Chapter 3 - Micro-Organisms

Question 1

What makes a Bacterial Cell different from an Animal or Plant Cell?

Answer 1

It has no organelles or nucleus.

Question 2

What is the function of Cytoplasm in a Bacterial Cell?

Answer 2

Contains enzymes and food molecules but no organelles.

Question 3

What does Glycogen do in a Bacterial Cell?

Answer 3

Stores food

Question 4

What is the function of Plasmids in a Bacterial Cell?

Answer 4

Carries a few genes

Question 5

What is the function of a Flagella in a Bacterial Cell?

Answer 5

Helps make the bacterial cell move.

Question 6

What is an Enzyme?

Answer 6

Any of various proteins, originating from living cells and capable of producing chemical changes in organic substances.

Question 7

How are Bacterias classified?

Answer 7

According to their shape and colour of colony.

Question 8

What is inside a Bacterial Cell?

Answer 8

It contains A CELL WALL, CELL MEMBRANE, SLIME COAT, PLASMIDS, CYTOPLASM, DNA, GLYCOGEN AND A FLAGELLA

Question 9

What is the process that Bacteria use to reproduce?

Answer 9

Binary Fission

Question 10

What is Binary Fission?

Answer 10

It is when the DNA in a bacterial cell multiplies, then the cell is divided in two (binary fission), the process is then repeated.

Question 11

When is a spore formed?

Answer 11

Spores are formed under unfavourable conditions. When a bacteria cell is in a bad condition, a spore is formed as a protective layer. The bacterial cell inside it is dormant. When it is good for the bacterial cell to come out the spore bursts open.

Question 12

Explain the resistance of bacteria to antibiotics.

Answer 12

Over time bacteria can become resistant to certain antibiotics. In large population of bacteria, there may be some that are not affected by the antibiotic. These survive and reproduce, creating more bacteria that are not affected by the antibiotic.

Question 13

Why are bacteria so successful?

Answer 13

They can survive in bad conditions such as drought, poisons and heat. They have a very fast reproduction rate.

Question 14

How do bacteria survive in bad conditions?

Answer 14

By producing a protective coat around themselves. (Spores)

Question 15

What is Saprotrophic Nutrition?

Answer 15

Organisms that live on decaying material (dead bodies).

Question 16

What are the different human uses of micro-organisms?

Answer 16

Getting rid of sewage
Making butter, yoghurt and cheese
Making linen
Brewing and baking
Making vinegar
Making silage
Making antibiotic
Genetic engineering
Producing edible proteins
Producing enzymes

Question 17

Using bread making, explain anaerobic respiration in yeast.

Answer 17

Anaerobic respiration in yeast is used during brewing and bread-making.
Glucose -> ethanol + carbon dioxide
Bubbles of carbon dioxide gas expand the dough and help the bread rise.

Question 18

Name at least 5 methods of food preservation techniques.

Answer 18

Smoking
Pasteurising
Canning
Cooling and Freezing
Irradiation
Pickling
Drying, salting or coating in Sugar
Cooking
Plastic/paper wrapping
Vacuum wrapping

Question 19

How does smoking technique help preserve the food?

Answer 19

Food develops hardened dry outer surface; smoke contains antibacterial chemicals.

Question 20

How does pasteurising technique help preserve the food?

Answer 20

Kills harmful microbes

Question 21

How does canning technique help preserve the food?

Answer 21

Food is heated and then sealed in airtight containers.

Question 22

How does cooling and freezing technique help preserve the food?

Answer 22

Don’t kill microbes but retard enzyme activity so that growth and reproduction is very slow

Question 23

How does irradiation technique help preserve the food?

Answer 23

Kills microbes by disrupting DNA synthesis/structure.

Question 24

How does pickling technique help preserve the food?

Answer 24

Kills microbes

Question 25

How does drying, salting, and coating in sugar technique help preserve the food?

Answer 25

Causes dehydration of microbes as water leaves cells by osmosis

Question 26

How does cooking technique help preserve the food?

Answer 26

Kills microbes

Question 27

How does plastic/paper wrapping technique help preserve the food?

Answer 27

Reduces exposure of food to contamination by microbes.

Question 28

How does vacuum wrapping technique help preserve the food?

Answer 28

Air is excluded so aerobic microbes can’t respire.

Question 29

Explain how saprotrophic organisms such as fungi digest food.

Answer 29

The release enzymes onto the dead animal or plant. These break down complex compounds into simple soluble ones that can be absorbed.