Waste

Question 1

How is waste created?

Answer 1

-metabolic reactions create waste product which can be toxic
-eg. CO2, nitrogenous waste

Question 2

What is excretion?

Answer 2

-removal of waste products

Question 3

What is CO2 waste from?

Answer 3

-respiration from the lungs

Question 4

What is nitrogenous waste from?

Answer 4

-urea
-created from excess amino acids in diet

Question 5

How is urea formed by the liver?

Answer 5

-excess amino acids cannot be stored so are broken down
-deaminated by liver to produced ammonia
-ammonia is soluble and toxic so converted to urea
-then excreted from kidneys

Question 6

What do fish produce?

Answer 6

-ammonia

Question 7

What do birds produce?

Answer 7

-uric acid paste
-to conserve waster

Question 8

What is the ornithine cycle?

Answer 8

-how urea is produced from ammonia
-can be transported to the kidneys for excretion

Question 9

What are the stage of the ornithine cycle?

Answer 9

-converts toxic NH3 into urea
-in one cycle, 2 molecules of NH3 are added to CO2 to produce urea
-urea still soluble but less toxic
-then secreted into blood by hepatocytes for excretion

Question 10

What is deamination?

Answer 10

-when the amine group is removed from amino acids
-converting it into ammonia

Question 11

Is urea toxic?

Answer 11

-yes but only in high concentrations