Biochemistry Exam 4 Flashcards
What uses ATP energy to build larger molecules?
- Anabolic reactions (metabolism)
What is the break down of large complex molecules to provide energy and smaller molecules?
- Catabolic reactions (metabolism)
It contains genetic information for the replication of DNA and the synthesis of protein.
- Cell Nucleus
Which molecule is used in anabolic reactions and considered the energy storage molecule?
- ATP
What is the product of ATP hydrolysis?
- Hydrolysis of ATP produces the energy needed for cellular metabolism 7.3 kcal/mole (31 kj/mole) and ADP + HPO4 (Pi) + H
- HPO4 can be abbreviated as Pi
- Further Hydrolysis of ADP will create AMP and more energy
The _______ is a series of reactions that connects the intermediate acetyl CoA from the catabolic pathways in stage 2 with electron transport and the synthesis of ATP in stage 3.
- citric acid cycle
What cycle and stage produces reduced coenzymes NADH and FADH2?
- The citric acid cycle (stage 3)
- operates under aerobic conditions.
- oxidizes the two-carbon acetyl group in acetyl CoA to CO2.
- produces reduced coenzymes NADH and FADH2.
- is named for the six-carbon citrate ion from citric acid (C6H8O7), a tricarboxylic acid, formed in the first reaction.
- is also known as the tricarboxylic acid (TCA) cycle or the Krebs cycle.
- The citric acid cycle (stage 3)
The fluid part of the cytoplasm that contains enzymes for many of the cell’s chemical reactions.
- Cytosol
It contains hydrolytic enzymes that digest and recycle old cell structures.
- Lysosome
Site of protein synthesis based on mRNA templates.
- Ribosome
It contains the structures for the synthesis of ATP from energy-releasing reactions.
- Mitochondrion
What are the stages of catabolism?
Stage 1: Digestion and hydrolysis (crossing cell membrane)
Stage 2: Degradation and some oxidation to smaller molecules (move into mitochondria)
Stage 3: Release of energy to synthesize ATP
What is Hydrolysis?
Hydrolysis is any chemical reaction in which a molecule of water ruptures one or more chemical bonds.
When _____ hydrolyzes, the energy released can be used to drive an energy-requiring reaction.
- ATP
How is glucose-6-phosphate created?
- ATP must undergo hydrolysis to produce the energy and phosphate group needed to breakdown glucose. This reaction leaves out H2O, it is implied that it happens while adding ATP and glucose.
- ATP + glucose —-> ADP + glucose-6-phospahate + 4kcal/mole (17kj/mole)
What is oxidation associated with?
- Loss of Hydrogen atoms (OIL)
What is reduction associated with?
- The gain of Hydrogen atoms (RIG)
_______ involves the loss of hydrogen or electrons by a substance or an increase in the number of bonds to oxygen.
- Oxidation
_____ is the gain of hydrogen ions and electrons or a decrease in the number of bonds to oxygen.
- Reduction
During oxidation and reduction reactions, _____ are required to carry the hydrogen ions and electrons from or to the reacting substrate.
- Coenzymes
______ is required in dehydrogenation reactions that produce carbon–oxygen double bonds, such as the oxidation of alcohols to aldehydes and ketones.
- NAD+
______ is a chemical reaction that involves the removal of hydrogen from an organic molecule
- Dehydrogenation
Storage of ____ as glycogen offers a readily available source of energy when dietary carbohydrate intake is low.
- carbohydrates
Important in the synthesis of Nicotinamide Adenine Dinucleotide PHosphate oxidase (NADPH), and nucleic acids (ribose).
- Carbohydrates
Important in the synthesis of Nicotinamide Adenine Dinucleotide PHosphate oxidase (NADPH), and nucleic acids (ribose).
Precursors of hormones, neurotransmitters, and other important signaling molecules (such as nitrous oxide).
- Amino Acids
Contributors to purines and pyrimidines, co-enzymes [NADH and flavin adenine dinucleotide (FADH2), and other fundamental biological molecules.
- Amino Acids
Excess can enter CAC and can be used to generate or store biological energy.
- Amino Acids
Some amino acids can be funneled into gluconeogenesis during fasting.
In adipose tissue,____are the major storage form of biological energy.
- triglycerides
____ oxidation yields more energy per carbon than carbohydrates.
- Lipid
Chemical breakdown through a reaction with water
- Hydrolysis
Lipolysis of triglycerides mobilizes fatty acids that generate energy through _____ and produces substrates necessary to make ketone bodies (acetoacetate and β-hydroxybutyrate) during starvation.
- β-oxidation
↑in harmful lipids/lipoproteins ______ has negative metabolic consequences that directly impact health and disease.
- (dyslipidemia)
Where does B-oxidation take place?
- mitochondrial matrix
After ingestion of carbs, glucose taken up by liver is converted to G6-P by _____ using ___ molecule, trapping glucose within hepatocytes.
