20 - Monera (bacteria)

Question 1

Bacterial types

Answer 1

Round
Rod
Spiral / vibrio

Question 2

Round

Answer 2

Found in pairs, chains or clusters

Pneumonia
Sore throat
Food poisoning or skin boils

Question 3

Rod

Answer 3

May contain spores

Tuberculosis
Tetanus
Botulism

Question 4

Spiral

Answer 4

Called vibrio when shaped like a comma

Syphilis
Cholera (vibrio)

Question 5

Reproduction

Answer 5

Reproduce asexually by a method called binary fission.

DNA strand copies itself at a certain size
Now two identical strand of DNA
Cell elongates with a strand of DNA attached to each end
Finally the cell splits into two similar sized cells.

Bacteria can divide every 20 minutes if conditions suitable this means a single bacteria could produce over 1 million bacteria in seven hours

Question 6

Mutations in bacteria

Answer 6

Bacteria reproduce asexually their offspring are genetically identical they can evolve very fast due to the speed which new mutations can spread. (Resistance to new antibiotics)

Question 7

Endospores

Answer 7

Bacteria can withstand harsh and unfavourable conditions by producing endospores.

Form when bacterial chromosome replicates with one of the new strands becoming enclosed by a tough walled endospore
Inside the parent cell
Parent cell breaks down and endospore remains dormant for a long time
When conditions are suitable, endospore absorbs water and the tough wall breaks down.
Chromosome is copied and a normal bacterium forms again which can then reproduce by binary fission.
Endospores are difficult to kill, withstand lack of food, water, most poisons and high temperatures.

Question 8

Nutrition

Answer 8

The way an organism gets its food

Question 9

Autotrophic

Answer 9

An organism that makes its own food with
Sources:
>Sun - photosynthesis
>Chemical reactions - chemosynthesis

Types of bacteria:
>Photosynthetic (use light e.g purple sulfúrico bacteria)
>Chemosynthetic (use energy from chemical reactions e.g nitrifying bacteria)

Photosynthetic bacteria have chlorophyll on membranes use the same type of light as plants.

Question 10

Chemosynthesis

Answer 10

Production of food using energy released from chemical reactions

Question 11

Heterotrophic

Answer 11

An organism takes in food made by other organisms

Bacteria types:
>saprophytic (feed on dead sources e.g bacteria of decay)
>parasitic (take food from live host e.g disease-causing bacteria)

Question 12

Saprophytes

Answer 12

Organisms that take in food from dead organic matter

Question 13

Parasites

Answer 13

Organisms that take food from a live host and usually cause harm

Question 14

Factors affecting the growth of bacteria

Answer 14

Temperature 
Oxygen concentration
pH
External solute concentration 
Pressure

Question 15

Factors affecting the growth of bacteria - Temperature

Answer 15

Grow well at 20 degrees C and 30 degrees C
Can tolerate much higher temperatures without being denatured
Low temps slow down the rate of bacterial growth

Question 16

Factors affecting the growth of bacteria - Oxygen concentration

Answer 16

Aerobic bacteria require oxygen for respiration low concentration of oxygen slow down bacterial growth
E.g streptococcus - sore throat bacteria

Anaerobic bacteria doesn’t require oxygen to respire.
E.g Clostridium - tetanus or botulism

Facultative anaerobes can respire with or without oxygen
E.g Escherichia Coli found in intestines

Obligate anaerobes can only respire in the absence of oxygen
E.g Clostridium tetani - tetanus

Question 17

Factors affecting the growth of bacteria - pH

Answer 17

Unsuitable pH = denatured

Most grow at neutral pH 7
Some can tolerate very low (acidic) or very high (alkaline) pH values

Question 18

Factors affecting the growth of bacteria - External solute concentration

Answer 18

Bacteria gain or lose water by osmosis
higher solute - dehydrates
lower solute - water will enter the bacteria the cell walls of bacteria can normally prevent bacterial cells from bursting
most bacteria live in less concentrated solutions

Question 19

Factors affecting the growth of bacteria - pressure

Answer 19

Bacterial walls are not strong enough to withstand the high-pressure however some such as those found in deep sea vents can

