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Question 32 — The Biochemistry of Movement (25 marks) (a) (i) Identify the role of glycogen in human muscle and liver - HSC - SSCE Chemistry - Question 32 - 2003 - Paper 1
Question 32
Question 32 — The Biochemistry of Movement (25 marks) (a) (i) Identify the role of glycogen in human muscle and liver. (ii) Describe the process of bond formation ... show full transcript
Worked Solution & Example Answer:Question 32 — The Biochemistry of Movement (25 marks) (a) (i) Identify the role of glycogen in human muscle and liver - HSC - SSCE Chemistry - Question 32 - 2003 - Paper 1
Step 1
Identify the role of glycogen in human muscle and liver.
Answer
Glycogen serves as a crucial energy reserve in human muscle and liver tissues. In muscles, glycogen is rapidly converted to glucose during periods of intense physical activity, providing energy for muscle contractions. In the liver, glycogen functions in regulating blood sugar levels by converting glycogen back into glucose and releasing it into the bloodstream as needed.
Step 2
Describe the process of bond formation when glucose molecules react to form glycogen.
Answer
The formation of glycogen from glucose involves a series of biochemical reactions called glycogenesis. Initially, two glucose molecules undergo a condensation reaction, which leads to the formation of a glycosidic bond between them, releasing water in the process. This reaction is catalyzed by enzymes such as glycogen synthase. As more glucose units join, branched chains of glucose molecules are created, forming the complex structure of glycogen, which is made up of both α(1→4) and α(1→6) glycosidic bonds.
Step 3
Describe the results of your investigation.
Answer
The investigation revealed distinct structural differences between fatty acids and glycerol. Fatty acids were observed to have long hydrocarbon chains, contributing to their hydrophobic nature, while glycerol displayed a smaller, more polar structure with three hydroxyl groups. This polarity made glycerol more soluble in water compared to the fatty acids. Furthermore, during the experiment, it was noted that fatty acids tended to aggregate in aqueous solutions, highlighting their hydrophobic properties.
Step 4
Outline why glycerol is more soluble in water than are fatty acids that are commonly found in the body.
Answer
Glycerol is more soluble in water due to its hydrophilic nature, attributed to the presence of three hydroxyl (-OH) groups. These polar functional groups can form hydrogen bonds with water molecules, enhancing glycerol's solubility. In contrast, fatty acids primarily consist of long hydrocarbon chains that are hydrophobic, making them less compatible with water and leading to lower solubility.
Step 5
Analyse how an understanding of the composition and structure of proteins led to the current theory of muscle contraction.
Answer
An understanding of protein composition and structure has been fundamental in elucidating the mechanism of muscle contraction, particularly through the sliding filament theory. This theory suggests that muscle contractions occur when myosin and actin (the major contractile proteins) interact. The structural arrangement of these proteins allows myosin heads to bind to actin filaments during contraction, which shortens the muscle fiber. Additionally, the role of ATP in energizing these interactions emphasizes the importance of both protein structure and the biochemical processes in muscle function and contraction.