Topic 1D Flashcards

Question

carbohydrate formula

Answer 1

Simple monomeric sugars: Cn(H₂O)n

Answer 2

single carbohydrate units; simplest = triose

Answer 3

Same D- and L- forms of the same sugar

Answer 4

The α form = anomeric carbon is in the axial position (OH below the plane) ‣ The β form = anomeric carbon is in the equatorial position (OH above the plane)

Answer 5

=nonsuperimposable configurations of molecules w/ similar connectivity; differs at least one but not all chiral carbons

Answer 6

(different configuration @ exactly 1 chiral carbon)

Answer 7

(subtype of epimers that differ at the chiral, anomeric carbon)

Answer 8

carbohydrates that contain an aldehyde group as their most oxidized functional group

Answer 9

has a ketone as their most oxidized functional group

Answer 10

◦ At least a 3-carbon backbone ◦ An aldehyde or a ketone group ◦ At least 2 hydroxyl groups

Answer 11

D-fructose

Answer 12

D-galactose

Answer 13

formed when two monosaccharides join together via a dehydration rxn (aka condensation rxn or dehydration synthesis). Here, the hydroxyl group of one monosaccharide combines with the H of another, releasing a molecule of water and forming a covalent bond = glycosidic linkage

Answer 14

made from α-glucose and β-fructose joined @ the hydroxyl groups on the anomeric carbons (creating acetals); glycosidic bond is formed b/t C1 of the α-anomer of glucose & C2 of the β-anomer of fructose; Glu(α1→β2)Fru Glucose-α-1,2-fructose

Answer 15

requires lactase to be hydrolyzed; made from β-galactose and α/β-glucose joined by a 1,4-linkage; Gal(β1→4)Glu ◦ Galactose-β-1,4-glucose

Answer 16

two glucose molecules; produced when amylase breaks down starch; Glu(α1→4)Glu

Answer 17

long chains of monosaccharides linked by glycosidic bonds

Answer 18

main energy storage form for plants; made of glucose molecules joined by α-1,4-linkages

Answer 19

linear polymer of glucose; connected by α-1,4-glycosidic bonds; 20%-30% of starch

Answer 20

made of α-1,4-glycosidic bonds and α-1,6-glycosidic branches every 24-30 units; 70%-80% of starch

Answer 21

main energy storage form for animals; has α-1,4-glycosidic bonds and α-1,6-glycosidic bonds

Answer 22

main structural component for plant cell walls; main source of fiber for humans; made of repeating β-1,4glycosidic bonds

Answer 23

major component of bacterial cell walls; polymer of carbohydrates that have been modified w/ amino acids

Answer 24

made of N-acetylglucosamine; connected by β-1,4-glycosidic bonds; major component of cell walls in the exoskeletons of crustaceans, insects, and fungi

Answer 25

hexokinase, phosphofructokinase, pyruvate kinase

Answer 26

Glycolysis = converts glucose (6-C) to 2 molecules of pyruvate (3-C each); 2 NADH made for every glucose

Answer 27

converts glucose → glucose 6-phosphate | present in the pancreatic β-islet cells; is responsive to insulin in liver; catalyzes an irreversible reaction

Answer 28

converts glucose → glucose 6-phosphate in peripheral tissues; is activated by insulin and inhibited by G6P and glucagon; also catalyzes an irreversible rxn

Answer 29

phosphorylates fructose 6-phosphate → fructose 1,6-ibsphosphate (rate-limiting step of glycolysis); is activated by AMP (indicates that energy is required → glycolysis is activated), fructose 2,6 bisphosphate, insulin (postprandial state); indirect stimulation by ↑ these levels; inhibited by ATP (energy is plentiful → slow glycolysis), citrate (indicates plentiful supply of intermediates for producing energy), low pH, in the liver only = glucagon = indirectly inhibits glycolysis by ↓ levels of fructose-2,6-bisphophate during fasting state; catalyzes an irreversible rxn

