Chp 13: Metabolism Of Carbs Flashcards

Question

Name the inhibitors of? 1. Aconitase? 2. a-ketoglutarate dehydrogenase 3. Succinate? 4. Name the vitamins essential for kreb cycle? 5. Name the coenzymes for?; a) @-ketoglurarate b) succinate dehydrogenase c) isocitrate dehydrogenase

Answer 1

1. Fluoroacetate (non-competitive) 2. Arsenite (non-competitive) 3. Malonate (competitive) 4. 5 B complex vitamins; **Thiamine**(as TPP) **Riboflavin**(as FAD) **Niacin**(as NAD+) **Pantothenic Acid**(as coA) **Lipoic acid**(vitamin-like) 5. a) @-ketoglurarate---**Thiamine**(TPP) b) succinate dehydrogenase----**Riboflavin**(FAD) c) isocitrate dehydrogenase----**Niacin** (NAD+)

Answer 2

1. 4: 3 NADH 1 FADH2 2. Total **10 ATPs** 3 NADH - - - **7.5** 1 FADH---- **1.5** 1 GTP----**1** Total = 10 3. **aerobic only** krebs cycle (TCA) ETC Fatty acid B-oxidation **Anaerobic only** Fermentation **both** Glycolysis Pentose phosphate pathway (HMP shunt) 4. **Pyruvate dehydrogenase** 5. 2/3

Answer 3

1. Gluconeogenesis is the metabolic process by which organisms produce **glucose from non-carbohydrate substrates**. These substrates include lactate, glycerol, and amino acids. **Partial reversal of glycolysis** This process occurs primarily in the **liver** and, to a lesser extent, in the **kidneys**. Gluconeogenesis is crucial during periods of fasting, intense exercise, or **when carbohydrate intake is low**, as it ensures a continuous supply of glucose, which is vital for energy production, particularly for the brain and red blood cells.. 2. Lactate **Pyruvate** Glucogenic aminoacids Propionate Glycerol 3. Cytosol & mitochondria In **liver** and **kidney matrix** 4. **120g** out of 160g per day 5. **Pyruvate carboxylase** (Pyruvate to oxaloacetate) **Phosphoenolpyruvate carboxykinase (PEPCK)** (Oxaloacetate to phosphoenolpyruvate (PEP)) **Fructose 1,6 bisphosphatase** (Fructose-1,6- bisphosphate to fructose -6- phoshpate) **Glucose 6 phosphatase** (Glucose 6- phosphate to glucose)

Answer 4

1. Malate (within cytosol oxaloacetate is regenerated) 2. **2 ATP** as compated to 1 for glycolysis 3. Smooth muscle & heart muscle Mg2+ ions 4. Present in **liver & kidneys** Absent in **muscle, brain, adipose tissue** 5. Leucine Lysine

Answer 5

1. Odd chain e.g **proprionate** **Propionyl coA carboxylase** Propinoyl coA-----methyl malonyl coA **B12 coenzyme** methyl malonyl coA-----succinyl coA 2. Oxidation of odd chain fatty acids and breakdown of amino acids (**methionine & isoleucine**)

Answer 6

1. Bcz of absence of enzymes; **Glucose 6- phosphatase & Fructose 6-phosphatase** So lactate-----blood----**liver**----oxidized to pyruvate------glucose----back to skeletal muscle 2. **NADH** 3. Synthesis of **glucose in liver** from the skeletal muscle **lactate** 4. Alanine

Answer 7

1. The Cahill cycle, also known as the **glucose-alanine cycle,** is a metabolic process where muscles and the liver work together to **recycle amino acids** and manage energy needs. Here’s a simple explanation: 1. **In Muscles:** When muscles break down proteins for energy during exercise, they produce amino acids like **alanine.** 2. **Alanine Transport:** Alanine is transported through the blood to the liver. 3. **In the Liver:** The liver converts alanine back into glucose through gluconeogenesis. 4. **Glucose Transport:** The new glucose is released into the bloodstream and can be used by muscles for energy again. This cycle helps the body manage energy and nitrogen balance during exercise and fasting.

