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Attempt either A or B - Scottish Highers Biology - Question 16 - 2022
Question 16
Attempt either A or B. Write your answer in the space below and on pages 30 and 31. A Write notes on metabolism under the following headings: (i) features of metab... show full transcript
Worked Solution & Example Answer:Attempt either A or B - Scottish Highers Biology - Question 16 - 2022
Step 1
Write notes on metabolism under the following headings: (i) features of metabolic pathways and types of reactions:
Answer
Metabolism consists of integrated pathways of reactions that can be classified as either a series of reactions or controlled/catalyzed by enzymes. There are key features of metabolic pathways:
- Reversible and Irreversible Steps: Metabolic pathways can include both reversible and irreversible steps, allowing for flexibility in biochemical processes.
- Alternative Routes: Some metabolic pathways can take alternative routes depending on the cellular environment and requirements.
- Anabolism and Catabolism:
- Anabolism: This is the process of building up complex molecules from simpler ones and requires energy (ATP). It includes synthesis processes necessary for growth and repair.
- Catabolism: This involves the breakdown of complex molecules into simpler ones, releasing energy in the form of ATP, which can be harnessed for cellular functions.
These pathways are crucial for maintaining cellular functions and energy balance.
Step 2
Write notes on metabolism under the following headings: (ii) roles of proteins embedded in membranes of cells.
Answer
Proteins embedded in cell membranes serve several essential functions:
- Transport Proteins: These proteins actively transport ions and other particles across the membrane, which is crucial for maintaining cellular homeostasis.
- Enzymatic Functions: Many membrane proteins act as enzymes to facilitate biochemical reactions directly at the membrane.
- Structural Roles: Proteins can also form pores, enabling selective permeability of the membrane, allowing certain substances to pass in and out of the cell effectively.
Step 3
Write notes on: (i) regulators
Answer
Regulators maintain a stable internal environment despite varying external conditions by performing several key functions:
- Maintaining Internal Homeostasis: Regulators keep their internal environment or temperature stable, regardless of the external environment.
- Metabolic Control: They utilize metabolic processes to control their internal conditions, adapting to changes in the external environment.
- Ecological Niches: Regulators often occupy a variety of ecological niches and have the flexibility to sustain different metabolic rates to thrive in diverse environments.
Step 4
Write notes on: (ii) thermoregulation by negative feedback in response to an increase in body temperature.
Answer
Thermoregulation through negative feedback mechanisms is crucial for maintaining body temperature. The process involves several steps:
- Detection of Temperature Change: A temperature increase is detected by the hypothalamus in the brain, which acts as the body's thermostat.
- Nervous Signals: The hypothalamus sends electrical signals via nerves to various effectors, such as sweat glands and blood vessels.
- Vasodilation: Blood vessels widen (vasodilation) to increase blood flow to the skin, facilitating heat loss.
- Sweating: Sweat production increases, with evaporation of sweat from the skin surface leading to cooling of the body.
- Metabolic Rate Adjustments: The metabolic rate is decreased, which helps in reducing the body's generation of heat during higher temperatures.