Answer 30

makes the F2,6-BP; activated by insulin; inhibited by glucagon

Answer 31

makes NADH which can feel into the ETC

Answer 32

substrate-level phosphorylation putting Pi onto ADP → ATP

Answer 33

substrate level phosphorylation, putting Pi onto ADP → ATP; converts PEP → pyruvate; activated by fructose 1,6-bisphosphate in a feed-forward stimulation; inhibited by ATP and alanine; catalyzes an irreversible reaction

Answer 34

complex of enzymes that convert pyruvate → acetyl coA; activated by insulin; inhibited by acetyl-coA

Answer 35

creates α-1,4-glycosidic links b/t glucose molecules

Answer 36

moves a block of oligoglucose form one chain and adds it to the growing glycogen as a new branch using an α-1,6 glycosidic link

Answer 37

removes a single glucose 1-phosphate molecule by breaking α-1,4 glycosidic links; activated by liver-glucagon to prevent low blood sugar; skeletal muscle— epinephrine & AMP to provide glucose for the muscle

Answer 38

moves a block of oligoglucose from one branch and connects it to the chain using an α-1,4 glycosidic link and removes the branch point

Answer 39

occurs in the mitochondrial matrix. Converts pyruvate (3-C) to an acetyl group (2-C). (Pyruvate decarboxylation / pyruvate oxidation) • Key enzyme: pyruvate dehydrogenase * 1 NADH made for every pyruvate * Only occurs in the presence of oxygen * Acetyl group attaches to Coenzyme A to make acetyl CoA

Answer 40

oxidizes NADH → NAD⁺ which replenishes the oxidized coenzyme for glyceraldehyde-3-phosphate dehydrogenase.

Answer 41

Pyruvate [reduction] → lactate

Answer 42

Pyruvate [reduction] → ethanol

Answer 43

converts pyruvate → oxaloacetate; activated by acetyl-coA from β-oxidation

Answer 44

converts oxaloacetate → phosphoenolpyruvate; activated by glucagon and cortisol; inhibited by insulin

Answer 45

converts fructose 1,6-bisphosphate → fructose 6-phosphate; activated directly by ATP and indirectly by glucagon (from ↓ levels of F2,6-BP); inhibited directly by AMP and indirectly by insulin (from ↑ levels of F2,6-BP); it bypasses phosphofructokinase; is the rate-limiting step of gluconeogenesis

Answer 46

converts glucose 6-phosphate → free glucose

Answer 47

the catabolism of glycogen (glycogen break down); is induced by adrenaline

Answer 48

= rate-limiting enzyme; converts the G1P → G6P Involves the removal of one glucose monomer via cleavage w/ an inorganic phosphate → glucose-1-phosphate which is then converted to glucose-6-phosphate * Process is caused by glucagon & epinephrine which stimulates glycogenolysis and are produced in response to low BGL * Takes place in the muscle (keeps the glucose) & liver tissue (releases the free glucose into the bloodstream)

Answer 49

a molecule that assists in the transfer of the CO₂ molecule from pyruvate to the TCA for energy production. It's produced by the oxidation of pyruvate (the end product of glycolysis). Acetyl-CoA acts as the link b/t glycolysis and the TCA. This step takes place in the mitochondrial matrix in eukaryotes, so pyruvate is first transported across the mitochondrial membrane. (Prokaryotes = cytoplasm).