Answer 8

1. **Inhibits** gluconeogenis Leads to **hypoglycemia** 2. **Pyruvate & oxaloacetate** made unavailable Due to overconsumption of NAD+ And **excessive production of NADH** (reduces Pyruvate to lactate--- so no pyruvate for gluconeogenesis ) In liver 3. **Glyoxylate cycle** 4. Acetyl coA (**beta oxidation**)

Answer 9

1. Pyruvate carboxylase 2. a-cells of islets of langerhans of pancreas By **Decreased pyruvate kinase** (Reduced PEP---Pyruvate) **Reducing fructose 2,6 bisphosphate** (Activates PFK & inhibits fructose 1,6 bisphosphate)

Answer 10

1. Mostly in **liver (6-8%)** **Muscle (1-2%)** 2. **liver (75g)** **Muscle (250g)** (3x higher) 3. **Acid maltase (a-1,4 glucosidase)** If deficient than glycogen storage type 2 disease ----**Pompe's disease** 4. Hormone - - - **insulin** Enzyme - - **Glycogen synthase** 5. **Glycogen phosphorylase**

Answer 11

1. **cAMP** 2. **Glycogen synthase** Active--- **dephosphorylated** **Glycogen phosphorylase** Active--- **phosphorylated** 3. cAMP dependant protein kinase and it **phosphorylates** glycogen synthase (from not phosphorylated form **a** to inactive (phosohorylated) **b**) So it **decreases glycogenesis** 4. **Protein phosphatase 1** (Dephosphorylates) 5. Epinephrine + Glucagon---- **activates** cAMP -----**glycogenolysis** Insulin ---- **lowers** cAMP levels 6. Phosphorylation; Inactivates glycogen synthase Activates glycogen kinase 7. **Calmodulin** Phosphorylase kinase Causes; **Glycogenolysis**

Answer 12

1. Activates glycogen synthase Inhibits glycogen phosphorylase 2. **a-1,4 & a1,6** 3. The glycogen so formed after the action of glycogen phosphorylase, with **4 glucose residuse on either side of branching point**, which cannot be further degraded by phosphorylase 4. **Pyridoxal phosphate** 5. 2 enzyme activities; **Glycosyl 4:4 transferase** Transfers glucose by cleaving and forming new **a 1,4** bonds **Amylo a-1,6 glucosidase** Breaks a **1,6 bond** at a branch and release free glucose 6. Bcz enzyme **glucose 6-phosphatase** is absent to convert glucose 6 phosphate to glucose

Answer 13

1. **Glucose 1-phosphate** & UTP by **UDP glucose phosphorylase** 2. **Glycogenin** protein 3. **Glycogen synthase** 4. **glucosyl a-4-6 transferase** 5-8 residues By breaking a 1,4 And forming a 1,6 5. One for **phosphorylation** of glucose Second for conversion of **UDP to UTP**

Answer 14

Glycogenesis is the process through which **glucose** molecules are converted **into glycogen** for storage in liver and muscle cells. Here's an overview of the steps involved: 1. **Glucose Uptake**: Cells take up glucose from the bloodstream using glucose transporters (GLUT proteins). 2. **Conversion to Glucose-6-Phosphate**: Glucose is converted to glucose-6-phosphate (G6P) by the enzyme hexokinase in muscle cells or glucokinase in liver cells. 3. **Conversion to Glucose-1-Phosphate**: G6P is converted to glucose-1-phosphate (G1P) by phosphoglucomutase. 4. **Activation of Glucose**: G1P is activated by reacting with uridine triphosphate (UTP), producing UDP-glucose (uridine diphosphate glucose). 5. **Glycogen Chain Elongation**: Glycogen synthase catalyzes the formation of α-1,4-glycosidic bonds between UDP-glucose molecules, extending the glycogen chain. 6. **Branching**: Glycogen branching enzyme transfers segments of glucose residues from one part of the chain to another, forming α-1,6-glycosidic bonds and creating branches within the glycogen molecule. 7. **Storage**: Glycogen molecules are stored in liver and muscle cells, providing a readily available reserve of glucose for energy production when needed. 2. **12-18 hrs**

