BIO 110 Exam Study Guide 2 CH. 5-8 Part 1
BIO 110 Exam Study Guide 2 CH. 5-8 Part 1 BIOL 110
University of Louisiana at Lafayette
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This 40 page Study Guide was uploaded by Kaylen Harrison on Sunday October 2, 2016. The Study Guide belongs to BIOL 110 at University of Louisiana at Lafayette taught by Patricia L. Mire-Watson in Fall 2016. Since its upload, it has received 122 views.
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Date Created: 10/02/16
Study Guide Exam 2 Kaylen Harrison CH. 5 1. Distinguish between transmembrane proteins, lipid anchors, and peripheral membrane proteins. Which would be easiest to remove? Transmembrane proteins o Membranes that pass all the wat through the hydrophobic region of the bilayer (two layers of phospholipids) o On one side of the membrane there's one part of it that sticks out of the membrane and out on the other and goes all the way through Lipid anchor proteins o Proteins that are covalently attached to a lipid o Lipids are part of the membrane o These are covalently attached Covalent (strong bond) o The reason it’s still integral is b/c its protein is covalently attached to the lipid so together they make up one whole molecule Peripheral o They hang out on the outside of the lipid bilayer and not covalently attached to anything o Non covalent bonds make them hold on to the surface regions of integral membrane proteins, or to the polar head groups of phospholipids. Ex. Of noncovalent interaction: Hydrogen bonds Van der Waal Ionic Hydrophobic interactions o Fig. 5.2 Go all the way through the phospholipid bilayer The parts that are sticking out of the membrane are hydrophilic because the cytosol is watery Middle part that goes through the fatty acid tail region=hydrophobic So this is amphipathic If you have another protein hanging out with the transmembrane protein and there's no covalent interaction that’s allowing the attachment to occur then the green protein is the peripheral protein and it can be on either sides, but this one happened to be in the cytosol Lipid linkedyou can see the protein covalently attached to a lipid Even though it looks like a peripheral protein, its covalently attached to the lipids and its stuck there Peripheral membrane proteins would be the easiest to remove because they are the ones that are not strongly attached to anything. They have non covalent interactions such as hydrogen bonds, Van der Waal forces, ionic bonds, and hydrophobic bonds which are all weak bonds individually. 2. List factors that affect membrane fluidity and explain how and why. Length of fatty acid The fatty acid tails are all hydrophobic Hydrophobic interaction: where things that are hydrophobic like to hangout with each other The longer the tails are, the more hydrophobic interactions there can be, so this makes the membrane more solid/ less fluid. Shorter tails =fewer hydrophobic interactions Presence of double bond in the tail A fatty acid with a double bond is unsaturated Single bond =saturated If they’re saturated, then they're all straight, so they can get really close together But if we have a kink in our tail then we have a covalent bond. That bond is what causes the kink The kinks represent bends in the tails, causing them to move father apart, making the membrane more fluid The saturated makes it more solid b/c all of the saturated ones have straight tails and are compacted real close together and that makes it more solid. Less fluid. More solid=less fluid So where you have unsaturated fatty acids in the phospholipids, you're going to have more fluid membranes there Presence of cholesterol Is complex Effects depend on temperature but it also tends to stabilize the membrane. Make it less fluid Stabilize =making less fluid Single bond =saturated 3. What is glycosylation? Why is it important in membranes? Glycosylation : gently attaching a carbohydrate to a protein or lipid On membranes of many kinds, especially of animals, there's a sprinkling of sugar on the membrane=A sugar coat Sugar coat =glycocalyx A shield Sugars attached to a lipid =glycolipid Sugars attached to a protein=glycoprotein These are important in cell to cell recognition When one cell meets up with another cell, one of the ways that they recognize each other is by noticing the sugar coats That is important for knowing that the cells in your body belong in your body and important for recognizing cells that are foreign and don’t belong in your body. Also helps cells to recognize what kinds of cells they are to each other The sugar plays a role in cell migration The sugar can absorb water Water sticks to the sugar b/c sugars are polar and water is polar Makes the cell have a slippery, slimy coat and allows cells to squeeze around and move around in your body Ex. White blood cells There are particular types of white