BioChemistry Exam #2
- cAMP - IP3 (inositol 1,4,5 triphosphate) - Epinephrine ( CORRECT!!) - DAG
- Of the following, all are secondary messengers in G-protein Coupled Protein Receptor signaling cascades EXCEPT: - cAMP - IP3 (inositol 1,4,5 triphosphate) - Epinephrine - DAG
- ALA can be converted to EPA and DHA
ALA is an essential fatty acid, what can it be converted to?
Activates gluconeogenesis and inhibits glycolysis
Activates glycolysis and inhibits gluconeogenesis OR Activates gluconeogenesis and inhibits glycolysis? --> increased glucagon levels
Activates gluconeogenesis and inhibits glycolysis
Activates glycolysis and inhibits gluconeogenesis OR Activates gluconeogenesis and inhibits glycolysis? --> increased levels of cAMP
Activates glycolysis and inhibits gluconeogenesis
Activates glycolysis and inhibits gluconeogenesis OR Activates gluconeogenesis and inhibits glycolysis? --> increased levels of fructose 2,6 biphophatase
Activates gluconeogenesis and inhibits glycolysis
Activates glycolysis and inhibits gluconeogenesis OR Activates gluconeogenesis and inhibits glycolysis? --> inhibition of PFK-2
Activates glycolysis and inhibits gluconeogenesis
Activates glycolysis and inhibits gluconeogenesis OR Activates gluconeogenesis and inhibits glycolysis? --> inhibition of fructose 2,6-biphosphatase (FBPase-2)
- pepsinogen
All of the following are zymogen secreted by the pancreas EXCEPT: - chymotrypsin - trypsinogen - proelaste - pepsinogen
Anabolic
Anabolic or Catabolic? --> Synthesizes macro molecules
Catabolic
Anabolic or Catabolic? --> Uses NAD+ as the electron carrier
Catabolic
Anabolic or Catabolic? --> breaks down macromolecules
Anabolic
Anabolic or Catabolic? --> requires energy inputs such as ATP
Catabolic
Anabolic or Catabolic? --> transforms fuels into cellular energy, such as ATP or ion gradients
Anabolic
Anabolic or Catabolic? --> uses NADPH as the electron carrier
In liver cells, fructose enters glycolysis as glyceraldehyde 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP). This bypasses one of the key regulatory steps of glycolysis, the reaction catalyzed by phosphofructokinase (PFK) that converts fructose 6-phosphate to fructose 1, 6-bisphosphate. This can result in an excess amount of fructose being ultimately converted to acetyl CoA, which is further converted to fatty acid and can eventually accumulate in the liver.
Based on where the fructose enters the glycolysis metabolic pathway in liver cells, briefly explain, based on your current understanding, why the fructose entry point of the liver cells has been correlated with something called fatty liver disease.
- Pyruvate undergoes lactic acid fermentation, reducing pyruvate to lactic acid.
Because the cancer cells cannot stop dividing, what is the fate of pyruvate in these cells that exist in low‑oxygen conditions?
- selective for K+ and not Na+, because Na + is too small to interact with carbonyl like K+ does - selectivity filter only K+ passes - K+ moves from low to high concentration - K+ is big enough to peel the oxygens off to make channel bigger to pass, perfect fit for that molecule - K+ moves 10 A- 3A
Briefly Describe thee potassium channel
Anabolic
Catabolic or Anabolic? --> non spontaneous --> use ATP and reducing sugar to synthesize large biomolecules
Catabolic
Catabolic or Anabolic? --> spontaneous --> combust carbon fuels to synthesize ATP or ion gradients
NAD+
Coenzyme A, NAD+, FAD? --> accepts two electrons and one proton
FAD
Coenzyme A, NAD+, FAD? --> accepts two hydrogen atoms when it is reduced
NAD+
Coenzyme A, NAD+, FAD? --> derived from the vitamin nicotinamide
Coenzyme A
Coenzyme A, NAD+, FAD? --> derived from the vitamin pantothenic acid (B5)
FAD
Coenzyme A, NAD+, FAD? --> derived from the vitamin riboflavin (B2)
Coenzyme A
Coenzyme A, NAD+, FAD? --> forms part of acetyl-S-CoAA (acetyl CoA), which is part of thee citric acid cycle
steroids w. 3 6 membered rings and one 5 membered ring
Compounds that contain a fused ring system are.....?
- uniport: one species - symport: 2 species, same direction (ex. SGLT transporter, Na+/ glucose) - antiport: 2 species, opposite directions ( ex. Na+-K+- pump)
Define & Give Examples: Uniport, Symport, and Antiport
- largest component by weight; variety of roles including membrane proteins
Define: Glycoproteins
Aldehydes or Ketones that contain 2 or more hydroxyls groups, C=O found is structures
Define: Monosaccharides
- mainly carbohydrate - protein attached by N-acetyl galactosamine - can be linked to the N atom in the side chain of asparagine or to the oxygen atom on the side chain of threonine or serine
Define: Mucins/ Mucoproteins
- two sugars, linked with o in the middle - product called glycoside - form ester linkages to phosphates
Define: O glycosidic bond
- the chiral carbon hat is at the very bottom far away from aldehyde at the top
Define: Penultimate Carbon
- attached to a particular type of polysaccharide called a glycosaminoglycan - mainly carbohydrate - act as structure or lubricants ( good for that b/c of abundance of OH groups that cause water to hang around and forma. jelly like substance)
Define: Proteoglycans
- long fatty acid forms aan esterlinkage to a long alcohol; extremely insoluble
Define: Waxes
- fat cells; liquid droplet contains triacylglycerol, takes up most of cell volume
Define: adipocytes
- repeating disaccharide units, one is amino derivative (negative charge either as a carboxylate or sulfate
Define: glycosaminoglycans
- anaerobic - occurs in yeast and certain bacteria - pyruvate is decarboxylated to acetaldehyde - NADH form of nad comes in and reacts with acetaldehyde to give ethanol and yields NAD+
Describe Pyruvate going to Ethanol
- anaerobic - occurs in animals - NADH reacts with pyruvate to give lactate which yield NAD+
Describe Pyruvate going to Lactate
- when a reaction includes an intermediate in which the enzyme is phosphorylated, such pumps are called P-type ATPases
Describe a P-type ATPase.
- ATP is limited--> ATP must be constantly recycled - ADP gets oxidized (oxidation of fuel molecules or photosynthesis
Describe the ATP/ ADP cycle?
The enzyme wraps around it's self to protect the active site from water because water can hydrolyze the ATP before it can get the chance to donate a phosphate group to glucose
Describe the induced fit of hexokinase.
