The process in your body that turns simple structures into more complex structures. It can happen within a single cell (or within a single organelle within a cell), or across multiple cells.

Biosynthesis

The chemical processes that occur in living organisms, involving biomolecules.

Biochemical Processes

Any metabolic process whereby cells break down complex substances into simpler, smaller ones.

Catabolism

Water-soluble substances produced from fatty acids by the liver during gluconeogenesis, a process that creates glucose in times of fasting and starvation.

Ketone Bodies

Step-by-step series of interconnected biochemical reactions that convert a substrate molecule or molecules through a series of metabolic intermediates, eventually yielding a product or products.

Metabolic Pathway

A general term that encompasses all chemical changes occurring in living organisms.

Metabolism

Metabolic pathways are irreversible.

TRUE

Catabolic and anabolic pathways must differ.

TRUE

Not all metabolic pathway has a first committed step.

FALSE

All metabolic pathways are regulated.

TRUE

Metabolic pathway in eukaryotic cells occur in specific subcellular compartments

TRUE

Each organelle (compartment) is dedicated to specialized metabolic functions and contains appropriate enzymes confined together.

TRUE

Eukaryotic cells are compartmentalized by an exomembrane system, advantageous for metabolism.

FALSE

The following are advantages of eukaryotic cells being compartmentalized, except..

Enzymes from competing pathways can interact

energy store

ATP

reduction equivalents

NADPH

Example of Anabolism

synthesis of sugar from CO2

The central role of ATP for energy exchange in biological systems was discovered in ________ by whom?

1941, Fritz Lipmann and Herman Kalckar

ATP-turnover

40 kg/day

Which is not a central role of Acetyl-CoA in metabolism?

Glycolysis

Linear metabolic pathway

Glycolysis

Which organ is considered the center of metabolism in the body?

Liver

Which organ stores glycogen and can convert it into glucose?

Liver

Which organ is responsible for synthesizing fatty acids, cholesterol, and bile salts?

Liver

Which organ can perform gluconeogenesis and release glucose into the bloodstream?

Kidney

Which organ primarily uses glucose as its fuel source and can use ketone bodies only after prolonged fasting?

Brain

Which organ utilizes glucose, fatty acids, ketone bodies, and amino acids as energy sources?

muscle

Which organ synthesizes fatty acids and stores them as triacylglycerols?

Adipose tissue

Which organ contains a reserve of creatine-phosphate for energy production without using glucose?

Muscle

Which organ plays a crucial role in maintaining blood glucose levels and regulating the concentration of metabolites in the blood?

Liver

Only the what organs contain glucose-6-phosphatase?

Kidney and Liver

Which organ releases triacylglycerols into the bloodstream when activated by glucagon?

Adipose tissue

What happens in the liver when blood glucose is high (fed state)?

Fatty acids are synthesized and converted into triacylglycerols.

What happens in the liver when blood glucose is low (fasting state)?

The liver produces ketone bodies.

What is the purpose of synthesizing triacylglycerols in the liver during the fed state?

To package fatty acids into VLDL for secretion into the blood.

What is the purpose of producing ketone bodies in the liver during the fasting state?

To fuel the heart and muscles.

What does the liver eventually provide as a fuel source for the brain during the fasting state?

ketone bodies

What metabolic process can the kidney perform?

Gluconeogenesis

How does the urea cycle in the liver affect blood pH?

It decreases blood pH.

Which enzyme in the kidney is responsible for cleaving glutamine into glutamate and ammonia?

Glutaminase

Which two hormones are primarily involved in hormone control?

Insulin and glucagon

When are high blood glucose levels detected by the pancreas?

After a meal

What is the main effect of insulin on muscle and adipose tissue?

Stimulates glycogen synthesis

What is the main effect of glucagon on the liver?

Stimulates glycogen degradation

Which hormone is released by the pancreas when blood glucose levels drop too much?

Glucagon

What is the main concept behind group transfer reactions?

Transfer of functional groups between molecules

What is a common example of a group transfer reaction in biological systems?

Transfer of phosphate groups

In the transfer of an amine functional group, which molecule serves as the donor molecule?

alpha-amino acid

In the transfer of an amine functional group, which molecule serves as the acceptor molecule?

alpha-keto acid

What class of enzymes catalyzes the formation and removal of carbon-carbon double bonds?

Lyases

What is a common type of reaction used to remove a carbon-carbon double bond?

