Week 4, 5 and 6 Bio

THe citric acid cycle starts with two carbon acetyl molecules and ends with what products being released as a waste and what is formed using the free energy release by all 8 reactions?

- (2CO2 are released as waster and 3NADH, 1 FADH2 and one ATP are made for each acetyl CoA oxidied.) x2 because 2 acetyl CoAs oxidized

Explain what primary structure is. how many are there? and give an example of what can happen if just one AA changes.

primary structure is the unique sequence of amino acids in each protein. Frederick Sanger figured this out studying insulin. There can be 20 ^n combinations of sequences where n is the number of amino acids in the structure. EXAMPLE-hemoglobin which binds O2. IN some individuals one of the two polypeptides that make up hemoglobin has one spot with a different AA than normal. The change in R group produces hemoglobin molecules that stixck to one another when there are low O2 levels, which clogs small blood vessles called capillarfies. This is sicle cell disease

All ____ reactions of glycolysis occurs in the ____.

- 10; cytosol

In photosynthetic organisms they use photosynthesis to produce glucose. What is this equation? How are photsynthetic organisims glucose molecules obatined by animals, fungi, bacteria and archae? What molecules are hydrolyzed into glucose monomers? What are the glucose molecules then used for?

- CO2 + H2O + sunlight -> (CH2O)n ususally n=6. -eating or decomposing those photsynthertic organmisms. -storage carbohydrates like starch and glycogen; to prduce ATP in either cellular respiration or fermentation

What molecules do we start with and end with in the citric acid cycle / Krebbs cyle? what reactions occur?

- Each acetyl CoA is oxidixed giving two Co2 molecules. In this sequnce of reactions, more ATP and NADH are produced and flavin adenine dinucleotide(FAD) is reduced to from FADH2

What is the ATP synthase "knob : component called ? what does it do? What is the membrne bound component part that transports protons called? F1 and F0 and connected by a ____ and a ____. the F0 serves as a rotator whose turning is passed to the F1 via the shaft..A flow of protons through the F0 unit causes F0 to rotate which causes the shaft to spin. As the shaft spinds within the F1 unit, it changs shape in a way that allows it to catalyze.... SO when protons pass through the ATPsynthase it spins and releases energy to make ATP. therefore, the energy needed to make ATP in oxidative phosphoylatin comes from a proton gradient.

- F1 unit, it makes ATP -F0 -shaft which is between the two and a stator which holds the two units in place. - the phosphorylation of ADP into ATP.

Carboxylic acid all have carboxyl functional groups. Early researchers identified eight carboxylic acids that oxidixe in sequence. Redox reactions that involve carboxylic acid often produce CO2. These 8 are involved in the ___ cycle In each cycle the energy released by the oxidation of one molecule of acetyl CoA is used to produce... in prokaryotes the enzymes involved in the Krebs cycle are in the ____ and in eukaryotes they are in the ____ Because glycolysis produces 2 pyruvate for every glucose, the cycle turns _____ for each glucose molecules

- Krebs cycle or citric acid cycle or tricarboxylic acid cycle - 3 molecules of NADH, 1 FSDH2 and one ATP or GTP depending on what cells. - cytosol; mitochandrial matrix -twice

What are functions of Carbs?

- attach to raw carbon skeletons that are used as building blocks in the synthesis of important molecules - serve as precursors for bigger molecules - provide fibrous structural materials, indicate cell identity, and store chemical energy.

are peptide bonds usually more or less stable compared to linkages in other macromolecules ? explain why

- MORE STABLE! this is because a pair of electrons on the nitroge is partially shared with the C in the C-N bond. This causes the peptide bond to have some double bond characteristics such as the fact that the peptide bond is planar so the attached atomns cant move( but all the other single bonds still can that are in the molecule)

What bonds two amino acids together when they polymerize? After dehydration synthesis and the peptide bond forms the carboxyl group is then a ____ and the amino group is a ______.

- a bond forms between the carboxyl group of one aminomacid and the amino group on another. The C-N covalent bond that results is called a peptide bond! - carbonyl functional group; NH

Carbohydrates are made of what kind of groups? How might this vary from a linear form to a ring ?

- a carbonyl group(C=O), a hydroxyl group(-OH) and multiple carbon hydrogen bonds(C-H). pg 109 of text has image! linear forms all have the carbonyl group(C=O) but often when rings form like with glucose, the C-1 CArbon ( the one clockwide of the O)forms a bond with oxygen atom of teh C-5 hydroxyl. THe hydrogen from the C-5 hydroxyl is transferred to the C-1 carbonyl but now it is no longer a carbonyl.

Monosccharides polymerize (grow) when... What reaction breaks them apart? when two sugars link together it is then called a ______.

- a condensation reaction/ dehydration synthesis reaction occurs between twon hydroxyl groups resulting in a covalent bond called a glycosidic linkage. -hydrolosis -disaccharide

What is the difference in aerobic and anaerobic respiration? How do the electron acceptors and donors in the two differ? Aerobic and anaerobic respiring cells both use ____ to create a proton motive force. In bacteria and archaea the ETC and ATP synthase are located in the _____.

- aerobic respiration- species that depend on oxygen as the electron acceptor for the ETC use aerobic respiration. ALL eukaryotes and some prokaryotes use aerobic respiration. -anaerobic respiration- is done by organisms that do not use oxygen as the electron acceptor( kinds of bacteri and archae). Many use things like nitrate, and sulfate as the electron acceptor. In addition many use an electron donor other than glucose like CH4, H2S or H2. - an ETC -plasma membrane

Cellular respiration is defines as.. All cells need a source of what 2 things?

- any set of reactions that uses electrons harvested from high energy molecules to produce ATP via an electroj transport chain - source of energy to generate ATP and a source of carbon that can be used to sybthesize DNA, RNA, proteins and fatty acids.

What is the uncontrolled oxidation reaction of glucose? What is this equation? glucose doesnt burn in cells though, instead it undergoes a lonmg series of controlled redox reactions. Instead of releasing all of this enrgy as heat, the released free nergy us used to make _____. Cellular respiration results in the _____ oxidation of glucose into CO2 and water. NOTE-fermentation doesnt completely oxide glucose, instead small organic molecules ar eproduces as waste. As a result cellular respieation releases more energy from glucose than fermenation does.

- burning, some of the potentnail energy atored in glucoses bonds is converted to kinetic energy in the form of heat and light. ; C6H12O6 +6O2 -> 6CO2 + 6H2O +heat and light(energy) -ATP -complete

What molecules do we start with and end with in pyruivate processing? what reactions occur?