- standard free energy of hydrolysis - means of comparing the tendency of organic molecules to transfer a phosphoyrl group to an acceptor molecule
Describe the phosphoryl-transfer potential.
- difference between + and - on both sides of membrane; negative on inside oof cell - the resting potential is largely due to the sodium potassium pump, but more specifically due to K+ concentration
Describe the resting potential of a cell.
- uses the energy of ATP hydrolysis to pump 3Na+ out of the cell and 2 K+ into the cell against their concentration gradients
Describe the sodium potassium pump.
increase
Does insulin increase or decrease in the fed state?
E1
E1, E2, E3? - pyruvate dehydrogenase - thiamine pyrophosphate (also called TPP or TDP) - formation of hydroxyethyl-TPP - hydroxyl group transferred to lipoamide
E3
E1, E2, or E3? - dihydrolipoyl dehydrogenase - FAD - transfer of elctrons to FAD and then NAD+
E2
E1, E2, or E3? - dihydrolipoyl transacetylase - lipoamide ( or lipoate/ lipoic acid) - transfer of acetyl group to coenzyme A
- glucose is a reducing sugar meaning that it is oxidized but only in it's straight chain form - copper is reduced
Explain the Glucose/ Copper reaction?
- a person takes a bite and begins to chew the complex carbohydrate into smaller pieces - the enzyme amylase, which is present in saliva, breaks polysaccharide chains into dissaccharides - amylase is deactivated by the low pH in the stomach - other enzymes int he small intestine further break the polysaccharide into monosaccharides - monosaccharides are absorbed through the intestinal wall
Explain the digestion process from when you first take a bite.
- exists as a dimer w/ or w/o ligand - primary messenger EGF binds to kinase which causes dimerization - kinase portion on bottom is now together, the bottom domain catalyzes the phosphorylation of tyrosine on the domain of the other monomer - the tyrosine phosphorylation causes lots of conformational changes - causes the GDP (inactive) to form GTP (active) which activates the Ras protein
Explain the process of Dimerization for receptors that ARE protein kinases.
- Receptor has a kinase that is tightly associated with it (JAK-2) - hormone-induced dimerization binds to the receptors and causes everything to bind - cross phosphorylation happens where a kinase acts on another kinase - tyrosine gets phosphorylated, this activates JAK2, which can now go on and phosphorylate other important enzymes (gene expression)
Explain the process of Dimerization--> cross-phosphorylation
Both
Facilitated Diffusion, Active transport, or both? - movement across a membrane - movement assisted by proteins
facilitated diffusion
Facilitated Diffusion, Active transport, or both? - movement to area of lower concentration - glucose transport into muscle cell
active transport
Facilitated Diffusion, Active transport, or both? - requires energy - sodium ion transport out of cell
Gluconeogenesis
Glycolysis, Gluconeogenesis, or Both? --> F 1, 6, bi phosphatase
Gluconeogenesis
Glycolysis, Gluconeogenesis, or Both? --> G6Phosphatase
Glycolysis
Glycolysis, Gluconeogenesis, or Both? --> Hexokinase
Glycolysis
Glycolysis, Gluconeogenesis, or Both? --> PFK
Glycolysis
Glycolysis, Gluconeogenesis, or Both? --> Pyruvate kinase
Both
Glycolysis, Gluconeogenesis, or Both? --> triose phosphate isomerase
forms fructose 1,6 biphosphate
Glycolysis: What is the purpose of PFK?
cleaves fructose 1,6 biphosphate
Glycolysis: What is the purpose of aldolase?
generates the second intermediate compound with a high phosphoryl-transfer potential
Glycolysis: What is the purpose of enolase?
generates the first intermediate compound with a high phosphoryl-transfer potential
Glycolysis: What is the purpose of glyceraldehyde 3-phosphate dehydrogenase?
Phosphorylates glucose
Glycolysis: What is the purpose of hexokinase?
generates the first molecule of ATP
Glycolysis: What is the purpose of phophoglycerate kinase?
converts 3-phosphoglycerate into 2- phosphoglycerate
Glycolysis: What is the purpose of phophoglycerate mutase?
converts glucose 6- phosphate into fructose 6 phosphate
Glycolysis: What is the purpose of phosphoglucose isomerase?
generates the second molecule of ATP
Glycolysis: What is the purpose of pyruvate kinase?
catalyzes the interconversion of three-carbon isomers
Glycolysis: What is the purpose of triose phosphate isomerase?
Gluconeogenic
Glycolytic vs Gluconeogenic? --> fasting
Glycolytic
Glycolytic vs Gluconeogenic? --> fed state
Glycolytic
Glycolytic vs Gluconeogenic? --> increase in AMP
Gluconeogenic
Glycolytic vs Gluconeogenic? --> increase in ATP
Gluconeogenic
Glycolytic vs Gluconeogenic? --> increase in acetyl coa
Gluconeogenic
Glycolytic vs Gluconeogenic? --> increase in citrate
Glycolytic
Glycolytic vs Gluconeogenic? --> increase in fructose 2,6- biphosphate
Gluconeogenic
Glycolytic vs Gluconeogenic? --> increase in glucagon
Glycolytic
Glycolytic vs Gluconeogenic? --> increase in insulin
Small G proteins
Heterotrimeric G Proteins, Small G proteins, or both? - activate by dimerized growth factor receptors - monomeric in both active and inactive forms
Heterotrimeric G Proteins
Heterotrimeric G Proteins, Small G proteins, or both? - activated by 7TM receptors - active form dissociates to G alpha and G beta, gamma
Both
Heterotrimeric G Proteins, Small G proteins, or both? - inactive form binds GDP - active form binds GTP
- the OH group of the penultimate carbon attacks the anomeric carbon
How are anomers formed?
- carbohydrates are broken down by amylase/hydrolases into their component parts of glucose/galactose or fructose - glucose/galactose enteer intestinal wall through SGLT symport & fructose enters through GLUT5 symport - Glucose, galactose, & fructose then enter the blood through GLUT2
How are carbs digested and absorbed?
- starts with bile--> solubilize the lipids---> bile salts act like detergents to help homogenize and disperse fats - Most lipids are in the form of triacyglycerol; these fats form droplets & bile salts that are synthesized through cholesterol, disperse the lipids so that lipases can get to them - triacylglycerols break down to fatty acids and monoacylglycerols--> broken down by enzyme FABP and go through the FATP port - triacyglcerols and SER (Phospholipids, cholesterol, and proteins) come together for TAG to create chylomicrons which go to the lymph system then to the blood stream -
How are lipids/fats digested and absorbed?
