13. (a) (i) Explain what is meant by the term homeostasis - Leaving Cert Biology - Question 13 - 2020
Question 13
13.
(a) (i) Explain what is meant by the term homeostasis.
(ii) Give one reason why homeostasis is important in organisms.
(iii) Explain what is meant by the ter... show full transcript
Worked Solution & Example Answer:13. (a) (i) Explain what is meant by the term homeostasis - Leaving Cert Biology - Question 13 - 2020
Step 1
Explain what is meant by the term homeostasis.
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Answer
Homeostasis refers to the ability of an organism to maintain a stable internal environment despite external changes. It involves various physiological processes that regulate factors such as temperature, pH, and the concentration of ions and nutrients.
Step 2
Give one reason why homeostasis is important in organisms.
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Homeostasis is vital for sustaining life because it ensures that the conditions within the body remain optimal for enzyme activity and metabolic processes.
Step 3
Explain what is meant by the term excretion.
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Answer
Excretion is the biological process of removing waste products from the body, which are generated during metabolism. This includes substances like urea, salts, and excess water that need to be eliminated to maintain homeostasis.
Step 4
State the precise location in the body where urea is made.
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Urea is primarily produced in the liver.
Step 5
Name the blood biomolecule from which urea is derived.
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Answer
Urea is derived from proteins, specifically from amino acids.
Step 6
In which part of the kidney is the Bowman's capsule located?
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The Bowman's capsule is located in the Cortex of the kidney.
Step 7
In which part of the kidney is the Loop of Henle located?
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The Loop of Henle is located in the Medulla of the kidney.
Step 8
Name the part labelled 'A'.
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Answer
The part labelled 'A' is the Ureter.
Step 9
Draw a large diagram of a nephron and its associated blood supply from a human kidney. Label the following parts:
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Answer
A well-drawn diagram would typically include the following labels: Bowman’s capsule, Loop of Henle, Proximal convoluted tubule, Collecting duct, Distal convoluted tubule, Glomerulus, and the associated blood vessels.
Step 10
What is the main difference between plasma and filtrate?
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The main difference is that blood plasma contains proteins (7 g/100 cm³), whereas glomerular filtrate contains none, indicating that proteins do not pass through the glomerular wall.
Step 11
Explain the results between blood plasma and glomerular filtrate.
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In terms of glucose, the molecules are small enough to pass through the glomerulus, so glucose is present in both blood plasma and glomerular filtrate, but at higher concentrations in blood plasma.
Step 12
Explain the results between glomerular filtrate and urine.
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Glucose is largely reabsorbed back into the blood from the renal tubules, so the concentration of glucose in urine is significantly lower, often negligible.
Step 13
What is the effect on the volume of urine produced by a high salt intake?
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High salt intake generally leads to decreased urine volume due to the activation of antidiuretic hormone (ADH), which makes the collecting ducts more permeable to water, promoting increased reabsorption.
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