- each of the pyruvate is processed to release one CO2 molecule from each. We then have 2 of the two carbon compounds called acetyl CoA. The oxidation of pyruvate results in more NAD+ beibng reduced into NADH

What molecules do we start with and end with in the electon transport chain / oxidative phosphylation? what reactions occur?

- elcgtrons from NADH and FADH2 move throuhg a series of proteins that rogether are called an electron transport chain. The energy released in this chain of redoxz reactions is used to create a proton gradient across a membran e, the ensuring flow of protons back across the membrane is used to make ATP. Because this mode of ATP production links phosphoylation of ADP and the oxidatin of NADH and FADH2, it is called osidative phosphorylation.

The mechanisms that regulate enzyme function also apply yo the individual steps in a pathway. Explain feedback inhibition:

- feedback inhibtion is a way to regulate metabolic pathways. The final product is used to inactivate the first enzyme. The final product binds to an allosteric site resulting infeedbcak inhibtion and the substrate cant bind to enzyme 1. THis allows the intial sunstrate to be stored instead o fwasted.

When all three types of molecules (carbs, fats and proteins) are available in cells to make ATP, what is the order of which they are used?

- first carbs, then fats, and then proteins

What makes starch and glycogen more efficent energy storges than the structural polysaccharides? What enzyme catalyzes the hydrolysis of alpha glycosidic linkages in glycogen? What enzyme does the same too starch? Where is the enzyme found?

- glycogen and starch both have alpha glycosidic linkags unlike structural polysaccharides that have Beta glycosidic linkages. THe alpha linkages are easily hydrolyzed to give glucose while structural polysaccharides cant be hydrolyzed easily. -a protein called phosphorylase breaks down glycogen to give glucose -amylases- salivary amylase is secreted in salivary glands and small intestine also produces amylase both to digest starch we eat in our mouth and intestine respectively.

What are the interactions involved in secondary structure?? In most proteins the polar groups are aligned and form hydrogen bonds with one another when the backbone bends to form what two possible structures? WHat influences which structure will form? Give an example . Are the interactions in secondary structure weak or strong?

- hydrogen bonding between functional groups in the backbone! The H bonds occur between the oxygen on the C=O group of one AA residue and the hydrogen on the N-H group of another. This hydrogen bonding is only possible when a polypeptide bends in a way that puts C=O and N-H groups close to one another. So involves backbone components 1. alpha helix- the polypeptides backbone is coiled 2. Beta pleated sheet- segments of a peptide chain bends 180 degrees and then fold - it depends on the geometry and properties of the amino acids in sequence. EXAMPLE- proline is almost always in Beta sheets because its unusual R group is connected to both the central carbon and the nitrogen of the core amino group. -Individual H bonds are considered weak compared to covalent bonds but there are so many in secondary structures that they are actually very stable

So what goes in and what goes out of pyruvate processing?

- in: pyruvate, NAD+, and CoA out: CO2, NADH, and acetyl CoA( what about C4 and C2 to C6? dini )

What is a fatty acids structure? What happens when two carbons form a double bond?Explain saturation and unsaturation Foods with polyunsaturated chains are said to .. Saturated lipids are ____ at room temp. Saturated lipids with very long tails like waxes are.. unsaturated lipids are_____ at room temp LOOK at steroid, fats and phospholiopids cards in week 3

- it is a lipid made of a hydrocarbon chain bonded to a carboxyl group. Fatty acids contain 14-20 Carbon atoms mostly found in their long tail. - the attached atoms are found in a plane instead of 3D tetrahedron. HTey cannot rotae freely like C-C bonds can. Double bonds often produce kinks in an otherwise straight hydrocarbon chain. THe chains with double bond are considered to be unsaturated. Saturated chains only have single bonds. - be healthier and help heart disease - solid -very stiff solids -liquid

Reactions happen when reactants have enough _____ ______ to overcome the activation energy barrier. The free energy of the transition state is high because.... delta G is the overall change in free energy as in products -reactants. If the products have lower energy than the reactants the reaction is ______. What is the products have higher energy? Reactions with high activation energy would be very _____ even at high temperatures. The more _____ the transition state the higher the activation enery and the less likely a reaction is to occur quickly. Reaction rates depend on both ___ and ____. How do enzymes lower the activation energy?

- kinetic energy - the bonds that existed in the substrates are destabilized- it is the transition point between breaking old bonds and forming new ones. -exergonic; endergnoic -slow -unstable - the kinetic energy of the reactants and the activation energy of the reaction. NOTE: if the kinetic energy of the reactant molecules as high such as at high temperatures the molecular collisions are more likely to overcome the activation energy -interactions with amino acid residues within the enzymes active site stabilize the transition state and thus lower the activation energy. R groups that line the active site form short lived covalent bonds that help assist the transfer of atoms or groups from one reactant to another. Acidic or basic R groups are very common in allowing reactants to gain or losw protons.

Note-Amino acids link to form proteins. Proteins are macromolecules. What is a macromolecule? A molecular subunit used to build macromolecules is called____. When large numbers of monomers come together they form a _____. Note-So amino acids are the monomers that polymerize to form proteins! What is polymerization?

- large molecules made up of smaller molecular subunits joined together. - a monomer -polymer - the process of linking monomers together

When fewer than 50 amino acids are linked the polymer is called an______ or ____. Polymers with 50 + AA's are called _______. When is a polypeptide called a protein?

- oligopeptide or just a peptide -polypeptides -when it is completely functional

What molecules do we start with and end with in glycolysis? what reactions occur?

- one six cafrbon molecule of glucose is broken down into two molecules of the three carbon compounds caled pyruvate. In this process, ATP is produced from ADP and a phosphate and nicotamide adenine dinucleotide (NAD+) is reduced to become NADH

How is it thought that thisn kind of oxidative phosphoylation may have come about in chemical evolution?

- researchers propose that the alkaline fluid which ha slow H concentraion was released from early hydrothermal vents in the ocean. The early earth ocean was very acidic so lost of H. BY harnessing the natural electrochemical gradient deep in the early oceans, oxidative phosphoylation may have evolved before the ETC existed.

THe overall glucose oxidation reaction equation is C6H12O6 + 6O2-> 6CO2 +6H2O + energy. we know where the 6CO2s are from (come from glucose) and we have some of the energy in the form of ATP. Give an equation accounting for the pieces we havent yet accounted for. So what happened to the O2 to cause it to give H2O?