blood cells that leave your blood vessels when you have an infection of some kind When the infection takes place, the blood cells without the infection start to crawl along the wall of your blood vessel And when they get to a space between the cells making up the wall of the blood vessel, they squeeze in between the space And they go out into the tissue and they'll find the bacteria that is causing the infection and gobble it up So b/c of their glycolayx they can do that 4. What does it mean to say that plasma membranes are “selectivity permeable”? o "Selectively permeable" Things can go in and out that are selected This allows to be sure that essential molecules can come into the cell, and waste products and other things can get out of the cell and for the things that need to stay in the cell, like the metabolic intermediate that needs to be used for things, can remain inside the cell 5. Define diffusion, passive diffusion, facilitated diffusion, and osmosis. o Diffusion : The movement of anything A substance from an area where there is more of it to an area where there is less of it The reason things diffuse like that has to do with the fact that they are always going to be in motion (kinetic energy) The tendency of the universe is to make things disordered so you have a collection of molecules and they are al in one area so that’s a very ordered space as opposed to be spread out everywhere There are solutes (substances dissolved in a solvent that will want to move from where there is a higher concentration to where there is a lower concentration) But if the substance is hydrophilic, it wont be able to pass through the membrane (lipid bilayer) to diffuse through the phospholipids (to diffuse from one side of the cell to the other) b/c it cant pass through the hydrophobic interior If they're hydrophilic they're going to need a transport protein to help them move through The only molecule that can move through the lipid bilayer without the help of a protein (just through the phospholipids) are the things that are hydrophobic and small Ex. Steroids can pass through b/c they're small Anything too large and hydrophilic wont be able to do it Gases can do it b/c they’re small and in the gaseous state, so they have a lot of kinetic energy that can put it through o Passive transport: There are different types of transports of substances that occur across the membrane Passive transport=cell doesn't have to use any of its own energy to move that substance Substance is going to move by its own kinetic energy 2 types of passive transport that cells participate in: i. Passive (simple) Diffusion: When a solute diffuses through the membrane without the help of a transport protein So what kind of molecules will be able to pass through the membrane without the help of a transport protein???? Hydrophobic b/c it’s relatively small Steroids b/c they're small Gases ii. Facilitated Diffusion: Cell is still not using its energy to move the molecule. Its still passive transport. The cell hasn’t expended any energy to move the solute across, but there has to be a protein there to make it safe for that substance to pass o Fig. 5.10a substance moving from the top towards the bottom Its pass through the lipid bilayer This is a passive transport and specifically passive diffusion At the bottom have a substance moving from the top to the bottom and it’s a higher concentration here Still a passive transport, but now there's a protein that provides a passageway for it to safely cross ==Facilitated Diffusion Blue molecule=hydrophilic Only hydrophilic molecules or molecules that are sometimes too large to go through the lipid bilayer would use facilitated diffusion There has to be a concentration gradient for facilitated diffusion There's nothing forcing the molecules to move here There moving by diffusion and they are going through the passageway made by the protein o Osmosis The movement of water across the membrane This affects both plant and animal cells, but plant cells have a better way of dealing with it than animal cells do Water is going to want to diffuse through a membrane from where there is more water, to where there is less water And if solutes can’t move across the membrane, then the water will move across the membrane All cells have an electronic pressure (refers to how much pressure is there on water to move into the cell) If animal blood cells, such as red blood cells are in a isotonic solution, the concentration of the solute across the cell is equal So there will not be any net movement across the red blood cell So there's still some water molecules coming from and then leaving, there's just the same number doing it these cells are not going to be happy cells it's important that the fluid (plasma) surrounding red blood cells concentration be the same as your cytosol concentration in red blood