B6 - Understanding microbes

Question 1

What is bacteria?

Answer 1

Bacteria are tiny single-cell microorganisms, usually a few micrometers in length that normally exist together in millions.

Question 2

What do scientists use to classify bacteria?

Answer 2

Scientists use the shape of bacteria to classify it.

Question 3

Which is larger, a plant cell or a bacterial cell?

Answer 3

A plant cell is about 10x larger than a bacterial cell.

Question 4

How do bacteria reproduce?

Answer 4

Bacteria reproduce asexually, by splitting in two.

Question 5

What does a flagellum do?

Answer 5

Flagellum helps bacteria to move.

Question 6

What does the cell wall do?

Answer 6

The cell wall helps bacterium keep its shape and prevents it bursting.

Question 7

What does bacterial DNA do?

Answer 7

Bacterial DNA controls the bacterium’s activities and its replication.

Question 8

What are the four shapes of bacteria?

Answer 8

• curved rod
• spherical
• spiral
• rod

Question 9

What are aseptic techniques?

Answer 9

Aseptic techniques are precautions taken to ensure there is no contamination when growing bacteria.

Question 10

What is binary fission?

Answer 10

Binary fission is the process of splitting in two.

Question 11

Give examples of aseptic techniques.

Answer 11

• never leave lids off the container
• disinfect working area
• sterilise equipment before and after use
• wear disposable gloves

Question 12

How do bacteria feed?

Answer 12

They consume organic nutrients such as carbohydrates and proteins.

Question 13

If bacteria can use photosynthesis to create their own food, which energy source do they depend on?

Answer 13

They would depend on light energy.

Question 14

Why is it difficult to stop bacteria?

Answer 14

They reproduce really quickly.

Question 15

Give some examples of diseases that bacteria can cause.

Answer 15

• food poisoning
• cholera
• whooping cough
• typhoid
• tetanus

Question 16

Why is it dangerous to eat food after its sell-by date?

Answer 16

Bacteria may have reproduced on it and could cause infections/diseases.

Question 17

Is yeast a bacteria, fungus or virus?

Answer 17

Yeast is a single celled fungus.

Question 18

Name the process by which yeast cells reproduce.

Answer 18

Yeast cells reproduce by budding.

Question 19

Write down one structure found in yeast and plant cells but not animal cells.

Answer 19

Plant cells and yeast cells have cell walls.

Question 20

Are viruses classed as living?

Answer 20

Scientists do not class viruses as living.

Question 21

What is the difference between viruses and bacterium?

Answer 21

Viruses require a living host in order to survive and are not classed as living where as bacteria can survive without a living host and are living.

Question 22

What conditions must be provided in order to maintain optimum growth of yeast?

Answer 22

• food
• optimum temperature
• optimum pH
• removal of waste products

Question 23

Describe the structure of a virus.

Answer 23

Viruses are made up of strands of genetic material surrounded by a protein coat.

Question 24

A plant virus will not harm a human. Suggest why.

Answer 24

Viruses attack different types of cell therefore they will not attack human cells.

Question 25

Describe how viruses reproduce.

Answer 25

1) the virus attaches to a specific cell, called the host cell
2) the genetic material from the virus is injected into the host cell where it enters the nucleus to make mRNA
3) new viruses are made using material inside the host cell and the genetic material from the virus
4) the cell splits open, allowing the virus to leave but killing the host cell

Question 26

Why do yeast cells start to die at high temperatures?

Answer 26

The enzymes become denatured.