- proteins encounter proteolytic enzymes released by the pancreas - proteins in the lumen are broken down into amino acids and oligoprotiens(bigger) - amino acids go straight into the intestinal cell while oligoproteins encounter peptidase which breaks the molecule down into di and tri peptides - di and tripeptides encounter peptidases which get broken down into amino acids and all of that enters the blood
How are proteins digested and absorbed?
ADP + Pi --> ATP
How can ATP be formed by thee oxidation of carbon fuels?
- formed from lactate int he liver by lactate dehydrogenase; cori cycle
How can pyruvate be formed starting form the liver?
- cyclic - isomers that differ at a new asymmetric carbon atom forme din the ring structure, anomeric carbon usually has different positioning for OH group
How can you spot anomers?
- they are isomers that are not mirror images - bottom is usually the same with two spots where positions are reversed
How can you spot diastereomers?
- they are non superimposable mirror images w/ a central carbon
How can you spot enantiomers?
- they are isomers that are not mirror images - differs at one of several asymmetric carbon atoms - bottom is usually the same with just one carbon switch
How can you spot epimers?
- positive on the outside, negative on the inside - the helices are closer to the cytosolic side of the bilayer, and this seals the channel
How do we know when the potassium voltage gated ion channel is in its closed conformation?
- negative on the outside, positive on the inside - the channel opens when charged helices move toward the extracellular side of the bilayer
How do we know when the potassium voltage gated ion channel is in its open conformation?
increases PFK activity, decreases FBPase activity
How does fructose 2,6‑bisphosphate (F26BP) affect the activity of the enzymes phosphofructokinase‑1 (PFK) and fructose 1,6‑bisphosphatase (FBPase)?
- stored as starch in 2 forms - Amylose: linear, alpha 1,4 linkages - Amylopectin: branched, alpha 1, 6 glycosidic bond for every 30 alpha 1,4 glycosidic bond
How is glucose stored in plants?
- covalent modification (phosphorylation) - glucokinase (hexokinase IV)
How is pyruvate kinase regulated in the liver? What the name of hexokinase in the liver?
- adenylate cyclase is turned off - alpha subunit of G-protein has GTP-ase activity intrinsic active site that converts GTP--> GDP + Pi - GDP dissociates from adenylate cyclase, this stops cAMP production - Beta & gamma subunits come back - final turn of factor is when primary messenger is no longer bound (AKA epinephrine)
How is the G-protein reset?
12
How many alpha helices does adenylate cyclase have?
- 3 - Alpha: does all the work of the pump ( 4 domains) - Beta & Gamma: orient the alpha subunit - Gamma:
How many subunits are involved in the Sodium Potassium Pump? What are the names and the functions?
- first number is total carbons in molecule - second number is total double bonds - delta superscript numbers tell us what carbon the double bonds are on ***Count down from carboynl carbon down
How to name fatty acids?
- the carbon bond directly to Oxygen
How to tell where an anomeric carbon is?
Fatty Acids
Hydrolysis of the ester bonds in triacylglycerols yields products including....
Monosaccharides
Hydrolysis of the glycosidic bond of carbohydrates yields....
Amino acids
Hydrolysis of the peptide bonds of proteins produces....
- Step 1: hexokinase--> the conversion of glucose to glucose 6‑phosphate - Step 3: PFK--> the formation of fructose 1,6‑bisphosphate from fructose 6‑phosphate - Step 10: pyruvate kinase--> the formation of pyruvate and ATP from phosphoenolpyruvate and ADP
Identify the irreversible reactions of glycolysis under intracelluar conditions.
NAD +
Identify the structure.
- other molecule is reduced - reducing agen tis oxidized
If something is a reducing agent that means that the other molecule is what? And what happens to the reducing agent?
Fructose 1, 6 biphosphatase
In gluconeogenesis, which of the following is the major regulatory enzyme?
- PFK
In glycolysis, which of the following enzymes is the major regulatory enzyme?
- The anomeric carbon is the carbonyl carbon (either ketone or aldehyde functional group) of the straight-chain form of the sugar. - anomeric carbon also has an OH group attached and is the closest to the O link
In the straight chain form of the sugar shown to the right, which carbon becomes the anomeric carbon?
- exergonic, releases a lot of energy
Is ATP hydrolysis exergonic or endergonic?
- Green domain: binding sites for Sodium & Potassium - Blue Domain: ATP binding site - Orange: Pi binding site - Purple: attenuator- helps binding site change
Look at the chart & explain the green, purple, orange and blue domains.
- micelles are the fatty acid droplets that form a ring with hydrophobic on the outside and hydrophilic on the inside - bilayer is like the standard cell membrane
Micelles/ Bilayer
Disaccharide
Monosaccharide, Disaccharide, or Polysaccharide?
Monosaccharide
Monosaccharide, Disaccharide, or Polysaccharide?
monsaccharide
Monosaccharide, Disaccharide, or Polysaccharide? --> Glucose
Polysaccharide
Monosaccharide, Disaccharide, or Polysaccharide? --> Glycogen
Dissacharide
Monosaccharide, Disaccharide, or Polysaccharide?---> C12H22O11
Polysaccharide
Monosaccharide, Disaccharide, or Polysaccharide?---? (C6H10O5)750
- Reduction
Oxidation or Reduction? --> decrease in number of carbon-oxygen bonds
Reduction
Oxidation or Reduction? --> gain of electrons
- Reduction
Oxidation or Reduction? --> gain of hydrogen
Oxidation
Oxidation or Reduction? --> gain of oxygen
Oxidation
Oxidation or Reduction? --> increase in number of carbon oxygen bonds
- Oxidation
Oxidation or Reduction? --> loss of electrons
- Oxidation
Oxidation or Reduction? --> loss of hydrogen
Reduction
Oxidation or Reduction? --> loss of oxygen
- E1--> PDH enzyme - E2--> dihydrolipoyl transferacetyl - E3--> dihydrolipoyl dehydrogenase
PDH Complex --> What are the 3 enzymes of the complex?
- TPP - lipoamide - FAD - NAD (cosubstrate) - Acetyl Coa (cosubstrate)
PDH Complex --> What are the 5 coenzymes including two of those that are co-substrates (stoichiometric)?
- Co A is associated with E2. The acetyl moiety is transferred to CoA I the active site of E2. This producesacetyl-CoA, which is released from the enzyme complex.
PDH Complex --> What enzyme is CoA associated with & what is its function?
- FAD is associated with E3. FAD oxidizes lipoamide back to the sulfhydryl form so it is ready to begin another reaction cycle.
PDH Complex --> What enzyme is FAD associated with & what is its function?
- NAD+ is associated with E3. It oxidizes FADH2 back to its FAD so FAD is ready for another reaction cycle, producing NADH.
PDH Complex --> What enzyme is NAD+ associated with & what is its function?