cells What happens if the plasma becomes hypotonic to your cells? There's less solute on the outside of the cell which means there's more water And the solute can't move, but the water can move into those cells. They swell and turn into little water balloons and they'll pop. This is called cytolysis. And when red blood cells pop, if enough of them pop, then you die. Salt water could cause the pop Salt causes a higher concentration then your plasma The salt concentration in the bottom (fig. 5.15) is higher in the solution than in the cytosol. So it’s a hypertonic solution. The solutes can't move but water can, so higher salt on the outside means lower water. Water will leave the cells and then shrink. This is called crenation. Crenation= when cells turn into little raisins in animal cells Plasmolysis=when cells shrink in plant cells o Cells don’t burst when put in hypotonic solutions o As water comes into the cell, the water gets stored into this large bubble which is the central vacuole o b/c the water is being put in a special space, its not out in the cytosol diluting all of the proteins and stuff in there. Its stored in the vacuole which is helpful. o This will increase its size as more water comes in and its going to start pushing on the cell wall. So once it gets filled enough, it puts a pressure onto the cell wall. The cell wall is rigid so its going to push back and that pressure of the cell wall is called turgor pressure. Turgor pressure forms when plant cells are in hypotonic solutions. o If cells stay like this for too long, they will die, but if they take in water soon enough, they can just reexpand again and get their turgor pressure again 6. Assuming only water can diffuse across a cell membrane, draw a picture of an animal cell in an 1) isotonic solution 2) hypertonic solution 3) hypotonic solution. o Tonicity Tonic=refers to solute Isotonic, hypertonic, hypotonic Refers to what the solute concentration is like across the membrane They're all used to compare a solution on one side of the membrane and 2 of the solutions on the other side of the membrane Isotonic Iso=the same on both sides Concentration of the solute is the same on both sides of the membrane Equal water and equal solute If solution is made up of a solute in water and the solute concentration is equal on both side, the water concentration also has to be equal Hypo=means less Less concentration than the other Hyper=means more Higher concentration than the other What you are can change depending on what's on the other side Can't just say the solution is hypertonic. Makes no sense. Hypertonic to what?? The cell. The cytosol is a solution so have to say to the cytosol Ex. The isotonic solution is hypertonic to the cytosol. If the solute concentration come across a membrane, it determines whether or not the solutions are iso, hypo, or hypertonic Water concentration also matters b/c the solute is dissolved in water o 7. Assuming only water can diffuse across a cell membrane, draw a picture of a plant cell in an 1) isotonic solution 2) hypertonic solution 3) hypotonic solution. 8. What are membrane channels? o Fig. 5.17 A protein that provides an open safe passageway for solutes to diffuse Channels participate in facilitated diffusion b/c the molecules still diffuse from where there's more of them to where there is fewer of them Molecules are still moving on their own by diffusion, but the protein is still providing the safe passageway Cells don’t have to use their own energy to make the molecules move Channels that are in cell membranes that provide passageway for water Ex. Kidney cells Red blood cells These have aquaporin's (water channels) 9. Distinguish between the 3 types of transporters. o Difference depends on how many substances they move and relative direction of those substances Uniporter One molecule or ion being moved by transporter Symporter (Co transporter) Two or more ions or molecules being transported in the same physical direction Antiporter (opposite) Two or more ions or molecules being transported in opposite physical directions These can be used for either passive or active transport 10. Distinguish between primary active transport and secondary active transport. Give an example of each. o Active transport Energetically unfavorable and requires input of energy Cell has to use energy to move these substances Movement of the solute from low concentration to high concentration (against gradient) Primary Active Transport uses ATP directly as a source of energy to transport the solute Secondary Active Transport Using concentration gradient of another substance to move a different substance against its concentration o Fig. 5.21 1st transporter primary active transport b/c see ATP Moving hydrogen ions, binding to the binding site and changing its conformation to release these hydrogen ions on this side