Ch.20 - Monera

Question 1

What is microbiology?

Answer 1

Microbiology is the study of microorganisms(really small living things).

Question 2

What is always part of the structure of bacteria?

Answer 2

Bacteria are composed of a cell membrane, cell wall(to prevent it from swelling), chromosome(unbounded by membrane, one loop of DNA), ribosome, storage granule and cytoplasm(containing all organelles).

Question 3

What is sometimes part of the structure of bacteria?

Answer 3

Bacteria can be composed of a capsule(semi-solid outer layer), flagella(makes the bacteria motile) and plasmid(contains genes).

Question 4

What are the bacterial types?

Answer 4

Bacteria are classified into the shapes: spherical, rod and spiral.

Question 5

Draw a diagram of the types of bacteria, providing examples.

Answer 5

Question 6

What is binary fission?

Answer 6

Binary fission is the name for asexual reproduction in bacteria. DNA copies itself, then the cell elongates and splits.

Question 7

What is an autotrophic organism? Name an autotrophic bacteria.

Answer 7

An autotrophic organism is one that makes its own food. Photosynthetic bacteria often have chlorophyll on membranes within the cell and use the same type of light as plants.

Question 8

What is chemosynthesis? Give an example of chemosynthesising bacteria.

Answer 8

Chemosynthesis is the production of food using the energy released from a chemical reaction. Nitrifying bacteria use chemosynthesis.

Question 9

What is a heterotrophic organism? Name heterotrophic bacteria.

Answer 9

A heterotrophic organism takes in food by other organisms, they may be saprophytes or parasites.

Question 10

What are saprophytes?

Answer 10

Saprophytes are organisms that take in food from dead organic matter.

Question 11

What are parasites?

Answer 11

Parasites are organisms that take in food from alive hosts and usually cause harm.

Question 12

How does temperature affect the growth of bacteria?

Answer 12

Most bacteria grow well between 20 and 30C, some can tolerate much higher temperatures. Low temperature slow down the rate of bacterial growth. Hot temperature kills bacteria.

Question 13

How does oxygen concentration affect the growth of bacteria?

Answer 13

Aerobic bacteria require oxygen for respiration. Low concentrations of oxygen can slow down bacterial growth.
Anaerobic bacteria do not require oxygen to respire. Clostridium is an anerobic bacterium that causes botulism or tetanus.

Question 14

How does pH affect bacterial growth?

Answer 14

Bacterial enzymes placed in unsuitable pH levels are denatured. Most bacteria grow near a pH of 7. Some bacteria can tolerate very low or high levels of pH.

Question 15

How does external solute concentration affect bacterial growth?

Answer 15

The growth of bacteria is affected by external solute concentration because bacteria gain or lose water by osmosis.

Question 16

How does pressure affect bacterial growth?

Answer 16

Bacterial walls are typically not strong enough to withstand high pressures. Some bacterial can withstand very high pressures.

Question 17

What are the economic advantages and disadvantages of bacteria?

Answer 17

Some bacteria are used to convert milk to other dairy products like cheese or yoghurt. Genetically modified bacteria are used to make a variety of products, including drugs, enzymes and alcohols.
However, bacteria cause food to decay (souring milk). Bacteria cause disease in all organisms (tuberculosis, cholera, salmonella and tetanus).

Question 18

What are pathogenic bacteria?

Answer 18

Pathogenic bacteria are bacteria that cause disease.

Question 19

What are antibiotics?

Answer 19

Antibiotics are chemicals produced by micro-organisms that stop the growth of, or kill, other micro-organisms without damaging human tissue. They do not affect viruses.

Question 20

How are antibiotics abused in medicine?

Answer 20

The overuse of antibiotics in medicine results in increased growth of antibiotic resistant bacteria. The failure of patients to complete their treatment of antibiotics allows the bacteria to survive and re-grow.

Question 21

Draw bacteria’s growth curve and describe the phases.

Answer 21

Question 22

What is a batch culture?

Answer 22

Batch culture is the growth of cells in a sealed container or bioreactor over a short period of time and under ideal conditions until all the nutrients are used up.

Question 23

What is a bioreactor?

Answer 23

A bioreactor is a vessel in which biological reactions take place.

Question 24

What is continuous flow?

Answer 24

Continuous flow food processing is the growth of cells in an open container or bioreactor, where nutrients are added and end products are removed all the time at a rate that maintains the volume of liquid and the number of cells.

Question 25

What are endospores and draw their formation.

Answer 25

Bacteria can withstand harsh and unfavourable conditions by producing endospores.

Question 26

Draw the structure of a bacterial cell. Include features that are always and sometimes present.

Answer 26

Question 27

Label this diagram of a bioreactor with one of a batch culture and one of a continuous flow.

Answer 27

Question 28

What are the advantages and disadvantages of batch culture food processing?

Answer 28

Batch culture only occurs for a short duration and there is a low risk of contamination. The main disadvantage is that it is unproductive in the time that it needs to be sterilised.

Question 29

What are the advantages and disadvantages of continuous flow food processing?

Answer 29

With continuous flow, there is higher volume of product produced and better process monitoring. However, it does need constant monitoring and has only a small number of applications (waste-water treatment).

Question 30

Describe, with the aid of a diagram, the process of bacterial reproduction.

Answer 30

Question 31

What might happen to bacteria after the death phase?

Answer 31

SOME MAY SURVIVE, endospores form to protect the bacteria, conserve the DNA and reproduce again when conditions are favourable.