- TPP is associated with E1. In the E1 active site pyruvate is decarboxylated and the hydroxyethyl-TPP intermediate is formed.
PDH Complex --> What enzyme is TPP associated with & what is its function?
- Lipoamide is associated with E2. Lipoamide swings into the E1 active site and accepts the activated 2C group.
PDH Complex --> What enzyme is lipoamide associated with & what is its function?
- saturated--> less fluid - unsaturated--> more fluid
Saturated vs Unsaturated: Membrane Fluidity
unsaturated
Saturated vs. Unsaturated Phospholipid: allow the membrane to remain fluid and flexible at low temperatures
unsaturated
Saturated vs. Unsaturated Phospholipid: contain one or more double bonds
saturated
Saturated vs. Unsaturated Phospholipid: fatty acid tail packed tightly together
Saturated
Saturated vs. Unsaturated Phospholipid: fatty acid tails are straight
unsaturated
Saturated vs. Unsaturated Phospholipid: have bent fatty acid tails
saturated
Saturated vs. Unsaturated Phospholipid: have no double bonds
unsaturated
Saturated vs. Unsaturated Phospholipid: maintains space between adjacent phospholipids
saturated
Saturated vs. Unsaturated Phospholipid: make the membrane somewhat rigid at low temperatures
- palmitic acid (saturated) - stearic acid (saturated) - oleic acid (mono-un) - linoleic acid (poly-un) - arachidonic acid (poly-un)
Saturated, Monounsaturated, or Polyunsaturated? - palmitic acid - stearic acid - oleic acid - linoleic acid - arachidonic acid
Starch
Starch, Glycogen, or Cellulose? - Made of two glucose polysaccharides: amylose and amylopectin
Starch
Starch, Glycogen, or Cellulose? - Major storage form of glucose in plants
Cellulose
Starch, Glycogen, or Cellulose? - Not digestible by humans
Glycogen
Starch, Glycogen, or Cellulose? - major storage form of carbs in animals
- oxidation- reduction
The mKO mice lack an enzyme necessary for the synthesis of the coenzyme NAD. Which type of reaction will be affected in muscles of the mKO mice?
Epimers
These monosaccharides are:
Reduced cofactors
Thioesters, Reduced Cofactors, or phosphorylated compounds? --> Ubiquinol
Thioesters
Thioesters, Reducing Cofactors, or phosphorylated compounds? --> Acetyl CoA
phosphorylated compounds
Thioesters, Reducing Cofactors, or phosphorylated compounds? --> Phosphocreatine
Thioesters
Thioesters, Reducing Cofactors, or phosphorylated compounds? --> the sulfur-carbon bond is hydrolyzed
phosphorylated compounds
Thioesters, Reducing Cofactors, or phosphorylated compounds? --> these compounded yield HPO 2- 4 upon hydrolysis
Reducing Cofactors
Thioesters, Reducing Cofactors, or phosphorylated compounds? --> these compounds accept electrons during the oxidation of substrates; energy is released when they are oxidized
True
True or False: A disaccharide with its anomeric carbons joined by the glycosidic linkage cannot be a reducing sugar.
False
True or False: A plant that produces more monounsaturated fatty acids than polyunsaturated fatty acids in its membranes in winter has an increased resistance to freeze damage.
False
True or False: A reducing sugar will not react with the Cu2+Cu2+ in Benedict's reagent.
True
True or False: Acetyl CoA has a high acetyl group transfer potential
True
True or False: Amphipathic (amphiphilic) lipids are the structural basis of biological bilayer membranes.
True
True or False: Cell membranes in cold tolerant winter wheat plants have a higher ratio of unsaturated fatty acids to saturated fatty acids than do cold intolerant wheat varieties.
False
True or False: Cell membranes in reindeer legs (near the hooves) are kept flexible because they have a large number of saturated fatty acids.
True
True or False: Cholesterol decreases membrane fluidity in areas called rafts, which contain large amounts of sphingolipids and cholesterol.
True
True or False: Cholesterol increases membrane fluidity in a membrane that otherwise contains mostly long‑chain saturated fatty acids.
False
True or False: Cholesterol inhibits the crystallization that would otherwise occur in membranes rich in unsaturated fatty acids.
False
True or False: Cholesterol is generally buried in the bilayer, with its planar rings oriented toward the solvent and its hydroxyl group aligned with the fatty acid tails of the bilayer.
True
True or False: D‑Glucose (an aldose) is a reducing sugar.
False
True or False: Enzymes present in saliva initiate the process of protein digestion.
False
True or False: Free amino acids are passively absorbed through the intestinal wall.
False
True or False: Gastric juices have a pH between 7.0 and 8.0.
False
True or False: Hydrophobic molecules are individually hydrated in water, increasing the entropy of the system.
True
True or False: Hydrophobic molecules clump together in water because fewer water molecules are required to surround them, which results in a smaller decrease in entropy than if the molecules were individually hydrated.
True
True or False: In the small intestine, trypsin attacks peptide bonds.
False
True or False: Nonpolar molecules are capable of forming micelles.
True
True or False: Pepsin causes the hydrolysis of some of the peptide bonds in proteins.
False
True or False: Reducing sugars contain ketone groups instead of aldehyde groups.
True
True or False: The oxidation of a reducing sugar forms a carboxylic acid sugar.
True
True or False: The rate of glycolysis is higher in cancer cells than in healthy cells.
True
True or False: The tendency of water to minimize its contact with nonpolar substances is called the hydrophobic effect.
True
True or False: Yeast cells that produce more unsaturated fatty acids than saturated fatty acids in response to cold have greater cold tolerance.
1. the binding of epinephrine to beta- adrenegic receptor causes a conformational change in 7TM/ GPCR , then in G- protein 2. Beta & gamma pieces fall off, GDP leaves 3. GTP comes in an bind to adenylate cyclase, this binding causes the activation to produce secondary messengers 4. adenylate cyclase amplifies the process 4. ATP goes to make cyclic AMP (2nd messenger) which then activates the protein kinase A 5. kinase is an enzyme that catalyzes transfer of a P from ATP to some other substrate
What actually happens when epinephrine binds to the 7 TM?
a fatty acid
What anchors the g-protein to the 7TM protein?
1. increase in entropy 2. stabilization by hydration 3. resonance stabilization
What are 3 factors that account for the high phosphoryl‑transfer potential of the nucleoside triphosphates, NTPs?
1. it's a fatty acid 2. embedded in the hydrophobic portion of the bilayer 3. chemical signaling molecules that call on inflammation or swelling 4. on the ER
What are 4 facts about peripheral proteins?
- heteropolysaccharides composed of repeating disaccharide units. These units have some similar characteristics that allow them to be identified as GAGs which are the continuing tails on each end - they can not be cut off
What are Glycosaminoglycans (GAGs)?