Answer 15

Glycogenolysis is the process of breaking down **glycogen into glucose-1-phosphate and glucose** molecules. 1. **Glycogen Phosphorylase Cleavage**: Glycogen phosphorylase cleaves glucose units from the non-reducing ends of glycogen chains, releasing **glucose-1-phosphate**. 2. **Debranching Enzyme Action**: When glycogen phosphorylase reaches within **four glucose residues of a branch point** (**limit dextrin**), the debranching enzyme acts: - **Transferase Activity**: It transfers a block of three glucose residues from the branch point to the non-reducing end of another glycogen chain. - **α-1,6-Glucosidase Activity**: It hydrolyzes the remaining glucose residue at the branch point, releasing free glucose. 3. **Formation of Glucose-1-Phosphate**: The glucose released from glycogen is converted to glucose-1-phosphate by phosphoglucomutase. 4. **Conversion to Glucose-6-Phosphate**: Glucose-1-phosphate is converted to glucose-6-phosphate by phosphoglucomutase. 5. **Glucose-6-Phosphatase (Liver Specific)**: In the liver, glucose-6-phosphate is converted to glucose by glucose-6-phosphatase. This step is crucial for releasing glucose into the bloodstream. 6. **Release of Glucose**: Glucose is released into the bloodstream from the liver to maintain blood glucose levels or utilized locally in muscle cells for energy production.

Answer 16

Futile substrate pathways, also known as futile cycles or substrate cycles, refer to metabolic pathways in which **two opposing biochemical reactions occur simultaneously**. These pathways often involve the **consumption of ATP** without producing a net gain of useful energy or products. Essentially, they result in a **"waste"** of energy. One well-known example is the cycle between **glycolysis and gluconeogenesis**. In glycolysis, glucose is broken down to produce pyruvate, ATP, and NADH. In gluconeogenesis, pyruvate is converted back into glucose, which consumes ATP. If both pathways operate simultaneously, ATP is consumed in the process of converting glucose to pyruvate and back to glucose without any net production of ATP, leading to a futile cycle. These cycles can serve important regulatory functions, such as maintaining metabolic flexibility, regulating heat production, and fine-tuning the levels of metabolic intermediates in response to changing cellular conditions.

Answer 17

Von Gierke's disease, also known as **Glycogen Storage Disease Type I (GSD I)**, is a genetic disorder caused by a deficiency of the enzyme **glucose-6-phosphatase**. This enzyme is crucial for converting **glycogen into glucose**, which the body uses for energy. Without this enzyme, **glycogen accumulates** in the liver and kidneys, leading to various symptoms such as: - Low blood sugar **(hypoglycemia)** - Enlarged liver **(hepatomegaly)** - Kidney problemsv - Growth delays - Increased levels of lactate, fats, and uric acid in the blood **Lactic acidemia Hyperlipidemia Hyperurecimia** Management of Von Gierke's disease typically involves maintaining normal blood sugar levels through frequent feedings of glucose or starch and dietary adjustments. 2. **Glycogenosis** Glycogen storage diseases 3. Deposition of glycogen in tissues 4. **glycogen synthase** in liver No deposition of extra glycogen in liver

Answer 18

**pentose phosphate pathway** -**ribose phosphates** 2. Phosphoribosyl pyrophosphate 3. **Purine nucleotides** 4. **4-7mg/dl**

