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Give a detailed biological explanation for each of the following - Leaving Cert Biology - Question 15(b) - 2018
Question 15(b)
Give a detailed biological explanation for each of the following. (i) Bile contains bile salts e.g. sodium hydrogencarbonate (NaHCO3). (ii) Active immunity results... show full transcript
Worked Solution & Example Answer:Give a detailed biological explanation for each of the following - Leaving Cert Biology - Question 15(b) - 2018
Step 1
(i) Bile contains bile salts.
Answer
Bile contains bile salts that play several essential roles in digestion. Firstly, these salts emulsify fats, breaking them down into smaller droplets, which increases the surface area for enzymes to act upon. This process is vital for the digestion and absorption of lipids. Moreover, bile salts help neutralize stomach acids as they enter the small intestine, ensuring that the pH is suitable for enzyme activity, particularly in the duodenum where digestive enzymes are more effective in a slightly alkaline environment.
Step 2
(ii) Active immunity results in long-lasting immunity.
Answer
Active immunity occurs when the body produces its own antibodies in response to an infection or vaccination. This process involves lymphocytes, particularly B cells, which differentiate into plasma cells that produce specific antibodies. Additionally, memory cells are formed during this response, which allows the body to recognize and respond more rapidly to future infections by the same pathogen, resulting in long-lasting immunity.
Step 3
(iii) Humans sweat during exercise.
Answer
During exercise, the body's temperature increases due to generated heat. To prevent overheating, the body initiates sweating. Sweat glands secrete water onto the skin surface, which then evaporates, taking heat away from the body and cooling it down. This evaporative cooling is vital for maintaining a stable internal temperature and preventing heat-related illnesses.
Step 4
(iv) Antibiotics should not be prescribed for the flu.
Answer
Antibiotics are designed to kill or inhibit bacterial growth and do not work against viruses, such as those that cause influenza. Prescribing antibiotics for viral infections like the flu is ineffective and may contribute to antibiotic resistance in bacteria. Therefore, they should not be used to treat viral illnesses.
Step 5
(v) High sugar or high salt concentrations are used in food preservation.
Answer
High concentrations of sugar or salt create an environment where bacteria and fungi cannot thrive. Sugar helps in food preservation by drawing water out of microbial cells via osmosis, causing them to dehydrate and die. Similarly, salt leads to osmotic pressure that can kill or inhibit the growth of bacteria. This process helps in prolonging the shelf life of food and preventing spoilage.