- attached to the N is Asn
What are N-linked molecules usually attached to?
- attached to the O of ser, thr
What are O-linked molecules usually attached to?
- chylomicrons are lipoproteins that transport dietary lipids from the intestines to other locations in the body - composed of cholesterol, triglycerides/cholesteryl esters, apolipoprotein, & phospholipids
What are chylomicrons and what is it composed of?
- membrane proteins
What are phospholipids and glycolipids classified as?
- via channel - polar molecules - Ex. Na+
What are some characteristics & an example of facilitated diffusion?
- directly through membrane - lipophilic molecules - Ex. O2
What are some characteristics & an example of simple diffusion?
- against concentration gradient - couples a thermodynamically favorable process with a non- favorable process to push a molecule against its' concentration gradient - pumps - requires energy
What are some characteristics of active transport?
- can be active or passive - uses transmembrane protein - water--> osmosis - facilitated by pores, carriers, permeases
What are some characteristics of facilitated transport?
- with concentration gradient - more rapid for hydrophobic solutes - slower for polar/charged solutes - passive diffusion - diffuse: CO2, O2 (small, hydrophobic)
What are some characteristics of non-mediated transport?
- atoms are connected in the same order but differ in spatial arrangement
What are stereoisomers?
- membrane proteins/ signaling molecules
What are steroids classified as?
- Glycoproteins - Proteoglycans - Mucins or Mucoproteins
What are the 3 classes of glycoproteins?
- Anaerobic--> Alcohol/ Ethanol or Lactate - Aerobic to Acetyl CoA then Citric Acid Cycle
What are the 3 fates of pyruvate?
- Glucose --> 2 pyruvate - 2 ADP --> 2 ATP - 2 NAD + --> 2 NADH
What are the 3 net yields of glycolysis?
1. amount of enzyme present- at level of gene transcription 2. catalytic activity of enzymes- allosteric or covalent modification 3. accessibility of substrates
What are the 3 ways the metabolic pathways are regulated?
- chymotrypsinogen--> chymotrypsin - trysinogen --> trypsin - procarboxypeptidase --> carboxypeptidase - proelastase--> elastase
What are the 4 pancreatic enzymes in their zymogen state & then their active state?
- close proximity helps reaction go faster - limits side reactions because enzymes aren't moving much - all enzymes are in proper amount sine the entire complex is together - more efficient because regulatory enzymes are part of complex
What are the 4 reasons a single large complex is an advantage?
1. Pyruvate reacts w/ tpp and is decarboxylated, forming hydroxyethyl- TPP 2. The lipoamide arm of E2 moves to the active site of E1, enabling the transfer of the acetyl group to the lipoamide 3. The acetyl lipoamide arm of E2 moves to the active site of E1, where the acetyl group is transfeerred to CoA, forming acetyl- CoA and the reduced form of lipoamide 4. The lipoamide arm moves to the active lipoamide and FADH2 5. HADH2 is reoxidized to FAD, reducing NAD+ to NADH
What are the 5 different steps of the oxidative decarboxylation of pyruvate by the PDH complex?
- intermediate: pyruvate 1. redox 2. condensation 3. hydrolysis 4. addition/ elimination 5. isomerization
What are the 5 reaction types and the intermediate that are common to all metabolic pathways?
1. integral protein: transmembrane all the way through 2. signaling protein: all the way across but w/ multi-subunit attached 3. multi-subunit protein: attached t signaling protein 4. tightly associated head group: right on top of membrane but not anchored 5. peripheral protein: lipid anchored protein covalently bound
What are the 5 types of proteins you expect to see in a membrane?
1. Pyruvate enters the active site of enzyme #1 & it will peel off the carbon dioxide and allow the remaining 2 carbons to bind to the TPP cofactor 2. enzyme #2 inserts the lipoamide arm deep into the channel of E1 leading to the active site--> there it reacts w/ the remainder of the substrate which is covalently bound to the TPP cofactor 3. E1 is going to catalyze the transfer of of the acetyl group to the lipoamide( the lipoamide goes to the active site of E1 and collects the acetyl group then goes to the E2 region--> when this happen lipiamide gets reduced & acetyl group is oxidized) 4. CoA is going to enter the E2 active site on the right and the Acetyl group will be transferred to Acetyl CoA 5. at the E3 active site, the lipoamide is oxidized by the coenzyme FAD and then it is reactivated, FAD gets reduced in the process then the lipoamide leaves the E3 active site & goes back to E2 6. the electrons that were picked up by FAD need to come off so FAD can be ready to go so NAD comes to collect the two electrons and shuttle them off into the electron transport chain
What are the 6 steps of the PDH complex?
- stimulate: ADP, Pyruvate - inhibit: ATP, Acetyl CoA, & NADH
What are the allosteric factors that stimulate & inhibit the complex?
- a catalytic enzyme can be regenerated and used again - lipoic acid - FAD - TPP
What are the catalytic coenzymes used in the PDH complex and what does catalytic mean?
- 2 fatty acids - a platform (glycerol or sphingosine) - a phosphate - an alcohol
What are the characteristics of a phospholipid?
- Carbon chain from palmitate, serine component, and forms an amide bond
What are the characteristics of a sphingosine?
- GAT GPPE - glucose 6 phosphate - aldolase - triose phosphate isomerase - glyceraldehyde 3 phosphate - phosphoglycerate mutase - phosphoglycerate kinase - Enolase
What are the enzymes that are shared between glycolysis & gluconeogensis?
1. release of a primary messenger ---> ghrelin, glucagon (liver, glucose breakdown) 2. reception of the primary messenger ---> reversible 3. generation of an intracellular 2nd messenger ( Ca2+, cAMP) ---> receptor changes protein structure ---> 2nd messenger is going to cause a chemical change that will cause an enzyme to start or stop some metabolic process 4. activation of effector results in physiological response 5. termination of signal cascade
What are the five stages of signaling proteins?
H: stabilization by hydration -Pi as well E: Increase in entropy (multiple molecules made) R: resonance stabilization --> Pi has more resonance C: charge repulsion --> many negative charges close to each other
What are the four reasons why ATP has a high phosphoryl- transfer potential?
- 7 alpha helices that span the membrane - the G- protein binds and changes conformation upon binding - the g-protein couple is the binding site for GDP/GTP
What are the main general details of the 7 transmembrane helix receptor?
1. N-acetyl- D-glucosamine 2. D-galactose--> defining: N-acetyl- D- GALACtosamine 3. L-fucose
What are the monosaccharides in Blood Type A? What is the defining monosaccharide?
