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Write notes on each of the following topics - Leaving Cert Biology - Question 14 - 2013
Question 14
Write notes on each of the following topics. You are required to make a minimum of three points concerning each topic. Marks will not be given for word diagrams alon... show full transcript
Worked Solution & Example Answer:Write notes on each of the following topics - Leaving Cert Biology - Question 14 - 2013
Step 1
(i) Metabolism.
Answer
Metabolism refers to the total sum of all biochemical reactions occurring in a cell or organism. This can be broadly categorized into two types:
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Catabolism: This is the process of breaking down larger molecules into smaller ones, releasing energy in the form of ATP. An example is the breakdown of glucose during cellular respiration.
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Anabolism: This is the process of synthesizing larger molecules from smaller subunits, which requires an input of energy. An example is the synthesis of proteins from amino acids.
In summary, metabolism encompasses all the chemical transformations in the body, crucial for energy balance and cellular function.
Step 2
(ii) Krebs Cycle.
Answer
The Krebs Cycle, also known as the Citric Acid Cycle, occurs in the second stage of cellular respiration primarily within the mitochondria. Key points include:
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Aerobic Pathway: The cycle operates in the presence of oxygen (aerobic conditions), utilizing Acetyl Coenzyme A derived from carbohydrates, fats, and proteins.
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Energy Production: During the cycle, ATP is generated along with reduced cofactors such as NADH and FADH2, which are crucial for the electron transport chain.
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Carbon Dioxide Release: The Krebs Cycle results in the production of carbon dioxide as a waste product, which is expelled from the cell and ultimately exhaled by the organism.
Step 3
(iii) ADP.
Answer
Adenosine diphosphate (ADP) is a low-energy molecule that consists of adenine, a ribose sugar, and two phosphate groups. Important points include:
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Role in Energy Transfer: ADP can be converted to ATP (adenosine triphosphate) by the addition of a phosphate group, thus storing energy that can be used in cellular activities.
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Energy Production: The conversion from ADP to ATP typically happens through cellular respiration processes like glycolysis and the Krebs Cycle.
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Biological Importance: ADP serves as a crucial precursor in energy metabolism, enabling the cell to perform work and maintain homeostasis.