10.1 WHAT IS EXCRETION

Question 1

What is the definition of excretion?

Answer 1

The removal of waste products made in cells of the body itself such as carbon dioxide and urea

Question 2

What are the importances of excretion?

Answer 2

1. Waste products from cells are toxic
2. Build up of waste products will damage cells

Question 3

Where is carbon dioxide produced?

Answer 3

Made in cells during cell respiration

Question 4

Where is urea produced?

Answer 4

Made in liver

Question 5

Where is water produced?

Answer 5

Made in cell respiration

Question 6

Where are mineral ions produced?

Answer 6

Released after digestion of food

Question 7

What are the excretory organs for carbon dioxide?

Answer 7

Lungs

Question 8

What are the excretory organs for urea?

Answer 8

Kidneys, skin

Question 9

What are the excretory organs for water?

Answer 9

Kidneys, skin

Question 10

What are the excretory organs for mineral ions?

Answer 10

Kidneys, skin

Question 11

What is carbon dioxide excreted as?

Answer 11

Gas in expired air

Question 12

What is urea excreted as?

Answer 12

Urine, sweat

Question 13

What is water excreted as?

Answer 13

Urine, sweat

Question 14

What are mineral ions excreted as?

Answer 14

Urine, sweat

Question 15

What is the process of excretion for urea in the kidney?

Answer 15

1. Urea excreted is produced in the liver from the breakdown of excess proteins
2. Urea is excreted by the kidney
3. Urea is removed from the body in the form of urine

Question 16

What are the effects of urea?

Answer 16

1. Urea is very toxic
2. High concentration of urea in body will damage organs and the brain and die

Question 17

What is the structure of the kidney?

Answer 17

1. Reddish brown organ
2. 10cm long
3. Surrounded by a thick layer of fat

Question 18

Why is urine yellow?

Answer 18

1. Urochrome makes urine yellow
2. It is a waste product produced from the breakdown of haemoglobin

Question 19

What are the factors that affect urine concentration?

Answer 19

1. Water intake
   - More water intake, more diluted urine
2. Temperature
   - Higher temperature, more water lost in sweat, more concentrated urine
3. Exercise
   - More exercise, more water lost in sweat, more concentrated urine

Question 20

What are the differences between excretion and egestion?

Answer 20

Excretion is the removal of waste products made in the cells of the body itself such as carbon dioxide and urea.
Egestion is the removal of undigested material, which is taken into the body as food but cannot be broken down. It is passed out of the body as feces.