Answer 50

◦ In β-oxidation, fatty-CoA is broken down, 2C at a time, to make acetyl-CoA which feeds into the TCA ◦ β-oxidation also produces FADH₂ & NADH. These feed into the ETC

Answer 51

The catabolism of some amino acids (phenylalanine, tyrosine, leucine, lysine, and tryptophan) can make acetyl-CoA

Answer 52

TCA consists of a series of rxns that produces 2 CO₂ molecules, 1 GTP/ATP, and reduced forms of NADH & FADH₂ • It takes place in the mitochondrial matrix; captures the energy stored in the bonds of acetyl-CoA from the products of glycolysis. The trapped energy from the TCA goes on to oxidative phosphorylation where its converted to the usable energy form ATP. AcetylCoA (main) & oxaloacetate are substrates for citrate synthase. Oxaloacetate can be produced by pyruvate carboxylase that converts pyruvate to oxaloacetate, however this is not as energy efficient. • In total for one round of the cycle (aka 1 pyruvate molecule) ◦ 1 GTP ◦ 3 NADH ◦ 1 FADH₂ ◦ 2 CO₂ ◦ 1 regenerated oxaloacetate molecule * Since each glucose molecule has 2 pyruvate molecules = 2 turns of the cycle so then we have 6 NADH & 3 FADH₂ per glucose * GTP produced becomes a phosphate donor to ADP → ATP Net yield of: ◦ 2 ATP/glucose molecule (per 2 acetyl CoA) = 4 ATP ◦ 3/turn = 6 NADH ◦ 1/turn = 2 FADH₂ ◦ 2/turn = 4 CO₂ ◦ 1 FADH₂ = 1.5 ATP ◦ 1 NADH = 2.5 ATP

Answer 53

Fatty acids bound to glycerol, phosphate, and other groups ◦ Amphipathic (hydrophilic + hydrophobic components) - used for cell membranes

Answer 54

◦ Fatty acids in ring form ◦ Cholesterol is amphipathic. The ring is nonpolar and the -OH head group is polar

Answer 55

◦ Derived from arachidonic acid ◦ Structure = 5-C ring; 20 C overall ◦ Includes prostaglandins (signaling molecules) & thromboxanes (clotting)

Answer 56

(mouth- lingual lipase), pancreas (pancreatic lipase), and bile (liver) facilitate fat digestion and their catabolism into fatty acids. Bile

Answer 57

(2C; inner mitochondrial matrix) = precursor for fatty acid synthesis. Acetyl-CoA is converted to citrate so that the citrate shuttle can transport it into the cytoplasm, where its broken back up to oxaloacetate & acetyl-CoA. For OAA to return to pyruvate, a C is lost as CO₂ and NADP⁺ is reduced to NADPH • Acetyl-CoAs are linked together → a large fatty acid chain = Palmitic acid (16C) = primary product of fatty acid synthesis in the body. Requires 8 acetyl-CoA molecules (since they're 2 C each). 7 ATP molecules are required for this rxn. 14 NADPH are required to reduce the carbonyl group in the acetyl-CoA to just C-C bonds; end up with 7 ADP & Pi & 14 NADP⁺ (thermodynamically unfavorable) = necessary to couple w/ ATP hydrolysis; charged with a CO₂ molecule

Answer 58

the enzyme that polymerizes the manlonyl-CoA subunits together. It has 2 identical subunits, each w/ a thiol group. Acetyl-CoA attaches to one and malonyl-CoA attaches to the other. Decarboxylation makes the carbon very nucleophilic, so it wants to attack the other carbon that's nearby, making a C=C. The ultimate fate of these fatty acids is to be attached to a glycerol backbone to form a triacylglycerol molecule, that are sent off by the liver via VLDL to deliver these fats to rest of our tissues.

Answer 59

enzyme in the wall of the small intestine; activates trypsin which then activates chymotrypsin. These enzymes liberate the individual AAs that conveyed across the intestinal wall into the cell; they're eventually transported into the bloodstream for dispersal to the liver and cells throughout the body to make new proteins.

Answer 60

E⊖ are transferred from NADH → DHAP making glycerol-3-phosphate. These e⊖ can then be transferred to mitochondrial FAD making FADH₂

Answer 61

E⊖ are transferred from NADH → oxaloacetate making malate which can then cross the inner mitochondrial membrane and transfer the e⊖ to mitochondrial NAD⁺ making NADH.

