A&P CH24 Metabolism

What is metabolism?

The sum of all biochemical reactions inside a cell involving nutrients.

What does anabolism refer to?

The synthesis of large molecules from small ones.

What is catabolism?

The hydrolysis of complex structures to simpler ones.

What is cellular respiration?

The process where food molecules are broken down in cells to release energy used for ATP synthesis.

What are the three stages in processing nutrients?

1. Digestion, absorption, & transport to tissues; 2. Cellular processing; 3. Oxidative of intermediates into CO2, water, and ATP.

Where does oxidative phosphorylation occur?

In the mitochondria.

What is phosphorylation?

The process of converting ADP to ATP.

What happens during glycolysis?

Glucose is broken down into 2 pyruvic acid molecules.

What are the final products of glycolysis?

2 pyruvic acid, 2 reduced NAD+ (NADH + H+), and a net gain of 2 ATP.

What occurs if oxygen is not present during glycolysis?

NADH gives hydrogen atoms back to pyruvic acid, reducing it to lactic acid.

What are the three main pathways needed for complete glucose catabolism?

1. Glycolysis, 2. Citric Acid Cycle (Krebs Cycle), 3. Electron Transport Chain & oxidative phosphorylation.

What is the role of NAD+ in glycolysis?

NAD+ must be present to accept hydrogen atoms for glycolysis to continue.

What is the Krebs cycle also known as?

The citric acid cycle.

Where does the citric acid cycle occur?

In the mitochondrial matrix.

What are the byproducts of the citric acid cycle?

2 CO2, 3 NADH, 1 FADH2, and 1 ATP per cycle.

What are the steps involved in the transitional phase of pyruvic acid?

Decarboxylation, oxidation, and formation of acetyl CoA.

What is the function of the electron transport chain?

Transferring high energy electrons from NADH and FADH2 to oxygen.

What is lipogenesis?

The synthesis of triglycerides when cellular ATP and glucose levels are high.

Where does gluconeogenesis occur?

In the liver.

What is the primary process that produces energy from fatty acids?

Beta oxidation.

What is ketosis?

A condition resulting from the accumulation of ketone bodies in blood.

What are the main roles of lipids in the body?

Structural materials for cell membranes and synthesis of hormones.

What happens during deamination of amino acids?

The amine group (NH2) is removed, producing urea.

What is the goal of amino acid degradation?

To produce molecules that can be used for energy in the citric acid cycle or converted to glucose.

How are amino acids used in protein synthesis?

They are the crucial anabolic nutrients needed to form all proteins.

What are the two types of phosphorylation mechanisms for ATP production?

1. Substrate-level phosphorylation; 2. Oxidative phosphorylation.

What is the significance of essential amino acids?

They must be acquired through diet and are critical for protein synthesis.

What happens when intracellular ATP levels rise?

They inhibit glucose catabolism and promote glycogen or fat formation.

How is glucose trapped inside a cell?

It is phosphorylated to glucose-6-phosphate; most cells lack enzymes to reverse this reaction.