of the membrane Hydrogen ions moving against the concentration gradient Can't use diffusion to do this Uniporter b/c only moving hydrogen ions 2nd Transporter Second active Transport Transporting 2 substances Bring transported in the same direction so a symporter Anytime even one of the substances are being moved against its concentration gradient, it’s going to be Active transport There's not ATP, so its secondary Energy comes from the triangle moving down their concentration gradient This transport protein is coupling Coupling an energetically favorable thing (downward movement of the triangle) to an energetically unfavorable thing (movement of the balls up their concentration gradientagainst) If triangles release enough energy as they're moving down their concentration gradient, then that energy can be used to move the ball up its concentration gradient Both moving in the same physical direction Moving according to a concentration is one thing Moving in the physical direction something different Symport b/c being moved in the same physical direction What happens if this protein stops working and runs out of ATP? So this protein will stop working and will affect the ability of the other protein Eventually going to get the same concentration on both sides Once the proton concentration is lost, the protein won’t be able to do its thing anymore Secondary active transporters depend on primary active transporters to establish and maintain the gradient that they are going to us e They don’t use ATP directly but indirectly, if the cell loses energy, they will eventually stop working too 11. Describe the Na+/K+ Pump. o Fig. 5.22 Sodium and potassium are both being transported 3 Na's (sodium's) are being exported while 2 potassium's (K) are being imported. So this is the opposite direction. So antiporter. Its primary b/c its ATP driven ions Using energy from ATP hydrolysis for it to work Exports 3 positives for every 2 positives it brings in Throws out 3 and lets in 2 So every time it works, the cell is losing a net of 1 positive This pump is extremely important for neurons b/c neutrons rely on that charge difference across an membrane to make electrocitity B/c it establishes a charge gradient (a charge difference) its called electrogenic Its generating a charge difference There's a place for sodium to bind and they bind to get transported 3 of those out of the cell and in potassium, 2 of those will bind and get transported into the cell Each of the ions that are being transported are being transported against their concentration gradients Sodium is going out and there's already high sodium out, so that goes against the concentration gradient Potassium is being brought in and there's already high potassium in it, so that goes against the concentration gradient too So could the cell use active transport to transport these two ions if it wanted to? Remember, with secondary an ion has to be transported with its gradient and the other against So NO, b/c they’re both being transported against the concentration Diffusion is driving the proteins to go through a channel Channels are always passive transports 12. Describe how cells transport large molecules or particles into or out of the cytoplasm. o Exocytosis & Endocytosis When cells want to transport a lot of something at once or large particles such as proteins, molecules, disaccharides, etc., they can transport these kinds of things by either exo or endocytosis. These particles can either move in or out. Exocytosis Things are going to be exiting Endo Coming in The cell does this by packaging these materials into vesicles (bubble shaped organelles in the cell) and they move the vesicles to where they need to go If Endocytosis, materials gets packaged into the vesicle by the membrane by invaginating If exocytosis, vesicle fuse with the plasma membrane 3 types of endo Cell eating phagocytosis Cell drinkingpinocytosis Receptormediated endocytosis Fig. 5.23 A vesicle building off of the Golgi (packaging/shipping center of the cell) Packaging something that it needs to ship out of the cell Cage around the vesicle is a coat of proteins that are needed to get the vesicles to be transported Vesicle is moved all the way to the plasma membrane, coat sheds and the lipids of the vesicle are going to fuse with the lipids of the plasma membrane Two membranes fuse and vesicles from a part of the plasma membrane and in doing so it spits out what was inside exocytosis Endocytosis Collect some cargo from the environment (extracellular space) by forming a pocket in the membrane =invagination (membrane forming a pocket) When it has enough cargo it pinched off of the membrane as a vesicle, the coat surrounds it, and the vesicle is brought to wherever it needs to go in the cell In many cases, this involves vesicles fusing with the lysosome and the lysosome digest