BSCI202: Metbolic Processes

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What is the sum of all the chemical reactions that take place in an organism known as?

Metabolism

This is the breakdown of large molecules into smaller ones; energy is generally released during this. What process am I?

Catabolism

The synthesis of large molecules from smaller ones; energy is generally absorbed during this. What process am I?

Anabolism

The process of catabolism and anabolism come togehter as series of consecutive reactions called what?

Metabolic pathway

What are the two types of metabolic pathway?

Linear and cyclic

What is the suffix (end word) of anabolism?

-genesis

What is the suffix (end word) of catabolism?

-lysis

What is making of glycogen known as?

Glycogenesis

What is making of triglycerides known as?

Lipogenesis

What is making of protein known as?

Protein synthesis

What is the production of glycose from noncarbohydrate sources knonw as?

Gluconeogenesis

What is the breakdown of glycogen known as?

Glycogenolysis

What is the breakdown of triglycerides known as?

Lipolysis

What is the breakdown of protein known as?

Protein breakdown (protein catabolism)

What is the breakdown of glucose known as?

Glycolysis

What is the equation of anabolism?

Smaller molecules + energy input → larger molecules

What is the equation of catabolism?

Larger molecules → smaller molecules + energy released

What are the two processes of carbohydrate anabolism known as?

Glycogenesis and gluconeogenesis

What are the two processes of carbohydrate catabolism known as?

Glycolysis and glycogenolysis

What is the sub-process of lipid anabolism known as?

Triglyceride synthesis

What is the sub-processes of lipid catabolism known as?

Beta oxidation and ketogenesis

What are the sub-processes of protein catabolism known as?

Transamination and oxidative deamination

In glucose metabolism, when high glucose is present, what does glycogenesis do?

B cells in the pancreas release insulin, excess glucose stored as glycogen

In glucose metabolism, when does glycolysis happen?

When muscles need energy, or during stress (fear, anger), or when oxygen is limited

In glucose metabolism, what does glycolysis do?

Glucose is broken down into pyruvate

In glucose metabolism, when does gluconeogenesis occur?

Starvation (when glucose is scarce)

In glucose metabolism, what does gluconeogenesis do?

Produces glucose from non-carbohydrate sources like proteins broken down in muscle cells

What is pyruvate in glucose metabolism?

Converted back to glucose via gluconeogenesis

What is ribose (from glucose) in glucose metabolism?

Glucose can make this for RNA and DNA synthesis

What happens in the absorptive (fed) state when glucose enters the blood?

Hyperglucemia

What does hyperglycemia do?

Stimulates insulin release from beta pancreatic cells

Which cells are insulin-dependent for glucose uptake?

Skeletal muscle fibers and hepatocytes

How do insulin-independent cells (e.g., neurons) take up glucose?

Based on blood glucose levels, regardless of whether insulin is present

After glucose uptake, in what order do cells utilize glucose?

Glucose catabolism, glycogenesis, lipogenesis

What is the primary role of glucose in cellular metabolism?

Major fuel of cells

What are the two types of glucose catabolism?

Aerobic and anaerobic catabolism

What is the list of stages of aerobic glucose catabolism in order?

Glycolysis -> krebs cycle -> electron transport chain

How much ATP does aerobic catabolism of one glucose molecule yield?

38

How much ATP does anaerobic catabolism of one glucose molecule yield?

2

What are the end products of anaerobic glucose catabolism?

Pyruvic acid -> lactic acid -> metabolic acidosis

What is glycogenesis?

Insulin acitvates the enzyme glycogen synthase to convert glucose ino glycogen

What is the glycogen storage limit in the body?

600g

What is lipogenesis?

Insulin stimulates conversion of excess glucose into triglycerides for storage

What intermediates join to form 3 fatty acid chains during lipogenesis?

Glyceraldehyde 3-phosphate (glycerol) and Acetyl CoA

What are the three phase pathway of glycolysis?

1. Glucose is oxidized into pyruvic acid

2. NAD+ is reduced to NADH + H+

3. ATP is synthesized by substrate-level phosphorylation

After glycolysis, what happens to pyruvic acid in an aerobic pathway (with O2)?

Moves on to the krens cycle

After glycolysis, what happens to pyruvic acid in an anaerobic pathway (if no O2)?

Reduced to lactic acid

Where does glycolysis occur?

Cytosol

Is glycolysis aerobic or anaerobic?

Anaerobic

Where does the citric acid cycle (Krebs cycle) occur?

Mitochondrial matrix

Is Krebs cycle aerobic and anaerobic?

Aerobic

How many times does the Krebs cycle happen?

Twice for each glucose (2 pyruvate) in glycolysis

What is gained during 1 Kreb cycle?