Answer 19

The **hexose monophosphate shunt**, also known as the **pentose phosphate pathway (PPP)** or **phosphogluconate pathway** or **Dickens Horecker pathway**, is a metabolic pathway **parallel to glycolysis**(alternate pathway for oxidation of glucose). It serves several important functions in cells: 1. **NADPH Production**: It generates NADPH, which is crucial for biosynthesis processes and acts as a reducing agent in various biochemical reactions, such as **fatty acid** & **cholesterol** synthesis and **antioxidant** defenses. 2. **Ribose-5-phosphate Production**: It produces ribose-5-phosphate, a precursor for **nucleotide** synthesis, which is essential for the formation of DNA, RNA, and ATP. 3. **Redox Homeostasis**: It helps maintain redox balance within cells by generating NADPH, which supports antioxidant systems that protect against oxidative stress. Overall, the hexose monophosphate shunt plays a critical role in providing reducing equivalents and nucleotide precursors necessary for cell growth, biosynthesis, and oxidative stress management. 2. Glycolysis & TCA cycle 3. No ATP 4. Cytosol

Answer 20

1. **Glucose-6-phosphate dehydrogenase (G6PDH)** Glucose-6-phosphate into **6- phosphogluconolactone** 2.**NADPH** 3. NADPH/NAD+ 4.**Epimerase**------xylulose-5-phosphate **Ribose-5-phosphate ketoisomerase** ----- ribose-5-phosphate 5. **Thiamine pyrophosphate**(TPP) Mg2+ ions 6. **Pentoses** (ribose-5-phosphate) **NADPH**

Answer 21

1. Pentoses NADPH 2. For synthesis of **Nucleic acids** (RNA & DNA) **Nucleotides** (ATP, NAP+, FAD, CoA) 3. Skeletal 4. For synthesis of **Fatty acids** **Steroids** 5. In tissues concerned with **lipogenesis** E.g, Adipose tissue Liver

Answer 22

1. **Glutamate dehydrogenase** 2. NADPH (Nicotinamide Adenine Dinucleotide Phosphate) plays a crucial role in the antioxidant defense system through its involvement with glutathione, a vital antioxidant within cells. Here's how it works: 1. **Glutathione Reduction**: - Glutathione exists in two forms: reduced glutathione (GSH) and oxidized glutathione (GSSG). - In its **reduced form, GSH** can neutralize free radicals and reactive oxygen species (ROS), thereby protecting cells from oxidative damage. - During this process, GSH is converted to its oxidized form, GSSG. 2. **Regeneration of Reduced Glutathione**: - For the antioxidant system to remain effective, GSSG must be converted back to GSH. - This conversion is catalyzed by the enzyme **glutathione reductase**. - NADPH provides the necessary reducing power for this reaction. It donates electrons to GSSG, reducing it back to two molecules of GSH. **(Detoxifies H2O2 peroxidase)** 3. **Role of NADPH**: - NADPH is generated primarily by the pentose phosphate pathway, which is a metabolic pathway parallel to glycolysis. - By maintaining a high ratio of NADPH/NADP+, cells ensure a continuous supply of reducing equivalents needed for various biosynthetic reactions and antioxidant defense mechanisms. 4. **Overall Antioxidant Defense**: - NADPH is essential for regenerating reduced glutathione, which in turn maintains cellular redox balance and protects against oxidative stress. - Additionally, NADPH is used by other antioxidant systems, such as thioredoxin reductase and catalase, further contributing to the cell's ability to mitigate oxidative damage. In summary, NADPH is critical in sustaining the antioxidant capacity of **glutathione** by ensuring the continuous **regeneration of its reduced form,** thereby helping to protect cells from oxidative stress.

Answer 23

1. Microsomal cytochrome P450 system 2. **Reduced Glutathione** By NADPH 3. Transparency of lens 4. Inherited **sex linked** On **X** chromosome So more in male 5. **RBC breakdown** As; No HMP shunt pathway, No NADPH No Glutathione No membrane integrity of rbc Accumulation of **methemoglobin** & **peroxides** In rbcs leading to **hemolysis** 6. HMP shunt