- glucokinase
- 1 ATP
_____ is metabolized in one of three pathways: glycogenesis for energy storage, glycolysis for ATP production, or the pentose phosphate pathway for NADPH and/or ribose’s production.
- G6-P
________ is primarily regulated by the availability of G6-P and NADP+.
- Pentose phosphate pathway
In the well-fed state, ↑[ATP] and [citrate] inhibit _______, the committing step of glycolysis (slowing the production of fructose 1,6-bisphosphate) leading to ↑ [G6-P].
-phosphofructokinase-1
____ stimulates glycogen synthase, leading to the formation of glycogen.
- ↑ [G6-P]
_____ indirectly inhibits glycogen phosphorylase thereby inhibiting glycogenolysis (glycogen degradation).
- ↑ [G6-P]
When ↑[NADP+] and ↓ [NADPH], _____ can be shuttled into the pentose phosphate pathway to generate NADPH (reductive energy) used to synthesize a variety of biomolecules such as, fatty acids, cholesterol, nucleotides and other cofactors as needed.
-G6-P
When ↓[NADP+] and ↑[NADPH], the pentose pathway will ______ regardless of the concentration of G6-P.
- not operate
What catalyzes Fructose 6-phosphate to become Frutose-2,6 -bisphosphate?
After catalyzation what does F-2,6-BP stimulate in a feed-forward reaction?
- phosphofrutokinase - 2
- phosphofrutokinase 1, which is involved in glycolysis reaction 3
↑ glucose causes beta cells in pancreas to release insulin causing absorption of glucose from the blood, which ______ glycogen synthase (glycogenesis) and ______ glycogen phosphorylase (no glycogenolysis).
- dephosphorylates
- phosphorylates
After glycogen is replaced, then ____ will be synthesized using excess carbohydrates.
- lipids
If cholesterol biosynthesis is active, excess ______ from fatty acid metabolism can be synthesized into cholesterol.
- acetyl-CoA
What enzyme converts pyruvate to acetyl -CoA?
- pyruvate dehydrogenase
_____ inhibits pyruvate dehydrogenase kinase (PDK) (keeping pyruvate dehydrogenase active) causing pyruvate to be oxidatively decarboxylated to acetyl-CoA.
- ↓energy
If ↑energy, then ↑ [NADH] and [acetyl-CoA] activate____ (turning off pyruvate dehydrogenase and CAC).
- PDK
↑ [ATP] and [acetyl-CoA] stimulate pyruvate carboxylase, the first step of _____ as an alternative pathway.
- gluconeogenesis
What converts pyruvate to lactate during anaerobic respiration?
- Lactate dehydrogenase
What stimulates lactate dehydrogenase under anaerobic conditions?
- Increased NADH levels
In the liver, lactate can be converted back to glucose for energy production via the ______.
- Cori cycle
Also known as the Lactic Acid Cycle.
Alanine produces ____ and is converted back to pyruvate in the process but the lactate pathway does not produce _____ when converted back to pyruvate.
- urea
_______ activates acetyl-CoA carboxylase (promotes FA synthesis) and inhibits phosphofructokinase-1 (blocking glycolysis).
- ↑ citrate
Insulin stimulates storage of excess ___ and ____.
- glycogen and triglycerides
Release is stimulated by ↑ glucose and potentiated by amino acids (Stimulates protein synthesis).
- Insulin
Liver: ↑ glycogenesis, FA synthesis, glycolysis, and PPP.
Adipose tissue: ↑ glucose & FA uptake; triglyceride synthesis.
Skeletal muscle: ↑ glucose uptake, glycogenesis, protein synthesis.
- Insulin causes
Insulin does NOT influence glucose absorption in the β-cells of the pancreas, RBCs, intestinal mucosa, central nervous system (brain), or nephrons of the kidney.
Glucagon signals via _____ coupled receptors and cyclic AMP.
- G-protein
Acts mainly on liver stimulating glycogenolysis, gluconeogenesis, and FA oxidation (but also effects lipolysis).
- Glucagon
Biochemicals, such as _____, can act as either a neurotransmitter or as a hormone depending on its specific utilization by the body.
- catecholamines
Similar influence on metabolism as epinephrine but functions via activation of transcription and translation of genes rather than modulation of enzyme activity (∴ slower timeline of response).
Stimulates enzymes involved in gluconeogenesis in the liver, and in the breakdown of muscle protein leading to restored blood glucose.
Increase in blood glucose is at the expense of muscle and bone and ultimately impairs immunological function.
- Cortisol
Both lacking the signaling effect of insulin in the presence of glucagon.
- DM Type 1 and 2
_______ are semipermeable so that nutrients can enter the cell and waste products can leave.
- Cell membrane
Cell membranes have an inner portion made of the ______ of phospholipids, with the ____ at the outer and inner surfaces.
- nonpolar tails
- polar heads
______, which moves particles from a higher to a lower concentration.
- diffusion (passive transport)
_______, which uses protein channels to increase the rate of diffusion.
- facilitated transport
________, which moves ions against a concentration gradient.
- active transport
