12 2 NUT CH7

How do we digest, absorb, and metabolize amylose (a component of starch)? Please list the enzymes involved in digestion and indicate where in the GI tract they function. Indicate the type of absorption and what is being absorbed. List the metabolic pathways involved in metabolism.

Amylose is digested beginning in the mouth with salivary amylase converting amylose to maltose. This is incomplete. In the duodenum (1st part of the small intestine) pancreatic amylase finishes the digestion of amylose to maltose. Maltose is further digested in the duodenum to 2 glucose molecules with the help of maltase. The glucose is absorbed by active transport (it requires a pump and ATP). Glucose goes through the pathways: glycolysis, TCA (Krebs cycle), and Electron Transport Chain.

The overall reaction for obtaining energy from glucose in the presence of oxygen can be represented chemically as?

C6H12O6 + 6O2 --> 6CO2 + 6H2O + ~36 ATP 1 glucose molecule + 6 oxygen molecules react to form 6 carbon dioxide and 6 water molecules and produce about 36 ATP (energy molecules)

Where does glycolysis occur?

Glycolysis occurs in the cytosol.

Glycolysis starts with the 6 carbon molecule __________ and ends with 2, 3 carbon molecules of __________.

Glycolysis starts with the 6 carbon molecule glucose and ends with 2, 3 carbon molecules of pyruvate.

Glycolysis uses _____ ATP and produces _____ ATP for a net production of _____ ATP.

Glycolysis uses 2 ATP and produces 4 ATP for a net production of 2 ATP.

When are ketone bodies produced in a person?

Ketone bodies are produced when a person fasts, is on a low carbohydrate diet, or has type 1 diabetes.

Where does the Electron Transport Chain occur?

The Electron Transport Chain occurs in the cristae of the mitochondria.

Where does the Krebs Cycle occur? (TCA or citric acid cycle)

The Krebs Cycle occurs in the matrix of the mitochondria.

Before amino acids can be used for energy what needs to be released from their structure? Where does this released product end up?

The amino group needs to be released. It ends up in the molecule urea in our urine.

The citric acid cycle requires the presence of __________ for completion.

The citric acid cycle requires the presence of oxygen for completion.