it Lysosomes have acid hydrolases. They hydrolyze it This one is receptor mediated b/c it involved some proteins that are binding the part that needs to be transported These proteins are very specific and will only bind to particular substances This allows the cell to take in substances that it wants and not just anything So cargo has to bind to the receptor first and then the rest of the process happens CH 6 13. Using the party analogy, describe metabolism. o Metabolism: A series of chemical reactions that transfer or transform energy You're having a party at your house, the cell is the house. During the party you have interactions. the people’s interactions represent the chemical reactions The people are the chemicals and they are interacting together with other people In order for these interactions to occur, the people have to have energy. At a party the energy comes from the pizza. Food=energy source Will be transformed and transferred by the people as they interact So, if this a party where nobody knows each other, what you will do to encourage people to interact act with each other is maybe play games. Ex. Twister, x box games So you say okay, everyone come over here, we're going to play this game. And you put them in a setting where they are encouraged to interact. SO this is one way to get them to interact. Can also get them to interact more by having a bunch of comfy sofas. They are comfy b/c they are soft and sag and form to your body. If 2 people sit in a comfy sofa at the same time, they will sag the sofa so that they will be closer together and this will encourage them to interact. So the twister game, x box, table, or sofa are the enzymes. These are places where people are encouraged to interact. So enzymes encourage interactions. 14. State the 2 Laws of Thermodynamics. o Energy cannot be created or destroyed by ordinary means Can be transferred or transported The amount of energy you start with is the amount of energy you get o When energy is either transferred from one thing to another or transformed from gentle kinetic, then there has to be an increase in entropy Entropy=describes the degree of disorder of a system The universe favors disorder Anything that creates more disorder is favorable 15. Distinguish between exergonic and endergonic reactions. Give examples of each type o Exergonic: Energy is released Energy exits These reactions have a Delta G that's less than 0 (negative number) If releasing free energy, the reaction goes "downhill" b/c the reaction is going down from a higher energy to a lower energy. So this energy difference exits this reaction and it’s going to be spontaneous, meaning that it happens eventually on its on This is a favorable reaction o Endergonic Inputs energy Ex She has a free energy of 20 but her reactants have a free energy of 6. So she has more energy, the product has more energy than the reactants so the reaction goes "uphill" energy wise, and it’s going to require free energy to enter and it’s not spontaneous. o Chemical reactions follow the laws of thermodynamics, so exergonic is creation disorder and that's why they are spontaneous. They create more disorder just by happening. o Energy has to enter endergonic reactions and is given off by exergonic reactions 16. Use a specific example to show how cells use ATP hydrolysis to run an endergonic reaction. Pg. 124 o Ex. ATP hydrolases is exergonic. It releases free energy and that free energy is put into some kind of endergonic reaction. This is called coupling. The endergonic reaction will occur if the net free energy of both processes is still negative If your delta G or negative reaction is bigger, than your delta G is a positive reaction Ex. A phosphate gets added to glucose to form glucose phosphate plus water This is a endergonic reaction b/c there's a positive delta G Also could have known that b/c water is a product so this is a condensation reaction and condensation reactions are endergonic ATP is the 2nd reaction plus water gets broken down to ADP plus Pi (the "I" stands for inorganic referring to that the phosphate is no longer attached to an organic molecule) This is a hydrolysis reaction Don’t see water anymore b/c its being split and attached to the ADP So it hydrolysis and exergonic So could we use hydrolysis to run the endergonic reaction of both? Could those two reactions be coupled together to run both? If we couple them together and we do them at the same time, in our coupled reaction we will get glucose plus ATP and the water gets cancelled out and we get glucose phosphate plus ADP The phosphate gets attached to the glucose Our delta G of the net reaction is 4. We know this b/c you combine them. You ignore the sign and subtract one from the other and take the sign of the larger and it’s a 4.0. A net release of free energy. If couple these two reactions together, you