excretion

Question 1

excretion

Answer 1

removal of toxic waste substances which have been made by cells

Question 2

respiration

Answer 2

waste product = co2

removed via lungs and leaves in plants

Question 3

carbon dioxide

Answer 3

made in respiring cells
made by respiration
removed via blood plasma

Question 4

urea

Answer 4

made in liver cells
made by breakdown of amino acids (deamination)
removed in kidneys and skins

Question 5

urea formation

Answer 5

deamination
amino acids filtered into liver along with rest of blood via hepatic artery
excess amino acids cannot be stored and need to be broken down so can be excreted
broken down into carbohydrates and ammonia
ammonia is toxic and must be broken down into slightly less toxic chemical called urea
amino acids that are needed and urea are released back into blood stream via hepatic vein

Question 6

kidney

Answer 6

kidney filters blood and removed excess materials and passes them to bladder to be excreted

cortex
medulla
pelvis

Question 7

ultrafiltration

Answer 7

artery size at exit of glomerulus is smaller than entrance
build up of pressure
pressure forces small molecules (urea, glucose, amino acids, salts) across into bowmans capsule and form glomerular filtrate
larger molecules (proteins, red blood cells) too big to fit across
stay in blood

Question 8

selective reabsorption

Answer 8

filtrate travels to PCT (proximal convoluted tubule)

specialised cells within PCT walls pump useful materials back into blood stream through active transport

all glucose reabsorbed
80% water reabsorbed

Question 9

water reabsorption

Answer 9

loop of henle and collecting duct involved

ADH