- so we know that redox reactions transfer electrons to NAD+ and FAD to form NADH and FADH2. AFter these molecules are formed the reaction pieces we havent accounted for yet is as follows : 10NADH +2FADH2 + 6O2+ 10H+-> 10NAD+ + 2FAD + 12H2O +energy NOTE: the H+'s are there because for every 2 e-'s NADH takes it only takes one proton - NADH and FADH2 are oxidized back into NAD+ and FAD and oxygen is reduced to form water

Chitin is a polysaccharide that.... Chitin is smilar to cellulose but how does it differ?

- stiffens the cell walls of fungi. It also is the most imortant components of the external skeleteons of insects and crustaceans. - instead of consisting of glucose residues the monosaccharide involved is called N-acetylglucosamine(NAG). These NAG monomers are joined by beta 1 4 glycosidic linkages. As in cellulose the gemoetry of the bonds results in every other residue being flipped in orientation. The NAG subunits form hydrogen bonds between adjacent strands to produce a stiff protective armor

Are monosoccharides usually linear or in rings? What occurs hwen glucose forms a ring?

- sugars that contain 5 or more carbons exist in rings usually! In aqueous solution, they spontaneously form ring structures hen the carbonyl group bonds to a hydroxyl group -the C-1 CArbon which is a carbonyl ( the one clockwise of the O)forms a bond with the oxygen atom of the C-5 hydroxyl. THe hydrogen from the C-5 hydroxyl is transferred to the C-1 carbonyl but now it is no longer a carbonyl.

What is the main idea of the chemiosmosis hypothesis? What does the word chemiosmosis describe? Describe the experiment done to prove this. This proved that ATP production depended sioley on the existemnce of a ______, which is based on a proton electrochemical gradient.

- that the ETC's job is to pump protons across the inner membrane of the mitochondria from the matrix into the intermembrane space. After, a proton gradient is established, ATPsynthase could synthesize ATP from ADP and P. - the use of a proton gradient to drive energy requiring processes like ATP production. Chemiosmosis involves diffusion along protons gradient. - 1. Produce vesicles from artiical membrane and add ATPsynthase. 2. add a protein called bacteriorhodopsin which acts as a light-activated proton pump. It pumps H from the interior of a membrane , out . 3. illuminate vesicles so bacteriorhodopsin pumps H out creating a H gradient. Results: ATP was produces in the vesicle, in the absence of the ETC. - proton motive force

How can different monosaccharides with same molecular formuls differ?

- the carbonyl groups can be found in different places making two different monosccharides.Example- an aldose has the carbonyl at the end wheras a ketose sugar has it within the Carbon chain( both trioses)

The location and geometry of glycosidic linkages vary in different polysaccharides due to.. An example of how the way polysccharides form can affect their function.

- the fact that gylcosidic linkages form between hydroxyl groups and every monosaccharide has at least two (the Cs are number clockwise starting with the one after the O in the ring) - some polysccharides like starch store enegry in plants wheras in insects a polysaccharide called chitin is used for structural support in the exoskeleton

What is enzyme kinetics? How does the line on a graph appear when rate of product formation is on the y and substrate concentration is on the x in catalyzed reactions and uncatalzyed reactions? Explain each. What does the catalyzed reaction prove?

- the rate of enzyme action -Catalyzed: when enzymes are involved, and the substrate is at low concnentation and steadily increasing, the rate of product increases quickly. As more and more substrate is involved the steep increase begins to flatten. And lastly, when the substarte concentration is very high, a plateua forms and the rate of product formation reaches a max rate. In uncatkyzed reactions- the speed is far slower but there is a continuous linear increase as substare concentration increases and ther eis no max rate seen in a plateua. It only increases because there are more substrate molecules interacting and colliding. it proves the idea of saturation kinetics. This means that in catalyzed reaCtions reaction ratew level off because all available enzymes are being used and thus are saturated with substrate.

The theory of chemical evolution states that monomers in prebiotic soup polymerized to form macromolecules. Why is this contradictory with the second law of thermodynamics?

- the second law would say that monmers would not spontaneouly assemble together because polymerization organizes monomers increasing organization and decreasing entropy. This means an input of energy would be required for the monomers to come together. Its possible that photons and lighting provided the energy.

What is the theoretical and actual yield of ATP per glucose in cellular respiration? Why the difference? what is the overall equation involved in cellular respiratin?

- the theoetical yield is 38 ATp and the actual is 29 ATP. THe difference is due to the fact that the proton motive force is used to drive other mitochnondrial acctivities such as the active transport of P into mitochondrial matrix. - C6H12O6 +6H2O +6O2 +29ADP +29P -> 6CO2 + 12 H2O+ 29 ATP

Even the simplest sugars/monosaccharides are very reactive because:

- there are carbonyl groups and multiple polar hydroxyl groups!! so the functional groups are hydrophilic and reactive making the monosaccharides polar and they easily dissolve in water because it bonds with H atoms of Water.

What occurs in the "energy payoff" reactions?Enzyme catalyzedf reaxctions that result in ATP production are called _____.

- this occurs in reactions 6-10. The first high energy molecules are made in reaction 6 when two NAD+ are reduced to form the high energy molecules NADH. In reactions 7-10, enzymes catalyze the transfer of a phosphate group from a phosphorylted substrate to ADP, resulting in ATP.; substrate level phosphoylation.

In what process do monomers polymerize? IN what process do they break?

- through condensation reactions aka dehydration reactions. The newlyh formed bond results in the loss of water. -hydrolysis: breaks apart polymers by adding a water molecule.

Maltose is a dissaccharide formed by... Lactose is a disaccharide formed by.. Maltos is formed by what linkage? What linkage is formed between the glucose and galactose in lactose?

- two glucose moleculs coming together -1 glucose and 1 galactose molecule coming together. - a alpha 1-4 glycosidic linkage. This means that the bond is between a C-1 on one glucose and C-4 on the other so that is where the dehydration synthesis is occuring. It is a alpha linkage because the hydroxyl groups are below the plane on the C-1 on both glucoses coming together. - a beta 1-4 glycosidic linkage. It is 1-4 becaise the linkage is occuring due to the dehydration synthesis between a C1 on galactose and a C4 on glucose. It is beta because the hydroxyl groups on C1s on the glucose and galactose is orinetated above the plane

SO for every one glucose molecule that goes through glycolysis, pyruvate processing, and the citric acid or Krebbs cycle that 1 glucose molecules is fully oxidized to 6 CO2 and the cell produced ____ NADH, __ FADH2, and ____ ATP

-10,2,4

for each molecule of glucose processed by glycolysis what is the net yield?

-2 NADH, 2 ATP, and 2 pyruvate

Proteins are made up of approximately ____ amino acids. IN all 20 AA's a ______ bonds covalenty to four different atoms or groups. What are the 4 groups? What changes how the molecules behave when the amino acid is "ionized" and explain why. Is this typical or not for AA's to be ionizxed?