put glucose + phosphate. The phosphate that we attach to the glucose to make glucose phosphate is going to come from the ATP once it gets hydrolyzed Water in the coupled reaction cancels out b/c one was a reactant and one was a product The coupled reaction will still happen b/c the net change is still negative. Your negative number is still bigger than your positive number 17. List 2 ways to increase rates of chemical reactions. Using a catalyst o Enzymes are catalyst, sped up the reaction and make it happen now Catalyst =aids in reaction But not a reactant It’s not changed in a reaction and doesn’t become a product The enzymes are mostly proteins. Some are RNA molecules. Why do spontaneous reactions need a catalyst? Why don’t they just happen instantly? For reactions to interact together to make a single product, they have to get close enough together and be oriented a certain so that the bonds will form Then if you take a molecule, and its going to be broken down into two smaller molecules, there has to be some amount of strain put on the bond for them to break So yes, this might just happen on its own, just by the molecule gaining enough kinetic energy (energy motion) But the amount of energy it takes to start the reaction, either by the amount of kinetic energy that the molecules have to have to either get close enough together or to twist enough to break that bond is called the activation energy If it’s a spontaneous reaction, eventually the reactions are going to gain that energy on its own But, enzymes can lower this activation energy by doing things like allowing two molecules to get close enough together It’s like the comfy sofa. Two people sit on the sofa and it kind of sags and they lean together. This gets them closer together It’s like being put on a traction table. Lie down on the table and it help bends your body. So this is what's going on with the enzyme energy. Its helping the reactants get to that state where they are needed to interact==transition state o Only other way to speed up reaction is to increase temperature When increase temperature, you’re adding heat, and adding kinetic energy b/c heat causes molecules to speed up. Cells can’t do this and just increase their temperature to speed up reactions Even if they could they wouldn’t want to b/c the cells could denature their proteins by increasing the temperature Denature=when proteins changes shape Wouldn’t want to do this b/c it's not specific. If you just increase temperature, you're going to increase the reaction rate of ALL of your chemical reactions. Not just some. This could cause complete chaos in the cell By having enzymes, cells selectively increase the reaction rate of only particular reactions 18. Thoroughly explain Fig. 6.5. o On the yaxis=free energy=G o On the xaxis=progress of the reaction So we have some reactant and products o At the start of the reaction, the energy of the reactants are about in the middle of the line The amount of free energy the reactants have o The product has less free energy o Reactants have more free energy than products so this is a exergonic reaction b/c its is releasing free energy o That energy that the reactants have is more than the energy the products have so that energy gets released o How much free energy gets released? The difference between the free energy of the reactants and the free energy of the product is your delta G So Delta G is negative b/c its products minus reactants So negative free energy which means its exergonic and spontaneous o This is a "downhill" type of reaction o In order for these reactants to actually roll down the hill and change into products they have to first achieve the transition state which requires a certain amount of energy That amount of energy is called activation energy o Looking at the red hill, on the section where there are no enzymes present, this is the amount of activation energy that is required to go over the hill (transition state) before the reactants can go "downhill". o Looking at the blue hill, where there is an enzyme, this is the amount of activation energy required which is less so its easier to get over this hill. This means that activation with enzymes make it easier for reactants to change into products. 