Excretion is an important process in homeostasis in living organisms - Leaving Cert Biology - Question 15 - 2022
Question 15
Excretion is an important process in homeostasis in living organisms.
(i) Explain the underlined terms.
(ii) Name one excretory organ in plants.
(b) The diagrams ... show full transcript
Worked Solution & Example Answer:Excretion is an important process in homeostasis in living organisms - Leaving Cert Biology - Question 15 - 2022
Step 1
Explain the underlined terms.
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Answer
Excretion is the process of removing metabolic waste products from a cell or an organism, which helps maintain internal balance by eliminating harmful substances. Homeostasis refers to the mechanisms that organisms use to maintain a stable internal environment, ensuring that conditions remain constant despite external changes.
Step 2
Name one excretory organ in plants.
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Answer
One excretory organ in plants is the leaf, particularly through structures known as stomata and lenticels.
Step 3
What is the function of this layer of fat?
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Answer
The layer of fat surrounding the kidneys serves to provide cushioning and protection against physical impacts, as well as to insulate the kidneys, helping to maintain their temperature.
Step 4
Identify the regions of the kidney labelled A, B and C.
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A = Cortex
B = Medulla (pyramid)
C = Pelvis
Step 5
Identify the region in the kidney, by name or label, where the process of filtration occurs.
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Filtration occurs in the Glomerulus.
Step 6
Explain the importance of blood entering the glomerulus under pressure.
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Answer
Blood enters the glomerulus under high pressure which facilitates the filtration process. The increased pressure forces water, salts, and small molecules through the capillary walls while retaining larger molecules such as proteins and blood cells.
Step 7
State two reasons why there are many capillaries surrounding the PCT, loop of Henle and DCT.
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The presence of many capillaries increases the surface area for absorption and secretion, allowing efficient exchange of substances.
Capillaries maintain a close proximity to the nephrons, enabling quick transport of reabsorbed substances back into the bloodstream.
Step 8
Describe how ADH (anti-diuretic hormone) affects the volume of urine.
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ADH acts on the DCT and collecting ducts to promote the reabsorption of water. When ADH levels are high, more water is reabsorbed, resulting in a lower volume of concentrated urine. Conversely, when ADH levels are low, less water is reabsorbed, leading to a higher volume of dilute urine.
Step 9
Outline the path taken by the urine labelled C on the diagram of the kidney.
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The urine travels from the collecting duct, through the renal pelvis, and then into the ureter, which directs it towards the bladder.
Step 10
Name the structure through which urine travels to the bladder.
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The structure through which urine travels to the bladder is the ureter.
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