Answer 24

Glucose-6-phosphate dehydrogenase (G6PD) deficiency confers some resistance to malaria, particularly Plasmodium falciparum, the most deadly malaria parasite. Here's how it works: **Oxidative Stress**: G6PD is an enzyme that helps protect red blood cells (RBCs) from oxidative damage by producing NADPH, which in turn maintains the levels of reduced glutathione. Reduced glutathione detoxifies reactive oxygen species (ROS) in cells. In G6PD deficiency, the ability to neutralize ROS is impaired, leading to higher oxidative stress within RBCs. **Environment for Parasite Survival**: Malaria parasites rely on a stable environment within RBCs to grow and reproduce. The increased oxidative stress in G6PD-deficient RBCs creates a hostile environment for the parasite, making it difficult for it to survive and multiply. **Premature RBC Destruction**: G6PD-deficient RBCs are more prone to hemolysis (destruction) under oxidative stress. This destruction can be triggered by infections, certain foods, and drugs. The premature destruction of RBCs can limit the availability of healthy cells for the parasite to infect, thereby reducing the overall parasite load in the body. 2. **HMP shunt** & **reduced glutathione** for their optimum growth in rbc 3. Hemolytic anemia Hemolytic jaundice 4. **Primaquine** (antimalarial) **Acetanilide** (antipyretic) **Sulfamethoxazole** (antibiotic) Ingestion of **fava beans** (**favism**)

Answer 25

1. **Hexoses** 2. **Wernicke-Korsakoff syndrome** 3. An alteration in **transketolase** activity (reduces its affinity to bind with **TPP**) Symptoms; Mental disorder Loss of memory Partial paralysis Manifested in **vitamin deficient alcoholics**

Answer 26

1. Wernicke-Korsakoff syndrome (WKS) is a neurological disorder primarily caused by a **deficiency of thiamine (vitamin B1)**. It is often associated with chronic **alcoholism** but can also result from malnutrition, eating disorders, prolonged vomiting, or other conditions leading to poor nutritional absorption. WKS comprises two separate but related conditions: 1. **Wernicke's Encephalopathy**: This is an acute, short-term condition that is reversible if treated promptly. It is characterized by: - Confusion and disorientation - Ataxia (lack of muscle coordination, particularly in the legs) - Nystagmus (rapid, involuntary eye movements) and ophthalmoplegia (paralysis or weakness of the eye muscles) Immediate medical intervention with thiamine replacement is critical to prevent progression to Korsakoff's psychosis. 2. **Korsakoff's Psychosis**: This is a chronic, long-term condition that typically follows untreated or inadequately treated Wernicke's encephalopathy. It involves severe memory impairment and cognitive deficits, including: - Anterograde amnesia (inability to form new memories) - Retrograde amnesia (loss of existing memories) - Confabulation (making up stories to fill in memory gaps) - Apathy and lack of insight into the condition **Causes**: - **Thiamine Deficiency**: The primary cause, often due to poor dietary intake, impaired absorption, or increased demand for thiamine. - **Alcoholism**: A major risk factor due to poor nutrition, impaired absorption, and the toxic effects of alcohol on the brain. 2. **C**------ confusion **O**------ opthalmoplegia **A**------ ataxia **T**------ thiamine deficiency **R**------ Retrograte Amnesia **A**------ Anterograte Amnesia **C**------ confabulation **K**------ Korsakoff psychosis

Answer 27

1. Essential pentosuria is a rare metabolic condition characterized by the excretion of excess pentoses (five-carbon sugars) in the urine. Here are the key points: ### **What is Essential Pentosuria?** - **Metabolic Disorder**: It involves the increased urinary excretion of pentoses, primarily xylose, which are normally present in very small amounts. - **Genetic Basis**: It is usually inherited in an autosomal recessive pattern, meaning both parents must carry the gene for the condition. ### **Symptoms and Diagnosis** - **Asymptomatic**: Most individuals with essential pentosuria do not have any symptoms and the condition is often discovered incidentally during routine urine tests. - **Diagnosis**: It is diagnosed through urine tests that show elevated levels of pentoses. 2. **Xylitol dehydrogenase** (NADP-dependent enzyme) So **L-xylulose** can't be converted into xylitol 3. **L-xylulose** in urine 4. **Aminopyrine** & **antipyrine** increase excretion of L-xylulose

