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Write an essay on one of the topics below - AQA - A-Level Biology - Question 7 - 2020 - Paper 3
Question 7
Write an essay on one of the topics below. Either The functions of enzymes and their importance in organisms. or The causes and importance of variation and diver... show full transcript
Worked Solution & Example Answer:Write an essay on one of the topics below - AQA - A-Level Biology - Question 7 - 2020 - Paper 3
Step 1
The functions of enzymes and their importance in organisms.
Answer
Introduction
Enzymes are biological catalysts that speed up chemical reactions in living organisms. They play crucial roles in various metabolic processes, ensuring that essential reactions occur at rates sufficient to sustain life.
Functions of Enzymes
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Catalytic Activity: Enzymes lower the activation energy required for reactions, enabling them to proceed more quickly. For instance, enzymes like amylase break down starch into sugars.
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Specificity: Enzymes are highly specific, meaning each enzyme typically acts on a particular substrate. This specificity is often due to the enzyme’s active site configuration, which fits the substrate much like a key fits into a lock.
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Regulation: Enzymes are regulated through various means, including allosteric regulation and feedback inhibition, allowing cells to control metabolic pathways according to their needs.
Importance of Enzymes
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Metabolism: Enzymes are essential in metabolic pathways like cellular respiration and photosynthesis, facilitating the conversion of substrates into energy and organic compounds.
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Homeostasis: By regulating biochemical reactions, enzymes help maintain homeostasis within organisms, ensuring that cells function optimally.
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Medical Applications: Enzymes are employed in various medical and biotechnological applications. For example, enzymes are used in diagnostic tests, drug formulation, and as therapeutic agents.
Conclusion
In summary, enzymes are vital for life, enabling numerous biochemical reactions essential for growth, reproduction, and overall health. Their role as catalysts, their specificity, and their regulatory mechanisms highlight their importance in biology.
Step 2
The causes and importance of variation and diversity in organisms.
Answer
Introduction
Variation and diversity among organisms are crucial for the adaptability and survival of species in changing environments. Understanding the causes of these variations offers insights into evolutionary processes.
Causes of Variation
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Genetic Mutation: Random mutations in DNA sequences can introduce new traits within a population, which may be beneficial, harmful, or neutral.
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Genetic Recombination: During sexual reproduction, genetic material is shuffled, resulting in offspring that have a combination of traits from both parents. This process increases genetic diversity within populations.
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Environmental Factors: Abiotic factors (like climate) and biotic factors (like food availability) can influence the expression of genetic traits, contributing to phenotypic variation.
Importance of Variation and Diversity
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Natural Selection: Variation is the raw material for natural selection, allowing certain traits to become more prevalent in a population over generations, promoting adaptation.
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Ecosystem Resilience: Biodiversity ensures ecosystem stability. Diverse populations can better withstand environmental stressors and changes.
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Human Benefits: Genetic diversity among species, particularly in agriculture, promotes food security. It enables the development of crops that can thrive under different conditions or resist disease.
Conclusion
In conclusion, the causes of variation are rooted in genetic and environmental factors, while the importance of diversity lies in its role in evolution, ecosystem health, and practical benefits to humanity. Maintaining biodiversity is essential for the sustainability of life on Earth.