Biological Membranes and Proteins Quiz

A type of feedback inhibition where the product of a metabolic pathway inhibits an earlier enzyme in the pathway.

The enzyme that phosphorylates pyruvate dehydrogenase (PDH), leading to increased activation.

The enzyme that removes the phosphate group from phosphorylated PDH, restoring its activity.

A molecule that regulates the activity of an enzyme by binding to a site other than the active site.

The central molecule in energy metabolism, produced from various fuel sources and used in the TCA cycle.

A series of biochemical reactions that oxidizes fuel molecules to produce ATP.

The process of using a substrate's energy to directly convert ADP to ATP.

Electron carrier proteins that transfer electrons in the electron transport chain (ETC).

The movement of electrons through a series of carriers, releasing energy to pump protons across the mitochondrial membrane.

An enzyme that uses the proton gradient across the mitochondrial membrane to synthesize ATP.

Anabolic pathways build complex molecules from simpler ones, requiring energy input.

Catabolic pathways break down complex molecules into simpler ones, releasing energy.

Enzymes are proteins that catalyze (speed up) biochemical reactions within metabolic pathways.

The net change in free energy (ΔG) determines whether a reaction is energetically favorable (negative ΔG) or unfavorable (positive ΔG).

Phosphoryl group transfer potential refers to the ability of a molecule to donate a phosphate group, releasing energy.

Glycolysis is a metabolic pathway that breaks down glucose into pyruvate, generating ATP and reducing equivalents.

The electron transport chain uses a series of electron carriers to generate a proton gradient across the mitochondrial membrane, ultimately driving ATP synthesis.

Beta oxidation is the catabolic process that breaks down fatty acids into acetyl-CoA, generating reducing equivalents (NADH and FADH2) for ATP production.

A process that regulates the transport of fatty acid molecules across the mitochondrial membrane, enabling them to be broken down for energy.

An enzyme that catalyzes the transfer of an acyl group from coenzyme A (CoA) to carnitine, allowing fatty acids to enter the mitochondria.

An enzyme that catalyzes the transfer of an acyl group from carnitine back to CoA, releasing the fatty acid into the mitochondrial matrix for breakdown.

A series of chemical reactions that occur in the mitochondria, oxidizing acetyl CoA to produce energy for the cell.

A process that uses the energy from glucose, fatty acids, and amino acids to create ATP, the primary energy currency of the cell.

The process of synthesizing fats from excess carbohydrates, proteins, or other molecules.

A metabolic process that generates glucose from non-carbohydrate sources like pyruvate, lactate, glycerol, and amino acids. It occurs primarily in the liver and kidneys, primarily when blood glucose levels are low.

A cycle where lactate produced in anaerobic conditions is transported to the liver and used as a substrate for gluconeogenesis. This process helps regenerate glucose from lactate, reducing lactic acid buildup in the body.

The irreversible steps of glycolysis involve enzymes that are bypassed in GNG. These are the steps that are highly regulated and can be influenced by hormonal signals.

• Step 1: Hexokinase / Glucokinase
• Step 3: Phosphofructokinase 1 (PFK1)
• Step 10: Pyruvate Kinase

The ability of a cell membrane to maintain its fluidity and flexibility, which is crucial for proper function. It allows molecules to move within the membrane and interact with each other.

Proteins that are embedded within the cell membrane, often spanning the entire membrane. They play crucial roles in transport, signaling, and other vital cellular functions.

Detergents are amphipathic molecules that can disrupt the lipid bilayer of cell membranes, allowing for the extraction of integral membrane proteins. Solvents like salt can also help solubilize and purify proteins.

The process where a substance moves across a cell membrane without requiring energy. The driving force is a concentration gradient or electrical potential.

The movement of substances across a cell membrane against their concentration gradient, requiring energy input. It's often facilitated by membrane pumps or other transport proteins.

In fatty acid synthesis, the initial step where malonyl CoA adds two carbons to a growing fatty acid chain, releasing CO2.

The second step in fatty acid synthesis, where a reducing enzyme (KR) uses NADPH to reduce the newly added carbons, resulting in a saturated chain.

The third step in fatty acid synthesis where the fatty acid chain undergoes dehydration, catalyzed by a dehydratase (DH), releasing water.

The fourth step in fatty acid synthesis where an enzyme (ER) utilizes NADPH to promote the reduction of a double bond in the growing fatty chain, resulting in a saturated chain.

The process of building fatty acid chains, involving the repetitive use of malonyl CoA and a series of enzyme-catalyzed reactions: condensation, reduction, dehydration, and reduction.

An enzyme responsible for converting acetyl CoA to malonyl CoA, a key step in fatty acid synthesis.

The process of forming triglycerides (TAGs) from glycerol and fatty acids.

Molecules that transport hydrophobic fats (like TAGs and cholesterol) through the bloodstream.

Proteins that are embedded in the surface of lipoproteins, facing the aqueous environment with their hydrophilic side and facing the hydrophobic core with their hydrophobic side.

A crucial component of cell membranes that is also used to synthesize hormones, bile salts, and vitamin D3.

The breakdown of fat reserves, primarily triglycerides, into glycerol and fatty acids. It occurs in the liver when glucose levels are low and acetyl-CoA levels are high. This pathway generates ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone) which can be used as energy by the brain, heart, muscle, and kidney cells.

A biochemical marker of anaerobic metabolism, indicating a lack of oxygen and the use of glucose for energy production without the electron transport chain.

A type of lipoprotein, also known as 'bad cholesterol,' that carries cholesterol from the liver to cells throughout the body. High levels of LDL increase the risk of heart disease.

A type of lipoprotein, also known as 'good cholesterol,' that picks up excess cholesterol from cells and transports it back to the liver for recycling.

A metabolic state characterized by high levels of ketone bodies in the blood, primarily due to prolonged fasting, low-carb diets, or poorly controlled diabetes. This can lead to a drop in blood pH, causing acidosis.

A hormonal signal that stimulates glucose uptake and storage as glycogen in cells. It also inhibits glucagon release, promoting energy storage.

A type of lipoprotein produced in the small intestine after a meal, responsible for transporting dietary fats (triglycerides) to the liver and other cells.

A protein that helps regulate the expression and/or activity of HMG-CoA reductase - the enzyme that controls cholesterol synthesis.

A type of lipoprotein that is responsible for transporting triglycerides from the liver to other cells for energy use.

The process of removing the amino group (NH2) from amino acids, a step in their metabolism. It's important as it generates ammonia, which needs to be detoxified through the urea cycle.

A type of lipoprotein that is formed from VLDL after some triglycerides have been removed, and it mainly carries cholesterol.

An enzyme that breaks down triglycerides, primarily found in tissues like heart, muscle, and adipose.

An enzyme that hydrolyzes glucose 6-phosphate to produce free glucose in the liver, allowing it to be released into the bloodstream.