Giải bài tập 25 Sinh trưởng và sinh sản ở vi sinh vật

How to solve Exercise 25: Growth and reproduction in microorganisms in the book Biology Grade 10 - Creative Horizon

In this exercise, we will discuss the concepts of growth and reproduction in microorganisms and provide detailed explanations for each question.

I. Concept of growth in microorganisms

Question 1: Based on Figure 25.2, observe the number of E. coli bacteria cells after each division. Then, explain the concept of growth in organisms.

Answer: The number of E. coli bacteria cells doubles after each division compared to the previous generation. The concept of growth in organisms is the increase in the number of individuals in the population of living organisms.

Question 2: Why is it said that growth in microorganisms is the growth of a population?

Answer: Microorganisms are very small in size, making it difficult to recognize an increase in size or mass. Therefore, we need to consider the population as a whole to observe growth.

II. Growth of microbial populations

Question 3: Read the information provided and observe Figure 25.3. Describe the characteristics of the growth phases of a bacterial population in discontinuous culture.

Answer:

• Lag phase: Bacteria engage in metabolic activities during this phase.
• Logarithmic phase: Bacteria show strong growth and maximum division rate due to abundant nutrients.
• Stationary phase: Alongside division, bacteria die due to decreasing nutrients. The number of new bacteria equals the number of dead bacteria.
• Decline phase: The number of dead bacteria increases due to nutrient depletion and accumulation of toxic substances.

By following these detailed explanations, you can better understand the growth and reproduction processes in microorganisms. We hope this helps students grasp the knowledge presented in the lesson effectively.