2 gets in the way of the HCO3- finding the H+ ion.
4. How is your breathing adjusted subconsciously to regulate blood pH? DONE
Our breathing is subconsciously adjusted to regulate blood pH by our brainstem, which contains our breathing control center. This breathing control center monitors the pH of the blood OF our cerebrospinal fluid – it realizes when the pH of our blood is too low or too high and sends signals through our nerves to the diaphragm and rib muscles to either make us breathe faster or slower, faster when more CO2 is being produced in cell respiration during exercise, so the CO2 is released, and slower when the pH levels are restored to normal.
Practice: For each set of terms, write a sentence or two to show a relationship between them.
1. enzyme, substrate, products DONE
—-The function of an enzyme is to break down substrates into products, or different water-soluble portions, in order for your body to absorb them. For example, the enzyme amylase breaks down carbohydrates in its active site, reducing stress between the bonds within the carbohydrate, making it easier to break down into different water-soluble portions.
2. decomposition reaction, active site, bonds DONE
Enzymes speed up decomposition reactions, such as hydrolysis, by lowering the activation energy of the reaction. When a substrate molecule enters the active site, or groove of an enzyme, the charges on the active site of the enzyme bond with the substrate molecule and began to apply pressure to the bonds holding the substrate molecule together. By applying enough pressure to these bonds, when another collision occurs, the activation energy has been lowered enough to break the bond completely. An example of this is when starch enters the active site of the enzyme amalyase, and the active site puts pressure on the covalent bonds in starch, ultimately decomposing it into glucose.
3. catalyst, energy of activation, reactants DONE
Enzymes are catalysts working within the human body. They are the only way to speed up the rate of chemical reactions in humans since we cannot speed up these reactions by raising our body temperature. We cannot do this because excessive heat denatures proteins and as a result, prevents body functions from happening. For example, enzymes lower the energy of activation in hydrolysis reactions by weakening the bonds of the reactants so they can break down quickly and easily.
4. lock and key, synthesis reaction, orientation DONE. I SHORTENED THE LAST SENTENCE. THERE WAS NO NEED TO WRITE ABOUT DECOMPOSITION REACTIONS TO SATISFY THE WORD REQUIREMENTS. MENTIONING DECOMPOSITION REACTIONS IN THE SAME SENTENCE AS SYNTHESIS REACTIONS WAS CONFUSING TO ME AS WELL
Enzymes have an active site where substrate molecules bind with it like a "lock and key". This makes the enzymes have a specificity that requires the substrate molecules to be correctly oriented during a synthesis reaction.
5. hydrogen bonds, renatured protein, shape DONE
Hydrogen bonds occur in a protein if two or more atoms are polar, which will alter the shape of the protein causing it to have its own distinctive shape. A change in temperature can break these hydrogen bonds, changing the shape of the protein. This is called a denatured protein, or a protein with an altered shape. However, if the temperature returns to normal, the hydrogen bonds will reform, creating a renatured protein, or a protein that has returned to its correct shape.
6. amino group, base, positive DONE
An amino group is an example of a potential part of an R-group for a protein. If you add acid (H+) to an amino group then the hydrogen ions in the acid link to an unshared electron pair on the Nitrogen atom. The chemical formula then becomes NH3+ transforming the amino group from a partial negative charge to a positive charge. However, if base (OH-) is added to the protein then the amino group will lose the positive charged hydrogen ion because the hydroxyl ions will attract the hydrogen ion to form a water molecule separate from the amino group.
7. charge, tertiary structure, R groups DONE
The charges on the R groups in a protein determine how the amino acids will bend and twist. For example, if two amino acids with positive charges are bonded together, they will repel each other, causing the protein to bend. In doing so they will determine the tertiary structure, or complex 3-d structure, of the protein. The tertiary structure is determined by the charges on the R groups and how they shape the protein's tertiary structure
8. hydrogen peroxide, water, poison DONE
Within a cell, water and oxygen is always present. Occasionally, these compounds combine to form hydrogen peroxide (H2O2). Hydrogen peroxide is poisonous when it is inside a cell and leads to death. The enzyme, peroxidase exists to prevent this from happening. It shifts the reaction that creates hydrogen peroxide to the right so the H2O2 breaks down into harmless H2O and O2. (2H2O2 ←peroxidase→ 2H2O+O2) When the peroxide is converted to water, the oxygen gas (O2) evaporates out so the reaction cannot shift back to the left, so it cannot revert back to hydrogen peroxide.
9. breathing, pH, cerebrospinal fluid DONE
Our breathing is regulated by the breathing control center, which decides whether to breathe faster or slower by monitoring the pH of our blood and our cerebrospinal fluid.
10. rib cage, diaphragm, inhalation DONE
Inhalation is controlled by the breathing control center in our brainstem. When our blood is too acidic or basic (doesn’t have an approximate pH of 7.4), the breathing control center sends signals through our nerves to make our rib cage and diaphragm move as we inhale and exhale. When we inhale the muscles in our between our ribs contract, raising the ribcage. While this is happening our diaphragm lowers causing the chest cavity to expand. When the chest cavity expands this causes a lower pressure in our lungs causing air to flow in to them. When we exhale our diaphragm raises up and our rib cage drops back down, causing our lungs to shrink and force the CO2 and air to come out. This lowers or raises the pH of our blood so it maintains the healthy average of 7.4.
