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Figure 17 shows colonies of bacteria growing on an agar plate - Edexcel - GCSE Biology - Question 9 - 2023 - Paper 1
Question 9
Figure 17 shows colonies of bacteria growing on an agar plate. Each colony starts as one bacterium. Every time bacteria reproduce, the number of bacteria in each c... show full transcript
Worked Solution & Example Answer:Figure 17 shows colonies of bacteria growing on an agar plate - Edexcel - GCSE Biology - Question 9 - 2023 - Paper 1
Step 1
Calculate the number of bacteria in a colony after five hours
Answer
To calculate the number of bacteria after five hours, we first determine how many 30-minute intervals are in five hours:
- Five hours is equivalent to 300 minutes.
- The number of 30-minute intervals is: rac{300 ext{ min}}{30 ext{ min}} = 10
- Since the number of bacteria doubles every interval, we can use the formula:
where:
- = initial number of bacteria (1)
- = number of intervals (10)
- Therefore, the final number of bacteria is: . Thus, there are 1024 bacteria in the colony after five hours.
Step 2
Explain why antibiotics can be used to treat bacterial infections
Answer
Antibiotics are effective in treating bacterial infections because they specifically target the biological processes of bacteria. They can inhibit the growth of bacteria by disrupting their cell wall synthesis, protein production, or nucleic acid metabolism. This selective targeting means that antibiotics can kill or inhibit bacteria without damaging human cells, making them a vital tool in treating infections.
Step 3
Calculate the magnification of this drawing
Answer
To calculate the magnification, we can use the formula: ext{Magnification} = rac{ ext{Size of drawing}}{ ext{Actual size}} Substituting the given values: ext{Magnification} = rac{80 ext{ mm}}{0.005 ext{ mm}} = 16000. Therefore, the magnification of the drawing is 16000.
Step 4
Describe the similarities and differences of a bacterial cell and a plant cell
Answer
Bacterial cells and plant cells share some similarities as both are types of cells essential for life. Both have cell membranes, contain genetic material (DNA), and perform essential metabolic functions.
However, they also have distinct differences. Bacterial cells are prokaryotic, meaning they lack a nucleus and membrane-bound organelles, whereas plant cells are eukaryotic and have a defined nucleus and organelles (like chloroplasts for photosynthesis). Additionally, bacterial cells typically have a simpler structure, while plant cells have a rigid cell wall made of cellulose, which supports their shape and provides protection.