Answer 62

* In eukaryotes, ETC is in the inner mitochondrial membrane | * In prokaryotes, ETC is in the plasma membrane

Answer 63

Q * Oxidized form = ubiquinone * Reduced form (QH₂) = ubiquinol * Partially reduced form (intermediate) = ubisemiquinone (example of a semiquinone) * Has 2 carbonyl (C=O) groups which can be reduced to hydroxyl (—OH) groups; carries 2 e⊖ Cytochrome C * Much larger than Q; is a hemeprotein * Mechanism of e⊖ shuttling is for the iron atom to alternate b/t the +2 & +3 oxidation state * Has the heme group and it only carries 1 e⊖

Answer 64

◦ NADH is a very good e⊖ donor (its e⊖ are at a high energy level) ◦ NADPH is primarily produced in the oxidative part of the pentose phosphate pathway and is used in anabolic synthesis to make cholesterol, fatty acids, transmitter substances & nucleotides ◦ NADH & NADPH are both reductive agents

Answer 65

the process that links the ETC (which creates an electrochemical gradient across the inner mitochondrial membrane) to the production of ATP through ATP synthase.

Answer 66

the movement of ions across a selectively permeable membrane, down their electrochemical gradient. It's used to generate 90% of the ATP made during aerobic glucose catabolism. (By H going through ATP synthase)

Answer 67

the relationship b/t the proton gradient and ATP synthesis is indirect; ATP is released by the synthase as a result of a conformational change caused by the gradient. The F₁ portion of ATP synthase harnesses the gradient energy for chemical bonding from the spinning that occurs when protons go through it.

Answer 68

* In both the TCA and OP, they are upregulated when the cell needs more ATP; negative feedback— certain products inhibit upstream steps. * 1st regulatory step: production of acetyl-CoA ◦ Pyruvate dehydrogenase complex converts pyruvate → acetyl-CoA and this is upregulated by high levels of AMP, CoA, and NAD⁺ (signs that the cell needs to make more energy). ◦ It is downregulated by ATP, NADH, and acetyl-CoA (indicates the cell has ample energy) ◦ High levels of fatty acids = major negative regulator of the PDC since these fatty acids have the potential to become acetyl-CoA • TCA is regulated @ 3 major exergonic steps: ◦ 1) formation of citrate ‣ Upregulated: high levels of ADP ‣ Downregulated: ATP, NADH, [citrate, and succinyl-CoA = negative feedback] ◦ 2) Conversion of isocitrate → α-ketoglutarate ‣ Upregulated: ADP ‣ Downregulated: ATP ◦ 3) α-ketoglutarate → succinyl-CoA ‣ Upregulated: Ca²⁺ ‣ Downregulated: NADH & [succinyl-CoA = negative feedback] • Regulation of OP: ◦ Upregulated via upstream elements like the TCA & glycolysis; large amount of ADP present ◦ Downregulated: ATP

Answer 69

signals produced in the endocrine system & released into bodily fluids to be transferred to the target cells.

Answer 70

released by the β cells of the pancreas; stimulates glucose uptake by target cells; is released upon the entry of glucose into pancreatic β cells through the GLUT2 glucose transporters.

Answer 71

``` synthesized by α-cells of the pancreas; compensatory ↑ in BGL by causing the liver to convert stored glycogen → glucose which is then released into the bloodstream. Glucagon antagonizes insulin's action on BGL (aka glucagon and insulin forms a feedback system that ensures blood glucose homeostasis if properly regulated) promotes lipolysis (breakdown of triglycerides) by activating protein kinase A → activates hormone-sensitive lipase → releases free fatty acids & glycerol into the bloodstream. Glycerol can enter the TCA (s/p conversion to glycerol 3-phosphate by glycerol kinase) in the liver & kidneys ```

Answer 72

ghrelin, orexin, and leptin

Topic 1D Flashcards

(99 cards)