Biology mock test preview

Question 1

Explain binary fission and how it works

Answer 1

1. Bacterial Doubling in every generation
2. Lead to quick population growth
3. The chromosome/DNA replicates/copies
4. The cytoplasm pinches in half
5. The bacteria divides into two

Question 2

What three conditions does bacteria exponential growth need

Answer 2

warmth, enough food, moisture, space

Question 3

Give TWO diseases that is caused by VIRUS infection

Answer 3

COVID 19, chickenpox, HIV, flu, influenza

Question 4

Why do we not want to culture bacteria at 37°C

Answer 4

25 degrees ensures the plates are warm enough to allow growth to occur / warmth is a condition needed for growth.
However, this is less than body temperature 37C to ensure that human pathogens do not grow.

Question 5

Why do the agar plates for culture need to be incubated upside down?

Answer 5

Plates are incubated upside down because condensation will form as they are being incubated. The water droplets carrying microbes could leak out which may be dangerous.

Question 7

Compare and contrast antiseptics and disinfectants. Give one example of each.

Answer 7

• Both stop bacteria reproducing and commonly used in daily life
• But disinfectant (e.g., Bleach) is VERY harmful to skin (living) cells so not used on human hands but
  Antiseptics (e.g., Betadine) are NOT harmful to skin cells so can be used for hand wounds/cuts.

Question 8

Sacchromycetes species (fungi) is commonly used in daily life, e.g., making bread, beers or fermented drinks like wine. Explain why this fungi is beneficial.

Answer 8

• Yeast convert sugar into ethanol (alcohol) and carbon dioxide by fermentation without oxygen.
• The carbon dioxide released during the fermentation process help bread dough to rise.
• The alcoholic drinks is produced because alcohol is produced

Question 9

Salmonellosis is a food poisoning disease that is caused by bacteria Salmonella species. Most salmonella can be found in chicken and poultry. Explain how salmonella may cause food-related disease and how to prevent such diseases in detail.

Answer 9

• In undercooked chicken salmonella bacteria is not killed off, it then can be allowed to multiply and spread
• if the chicken is left in warm conditions for a period of time, it can also multiply and spread
• Ensure chicken is cooked to the required temperature/thoroughly to kill all bacteria
• not stored in warm conditions for an excessive period of time to prevent bacteria over growth and spread

Question 10

List TWO reasons why antibiotic resistance occurs and explain how we can prevent it in future.

Answer 10

• Unnecessary use antibiotics for viral infections - Only take antibiotics when there is an obvious bacterial infection.
• not finish the full course - Finish all courses of antibiotics to ensure that all the bacteria are killed thoroughly!