Biochem revision

Question 1

What is enzyme immobilisation?

Answer 1

The restriction of enzyme mobility in a fixed space.

Question 2

What are the (6) major interactions between two organisms in a mixed culture?

Answer 2

• Neutralism
• Competition
• Commensalism
• Amensalism
• Mutualism
• Prey - Predator

Question 3

What is the definition of neutralism (mixed culture)

Answer 3

Neutralism is an interaction where neither population is affected
by the presence of the other Each species consumes different
limiting substrates and neither species is affected by the end
products of the other.

Question 4

What is the definition of competition (mixed culture)

Answer 4

Competition is an indirect interaction between two populations
that has negative effects on both In competition, each
population competes for the same substrate.

Question 5

What is the definition of commensalism (mixed culture)

Answer 5

Commensalism is an interaction in which one population is
positively affected by the presence of the other However, the
second population is not affected by the presence of the first
population.

Question 6

What is the definition of amensalism (mixed culture)

Answer 6

Amensalism is the opposite of commensalism In amensalism
population A is negatively affected by the presence of the other
population B However, population B is not affected by the
presence of population A.

Question 7

What is the definition of mutualism (mixed culture)

Answer 7

Mutualism is an interaction where the presence of each
population has a positive effect on the other This interaction is
essential to the survival of both species.

Question 8

What is the definition of predation (mixed culture)

Answer 8

Predation involves the ingestion of prey by the predator
organism In this interaction, one population benefits at the
expense of the other In general, predators tend to be larger
than their prey, and consume many prey during their lifetimes.

Question 9

Define sterility

Answer 9

The absence of detectable levels of viable organisms in a culture medium or in a gas.

Question 10

List some reasons for sterilisation.

Answer 10

• Many fermentations must be absolutely devoid of foreign
  organisms (otherwise production organism must compete
  with the foreign contaminant organisms for nutrients)
• Foreign organisms can produce harmful (or unwanted)
  products which may inhibit the growth of the production
  organisms
• Economic penalty is high for loss of sterility
• Vaccines must have only killed viruses
• Recombinant DNA fermentations exit streams must be
  sterilised

Question 11

Define biohazard

Answer 11

Any organism or its toxin that is known to cause
disease in humans or animals or that is a potential hazard to
humans, animals or the environment

Question 12

Define biosafety

Answer 12

Biosafety:
the combination of measures employed when
handling biohazardous materials to
Protect
personnel from exposure to infectious agents
Prevent
environmental contamination
Comply
with applicable federal, provincial and municipal
requirements

Question 13

What does COSHH mean

Answer 13

control of substances hazardous to health

Question 14

COSHH Hazard group 1

Answer 14

Hazard group 1: unlikely to cause human diseases

Question 15

COSHH Hazard group 2

Answer 15

Hazard group 2: can cause human disease and may be a hazard to
employees; but is unlikely to spread to community
and there is usually effective prophylaxis or
treatment available

Question 16

COSHH Hazard group 3

Answer 16

Hazard group 3: can cause severe human disease and may be a
serious hazard to employees; it may spread to the
community, but there is usually effective prophylaxis
or treatment available

Question 17

COSHH Hazard group 4

Answer 17

Hazard group 4: causes severe human disease and is a serious
hazard to employees; it is likely to spread to the
community and there is usually no effective
prophylaxis or treatment available

Question 18

Risk group 1 agents

Answer 18

• E.coli K-12
• Transgenic plants
• Fungi
• Mould
• Yeast

Question 19

Risk group 2 agents

Answer 19

• Human or primate cells
• Herpes simplex virus
• replication incompetent attenuated human immunodeficiency virus
• patient specimens

Question 20

Risk group 3 agents

Answer 20

• Human immunodeficiency virus
• Mycobacterium tuberculosis
• Coxiella burnetii

Question 21

Risk group 4 agents

Answer 21

• Lassa fever virus
• Ebola hemorrhagic fever virus
• Marburg virus
• Herpes B virus

Question 22

Biosafety level 4

Answer 22

• Dangerous exotic agents
• lie threatening disease
  -aerosol transmission or health affects
• No known treatment

Question 23

Define the term containment

Answer 23

The confinement of a biohazardous agent that is being stored, manipulated, transported, or destroyed in order to prevent or limit its contact with people and/or the environment.