-20 - central carbon atom called the alpha carbon - 1.an H atom 2. NH2- an amino functional group 3. COOH a carboxyl functional group 4. a distinctive "R group" aka side chain - the amino and carboxyl groups. In a pH of 7 like water the amino acids ionize. WHen they ionize, the concentration of protons at this pH causes the amino group to act as a base so it gains a proton and becomes NH3+. The carboxyl group acts as an acid and the two Os pull the electrons away from the hydrogen so COOH becomes COO-. IMPORTANT- these functional group charges 1. help amino acids stay in solution where they interact with one another and other solutes 2. they affect the amino acids chemical reactivity. THis is normal!! ALsmot all AA''s will be in this state since bodys ph is about 7 normally.

Explain how the reaction occurs stepwise in a metabolic pathways (as in how one product is the next reactant). What are B and C referred to as? Are the products or reactant concentrations higher ?

-A will be turned into B by enzyme 1, then B will be turned into C by enzyme 2, then C will be turned into D by enzyme 3. - intermediates because they are products that are then used as reactants. - product! so D is the highest because it is the overall product.

What is the name of the complex that can synthesize ATP? Briefly explain how this was discovered.

-ATP synthase! A man names Efraim used mitochandrial membranes to make vesicles and noticxesn that somes formed with their membranes inside out. ELectron miscroscopy showed that the inside out membranes had large proteins on the surface that faced outward even though it usually faced in toward the mitochandrial matrix. When trated with ura he could isolate the part of the protein complex. He found that ATP synthase is an enzyme that synthesizzes and hydrolyzes ATP. THe membrane bound base is a proton chanel and the stalks process ATP.

Glucose is used to provide... Briefly explain this process

-ATP! The energy that is released when sugars are processed is used to synthesize ATP from a precuroser molecule called adenosine diphosphate and a free inorganic phapsphate. The overall reaction is: (CH2O)n +O2+ ADP+P-> CO2 + H2O+ ATP The chemical energy store in C-H and C-C bonds is released when new C=O bonds and some of that energy is transferred to bond the phosphate to ADP.

What fuels life in cells? Metabolic pathwasys harvest energy from high energy molecules like ...

-ATP! aka a nucleotide called adenosine triphosphate which has high potential energy and allows cells to overcome lifes energy barriers -the sugar glucose- the most common sourse of chemical energy in organisms. As cells process sugars, the energy that is released is used to transfer a phosphate group to ADP to make ATP.

Glycolysis was accidently discovered by ____ and ____. Brieflt explain how.

-Han and edward Buchner. They were working out tech ique sfor breaking open bakers yeast cells and extratcing contents for medicianl use. They added sucrose which at the time was a perservative and instead of perservin ght e yeast extracts, the sucrose was broken down and alcohol appeared. Most tests helped them figure out the 10 steps of glycolysis.

Enzymes bring substrate molecules together in a substrate binding site known as the enzymes______. Most enzymes are ____ proteins. When reactant molecules bind to the active sit many enzymes undergo a confirmational change called _______ How are substrate molecules held in place when they enter the active site? Once the substrate is bound what interactions occur? which forms the _____. To meet the transition state what must happen?

-active site: is in a cleft or cavity in the enzyme -globular -an induced fit - by hydrogen bonds or other weak interactions with amino acid residues in the active site. - R groups start to interact. The iteractions between the substrate and enzyme increases and reqaches a maximum when a temperoary unstable intermediate condition called the TRANSITION STATE is formed. -substrate must bind AND a certain amount of kinetic energy called the activation energy must be met to strain the chemical bonds in substrates so they can achieve thr transition state.

When AA's are linked in a chain by peptide bonds they are then referred to as..

-amino acid residues!

proteins can also be catabolized so they can be broken down and used to produce ATP. First they are hydrolyzed into their individual aminio acids and then enzyme caytalyze reacrtions remove the ____ which is then lost in urine and then the remaining carbon comounds are converted into ____, _____ or other intermediaries in _____ and ______.

-amino groups; pyruvate, acetyl CoA; glycolysis and citric acid cycle.

Sets of reactions that break down molecules are called____ ____. These reactions often harvest stored chemical energy to help produce ATP\ Sets of reactions that syntehsize larger molecules from smaller compounds are called _______ ______. These often used energy in the form of ATP

-caabolic pathways -anabolic patheways

Lipid is a term for.. Give an example if a hydro carbon compound- What are hydrocarbons?

-carbon containing compounds that are usually nonpolar and hydrophobic. They dont dissolve in water but do in organic things. -isoprenes is a 5 carbon chain and when linked together it is called a isoprenoid. Isoprenids serve as pigments and precursors to sex hormornes and more. - only carbon and hydrogen containing compounds that are veruy nonpolar ebcause H and H has similar EN and share e equally, thus it cant dissolve in water because hydrocarbons have no dipole.

enzymes are ______, which.. Enzyme specifity is a product of.. WHat 2 "hurdles" must be cleared for a reaction to take place?

-catalysts; bring substrates together in a precise orientation that makes reactions more likely. - the geometry and chemical properties of sites where substrates bind. 1. reactants need to collide in a precisenorientation 2. reactants need to have enough kinetic energy to overcome repulsion between electrons that come into contact as a bond forms.

In plants the major cell wall compenant is _______. Cellulose is a polymer made from.. How does the geometry of the linkages affect the chain and why is this important?

-cellulose - beta glucose monomers joined by Beta 1 4 glycosidic linkages. -Each glucose residue in the chain is flipped in relation to the adjacent residue. THe flipped orientation is important because 1) it generates a linear molecule rather than helix 2) it permits multiple hydrogen bonds to form adjacent parallel strands that are joined by hydrogen bonds. The interacting cellulose fibers are strong and give the cell structural support. look at textbook pg 111

What carbohydrates provide structural support? How does this happen? Structural carbohydrates are also durable due to the fact that.. How does cellulose help in the human diet?