Hydrogenation reaction

What is the main characteristic of isomerization reactions?

They involve the rearrangement of atoms in a molecule.

What is the significance of isomerization reactions in biological systems?

They enable the interconversion of molecules with different biological functions.

How many different tRNA molecules and synthetase enzymes are there for the 20 amino acids?

1 tRNA molecule and 1 synthetase enzyme for each amino acid

What is the main characteristic of ligation reactions?

They use the energy of ATP to join two molecules together.

What is an example of a ligation reaction in biological systems?

Joining of an amino acid with tRNA during protein synthesis

What is the main characteristic of hydrolysis reactions?

Addition of water to break apart a molecule

What happens during normal digestion of food molecules?

Macromolecules are broken down into building blocks through hydrolysis.

How is dehydration synthesis related to hydrolysis reactions?

It is the reverse reaction of hydrolysis.

What is an oxidation-reduction (redox) reaction?

A reaction that involves the transfer of electrons between atoms or compounds.

Which molecule is a major fuel for most organisms in carbohydrate metabolism?

Glucose

How is glucose transported throughout the body in vertebrates?

Through the circulatory system in the blood

What are the three stages of glucose metabolism? (in correct order)

Glycolysis, the Krebs Cycle, oxidative phosphorylation

Where does glycolysis occur?

Cytosol

What is the final product of glycolysis?

Pyruvate

What is the role of phosphofructokinase (PFK) in glycolysis?

Regulates the breakdown of glucose for energy

What is the main purpose of the Krebs Cycle?

Production of NADH and FADH2

Where does the Krebs Cycle take place?

Mitochondria

What is the primary energy production pathway when oxygen is limited?

Anaerobic glycolysis

Which hormones primarily regulate glycogenesis and glycogenolysis?

Insulin, glucagon, and epinephrine

When does glycogen synthesis occur?

After a meal when blood glucose levels are high

What is the role of the branching enzyme in glycogen synthesis?

It creates (1,6) linkages for branches in the glycogen molecule

What is glycogenolysis?

The breakdown of glycogen

How does glycogenolysis come to an end?

When only four glucose residues remain at each branch point

Which disease is characterized by the impaired ability to store glucose as glycogen?

Diabetes Mellitus

What characteristic of fatty acid chains makes them hydrophobic?

Nonpolar C-H bonds

Which type of fat is composed of three fatty acids bonded to one glycerol molecule?

Triacylglycerol

How are glycerol and fatty acids linked together in fat formation?

By ester linkages

Which statement is true about saturated fats?

They have a carbon skeleton bonded to the maximum number of hydrogens.

What is the structure of a phospholipid?

Glycerol attached to two fatty acids and a phosphate group

How is acetyl-CoA generated during the degradation of fatty acids?

By the oxidation of fatty acids

What are triacylglycerols converted into within the enterocytes?

Chylomicrons

What is the primary function of enterocytes in the digestion and absorption of triacylglycerols?

Reconversion of fatty acids and monoacylglycerol into triacylglycerols

Which of the following is NOT a ketone body?

Malonyl-CoA

Where does the synthesis of ketone bodies occur?

Mitochondria of liver cells

What is the rate-limiting step in fatty acid synthesis?

Formation of malonyl-CoA

Which enzyme catalyzes the reduction of acetoacetyl-ACP during fatty acid synthesis?

β-Ketoacyl-ACP reductase

Fatty acid elongation primarily occurs in which cellular compartment?

Endoplasmic reticulum

Fatty acid elongation is important for the synthesis of:

Membrane lipids

What are the four sequential reactions involved in microsomal fatty acid chain elongation?

Condensation, reduction, dehydration, reduction

What is the approximate daily rate of cholesterol synthesis in normal healthy adults?

1g/day

How is the level of cholesterol in the blood primarily regulated?

By controlling de novo synthesis

What does "de novo synthesis" refer to?

Synthesis of complex molecules from simple molecules

Where does cholesterol synthesis occur in the cell?

Cytoplasm and microsomes (ER)

Which organs contribute to the endogenous synthesis of cholesterol?

Liver and intestines

What is the rate-limiting enzyme in cholesterol synthesis?

HMG-CoA reductase

What is the role of HMG-CoA reductase in cholesterol synthesis?

Converts HMG-CoA to mevalonate, the precursor of cholesterol

Which mechanism regulates the activity of HMG-CoA reductase?

Feed-back inhibition

100

What are the major components of bile?

Bile salts and bile pigments