1. N-acetyl- D-glucosamine 2. D-galactose--> defining: D-galactose 3. L-fucose
What are the monosaccharides in Blood Type B? What is the defining monosaccharide?
1. N-acetyl- D-glucosamine 2. D-galactose 3. L-fucose
What are the monosaccharides in Blood Type O?
-: F 2, 6 BP -: AMP +: Citrate
What are the positive & negative effectors of Fructose 1,6- biphosphatase?
-: ADP
What are the positive & negative effectors of PEP?
+ : AMP +: F 2 6 BP -: ATP - : Citrate -: H+
What are the positive & negative effectors of PFK?
- ADP + Acetyl CoA
What are the positive & negative effectors of Pyruvate Carboxylase?
+: F 1 6 BP -: ATP -: Alanine
What are the positive & negative effectors of Pyruvate Kinase?
- glucose - 4 ADP - 2 GDP - 6 Pi - 2 NAD+
What are the products of gluconeogensis?
- Pyruvate - Carboxylation of pyruvate - phosphorylation of 3-phosphoglycerate - hydrolysis of F 1, 6, biphosphate - isomerization of fructose 6-phosphate - hydrolysis of glucose 6 phosphate - glucose
What are the steps for gluconeogenesis, from pyruvate to glucose?
- triglycerols enter the stomach - undigested fats enter the small intestine - the gallbladder secretes bile into the small intestine -pancreatic lipase hydrolyzes TAGs in lipid droplets - insoluble lipids, in micelles, are absorbed through the lining of the small intestine - TAGs in chylomicrons enter the lymph system - TAGS in chylomicrons enter the blood stream - triacyglycerols absorbed into cells
What are the steps fro fat digestion and absorption?
- a stoichiometric enzyme can only be used once - Coenzyme A - NAD+
What are the stoichiometric coenzymes used in the PDH complex and what does stoichiometric mean?
1. power muscle contraction 2. active transport of molecules 3. biosynthesis
What are the three fundamental needs that energy is required to meet?
- 7 transmembrane-helix receptors, associated with heterotrimeric G-proteins - Dimeric membrane receptors that recruit protein kinases - Dimeric protein receptors that are protein kinases
What are the three major classes of receptors & describe them
- Girls get fine food --> Glucose, Glucose 6 Phosphate, Fructose 6 Phosphate, Fructose 1,6 biphosphate - Gentlemen dine Babes --> GAP, DHAP, 1,3, - biphosphoglycerate - preferring to pick up pepperoni pizza --> 3 PG, 2 PG, PEP, Pyruvate
What are the three mneumonic devices for the substrates of glycolysis?
1. decarboxylation 2. oxidation 3. acetyl transfer
What are the three steps involved int he conversion of pyruvate into acetyl CoA?
- gene level --> hours - covalent modification --> seconds - allosteric regulation --> miliseconds
What are the three types of control enzymes & how long do they last?
- phospholipid, glycolipid, cholesterol
What are the three types of membrane lipids?
1. biosynthesis of more complex molecules 2. active transport 3. muscle contraction
What are the three ways cells use energy?
- placing carrier proteins in the membrane - placing intracellularly-directed and extra cellularly directed pumps in the membrane - most efficient: carrier proteins
What are the two conditions that can equalize the intracellular and extracellular concentrations of this molecule? And which is the most efficient?
- Omega 3: first double bond on the 3rd carbon from end of chain - Omega 6: first double bond on 6th carbon from end of chain
What are the two essential omega fatty acids?
- citrate - fructose 2, 6- bisphosphate
What are the two key regulators for the liver?
- E1: open to ICF - E2: open to ECF
What are the two states of the sodium potassium pump?
- NAD/P - FAD - Acetyl CoA
What are three big carriers in biochem?
1. solidifies easily 2. relatively high melting temp 3. dispersion forces (nonpolar- H bonds)
What are three characteristics of saturated fatty acids?
- carriers are kinetically stable in the absence of specific catalysts --> high activation energy - the metabolism of activated groups is accomplished with a small number of carriers - activated carriers exemplify the modular design & economy or metabolism
What are three key facts about activated carrier?
- insulin is a hormone secreted from the pancreas when blood glucose level is high - insulin receptor is a receptor tyrosine kinase - unlike other receptors of this class, this receptor exists as a dimer even in the absence of insulin
What are three key facts of insulin?
- a member of family of signal proteins called small G proteins or small GTPases - --> monomeric (not heterotrimeric like normal proteins) - members of this family control a variety of cellular processes - other proteins modulate RAS activity
What are three key facts of the RAS protein?
1. hormones- chemical messengers ( ghrelin, insulin, glucagon) 2. Photons- rhodopsin protein in the eyes, takes photon energy and transmits to chemical 3. Neurotransmitters
What are three primary messengers?
- intracellular domain undergoes structural changes upon extracellular ligand binding - signal molecule binding site on the extracellular domain
What are two structural features common to all membrane-bound receptors?
- A saturated fatty acid with a greater molar mass has a higher melting point than a saturated fatty acid with a lower molar mass. - A saturated fatty acid has a higher melting point than an unsaturated fatty acid.
What are two true statements about fatty acids & melting points?
fiber
What can be included in diet that helps lower cholesterol?
- carbon skeletons of amino acids can be converted to gluconeogenic intermediates
What can carbon skeletons do?
- derived from the hydrolysis of triacyl glycerols & canbe converted to DHAP
What can glycerol be converted into fro the sake of glycolysis/ gluconeogensis
- NADH can be oxidized to NAD+ to give energy
What can provide energy when the citric acid cycle and oxidative phosphorylation are not available?
- from high to low concentration - spontaneous
What direction do molecules normally move?
- small intestine
What does absorption. take place?
Form micelles, circular formations of fat
What does monoacyglycerol form?
- hangs out in zymogen form until food arrives, decreasing pH which converts from inactive --> active
What does pepsinogen usually do?
- requires pyruvate carboxykinase ( in mitochondria) and pep carboxykinase (in cytoplasm) - pyruvate to oxaloacetate occurs in 3 steeps --> requires biotin as a cofactor carries carboxylate groups (COO)
What does step one of gluconeogensis require?
- trypsinogen has intrinsic proteolytic activity, will spontaneously converts to trypsin - trypsin converts the rest of the zymogens into their active form
What does trypsinogen usually do?
- hydrophobic effect
What drives the spontaneous formation of bilayers?
- increases membrane fluidity, decreases packing - can form a complex with lipids and proteins, or hold a set of proteins together called a lipid raft; locally these decrease membrane fluidity
What effect does cholesterol have on membrane fluidity?
-Hydrolysis of pyrophosphate shifts the equilibrium of the reaction to the right, making the formation of acetyl‑CoA energetically more favorable.