-cellulose, chitin and and modified polysaccharide peptidoglycan form fibers that give cells strength and elasticity -all 3 of these form long strands and form bonds between adjacent strands. For example, in plant cell walls, a collection of near 80 cellulose molecules are cross linked by hydrogen bonding to produce a tough fiber. These cellulose fibers in turn crisscross to form a tough sheet that withstands tension and compression. - so most organisms produce enzymes that break the alpha glycosidic linkages in starch and glycogen molecules, but very few organisms have enzymes that can digest cellulose, chitin, or peptidoglycan. These fibers are insoluble due to tthe strong interactions between strands of beta 1-4 glycosidic linkages. The exclusion of water in these fibers makes their hydrolysis difficult. - the cellulose we eat in plants-dietary fiber- forms a porous mass that absorbs and retains water. This sponge like mass adds moisture that helps fecal material move through the intestinal tract preventing constipation. \]//

The molecules responsible for the oxidation or NADH and FADH2 are called the _____ ______ ______. Where does this take place? Most of the molecules that make up the ETC are ___ that contain distinctive cofactors and prosthetic groups where the redox events take place. Give a few examples. What is ubiquinone? aka.. lipid or water soluble? In what ways do the molecules involved in processing NADH and FADH2 differ? WHat idea did the above differentiation suggest?

-electron transport chain!! in eukaryotres, the mitochandrial inn er membrane or cristae and in prokaryotes the P.M.. -proteins; iron-sulfur complexes, ring-containing structures called flavins, or iron-containing heme groups called cytochromes. Each groups is readily reduced or oxidixed. - is NOT a protein. It is in the inner mitochandrial membrane. It is very rare in orgaisms and belongs to a family called quinones. ; aka coenzyme Q or just Q, it is lipid soluble and so it can easily move throughout the interior of membranes. - their redox potentials! this means that all of the molecules differ in their ability to accept electrons in a redox reaction. In addition some of the molecules pick up a proton with each electron while others only take an e-. - electrons pass from a molecule with lower redox potential to one with higher redox potential. As a result, a small amount of energy would be released in each reaction and the potential energy in each succesive bnond would lessen.

Using enzyme catalyzed reactions, cells can break down(catabolic) and transform other carbs like sucrose, maltose, glycogen or starch into...

-glucose or intermediaries in cellular respiration

What polysaccharide in animals performs the same function as starch in plants(supply energy)? Where is glycogen stored in humans and how does it supply energy? how is glycogens structure similar to starch and how is it different?

-glycogen - in cells of liver and muscle tissue. When you exercise enzymes break down glycogen into glucose monomers which are processed in muscle cells to supply energy. -glycogen is a helical polymer of alpha glucose and like starch has mostly alpha 1-4 glycosidic linkages and some alpha 1-6 linkages but glycogen has an alpha 1-6 linkage every 10 glucose subunits instead of every 30 so glycogen has more alpha 1-6 glycosidic linkages making it highly branched

in cells, enzymes break down fats(catablolized) to release glycerol and fatty acids. The gkycerol is processed and enters _____and fatty acids are converted into ____ and enter ______.

-glycolysis; acetly CoA; citric acid cycle

Glycolysis is controlled by... - What reaction and how does ATP affect if it is at very high levels? - Why is glycolysis regulated at step 3 instead of previous steps? - ATP is a substrate (meaning its required for it to occur) for reaction 3, so why is it also an inhibitor? - Why is this important that ATP is the inhibitor? - How is it that ATP can act as an inhibitor and substrate?

-high levels of ATP -reaction 3; when ATPis at high levels it inhibits the glycolytic enzyme called phosphofructokinase which synthesizes fructose 1-6 biphospbate from fructose-6-phosphate. - the products of reaction 1 and 2 can be easily converted back to glucoe by enzymes. BUT once fructose 1-6 biphospahte is made it cant be converted back to glucose. - recall that ATP is also the end product of the overall catabolic pathway or glycolysis. Recall that when an enzyme is inhibited by the product of the reaction sequence this is called feedback inhibition. When the product is too high it can inhibit its own production by interfering with a rection used to create it. - cells that are able to stop glycolytic reactions when ATP is abundant can conserve their stores of glucose for time when ATP is scarce. As a rsult homeostasis is maintained via feedback inhibition - ATP can bind at the enzymes active site where it is used to phosphoylate fructose-6-phosphate or at a regulatory or allosteric site, where it turns off the enzyme. When ATP concentration is low, it binds only to the active site which has a greate affinity for ATP than the regulatory/allosteric site. As ATP concentration increases it also binds to the allosteric site on phosphofructosekinase. When it binds it causes the enzyme to change shape making the active site unavailable to substrates.

The krebbs cycle is also regulated by feedback inhibition. So reaction rates are when... low when ... Explain what 3 steps of the 8 are involved in regulation.

-high when ATP and NADH are scarce and low when ATP and NADH are abundant 1.in step 1, the enzyme that combiones acetyl CoA and oxaloacetate to form citrate is shut downm when ATP is in high concentration and ATP binds at an allosteric regulatory site som ATP is a allosteric inhibitor. 2. in step 3, NADH interferes with the reaction by acting as a competitive inhibitor and binding to the active site 3. in step4, ATP again functions as an allosteric inhibitor/ regulator (difference in two ?)

A proteins distinctive 3D shape is called______ and results from... Note- in contrast to secondary structures which have only H bonds between backbone components, tertiary structures form using bonds and interactions between 2 R groups or between a R group and backbone element. What are the 5 most important interactions? NOTE- tertiary structures depends on primary and secondary structure

-its tertiary structure; interactions between residues that come together as the chain bends and folds. 1. hydrogen bonding- form between polar side chain and opposite partial charges either in the peptide backbone or other R groups. 2. Hydrophobic interactions- in an aqueous solution, water molecules interact with the hydrophilic polar side chains of a polypeptide forming more H bonds. This also forces the hydrophobic nonpolar side chains to come together. 3. Van Der Waals interactions Once hydrophobic chains are forced together they become more stabilized by electrical attractions aka van der waals. These interactions occur because of the constant motion of electrons. If nonpolar molecules get really close the minute partial charge on one induces an opposite partial charge on the other causing attraction. Although this is very weak compared to covalent or H bonds, a large number of VDW interactions increase stability 4. Covalent Bonding- covalent bonds can form between the side chains of two cysteines through a reaction between the sulfhydryl groups. These disulfide bonds afre referred to as bridges 5. Ionic bonds- can form between groups that have full and opposite charges such as ionized acidic and basic side chains.

Molecules of life are each built by a series of reactions each catalyzed by a different enzymes. these processes are referred to as__________ _________.

-metabolic pathways.

In eukaryotes, the oyruvate produced by glycolysis is transported from the cygtosol to the ______. RECALL: mitochondria have 2 membranes called the outer membrane and innner membrane. Portions of the inner membrane fill the interior of the organelle with sac ike structures called cristae. The regions between the inner and outer membrane and within the cristae is called intermembrane space. The regions enclosed by the inner membrane (so not in the cristae) is called the mitochandrial matrix. How do the pyruvate get into the matrix? reactions of "processing pyruvate" occurs in what enzyme complex within the matrix? Where is this enzyme in eukaryotes vs bacter or archae? What reactions occur in pyruvate processing?

