Biochemistry Chapter on Lipids

<p>Transketolase (C)</p> Signup and view all the answers

<p>Increased glucose utilization through glycolysis. (B)</p> Signup and view all the answers

<p>Starved state (C)</p> Signup and view all the answers

<p>PEPCK (C)</p> Signup and view all the answers

<p>To prevent oxidative damage to cells. (D)</p> Signup and view all the answers

<p>Activating protein phosphatase 1 and phosphodiesterase (C)</p> Signup and view all the answers

<p>cAMP (C)</p> Signup and view all the answers

<p>Phosphorylation of enzymes (A)</p> Signup and view all the answers

<p>Muscle and adipose tissues only (A)</p> Signup and view all the answers

<p>Generating superoxide from oxygen (C)</p> Signup and view all the answers

<p>Insulin initiates energy storage, while glucagon initiates energy mobilization. (D)</p> Signup and view all the answers

<p>Complex II can form superoxide if electrons are not flowing down the chain. (A)</p> Signup and view all the answers

<p>Fats and stored glycogen (B)</p> Signup and view all the answers

<p>Competitive inhibition of HMG-CoA reductase (D)</p> Signup and view all the answers

<p>7a-hydroxylase (C)</p> Signup and view all the answers

<p>They are dehydroxylated and deconjugated (A)</p> Signup and view all the answers

<p>In the bloodstream (C)</p> Signup and view all the answers

<p>It binds bile acids to form insoluble complexes (B)</p> Signup and view all the answers

<p>They are less polar and more prone to excretion (D)</p> Signup and view all the answers

<p>They accumulate and cause cellular dysfunction (B)</p> Signup and view all the answers

<p>Conversion of cholesterol to bile salts in the liver (B)</p> Signup and view all the answers

<p>They contain oxygen and have reactive properties. (A)</p> Signup and view all the answers

<p>Superoxide anion (O2•‒) (D)</p> Signup and view all the answers

<p>Superoxide dismutase (C)</p> Signup and view all the answers

<p>Vitamin C, Vitamin E, and Niacin (D)</p> Signup and view all the answers

<p>As a reducing agent donating electrons (C)</p> Signup and view all the answers

<p>It can induce base damage or strand breaks in DNA and RNA. (C)</p> Signup and view all the answers

<p>It breaks down hydrogen peroxide into water. (C)</p> Signup and view all the answers

<p>Sufficient amounts of metal ions like Zn+, Cu+, or Mn2+. (D)</p> Signup and view all the answers

<p>Tryptophan (C)</p> Signup and view all the answers

<p>It donates methyl groups for neurotransmitter synthesis. (D)</p> Signup and view all the answers

<p>Histamine (D)</p> Signup and view all the answers

<p>They decrease the reuptake of serotonin, increasing its presence. (D)</p> Signup and view all the answers

<p>Arginine, glycine, and methionine (A)</p> Signup and view all the answers

<p>Glutamate (C)</p> Signup and view all the answers

<p>Vasodilation and lowering blood pressure (D)</p> Signup and view all the answers

<p>Leucine, isoleucine, and valine (B)</p> Signup and view all the answers

<p>Abnormal enamel thickness (A)</p> Signup and view all the answers

<p>Autosomal dominant (A)</p> Signup and view all the answers

<p>Neurofibromatosis type 1 (B)</p> Signup and view all the answers

<p>Fracture prevention (B)</p> Signup and view all the answers

<p>Multiple basal cell carcinomas (C)</p> Signup and view all the answers

<p>Benign neurofibromas (C)</p> Signup and view all the answers

<p>Hereditary hemorrhagic telangiectasia (A)</p> Signup and view all the answers

<p>Hearing loss due to vestibular schwannomas (B)</p> Signup and view all the answers

HMG-CoA reductase activity is controlled by transcriptional changes, protein breakdown (proteolysis), and modifications (phosphorylation).

Cholesterol synthesized in the liver is transported to other tissues via VLDL, IDL, and LDL.

The enzyme 7α-hydroxylase controls the speed of bile acid synthesis.

Converting cholesterol to bile salts is the main method of removing excess cholesterol from the body, primarily in the liver.

Primary bile salts are created directly from cholesterol in the liver. Secondary bile salts are modified primary salts by gut bacteria.

Statins inhibit HMG-CoA reductase, the key enzyme in cholesterol synthesis

The cyclical process of cholesterol removal through bile salts, from the liver to bile to the intestine, back to the liver, and finally becoming part of feces.

Both LCAT and ACAT convert cholesterol into cholesterol esters. LCAT acts in the bloodstream, while ACAT acts within cells.

Glucagon inhibits F-2,6-BP formation and stimulates its breakdown in the liver, thus decreasing glycolysis.

Glycolysis is active when blood glucose, insulin, and F26BP are high; gluconeogenesis is active when blood glucose, insulin, and F26BP are low.

Pyruvate carboxylase and PEPCK are required, along with 2 ATP equivalents.

