Introduction to Gene Expression and Translation

Glycolysis is the sole energy source for red blood cells (RBCs) because they lack mitochondria.

The main energy source for muscles during strenuous activity, it functions in the absence of oxygen.

Under anaerobic conditions, NADH+H+ is reoxidized via lactate formation, enabling glycolysis to continue without oxygen.

A condition that leads to a decrease in ATP production in red blood cells, resulting in hemolytic anemia.

Glycolysis is a preliminary step in complete oxidation and provides building blocks for amino acids and fats.

Hexokinase, phosphofructokinase (PFK-1), and pyruvate kinase are the key regulatory enzymes of the glycolytic pathway.

Insulin activates glycolysis (by dephosphorylation), while glucagon inhibits it (by phosphorylation).

Mercury inhibits glyceraldehyde-3-P dehydrogenase, and fluoride interferes with enolase activity.

Biotin deficiency, even mild, impacts cellular energy production, leading to symptoms like hair loss, thin nails, and conjunctivitis.

In anaerobic conditions, glycolysis produces only 2 ATP molecules, and pyruvate is converted to lactate, not Acetyl CoA.

During intense exercise, high NADH production outpaces the electron transport chain, resulting in lactate build-up.

Lactate accumulation during intense exercise lowers intracellular pH and can lead to muscle cramps.

Lactate produced in muscles and RBCs travels to the liver, where it's converted back to pyruvate and then glucose, to be reused.

Lactic acidosis is a condition caused by a deficiency in tissue perfusion, like severe hypotension, heart attacks, or hemorrhage, affecting ATP production.

Lactic acidosis involves high lactate levels in the blood and is associated with decreased oxidative phosphorylation and ATP synthesis.

A specific irreversible reaction is essential to maintain the intermediate balance of the Citric Acid Cycle.

In anaerobic respiration, NADH produced during glycolysis is used up by lactate dehydrogenase, preventing further energy generation from the electron transport chain.

Pyruvate is converted to lactate by the action of Lactate Dehydrogenase (LDH) enzyme in a reversible reaction in anaerobic conditions, as it is important to maintain energy production.

Metabolic process that uses oxygen to produce energy.

Metabolic process that doesn't use oxygen to produce energy.

Enzyme complex that converts pyruvate to Acetyl CoA.

Metabolic pathway that breaks down glucose into pyruvate.

Cellular organelles where aerobic respiration occurs.

Muscles use anaerobic respiration during high activity levels when oxygen supply is insufficient.

Cells lacking mitochondria that always use anaerobic respiration.

Electron carrier molecule important in cellular respiration..

Intermediate molecule connecting glycolysis to the Krebs cycle.

A process that modifies RNA sequences after transcription, often leading to changes in protein structure or function. In the case of apolipoprotein B, RNA editing creates a premature stop codon, resulting in a shorter protein (B-48) in intestinal cells.

Small non-coding RNA molecules that regulate gene expression by binding to target messenger RNAs (mRNAs), leading to either degradation or blocking of translation of the target mRNA.

The phosphorylation of eukaryotic initiation factor 2 (eIF2) inhibits its activity, thereby slowing down protein synthesis. This is a key mechanism for regulating translation in response to stress.

Drugs that block the activity of proteases, enzymes responsible for breaking down proteins. They are used in treating viral infections like HIV and Hepatitis C by inhibiting the processing of viral proteins.

After glycolysis, pyruvate is transported into mitochondria via a special transporter where it is converted into Acetyl CoA.

PDH is a complex of 3 enzymes that catalyzes the irreversible conversion of pyruvate to Acetyl CoA, a key step in cellular respiration.

PDH requires 5 coenzymes: thiamine pyrophosphate (TPP), lipoic acid, Coenzyme A, flavin adenine dinucleotide (FAD), and nicotinamide adenine dinucleotide (NAD).

Elevated levels of acetyl CoA inhibit PDH allosterically, slowing down pyruvate's conversion to Acetyl CoA.

High levels of NADH+H+ also allosterically inhibit PDH, as a way to regulate the flow of pyruvate into the citric acid cycle.

Insulin activates PDH by promoting its dephosphorylation, increasing pyruvate conversion to Acetyl CoA.

Mercury inhibits the activity of PDH, interfering with the conversion of pyruvate to Acetyl CoA.

Arsenic poisoning inhibits PDH by interfering with the action of lipoic acid, a vital coenzyme for its function.

Pyruvate dehydrogenase deficiency is a rare, serious condition where the PDH enzyme complex is impaired, leading to insufficient energy production.

PDH deficiency can cause severe health problems like lactic acidosis, neurological issues, and even death. Often, it's caused by nutritional deficiencies.

Glycolysis is the breakdown of glucose into pyruvate, generating ATP (energy) for the cell. It occurs in the cytoplasm and doesn't require oxygen.

Red blood cells (RBCs) rely solely on glycolysis for energy because they lack mitochondria, the powerhouse of the cell.

Anaerobic glycolysis fuels muscles during strenuous exercise when oxygen is limited. It produces less ATP but allows the muscles to keep working.

A deficiency in the enzyme pyruvate kinase disrupts ATP production in RBCs, leading to hemolytic anemia. Less energy means fragile RBCs.

Three enzymes – hexokinase, phosphofructokinase (PFK-1), and pyruvate kinase – control the speed of glycolysis.

Insulin, released during feeding, activates glycolysis, while glucagon, released during fasting, inhibits it.

Mercury and fluoride disrupt key enzymes in glycolysis, leading to energy production failure and potentially cell death.

Aerobic respiration uses oxygen to produce energy, while anaerobic respiration does not. Anaerobic respiration occurs when oxygen supply is limited, like during intense exercise or in cells lacking mitochondria.

Glycolysis is the first stage of cellular respiration, breaking down glucose into pyruvate. It occurs in both aerobic and anaerobic conditions.

In aerobic conditions, pyruvate is transported into mitochondria where it is converted into Acetyl CoA by the Pyruvate Dehydrogenase Complex (PDH). Acetyl CoA then enters the citric acid cycle to generate more energy.

Anaerobic respiration occurs in cells lacking mitochondria, like red blood cells, and in tissues experiencing oxygen deprivation, like muscles during intense exercise.

In aerobic conditions, NADH produced during glycolysis is transported to the mitochondria where it is oxidized, generating ATP. This is a crucial step for maximizing energy production.

Biotin (vitamin B7) deficiency, even mild, disrupts cellular energy production, causing symptoms like hair loss, brittle nails, eye inflammation, and neurological problems.

In the absence of oxygen, glycolysis produces only 2 ATP molecules per glucose molecule, with pyruvate converted to lactate instead of Acetyl CoA.

Excess lactate in muscles lowers the internal pH and can cause cramps, as your body struggles to cope with this acidic environment.