What effect does the presence of inorganic pyrophosphates have on the synthesis of acetyl- CoA?
- kinases are enzymes that phosphorylate a substrate at the expense of a molecule of ATP; phosphorylation of an enzyme regulates the activity of that enzyme
What exactly are kinases?
- much less dispersion forces because of kinks created
What happens to dispersion forces when you have a mixture of saturated and unsaturated fatty acids?
- PFK 2 - broken down by fructose biphosphatase
What is F-2, 6 BP synthesized by?
- 5-7 alpha helices that span the membrane - uses light energy to pump protons - transmembrane portion is alpha helices - bacteriorhodinopsin
What is a common motif for transmembrane proteins w/ alpha helices?
- beta sheets folded into a beta barrel - channel with the barrel to allow passage of things - bacterial porin
What is a common motif for transmembrane proteins w/ beta sheets?
- a carbohydrate that is covalently linked to a lipid
What is a glycolipid?
a lipid molecule that contains at least one carbohydrate unit
What is a glycolipid?
- carbohydrate that containing lipids that is found on the outside on the plasma side of the cell--> used for cell-cell recognition - cerebrosides
What is a glycolipid? What is the simplest glycolipid?
- a protein that is the inactive form of an enzyme
What is a zymogen?
- Ex. human growth hormone receptor - 7TM- tertiary structure change - These receptors exist in monomers or dimers, depending on their activation. They have an intracellular component and an extracellular component. Binding of a ligand to the extracellular component of the receptor leads to dimerization of the receptor and thus its activation by bringing together also the intracellular component. Oftentimes this brings together two kinases that, upon dimerization, are activated.
What is an example of a dimeric membrane receptor that recruits protein kinases and what typically happens?
- ex. EGF ( Epidermal Growth Factor) receptor and insulin receptors
What is an example of a dimeric protein receptor that are protein kinases?
catabolism
What is another name for energy metabolism?
Glycoplipids
What is formed when a carbohydrate is glycosidically linked to a hydroxyl group of a lipid?
phosphoglyceride
What is formed when glycerol is esterified to two fatty acids and a phosphoric acid molecule?
hormone that starts phosphorylation cascade that end ip phosphorylating pyruvate kinase
What is glucagon?
- rapid - particle moving side by side from one end to another
What is lateral diffusion?
sphingolipids
What is made up of a long‑chain amino alcohol joined to a fatty acid, either by a glycosidic linkage or a phosphodiester linkage & DO NOT contain glycerol?
- it is a controlled way to move energy around -Ex. sodium potassium pump coupled with ATP hydrolysis
What is meant by ATP is the energy currency of life?
Cells have a decreased response to the normal level of circulating insulin.
What is meant by the term insulin resistance?
- 2 different proteins/ pumps - one uses ATP, the other uses the concentration gradient created by the first - Example: Sodium Potassium pump coupled w/ Na+ glucose symport
What is secondary transport, and give an example?
ATP <--- energy + precursors---> complex molecules
What is the anabolic equation?
- 3 cyclo hexanes - 1 cyclopentane
What is the basic structure of a steroid?
- the transmembrane protein changes conformation which transfers signal across the membrane
What is the big idea with the transmembrane protein?
- large molecules are broken down in smaller molecules - these smaller molecules go on to form acetyl coa - the molecules are then converted into energy--> acetyl coa to the citric acid cycle to produce electrons for oxidative phosphorylation and then ATP
What is the big picture of energy metabolism?
fuel--> CO2 + H2O + energy --> ATP synthesis
What is the catabolic equation?
= RTln(final position/ initial position) + ZFdelta(prong) - Z = charge of particle - F= faraday's constant (96480) - delta(prong) = membrane potential
What is the delta G equation for calculation involving charged particles moving across a gradient?
= RTln (final position/initial position)
What is the delta G equation for calculation involving uncharged particles moving across a gradient?
- D has an OH group on the bottom right - L has an OH group on the bottom left - D-form to be biologically functional
What is the difference between D/L- glceraldehyde? What form are biologically functional saccharides found in?
- a channel allows a molecule to just pass - a pump uses ATP to help
What is the difference between a channel & a pump?
- production of bile
What is the digestive function of the liver?
deltaG standard + RTln(Q) - Q is products/ reactants
What is the equation for delta G free energy including delta G standard?
= -RTlnK
What is the equation of delta G standard?
NAD serves as a cofactor for dehydrogenases, reductases and hydroxylases, making it a major carrier of H+ and e- in major metabolic pathways such as glycolysis, the triacarboxylic acid cycle, fatty acid synthesis and sterold synthesis
What is the function of NAD/P?
- E1 site of regulation - kinase come to add phosphate which inactivates site (covalent modification) - phosphatase comes in to remove phosphate which activates the enzyme ( covalent modification)
What is the key site of regulation in the PDH complex?
1. two individual pieces consisting of one alpha helix each 2. growth hormone introduced which is the primary messenger that binds to one of the pieces 3. cause both pieces to come together and form an activated dimer molecule
What is the main overview of the dimerization process?
- phosphoglycerides - phosphoglycerols
What is the name of phospholipids with a glycerol platform?
- Glucose 6/ Glycerol 3 (lowest) - ATP (central) - Creatine Phosphate - 1,3- Biphosphoglycerate (1,3-BPG) - Phosphoenolpyruvate (highest)
What is the order from low to high of various phosphoryl potentials of different molecules?
thiamine diphosphate
What is the other name for TPP (thiamine pyrophosphate)?
pyruvate + CoA + Nad+ --> acetyl CoA + NADH + H+ + CO2
What is the overall reaction of the pyruvate dehydrogenase complex?
- fuel
What is the purpose of fatty acids?
- control the flow of energy and matter through a series of enzymatically chemical reactions
What is the purpose of metabolic pathways?
- storage form of energy
What is the purpose of triacylglycerols?
inverse relationship, if one is inactive that means the other one has high levels
What is the relationship b/t Fructose 1,6‑bisphosphatase & Fructose 2,6‑bisphosphatase?
- these two hormones are waiting for the signal of digestion products in the stomach so they could then send a signal to the pancreas to release the pancreatic enzymes
What is the role of Secretin & CCK?
triacylglycerols
What is the storage form of lipids?
- function: transfer of acyl groups - straight chain with thioester, pantothenate unit, and ADP
What is the structure and function of Coenzyme A?
- function: transfers electrons, gets reduced - biggest molecule with big chain of C's & H's (linear ribose) - derivative of riboflavin - ADP w/ 3 hexose base
What is the structure and function of FAD?
