Nitrogen 2

Question 1

<p>What is the only way that nitrogen can get in and out of the body?</p>

Answer 1

<p>Through glutamate</p>

Question 2

<p>How do we excrete nitrogen?</p>

Answer 2

<p>By producing urea (from amino acids) and uric acid (from purines)</p>

Question 3

<p>What is ammonia transported in the bloodsteam as?</p>

Answer 3

<p>Glutamine, with excess glutamine beingprocessed in the intestines, kidneys and liver</p>

Question 4

<p>How can pyruvate be converted into alanine?</p>

Answer 4

<p>By glutamate donating an amino group</p>

Question 5

<p>What does pyruvate being converted into alanine during vigourous exercise prevent?</p>

Answer 5

<p>A build up of lactice acid</p>

Question 6

<p>Where is the alanine that can be built up during vigorous exercise transported to?</p>

Answer 6

<p>The liver</p>

Question 7

<p>What is the process of the glucose-alanine cycle?</p>

Answer 7

<ol> <li>Proteins are broken down in exercising if required</li> <li>Transported to the liver as alanine</li> <li>Resulting carbon skeleton in converted into pyruvate</li> <li>Nitrogen exreted as ammonia and converted to urea</li> <li>Pyruvate is converted in glucose by gluconeogenesis</li></ol>

Question 8

<p>Why is glutamine and alanine used for transport and not glutamate?</p>

Answer 8

<p>They have no charge so can pass through membranes much easier</p>

Question 9

<p>Where is excess glutamate metabolised?</p>

Answer 9

<p>Mitochondria of hypatocytes (liver cells)</p>

Question 10

<p>What happens to the ammonia once glutamate is broken down in the liver?</p>

Answer 10

<p>Recaptured by the synthesis of carbamoyl phosphate which is the first nitrogen acquiring reaction</p>

Question 11

<p>What is the first nitrogen acquiring reaction?</p>

Answer 11

<p>Capture of amino gorup from breakdown of glutamate by carbamoyl phosphate</p>

Question 12

<p>What is the second nitrogen acquiring reaciton?</p>

Answer 12

<p>Entry of asparate into the urea cycle</p>

Question 13

What does a summary of the entry of intermediates from glycolysis, beta oxidation and the breakdown of amino acids into the citric acid cycle look like?

Answer 13

Question 14

<p>What are the 6 compounds that the 20 amino acids can enter the citric acid cycle through?</p>

Answer 14

<p>Acetyl coenzyme A</p>

<p>Pyruvate</p>

<p>a-ketoglutamate</p>

<p>Succinyl coenzyme A</p>

<p>Fumarate</p>

<p>Oxaloacetate</p>

Question 15

<p>What is the main role of carbohydrates and fats?</p>

Answer 15

<p>To provide energy</p>

Question 16

<p>What is the main role of amino acids?</p>

Answer 16

<p>Used as a building block for protein</p>

Question 17

<p>How many of the 20 amino acids are essential?</p>

Answer 17

<p>8</p>

Question 18

<p>What are the 2 fates of amino acid carbon skeletons?</p>

Answer 18

<p>If they are glucogenic they feed into gluconeogensesis</p>

<p>If they are ketogenic they feed into acetoacetyl coA (which becomes) or acetyl conenzyme A</p>

Question 19

<p>Can amino acids be both glucogenic and ketogenic?</p>

Answer 19

<p>Yes</p>

Question 20

What does the pathway of glucogenic amino acids look like?

Answer 20

Glucogenic amino acids form pyruvate, α-ketoglutarate, succinyl CoA, fumarate, or oxaloacetate.

glucogenic amino acid (or glucoplastic amino acid) is an amino acid that can be converted into glucose through gluconeogenesis

Question 21

What does the pathway of ketogenic amino acids look like?

Answer 21

Ketogenic amino acids form acetoacetate or acetyl CoA