Answer 28

1. **Increases** the uronic acid pathway (**Barbital**, **Chlorobutanol**) Drugs can increase the activity of the uronic acid pathway primarily because of the **body's need to detoxify and excrete** these substances. Here's how this works: ### Detoxification Process 1. **Drug Metabolism**: - When drugs are ingested, they undergo metabolism in the liver to become **more water-soluble** so they can be excreted from the body. - This metabolism often involves two phases: Phase I (modification) and Phase II (conjugation). 2. **Glucuronidation**: - During **Phase II metabolism**, one common process is **glucuronidation.** This involves the addition of glucuronic acid to the drug or its metabolites. - The enzyme **UDP-glucuronosyltransferase (UGT)** facilitates the **attachment of glucuronic acid to the drug**, forming a glucuronide conjugate. 3. **Excretion**: - The **glucuronide conjugates are more water-soluble**, which makes it easier for the kidneys to filter them out of the blood and excrete them in the urine, or for the liver to excrete them into bile. ### Increased Demand - **Increased Substrate Load**: When drugs are present in the body, they increase the demand for glucuronic acid because the liver needs to conjugate these substances to detoxify them. - **Enzyme Induction**: Some drugs can induce the production of enzymes involved in the uronic acid pathway, leading to an increased capacity for glucuronidation. 2. **Aminopyrine Antipyrine** 3. **L-Gluconate** 4. The enzyme **L-Guloconolactone oxidase** Which converts gulonate to ascorbic acid is absent in; **Man Other Primates Guinea pigs**

Answer 29

1. **UDP**-glucoronate Conjugation with Bilirubin Steroid hormones Certain drugs 2. **UDP-glucoronate** 3. In Most of the pathways of carb metabolism **phosphate ester** participates Whereas in uronic acid pathway **Free sugars or sugar acids** are involved __________________ 4.The uronic acid pathway is a metabolic process in the body that converts **glucose into** other important substances, including **glucuronic acid.** Here’s a simplified overview: 1. **Conversion of Glucose**: The pathway begins with glucose, a type of sugar. Glucose is converted into glucuronic acid through a series of chemical reactions. 2. **Glucuronic Acid Formation**: Glucose is first turned into a compound called UDP-glucuronate. UDP-glucuronate is then used to produce glucuronic acid. 3. **Detoxification**: Glucuronic acid plays a crucial role in detoxifying the body. It combines with various toxins, drugs, and waste products, making them more water-soluble. This makes it easier for the body to excrete these substances through urine or bile. 4. **Support for Connective Tissues**: Glucuronic acid is also a component of important molecules called **glycosaminoglycans**, which help form and maintain connective tissues like cartilage and skin. In short, the uronic acid pathway helps the body **get rid of harmful substances** and supports the structure of connective tissues.

Answer 30

1. The glyoxylate cycle is a metabolic pathway found in **plants, bacteria, and fungi** (**Not in Animals**) that enables the conversion of **fatty acids into carbohydrates**. This cycle is crucial for organisms that need to produce **glucose from fats** when other sources of carbohydrates are not available. Here’s a simplified explanation: **Purpose**: The glyoxylate cycle allows organisms to convert **acetyl-CoA** (derived from fatty acid breakdown) into **glucose**. This is important for organisms like plants, which need to convert stored fats into sugars for energy and growth. **Location**: The glyoxylate cycle occurs in specialized organelles called **glyoxysomes** in plants and certain fungi and bacteria. **Key Reactions**: - **Formation of Glyoxylate**: **Two** molecules of **acetyl-CoA** combine to form a molecule of **succinate**, with **glyoxylate** as an intermediate. - **Conversion to Malate**: The glyoxylate cycle produces malate from succinate. - **Formation of Oxaloacetate**: Malate is converted into oxaloacetate, which can then be used to form glucose through gluconeogenesis. **Key Enzymes**: - **Isocitrate Lyase**: Converts isocitrate into succinate and glyoxylate. - **Malate Synthase**: Converts (another molecule of) acetyl-CoA and glyoxylate into malate. **Significance**: - **Energy Storage**: It helps in converting stored fats into carbohydrates, which can be used for energy or growth. - **Adaptation**: It allows organisms to survive and grow in environments where carbohydrates are limited but fats are available. 2. **Citric acid cycle** (Citric acid cycle bypassed by **isocitrate lyase** 3. Animals 4. When **hydroxyl group** of sugar is replaced by **amino group (-NH2)** Imp are; **Glucosamine Galactosamine Mannosamine Sialic acid** 5. **N-acetylneuraminic acid (NANA)** 6. 20% 7. Fructose-6-phosphate