Question 24

What are the seven principles of HACCP

Answer 24

1. Conduct hazard analysis
2. Identify critical control points
3. Establish critical limits
4. Establish monitoring procedures
5. Establish corrective actions
6. Establish verification procedures
7. Establish record system

Question 25

what is GMP

Answer 25

Good manufacturing practices

Question 26

Examples of GMP

Answer 26

* personnel hygiene and training; * cleaning and sanitation; * maintenance and services; * pest control; * maintenance and services of plant, equipment, premises and structure; * storage, distribution and transport; * waste management.

Question 27

HACCP principle 1

Answer 27

Those involved in designing food processing equipment and production lines must proactively analyse designs to identify potential food safety hazards If the hazard analysis reveals contaminants are likely to find their way into food products, then preventive measures are put in place in the form of design revisions

Question 28

HACCP principle 2

Answer 28

A critical control point ( is a step in the design process at which a control can be most effectively introduced to prevent or eliminate hazards In this context a “ would be a design revision to eliminate hazards identified during the Principle 1 stage

Question 29

HACCP principle 3

Answer 29

A critical limit is a boundary of safety for each critical control point ( Critical limits can be obtained from regulatory standards, scientific literature, experimental studies, as well as information provided by consultants These critical limits come into play with issues as varied as machine design, raw material temperatures, and overall safe processing times

Question 30

HACCP principle 4

Answer 30

Monitoring activities are necessary to ensure that the critical limits established at each critical control point ( established under Principle 3 are working as intended

Question 31

HACCP principle 5

Answer 31

When an established critical limit at a designated critical control point ( has been found not to be functioning as intended, design engineers must enact corrective measures to resolve the issue as soon as possible

Question 32

HACCP principle 6

Answer 32

It follows up on the guidelines established in Principles 1 through 5 organizing activities into written procedures For each step, responsibilities of key individuals involved must be clearly defined and sequentially ordered Training may be necessary, and management must decide what form that educational process takes to be most effective

Question 33

HACCP principle 7

Answer 33

This HACCP principle requires that all food manufacturing plants maintain records to show they implemented a HACCP plan, are following all principles, and the plan is working effectively

Question 34

Define what a biofilm is

Answer 34

Biofilm is a complex accumulation of microorganisms growing on a solid substrate These microorganisms can be bacteria, fungi or algae, and they usually enclose themselves in a slimy matrix consisting of extracellular polymeric substances that they have produced

Question 35

What is biofouling?

Answer 35

Biofouling is the undesired accumulation of living organisms (such as bacteria, algae, fungi, etc on a surface Biofouling is usually a problem where it occurs, as they can alter or even destroy the surface

Question 36

Why is biofouling a serious problem for cooling cycles in energy industry

Answer 36

- Reduced heat transfer efficiency - Increases drag resistance - Biocorrosion

Question 37

What is corrosion

Answer 37

- Electrochemical reaction involving an anode and a cathode - Degradation of materials properties due to interactions with the environment - The fundamental cause or driving force for all corrosion is the lowering of a systems gibbs energy

Question 38

Explain uniform corrosion

Answer 38

- Most common - Uniform in nature, leaves scale or deposit over entire exposed area - fairly predictable and therefore the effects can be minimised < 2 mm/yr - necessary for food containment 20 mm/yr = conservative estimate for general atmospheric corrosion prevented by removing electrolye (lower relative humidity below 30%) Choose material that doesnt rust in a particular environment apply suitable coatings (or paints) when possible include corrosion allowance during redesign

Question 39

Explain pitting corrosion

Answer 39

- Extremely localised corrosion that leads to the creation of small holes in the metal surfaces - A pit can be initiated by a localised surface defect, scratch or slight variation in composition. - More of a problem in stagnant solutions Prevention: - Material selection - Avoid stagnant flow - Alloy SS with about 2% molybdenum

Question 40

The 6 steps of biofilm formation

Answer 40

1) Reversible adsorption (attachment) of bacteria to a surface (seconds) 2) Irreversible attachment of bacteria (seconds - minutes) Quorum sensing occurs 3) Growth & division of bacteria within a slimy matrix (hours -days) 4) Expolymer production & biofilm formation (hours - days) 5) Attachment of other organisms to biofilm (days - months) 6) Single cells can escape from the outermost surfaces of their biofilm to start a new biofilm.