- has AMP attached - two nucleotides - has a nicotinamide on the second/ top nucleotide - the 2' carbon position can have a phosphate attach ----> if there is an OH in this position then it is NAD (catabolic) ----> if there is a PO-2 4 then it is NADP (anabolic)
What is the structure of NAD/P?
- there is a hydrophilic polar end group - a hydrophobic hydrocarbon tail
What is the structure of a fatty acid?
- glycerol backbone, ester linkages to fatty acids - glycerol + 3 fatty acids
What is the structure of a triacylglycerol?
- cells are more negative on inside than outside - usually more ATP in the cell
What is the typical charge & molecule distribution of cells?
- AKA flip flop - very slow - particle moving from one end to another end of membrane - charged head group has to flip across non polar region - enzyme mediated
What is transverse diffusion?
Phosphoglycerides
What molecule do these words describe? - membrane component - two fatty acid chains - alcohol group - phosphate group glycerol backbone phosphorylated alcohl attached to the back bone at C-3
Sphingolipid
What molecule do these words describe? - sphingosine backbone - one fatty acid chain attached to the backbone of an amide bond
Triacyglycerols
What molecule do these words describe? - 3 fatty acid chains - energy storage
- cleavage of ATP, leaving Pi bound
What triggers the sodium potassium pump to go from E1--> E2?
- hydrolytic cleavage of Pi off orange domain and the binding of ATP
What triggers the sodium potassium pump to go from E2--> E1?
Alpha 1-4
What type of bond is this?
Alpha 1-Alpha 1
What type of bond is this?
Beta 1-4
What type of bond is this?
- fructose 6P point before PFK in the adipose tissue - DHAP/GAP step after PFK int he liver
Where are the two different spots fructose can enter? Where is the main entry point?
- can be derived from diet or the body can synthesize from tryptophan - tryptophan is an essential amino acid, so it comes from the diet as well
Where does nicotinamide come from?
- Beta is more prevalent, more stable in chair conformation
Which conformation is more stable? Alpha or Beta?
All but Pyruvate Carboxylase - this enzyme is only specific to gluconeogensis
Which enzymes are part of glycolysis AND gluconeogensis? - Phosphoglycerate Kinase - Aldolase - Phosphoglucose Isomerase - Enolase - Pyruvate Carboxylase
Ethanol
Which is more reduced?
Isocritrate
Which is more reduced?
Lactate
Which is more reduced?
Malate
Which is more reduced?
Succinate
Which is more reduced?
- our enzymes recognize & digest these linkages ( alpha 1,4) - our enzymes do not recognize ( beta 1,4)
Which linkages do our bodies digest? Which linkages do they not?
essential fatty acids
Which lipid or lipids must be obtained in the diet?
Membrane-spanning Beta strands
Which membrane protein? - amino acid sequence pattern: non polar R group, polar R group (repeats)
Membrane Spanning alpha helix
Which membrane protein? - composed of about 20 hydrophobic residues
Lipid-anchored membrane protein
Which membrane protein? - often contains residues with covalently attached fatty acyl groups
NADH
Which molecule is this? - FMNH2 - NADH - FMN - FMNH+ - NAD+
- cAMP - calcium ions - IP3
Which molecules are used as second messengers in the signal transduction pathways?
-a, b,c
Which of the following are transmembrane protein(s)? (Select all that apply)
-dehydration of an acetate group
Which of the following is not a reaction occurring during oxidative decarboxylation of pyruvate within the pyruvate dehydrogenase complex? - removal of CO2 - dehydration of an acetate group - addition of Coenzyme A to a 2- carbon fragment - reduction of NAD+
Janus kinase 2 (JAK2)
Which of the following is responsible for phosphorylating the JAK2 proteins associated with the growth hormone receptors upon dimerization of said receptors?
Fatty acids
Which of the following lipids spontaneously form micelles when placed in an aqueous solution?
- the signaling pathway could be activated for an extended period, possibly resulting in undesirable cell proliferation - the concentration of cAMP in the cell would be continuously elevated -G alpha would be activated for an extended period
Which of the outcomes could potentially result if a mutation in the gene encoding the Galpha subunit eliminates its GTPase activity?
- G alpha
Which of the subunits in a G-protein, when, activated, associates with adenyl cyclase and enables it to assume a more catalytically active conformation?
- step 6- GAP dehydrogenase - oxidize GAP to 1,3- BGP
Which reaction in glycolysis is the redox reaction? what is being oxidized?
1. False 2. True 3. True 4. True 5. False
Which statements are true? 1. Triacylglycerols (triglycerides) are carboxylic acids. 2. Saturated fats are more likely than unsaturated fats to be solid at room temperature. 3. Triacylglycerols (triglycerides) contain ester bonds. 4. Fats that contain more unsaturated fatty acid residues than saturated fatty acid residues are more likely to be liquid at room temperature. 5. Saturated fats have lower melting points than unsaturated fats.
step 6: involves NAD+, GAP going to 1,3, biphosphoglycerate enzyme: glyceraldehyde-3-phosphate dehydrogenase
Which step is the oxidation reduction step in glycolysis?
Step 9- fructose‑1,6‑bisphosphatase
Which step of gluconeogenesis is the main negative control point?
- carbs + protein
Which two macromolecules together impair protein function?
- insulin - platelet-derived growth factor
Which two molecules bind to receptors that have intracellular tyrosine kinase domains?
peripheral membrane proteins
Which type of protein? - attach at the cell membrane surface - often tethered to membrane via- membrane embedded protein - can usually be released from the membrane by concentrated salt solutions
integral membrane proteins
Which type of protein? - reach through all or part of the membrane - can move laterally (sideways) in the hydrophobic part of the membrane - act as tunnels through the cell membrane
- alpha: down - beta: up
Which way do alpha linkages point? Which way do beta linkages point?
- diastereomers - epimers
Which words describes these two compounds? - anomers - diastereomers - enantiomers - epimers
- enantiomers
Which words describes these two compounds? - anomers - diastereomers - enantiomers - epimers
- the GLUT transporter doe snot recognize it
Why cant glucose leave once it's in the cell?
- Humans, and most vertebrates, lack the enzyme cellulase. - Vertebrate enzymes hydrolyze (α 1-4) glucose linkages, but not glucose in the β configuration.
Why is cellulose not a source of nutrients for humans?
- it is the critical link between glycolysis and the citric acid cycle--> CAC goes on to shuttle electrons int a transport chain to bee used all over the body
Why is the PDH complex so important?
Aldose--> no double bonds Ketose--> carbon, oxygen double bond
what is the difference between an aldose & a ketose?
- energy costs, it is too energetically costly to dehydrate Na+ - ionic radius, Na+ is too small
why do K+K+ channels not enable Na+Na+ ions to cross the membrane?