Answer 31

1. **Uric acid** leading to gout Increased uric acid levels in the blood from high fructose consumption occur due to the following process: 1. **Fructose Metabolism**: When fructose is consumed, it is metabolized primarily in the liver. The enzyme fructokinase converts fructose into fructose-1-phosphate. 2. **ATP Breakdown**: The metabolism of fructose-1-phosphate uses up ATP (adenosine triphosphate), which is the primary energy molecule in cells. This breakdown of ATP leads to the production of ADP (adenosine diphosphate) and then AMP (adenosine monophosphate). 3. **AMP Degradation**: AMP is further broken down into **uric acid** through a series of enzymatic reactions. This process increases the production of uric acid. 4. **Uric Acid Accumulation**: Excess uric acid can accumulate in the blood, leading to hyperuricemia. This can contribute to conditions like gout, where uric acid crystals form in joints, causing pain and inflammation. 2. **aldolase B** (Breaks down fructose 1 phosphate into dihydroxyacetone phosphate and glyceraldehyde 3 phosphate) **Fructose 1 phosphate** accumulates 3. **Hypoglycemia** (as fructose 1 phosphate blocks glycogenolysis) 4. Hepatic **fructokinase** (So fructose not converted to fructose 1 phosphate) So fructose in urine 5. Fructokinase has more activity--- converts fructose to **fructose 1 phosphate** So Pi binds to fructose so less Pi available

Answer 32

1. **Glucose** converted to **fructose** through sorbitol Converts Glucose--- sorbitol **(aldose reductase)** (NADPH dependant) Sorbitol--- fructose **(sorbitol dehydrogenase)** (NAD+ dependant) 2. In liver (bcz aldose reductase absent in liver) Found in; Lens Retina Kidney Placenta Shwann cells of peripheral nerves Erythrocytes Seminal vesicle 3. Uncontrolled diabetes (hyperglycemia) **Diabetes mellitus** 4. Due to sorbitol pathway 5. In diabetes mellitus, More glucose---- more sorbitol due to **more activity of aldose reductase** & less activity of sorbitol dehydrogenase Sorbitol accumulates (hydrophilic--- osmotic changes) ----leads to Cataract Peripheral neuropathy Nephropathy

Answer 33

1. Bcz rate limiting rxn of glycolysis (by **phosphofructokinase**) is **bypassed** 2. **Aldose B** Splits fructose-1-phosphate Into Glyceraldehyde 3 phosphate Dihydroxyacetone phosphate (DHAP) **Aldose A** Converts **fructose-6-phosphate** to **fructose-1,6-bisphosphate** Then Splits into G-3-P & DHAP 3. **Galactose 1-phosphate uridyltransferase** - autosomal recessive - **galactitol (dulcitol)** By enzyme aldose reductase 4. Galactitol (dulcitol) 5. 5. Activity of **galactose 1 phosphate urididyl transferase in erythrocytes**

Answer 34

1. Fructose Sorbitol 2. Galactitol 3. **L glucolactone oxidase** 4. Essential Fructosuria---**fructokinase** Essential Pentosuria---**xylitol dehydrogenase** Heriditary fructose intolerance---**aldolase B**