-mitochandria! - through small pores in the outer membrnae and through carrier proteins in the inner membrane. - pyruvate dehydrogenase;mitochandrial matrix vs cytosol - one of the pyruvates carbons is removed in the form of CO2 and NAD+ is reduced to NADH. The remaining 2 carbon acetyl unit is reacts with coenzyme A (aka CoA-SH because ofnits sulfehydral group) producing acetyl CoA

Carbs, or sugars, monomer are... A small polymer chain is called .. large polymers are called..

-monosaccharides(simple sugars) -an oligosaccharide -polysaccharides

Bacterial cell walls consisit of a polysaccharide called _______. the backbone is made of... What is attached to the C-3 carbon of NAM? When molecules of peptidoglycan align, what links the amino acid chains on adjacent strands? What do these links do?

-peptidoglycan - it is formed by monomers of NAG and N-acetylmuramic (NAM) that alternate with each other and are linked by Beta 1 4 glycosidic linkages. - a short chain of amino acids -peptide bonds- give the structure strength for the cell wall.

Pyruvate processing is also regulated by feedback inhibition. Pyruvate processing stops when the dehydrogenase complex becomes _____ and changes shape. A high or low concentration of substrates(indicating low ATP supplies) results in more dephosphoylated and active pyruvate dehydrogenase complexes? Thus large supplies of reactants or low supplies of products... Large or low supplies of product inhibit the enzyme comlex? NOTE: pyruvate processing involves positive and negative regulation.

-phosphoylated -high, stimulate the enzyme complex. -large

In what process can light energy be transformed to chemical energy in the form of sugars? Photosynthesis occurs in ... What equation sums up photosynthesis? How are the positions of the electrons in the reactants and products different? KEY- C-C and C-H bonds have higher potential energy because the atoms have similar EN and share the elctrons equally. C-O bonds in contrast have low potential energy becuase O holds the electrons so tightly. Key- Both Carbohydrates and fats ar use as fuel in cells BUT why are fats more efficent?

-photosynthesis! -plants, they harvest the energy in sunlight and store it in the bonds of carbohydrates. - CO2 + H2O + sunlight ----> (CH2O)n + O2 1. The electrons in the C=O bonds of Carbon dioxide and C-O bonds of carbohydrates are held tightly because of Os high electronegativity, so they have low potential energy 2. The electrons in C-H bonds of carbohydrates are equally shared because they have very close EN thus the bonds are weaker and these electrons have higher potential energy 3. Electrons are also shared equally in C-C bonds of carbohydrates so they also have high poteintial energy. SO because C-C and C-H bonds have way more potential energy than C-O bonds, carbohydrates store more chemical energy than Co2 does. - fats store twice as much energy(calories) per gram compared to carbohydrates.

Hydrophilic R groups include: Hydrophobic R groups inlcude: What are the 3 groups of amino acid R groups?

-polar and electrically charged R groups interact with water and easily dissovle in water. - nonpolar R groups lack charged or highly electronegative atoms that can H bond with water. - Chared(acidic or basic), uncharged polar, and nonpolar

What is a 3rd way monosaccharides can vary? How do glucose and galactose vary spatially? What is imortant to note about the result of these two sugars differing structurally even though in such a small way?

-spatial arrangements of their atoms - Although they have the same formula they doffer in the orientation of the hydroxyl group on their 4th Carbons. -Because their structures differ their functins also do. Glucose is a source of chemical energy and a source of Carbon atoms used to mak eother molecules. Galactose must first be converted into glucose to be able to do the same things.

What supports the idea that polysaccharides played no role in the origin of life?

1. No plausible mechanism exists for the polymerization of monosaccharides under conditions that prevailed early earth. In cells and in lab experiments glycosidic linkages form only with the aid of protein enzymes. No enzyme like RNAs are known to catalyze these reactions. 2. No polysacchardies have been discovered that can catalyze polymeriztion reactions. Even though polysaccharides contain reactive hydroxyl and carbonyl groups, they lack the structural and chemical complexity that makes proteins effective catalysts. 3. THe monomers in polysaccharides are not capable of complementary base pairing. Unlike nucleic acids, polysaccharides cant serve as templates for their own replication.

What is a way that polysaccharides/carbohydrates involved in cell identity differ from structural carbohydrates? Polysaccharides can act as an identifier badge on the outer surface of the plasma membrane. What are these structures? GLycolipids and glycoproteins are involved in... Give an example of this. What big event in the life cycle of many multicellular organisms are carbohydrates very important in? Explain the experiment done to figure this out. How did they determine whether the protein or carbohydrate was essential for recognition and attachment?

-structural carbohydrates normally only consist of one or two types of monosaccharides. Identity ones vary in many ways. - Carbohydrates attached to lipids or proteins on the cell membrane extend out into the exterior environment. A GLYCOLIPID is a lipid that has been "glycosylated" meaning it has one or more covalently bonded carbohydrates. A GLYCOPROTEIN is a protein that is bonded to carbohydrates.-usually shorter chains like oligosaccharides. -cell-cell recognition and cell-cell signaling FOR EXAMPLE- our blood type is determined by the type of oligosaccharides present on the cell surface. . A, B and O antigens are different due to the carbohydrates in glycolipids. ANOTHER EXAMPLE- each distinct type of ac ell in multicellular organisms-like nerve and muscle cells- have different glycoproteins helping them recognize each other -sexual reproduction! Paul Wassarman invesitgatd the role of glycoproteins in cell-cell recognition between sperm and eggs during fertilizationin a step that gurantees specificity-- sperm normally recognized and bind to only eggs of their own species. - Researchers mixed sperm with purified eff surface glycoprotein and discovered that after they were exposed to it when they were put with an egg again they couldn't attach. This loss of function is an example of competitive inhibition. The glycoproteins had bound to the sperm blocking it from binding to the egg. This result showed that sperm attach to eggs via egg glycoproteins. - When sperm were mixed with purified carbohydrates alone most were then unable to attach to eggs. BUT the sperm treated with purified protein alone were not inhibited and still attached to eggs.

Protein folding tends to be spontaneous due to... What are molecular chaperones? What does it mean if a protein denatures and how was this discovered?