19. Use Fig. 6.6 to explain why an enzyme is more like a sofa than a lock. o An enzyme and reactant molecule are being converted into products This enzyme is acting like a comfy sofa o There are two reactant molecules being converted into products o Enzymes lower the activation energy to get the reactions over o They do it by either the comfy sofa thing by positioning the reactants closely together so they will want to interact or they can be like the traction table where they stretch the bonds, twist the bonds or strain the bonds, so that the reactant will go in o In order for the reactions to be assisted by the enzyme they have to bind to the enzyme o So the place where the reactants bind is called the active site This is where the reactions happen Where the activity happens and the reactants that bind to enzymes are specifically called substrates o When the substrate is bound to the enzyme, it temporarily forms a complex==enzyme substrate complex So it’s an enzyme and at least one substrate. Maybe more than one o That’s when the substrate will be converted into a product o What determines whether or not an enzyme will be able to bind to a particular substance? The difference in the shapes of the active site will determine which substrates gets to fit there==enzymes specificity Makes them specific for binding of two particular substrates In addition to its shape, charges would help the binding of the substrate to the enzyme Enzymes are proteins and are made up of amino acids Opposite charges, partial charges and polar things like each other These types of things will determine which substrate will be able to bind there Based on complementary shapes of active site (lock) and substrate (key) It was said that the enzyme was the lock and the substrate was the key Key goes into lock and each lock fits a certain key Instead of the lock and key, it’s an induce fit Its more like the comfy sofa with the people sitting b/c the binding of the substrates to the enzymes causes it to change its shape slightly and that will help it to cause the reaction to occur That slight change in its shape its what the induce fit needs and is necessary for the enzyme to do what it needs to do The binding causes them to get closer together ==sagging of the comfy sofa. It’s going to force the AT and glucose closer together. Will encourage the breaking of a phosphate group off of the ATP and the phosphate group will be attached to the glucose. The free energy that's released when the phosphate is broken off is used to attach that phosphate to the glucose and then they leave and wait around for another unsuspecting group to come by. 20. List factors that affect the function of enzymes and explain what each factor does. o Enzymes are affected by their environment Temperature and pH in their environment will affect their ability to function There's a particular range of temperature and pH that will allow protein to function Why does this affect the ability for the protein to function? B/c increases in temperature can make it denature b/c the kind of bonds that keep those proteins in its shape are things like: Hydrogen bonds Ionic bonds Hydrophobic interactions Van der Waal forces These are all relatively weak bonds individually So the 3D shape of a protein (tertiary structure) depends on the interaction of at least 4 types of weak bonds If you start increasing temperature you are adding kinetic energy The 3D structure holds long as there isn't a whole lot of kinetic energy those bonds can hold. Why pH? When change the pH of something you are really changing the hydrogen ions concentration The difference between a hydrogen ion and a hydrogen atom is the ion is a charge So when change the charge around a protein, you are effecting the bond b/c some bonds are based on charges as ionic and hydrogen bonds When change the pH, you changing the concentration of charged particles, hydrogen ions in particular If you are a protein and lose your shape, you cannot function The only other bond that is present in holding a 3D shape of a protein together are Disulfides. Disulfides are covalent bonds Disulfide bridges would not be broken by changing the pH or the temperature But that’s only going to happen between cysteine amino acids. 21. Distinguish between anabolic and catabolic pathways. Give an example of each. o Metabolism consists of chemical reactions that occur in a series or in pathways. During those pathways, enzymes are catalyzing each reaction. we have pathways that start with big things and end up with small things =Catabolic (everything is broken down) Exergonic Hydrolysis Any kind of hydrolysis is catabolic pathway Ex. Hydrolysis of ATP Pathways that start with small things and build them =anabolic Endergonic Any reactions that involve condensation b/c putting things together to make something bigger o Cell has to run both kinds and does this by coupling It couples the exergonic ones to the endergonic o Enzymes are the places where coupling occurs o Reactants get broken down during catabolic reactions Why do these things happen in the cells? It gives off free energy so that free energy can be used to run endergonic reactions Also, used for recycling components Ex. If you break down a polypeptide you are left with amino acids and can use those amino acids and can put those together in a different arrangement The release of energy from the exergonic reaction normally is stored after its released in molecules that the