Thymine is required as a cofactor for transketolase.

Insulin stimulates glycolysis in the liver by promoting F-2,6-BP production via PFK2.

The pathway takes place in the cytosol of the cell.

NADPH is used for biosynthesis, oxidative stress protection, and in some cases, reactive oxygen species generation.

Glycolysis is favored with elevated blood glucose, insulin, and F26BP.

Neurotransmitters are created from specific amino acids, and their production can be influenced by activity in these pathways.

SAM (S-adenosyl methionine) is a key methyl group donor involved in the synthesis of certain neurotransmitters by donating a methyl group.

Catecholamines, including norepinephrine and epinephrine, are derived from the amino acids phenylalanine and tyrosine.

Serotonin and melatonin are synthesized from tryptophan. Serotonin is converted into melatonin in the pineal gland and plays a crucial role in regulating sleep-wake cycles.

Selective serotonin reuptake inhibitors (SSRIs) can cause xerostomia (dry mouth), which increases the risk of dental carries and other oral health problems.

Glutamate is an excitatory neurotransmitter, while GABA is an inhibitory neurotransmitter.

Nitric oxide (NO) is synthesized from arginine. NO acts as a vasodilator, relaxing arterial smooth muscle and helping to lower blood pressure.

Branched chain amino acids (leucine, isoleucine, and valine) are deaminated and metabolized in muscle and brain to fuel ATP production.

A rapid increase in oxygen consumption and production of reactive oxygen species (ROS) by cells, particularly immune cells like neutrophils and macrophages, during immune responses.

Enzymes that catalyze the transfer of electrons from NADPH to molecular oxygen, generating superoxide radicals (O2-) as a byproduct.

Oxygen-containing molecules with reactive properties, such as superoxide anions (O2-), hydrogen peroxide (H2O2), and hydroxyl radicals (HO ), which can damage cells.

Enzymes that convert superoxide radicals (O2-) into hydrogen peroxide (H2O2), providing enzymatic protection against ROS.

An enzyme that converts hydrogen peroxide (H2O2) into water (H2O) and oxygen gas (O2), further neutralizing ROS.

A tripeptide (Glu-Cys-Gly) that acts as a primary cellular antioxidant, donating electrons to neutralize ROS.

Damage to lipids (fats) caused by ROS, leading to cell membrane damage and other problems.

ROS can cause damage to DNA, lipids, and proteins, leading to various cellular malfunctions and diseases.

A genetic disorder impacting enamel development, leading to abnormal enamel thickness, color, and structure. This results in discolored, decay-prone, and sensitive teeth.

A genetic disorder causing abnormal blood vessel formation, resulting in dilated blood vessels (telangiectasias) and arteriovenous malformations (AVMs).

A genetic disorder characterized by benign tumors (neurofibromas) developing on nerves and skin.

A group of genetic disorders characterized by fragile bones due to defective collagen production. Features include frequent fractures, blue sclera, dental imperfections, and hearing loss in some types.

A genetic disorder predisposing individuals to various tumors, especially basal cell carcinomas (BCCs). Other features include jaw cysts (odontogenic keratocysts), palmar and plantar pits, and skeletal abnormalities.

An increased risk of certain tumors, learning disabilities, and other neurological symptoms associated with Neurofibromatosis.

Mostly autosomal dominant, with some forms being autosomal recessive.

Regular skin checks for early detection of skin cancers and treatment of associated conditions.

Insulin and glucagon are hormones that act as a binary switch to regulate fuel metabolism. Insulin dephosphorylates key enzymes, promoting glucose uptake and storage, while glucagon phosphorylates these enzymes, promoting glucose release and utilization. This opposing action is crucial for maintaining blood glucose levels.

Insulin enhances glucose uptake primarily in muscle and adipose tissue by activating the GLUT4 transporter. This process is crucial for storing glucose as glycogen during periods of high blood glucose.

Phosphorylation acts as a molecular switch by modifying the activity of enzymes involved in fuel metabolism. Insulin dephosphorylates key enzymes promoting glucose storage, while glucagon phosphorylates, enabling glucose release.

Glucagon acts primarily in the liver, stimulating glycogen breakdown and glucose release into the bloodstream. This is crucial during periods of low blood glucose.

Insulin secretion increases following a meal, when blood glucose levels are elevated, promoting glucose uptake and storage. Glucagon is released during fasting or exercise, when blood glucose is low, signaling the liver to release stored glucose.

NADPH oxidases are enzymes that generate reactive oxygen species (ROS) by transferring electrons from NADPH to oxygen. This process produces superoxide, which can be used for various cellular functions, such as fighting pathogens.

In the electron transport chain, ROS can be generated when electrons leak from the chain and react with oxygen. This occurs mainly at Complex I and III, leading to the formation of superoxide.

Macrophages and neutrophils use ROS as a weapon to destroy pathogens. They increase their oxygen uptake in the presence of microorganisms, generating ROS to combat infection.