1 ATP, 3 NADH, 1 FADH2, 2 CO2

What is A?

2

What is B?

6

What is C?

18

What is D?

4

What is E?

38

When the cell’s energy requirement is met, what happens to excess glucose?

It is converted to glycogen

What is glycogen?

A polysaccharide and the storage form of glucose in animal cells

What is the name of the anabolic process that converts glucose to glycogen?

Glycogenesis

What enzyme catalyzes glycogenesis?

Glycogen synthase

What potential problem can high glycogen content cause in a cell?

It sets up an osmotic gradient that draws water into the cell, which could lyse the cell

What occurs in between meals in the fasting (postabsorptive) state?

Hypoglycemia

What is the process of glycogenolysis?

Activation of the enzyme Glycogen Phosphorylase (phosphatase) -> Glucose-6-phosphate in skeletal muscle fibers and the liver

What does glycogen phosphorylase do?

Catalyzes the conversion of glycogen

Glucose-6-phosphate in the liver is cleaved by what unique enzyme?

Glucose-6-phosphatase

When Glucose-6-phosphate is cleaved, what does it do?

Release glucose which diffuses into blood to increase blood glucose levels back into normal range

What contains a high level of glucose-6-phosphatase?

Hepatocytes

Lipolysis is the breakdown of sotred lipid into what?

Glycerol and fatty acids

What is used in energy production and in gluconeogenesis?

Glyceral

What is done via beta oxidation and used in energy production and the formation of the ketone bodies?

Fatty acids

In beta oxidation, what process is the formation of ketone bodies (acetone, acetoacetic acid, and beta-hydroxybutyric acid/metabolic acidosis) known as?

Ketogenesis

What are the substrates for gluconeogenesis?

Lactate, glycerol, amino acids

In gluconeogenesis, where is lactate from?

Pyruvic acid (pyruvate) from anaerobic respiration

In gluconeogenesis, where is amino acids from?

Protein breakdown

In lipid catabolism, what does the hormone-sensitive lipase (HSL) do?

Hydrolyzes lipids into glycerol and fatty acids

What are fatty acids and other hydrocarbons catabolized by?

Beta oxidation

Where can catabolic products be further broken down in?

Glycolysis and Krebs cycle

What is the first step in catabolizing, or breaking down, an amino acid?

Removal of amine group (-NH3)

Removal of the amine group (-NH3) is the first step in catabolizing an amino acid. To do this, the amine group can be transferred through what?

Transamination

Removal of the amine group (-NH3) is the first step in catabolizing an amino acid. To do this, the amine group can be removed as ammonia through what?

Oxidative deamination

What is the equation for transamination?

AA + Keto acid -> New AA + New Keto acid

What is the equation for deamination?

a-amino acid -> a-keto acid + NH4+

What is A for insulin?

Hyperglycemia and hyperaminoacidemia

What is A for glucagon?

Hypoglycemia and hyperaminoacidemia

What is A for cortisol?

Hypoglycemia

What is A for growth hormone?

Hypoglycemia and hyperaminoacidemia

What is A for catecholamines?

Hypoglycemia

What is B for insulin?

Glucose uptake, Glycolysis, Glycogenesis, Lipogenesis, Protein synthesis

What is B or glucagon and catecholamines?

Glycogenolysis, Lipolysis, Gluconeogenesis

What is B for cortisol?

Glycogenolysis, Gluconeogenesis

What is the difference between protein catabolism and protein synthesis?

Catabolism occurs in skeletal muscles, synthesis occurs in liver

What is B for growth hormone?

Glycogenolysis, Lipolysis, Gluconeogenesis, Protein synthesis

What is C for insulin?

Glycogenolysis, Lipolysis, Protein catabolism, Gluconeogenesis

Since insulin stimulates glycogenesis, lipogenesis, and protein synthesis, what is it referred to?

Anabolic hormone

Gluconeogenesis is an anabolic process _____ by insulin; Glycolysis is the only catabolic process stimulated by insulin.

Inhibited

Since insulin is released in response to hyperglycemia and works via negative feedback to stimulate the cellular uptake, usage and storage of glucose to decrease the blood glucose levels, insulin is known as what?

Hypoglycemia hormone

Since glucagon, cortisol, growth hormone, catecholamines are released in response to hypoglycemia, they work through negative feedback to increase blood glucose levels by stimulating glycogenolysis, lipolysis and gluconeogenesis so they are known as insulin antagonists or what?

Hyperglycemia hormone

What is a major gluconeogenic hormone, and directly stimulates protein catabolism in skeletal muscles to provide amino acids for gluconeogenesis?

Cortisol