cell uses as energy money like ATP. ATP and NADH is energy money 21. Define redox, reduction, and oxidation. Give an example of a redox reaction. o During chemical reactions, sometimes electrons are moved from one atom to another atom o Or hydrogen atoms are moved from one molecule to another molecule These are called Redox reactions Redox is short hand wat of saying reduction oxidation o If one molecule or one molecule loses hydrogen atoms or loses some electrons they have to go somewhere. They can't just disappear o So another molecule is going to gain them o So when you have oxidation (loss of an electron or hydrogen), you also have to have reduction o So you don’t have one without the other o OIL RIG Oxidation is Loss Reduction is Gain o A e+ B → A + B e A chemical reaction A is losing an electron and giving it to B A is oxidized B is gaining so B is reduced Sometimes instead of it being an electron, it can be a hydrogen atom Hydrogen atoms are an electron and a proton together. So transferring an electron but also a proton CH 7 23. Write the general equation for aerobic cellular respiration. Organic molecules + O → 2 + H2O + 2nergy (general equation) o Oxygen is being reduced to the water o Catabolic process B/c bigger molecules 24. List the 4 pathways in glucose metabolism. 4 metabolic pathways Glycolysis Breakdown of pyruvate Citric acid cycle Oxidative phosphorylation 25. Where does glycolysis occur? Describe the starting materials and the end products. o Stage 1: Glycolysis: breaking down glucose Glycolysis has 10 steps split up into 3 phases 1st phase=energy assessment Use 2 ATPhave to have some ATP to start glycolysis and specifically need 2 molecules of ATP 2nd phase =cleavage (split) Splitting hexose (6 carbons) into two trioses (3 carbons) so 2 of them Name of those trioses are pyruvates This is when you get your 2 ATP. After this gets broken down, this will liberate energy and the energy will be used to make 2 ATP Also is used to reduce 2 NADH's i. Making 2 BUCKS here and have store energy that’s going to be used later to get some more ATP Glycolysis doesn’t require oxygen. It can happen with or without oxygen. It doesn’t use oxygen and it happens in the cytosol of the cells. 1. All cells on the planet do glycolysis and it happens almost identically in all cells a. Happens very similarly in bacteria to how it happens in our cells 2. Glycolysis uses glucose, NAD and ATP and produces NADH and ATP 26. Where does the breakdown of pyruvate occur? Describe the starting materials and the end products. Stage 2: Breakdown of Pyruvate o Happens in matrix of mitochondria o Catalyzed by the enzyme: pyruvate dehydrogenase Dehydrogenase: taking away hydrogens from pyruvate o When this happens, left with CO2. The hydrogens are used to reduce (Reduction is Gain). NAD's to NADH's. And have 2 carbon molecules left which are the acetyl groups. o To get into the citric acid, those acetyl group have to be attached to a co enzyme called CoA. SO will have acetyl CoA. And get 1 NADH for one pyruvate o 3 carbons o 2 pyruvates Those pyruvates are being changed to an acetyl 1 How many carbons are in acetyl? a. 2 So you lose a carbon and it went towards the carbon dioxide When each of these pyruvates get broken down into acetyl you lose a carbon dioxide o When each of these pyruvates get broken down into acetyl you lose a carbon dioxide to get rid of that carbon 27. Where does the citric acid cycle occur? Describe the starting materials and the end products. Stage 3: Citric Acid Cycle o Regenerate starting materials during the process Certain molecules come in and some come out In the end, going to produce 2 CO2's, 1 ATP, 3 NADH's and 1 FADH2 for each pyruvate that you had in the pyruvate breakdown (each acetyl) Have to run the citric acid cycle twice b/c have 2 acetyls and 2 pyruvates During the citric acid cycle, the acetyl's go into the citric acid cycle Each of those are a two carbon molecules so 4 carbons in total going into the citric acid cycle b/c you start with 2 pyruvates, 2 acetyls so a total of 4 CO2, 2 ATP, 6 NADH, 2 FADH Reason called the citric acid cycle b/c the first step is going to be taking acetyl and attaching it to another molecule. Citrate forms when this happens which is the same thing as citric acid. This is the first substance that gets formed. Also known as the kreb cycle. This occurs in the mitochondrial matrix (liquid portion inside the mitochondria). Overall, get 4 molecules of CO2 b/c going to have 2 pyruvates broken down and 2 acetyls’ that you have to run Lose all the carbons from glucose b/c they are given off as carbon dioxide so that’s why there are 4 CO2. Make 2 ATP here but still have made in total 4 ATP b/c 2 from glycolysis and 2 from citric acid cycle 28. Where does oxidative phosphorylation occur? Descri
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