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Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
DNA (Deoxyribonucleic Acid) molecules in the chromosomes of the nucleus are the information source for making proteins. If the information is changed, different proteins will be made, leading to altered body designs.
The basic event in reproduction is the creation of a DNA copy. Cells use biochemical reactions to create two copies of the DNA in a reproducing cell.
DNA copying is always accompanied by the creation of an additional cellular apparatus. The DNA copies then separate, each with its own cellular environment, effectively dividing one cell into two.
No biochemical reaction is absolutely reliable. Therefore, the process of copying the DNA will have some variations each time. As a result, the DNA copies generated will be similar, but may not be identical to the original.
Variation during reproduction is the basis for evolution. While individual organisms might not survive extreme environmental changes (like temperature shifts or changes), variations ensure that at least some members of a species survive, maintaining the continuity of the species.
📐Formulae
💡Examples
Problem 1:
Explain the significance of DNA copying in reproduction.
Solution:
DNA copying is essential because it carries the genetic information from the parents to the offspring. It ensures that the offspring has a similar body design and functional characteristics as the parents. Without DNA copying, the blueprints for cellular structures and proteins would not be transmitted to the next generation.
Explanation:
DNA serves as the master blueprint. If a cell divided without copying its DNA, one daughter cell would lack the instructions necessary to function and produce proteins.
Problem 2:
If a population of bacteria living in temperate waters undergoes a sudden increase in temperature due to global warming, what is the role of variation here?
Solution:
Most of the bacteria would die because they are suited for temperate conditions. However, a few individuals might possess a variation (a 'mutation' in their DNA) that makes them resistant to heat. These variants will survive and multiply.
Explanation:
Variation provides a buffer against environmental changes. If all bacteria were identical copies, the entire species might go extinct. The survival of heat-resistant variants allows the species to persist in the new environment.