-the chemical bonds and interactions that occur release enough energy to overcome the decrease in entropy and it will increase entropy in the environment. - cells have these chaperones that can facilitate protein folding. These chaperones belong to a family of molecules called the heat shock proteins because they aren produced after cells experience denaturing effects due to high temp. Chaoerone recognizes denatured proteins by binding to hydrophobic portions that shouldnt show when the proteins is folded properly. - Christian Anfinsen studies a protein called ribonuclease that cleaves ribonucleic acid polymers. He found that ribonuclease could be unfolded or denatured by treating it with compounds that break H and disulfide bonds. GThe protein could no longer function normally. Once the denaturing agents were removed ribonuclease spontaneously refolded and assumed function again. The led researchers to believe the primary sequence contains what is needed for folding.

THe number of Carbon atoms also differ between monosaccarides. A monosaccarides with 3 Carbons is called______. 5? 6?

-triose -pentose like ribose which acts as a building block for nucleotides -hexose, like glucose

1. THe components of the ETC are organized into how many "complexes"? 2. Q and the protein cytochrome c ast as.. 3. when is the oxidation of glucose complete? 4. THe total potential energy differnece from NADH to Oxygen is ___ kcal/mol. 5. oxidation of the 10 NADH molecules per each glucose accounts for ____ % of the total energy released from the glucose.

1. 1-4! 2. shuttles that transfer electrons between the 4 complexes. 3. when the elctrons at the bottom of the ETC are accepted by Oxygen giving H2O. 4. 52 5. 80%

Ions or molecules that are not part of an enzymes primary structure are often required for an enzyme to function normally. These molecules fit into what 3 categories: Give an example of What can happen without these helpers?

1. Cofactors: are inorganic ions such as metal ions like Fe, Zn and Mg. They all reversibly interact with e zymes. Cofactors are thought to have been involved in catalysis early in chemical evolution. 2. Coenzymes: are organic molecules that interact reversibly with enzymes 3. Prosthetic groups: are non amino acid groups or molecules that are permanently attached to proteins such as the molecule retinol that converts light to chemical energy. Note- these enzyme helpers are often part of teh active site and help stabilize the transition state making them essential to the enzymes function. -Vitamins often are needed for the production of coenzymes. Lack of coenzyme can often cause disease. For example, thiamine (vit B1) helps produce a coenzyme needed by 3 different enzymes. Without this vitamin, you dont have this co enzyme which means the enzymea can t function. This results in a disease called beriberi which is a nervous system disorder.

Many molecules regulate enzyme activity by noncovalently and reversivly binding to the enzyme tot alter reaction rate. What are the two ways that reversible interactions affect enzyme function?

1. Competitive inhibition: The regulatory molecules is similar in size and shape to the enzymes natural substrate and the regulatory molecules binds to the enzymes active site itself, inhibiting catalysis by inhibiting the substrate from binding. 2. Allosteric regulation: the regulatory molecule binds at a location other than the active site and changes the enzymes shape. Allosteric regulation can cause activation which means the active site becomes available t substrates when a regulatory molecule binds at the allosteric site. OR allosteric regulation can cause inhibition meaning that the active site becomes unavailable to substrates when a regulatory molecules binds to the allosteric site.

What has made origin of life researchers think that amino adids were present during chemical evolution?

1. In stanley Millers and other experiments mimicing early earths environment amino acids were created 2. AMino acids were found in meterorites 3. AMino acids have been produced in experiments similiar to the environment of space

What are the key features to note when reffering to the peptide bonded "backbone"?

1. R group orientation- the side chains of each fesidue extend out from the backbonde and can interact with each other and water 2. directionality- there is a freeamino group (NH3+) on one end of the backbone which is referred to as the N-terminus. On the other end there is a free carboxyl group(COO-) referred to as the C-terminus. Always write amino acid residue sequences left to right so N terminus to C!! 3.Althought the peptide bonds cant rotate themselves because its similar to a double bond, all the single bonds on either side can rotate!

ETC NADH donates an electron to 1._____ at the top of the chain while FADH2 donates electrons to 2.______ that then passes them directly to 3.____. After passing through each of the remainkng components, the elctrons eventuall are accepted by 4.____. -In the ETC, what is the final electron acceptor? WHat is formed as a byproduct?

1. a flavin containing protein called FMN 2.an iron and sulfur containing protein (FeS); 3.Q 4.oxygen - oxygen, forms H2O!

How is it thought that carbohydrates/ their monosccharides formed by chemical evolution?

1. labratory experiments have shown that monosaccharides are easily made under conditions thought to exist in early Earth. FOr example when formaldehyde (CH2)( when heated forms pentoses and hexoses. 2. Researchers found 3 Carbon ketose and other sugars on the meteorite in Australia which caused them to believe that sugars were synthesized on dust particles in space and rained down when earth was forming.

Give examples of how cells get the precursor molescles required to syhnthesize AA's, RNA, DNA, phospholipids, and etc. (hint- it usually involved cellular erspiartion intermediaries)

1. many amino acids can be synthesozed from molecules siphoned in hte citric acid cycle 2. acetyl CoA (acetate) is the starting point for anabolic pathways that synthesize fatty acids which are in turn used to make phospholipids and fats 3. intermediaries in glycolysis can be used to synthesize nucleotides like ribonucletides and deoxynulceotides which then are use to make DNA and RNA 4. If ATP is abundant, pyruvate and lactat(this is from fermenatation) can be used to synthesis glucose. That excess glucose is then converted to glycogen or starch and is stored in this way

What experiemnts has made researchers think that amino acid monomers could have come together despite the second law?

1. researchers have been able to generate polymers in the lab by mixing free AA's with a sourse of chemical energy and tiny mineral particles 2. In conditions that stimulate hot, metal rich environments of unde® sea volcanoes, researchers have observed aminon acis being formed and polymerizing 3. In another lab experiment amino acids have joined into polymers in cold water with an energybrich carbon and sulfur containing gas which is present in undersea volcanoes.

What two big things do plasma membranes do?

1. serve as a selective barrier 2. keeps chemicals in an enc losed area making chemical reactions more efficent.

What are two factors that can majorly affect enzyme function? Explain each. What example illustrates How can enzymes vary in the way they function at different temperatures and pH? NOTE- pH and temp affect enzyme shape and reactivity. only temp affects kinetic energy of substrates.

1. temperature- Affects the folding and movement of an enzyme. Also affects the kinetic energy of the substrates. 2. pH- affects enzyme structure and function. pH affects the charge on carboxyl and amino groups on side chains and also affects the active sites ability to participate in reactions that involve proton or electron transfer. - the enzyme chitinase is an enzyme that is used by bacteria to digest cell walls of fungi. 2 different organisms have the same enzyme but their enzyme difefers because the two versions are adaptations that allow each species to thrive in different conditions. The organism that lives in hot and acidic environments has a version of the enzyme that performs best at high temps and low pH. The organism that lives in cool neutral soil has a verion of the enzyme that functions best atr cooler temperatures and neutral pH.