Question 20

Economic importance of bacteria - benefits

Answer 20

Convert milk to products such as butter yoghurt and cheese

production of vinegar silage pickles and antibiotics

genetically modified bacteria used to make insulin drugs enzymes amino acid’s vitamins food flavourings alcohols and a growing range of new substances

Question 21

Economic importance of bacteria - disadvantages

Answer 21

Cause food to decay for example they cause milk to turn sour

cause human animal and plant diseases such as tuberculosis 
Whooping cough 
septic throat  
meningitis 
typhoid 
cholera
Diphtheria
Dysentery 
food poisoning
Mastitis 
Brucellosis

Question 22

Antibiotics

Answer 22

Used to control bacterial infection can treat some fungal diseases do not affect viruses

Produced by genetically engineered bacteria for example streptomycin, neomycin and tetracycline

Question 23

Pathogenic bacteria

Answer 23

Cause disease

Question 24

Antibiotics definition

Answer 24

Chemicals produced by microorganisms that stop the growth or kill other microorganisms without damaging human tissue

Question 25

Antibiotic resistance

Answer 25

Antibiotic resistance bacteria have developed by mutations not affected by the antibiotics being used new antibiotics must be produced to continually to treat new resistant bacteria

Gene for antibiotic resistance located on a plasmid pass copies of their plasmid onto other bacteria,in this way antibiotic resistance can pass from one bacteria to another

Bacterial strains that are resistant to almost all known antibiotics are said to be multi-resistant

Question 26

Potential abuse of antibiotics in medicine

Answer 26

Overuse of antibiotics in medicine results in increased growth of antibiotic resistant bacteria
this can happen when doctors prescribe antibiotics unnecessarily like for virus infections
and the failure of some patients to complete their treatment of antibiotics, allows the bacteria to survive and regrow

Question 27

Bacteria are prokaryotes

Answer 27

Bacteria belong to the kingdom monera
prokaryotes are organisms that lack a membrane enclosed nucleus or membrane enclosed cell organelles such as mitochondria and chloroplasts

Apart from the kingdom monera all other kingdoms contain eukaryotes

Question 28

Lag phase a

Answer 28

Numbers remain constant adopting themselves to their new environment producing new enzymes to digests the nutrients in which they are to grow

Question 29

Log phase b

Answer 29

Bacterial numbers increase rapidly reproducing at their maximum rate the number of bacteria is doubling in every new generation this is as a result of ideal conditions food moisture space or oxygen
also called the exponential phase

Question 30

Stationary phase c

Answer 30

There is no increase in bacterial numbers production of new bacteria is compensated for by the death of equal numbers

rate of growth slows down because of lack of food space moisture oxygen and the buildup of toxic waste products

Question 31

Decline phase d

Answer 31

In the decline or death phase the number of bacteria falls rapidly the death rate is greater than the rate of reproduction
slow rate of reproduction caused by the same factors as in the stationary phase

Question 32

Survival phase e

Answer 32

A small number of bacteria survive by remaining dormant as spores which can survive for a long time by remaining dormant until conditions are suitable again

Question 33

Food processing

Answer 33

Production of useful products using enzymes include dairy products such as yoghurts and cheese is artificial sweeteners amino acid’s vitamins flavourings flavour enhancer is an alcohol products such as wines and beers this is called single cell production there are two main methods of production batch culture or fermentation and continuous flow culture or fermentation

Question 34

Batch culture

Answer 34

Fixed amount of sterile nutrient is added to the micro organisms in the bioreactor
Other conditions include suitable temperatures pressure aeration and pH the micro organisms go through the lag the log and the stationary but rarely decline and survival stage
As this happens the nutrients are used up and the product is formed
At the end of production the bioreactor is emptied separated from the solution and purified the bioreactor is cleaned resterilised and the process is repeated

Question 35

Continuous flow continuous flow

Answer 35

Nutrients are continuously fed into the bioreactor
culture medium continuously withdrawn at same time
volume of material in the bio reactor remains constant

microorganisms maintained more or less constantly in the log stage of growth

they are growing rapidly and producing the product at a fast pace

Factors such as 
PH 
temperature 
the rate of stirring 
and the concentrations of nutrients 
oxygen and waste products are kept constant 

maintaining constant conditions is very difficult for this reason continuous flow processing is limited to a small number of applications