When the ring structure is formed in sugars the position of the newly formed C-1 hydroxyl groups will be fixed in what 2 possible orientations? Which type of glucose is more common?

1. the hydroxyl group can be above the plane of the ring(beta) 2. it can be below the plane of the ring(alpha) The two forms are called alpha and beta glucoses. Beta glucose is more stable and more common

Cellular respiation consits of what 4 processed to convery the chemicla energy in glulcose into chemical enrgy in ATP.

1.Glycolysis 2. Pyruvate processing 3. Citric acid Cylce 4. Electron transport chain

how can functional groups affect reactivity?

1.Side chains that contain functional groups such as cafboxyl, sulfydryl, hydroxyl, or amino groups all can partiicapte in chemical reactions. For example, amino acids with a sulfhydryl group in their side chains can form disulfide bonds that help link parts of large proteins. SUch bonds occur between proteins in our hair, resulting in curlier hair. 2. The R groups with only C and H atoms hardly participate in chemical reactions. Instead these amino acids influence protein function depending on their size and shape instead of reactivity.

Give a few examples as to how protein structure corresponmds with its shape:

1.collagen: provides structural support and is a triple helix that forms long cable like fibers 2. TATA box binding protein: has a groove where a molecule of DNA fits, the groove interacts with specific regions of DNA 3. porins: has a pore in its center so a porin fits in the PM and lets certain hhdrophilic things pass.

What are catabolic pathways? Anabolic pathways?

Catabolic pathways: nreak down molecules for sources of energy and carbon building blocks Anabolic pathways: use energy and carbon building blocks to make molecules

The function of an enzyme can also be altered by a chemical change in its primary structure. Give an example of a irreversible change and a reversible change.

Irriversible changes are often result from the cleavage of peptide bonds that make up the primary structure of th enzyme. afor example the enzyme trypsin is not functional until a small section of the protein is removed by anothe enzyme called protease. Reversible: The most common modification of enzymes is the addition of one or more phosphat groups. The transfer of a phosphate from ATP to the enzyme is catlayzed by the enzyme itself or by another enzyme. When phosphoryation adds a negative charge to amino acid residues in a protein, the chemical bonds that support the enzymes structure change configuration. this change can activate(make available ) or inactivate(unavailable) the active site. The removal of phosphates (dephosphoylation) can return the protein to its previous shape.

An enzyme does or does not affect delta G? Do most enzymes assist onlyu type of reaction or many? Is an enzyme used once or many times? Explain the three steps as to how enzymes catalyze reactions:

NOT, enzymes dont affect the energy of the ractant and products and thus doesnt change delta G. An enzyme only lowers the activation energy required to achieve transition state. - one! -many! an enzyme is not consumed in the reaction, the enzyme is the same at the end as itn was at begininng of reaction. 1. Instead of substrates occasionally colliding in a random fashion, enzymes precisely orient the substrates within the active site. When the substrates bind to the active site of the enzyme a enzyme-substrate complex is formed. 2. Transition state facilitation: inside an enzyme's active site substrates are more likely to reach their transition state. BECAUSE: The transition state is stabilized by a change in the shape or interactions between the substrate and R groups in the enzymes active site lower the activation energy required for the reaction. 3. termination: Products have lower affinity for active sites and are released. Enzyme is unchaged and can be used again.

What is quaternary structure? What bonds hold them together? Give an example of a protein that is simple with quarternary structure and one with multiple different polypeptides? WHat is a macromolecular machine?

Proteins that contain multiple polypeptides that interact to form a single functinal structure. Each polypeptide is refered to as subunits the same as tertiary structure - a virus called bacteriophage is made uf 2 identicla polypeptides wheras hemoglobin are made of 2 identical copies of alpha subunit and 2 identical copies of a beta subunit. Hemoglobin is a tetramer. - groups of multiple proteins that assemble to carry out a particular function. Some include multiple macromolecules like a ribosome which has 50 different proteins and many nucleic acids.

Explain the "energy investment phase" of glycolysis"

SO, glysolysis starts by using ATP. in the first step, glucose is phosphoylated to from glucose-6-phosphate. After the second reaction changes the sugar into fructose-6-phosphate, the third reaction adds a second phosphnate group forming fructose 1-6 biphosphate. SO in reactions 1-5 , (important follows -> )two ATP moleculs are used up before any ATP is made.

in plant cells monosacchardies are polymerized and stored for later use in the form of _________. Starch consists of entirely .... most linkages occur between ... The chain is shaped in what structure? What are the two polymers of starch and how do they differ?

Starch alpha glucose joined by glycosidic linkages. C-1 and C-4 Carbons helix Amylose- is an unbranched molecule which only has alpha 1,4 glycosidic linkages. Amylopectin- is a branched molecule and the branching occurs when a glycosidic linkage occurs between a C-1 and C-6 carbon. In amylopectin, bran chin occurs at one out of every 3o glucose residues.

Explain what homeostasis is-

a condition that is met by regulating key reactions involved in catabolic and anabolic pathways. The cell is able to maintain its internal environment even under different environment conditions.

Carbohydrates main role-

energy

Explain the idea of "retro-evolution" Explain the patchwork evolution hypothesis. briefly explain evidence of patch work evolution

this model says that enzymes first would have evolved to make the building blocks of life from readily available substrates. If the original substrate were depleted, natural selection would cause a new enzyme to make more of the original substrate from other available molecules. By evolving a new reaction step to produce the original substrate- now serving as an intermediate in a two-step path- the original enzyme could still then produce the building blocks from the "original "substrate that the newly evolved substrate produced. SO enzyme 1 evolves and coverts substrate 1 into a building block of life. Once substrate 1 is depleted, a new enzyme, enzyme 2, evolves to produce substrate 1 from another substrate, substrate 2. Substrate 1 is then used by enzyme 1 as before. If substrate 2 is depleted, enzyme 3 evolves and converts substrate 3 into substrate 2 and enzyme 2 converts it into substrate 1. substrate 1 is the converted bu enzyme 1 into building blocks of life. This cycle can repeat and repeat. as early pathways emerged, enzymes may have been recruited from other pathways to become part of new ones to perform new tasks. It is called pathwork because the new reaction series consist of enzymes brought together from different pathways. Evidence of this has evolved in a bacterial species that used a human made pollutant- a pesticide caled pentachlorophenol- as a source of energy. The new oathway evolved by using enzymes from 2 preexisting ones. The metabolic pathways of microbes is now being examined and engineered to clean up human made pollutants- this new technology is called bioremediation.