Biology- Unit 6 Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What is the lag phase?

A

Microorganisms are adjusting to the environment before starting to reproduce

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the log phase?

A

Population size grows exponentially, every round of division doubles population size

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the stationary phase?

A

When population reaches maximum due to decreasing nutrient levels and build up of toxic substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the death phase?

A

Lack of nutrients and toxic products causes death of organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How would a cell count be carried out?

A

Haemocytometer
Sample of broth is diluted 1:1 with trypan blue (stains dead cells blue)
Counted cells have to be fully in boxes
Useful because it only counts living cells and is accurate- but slow an expensive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How would turbidimetry be carried out?

A

Form of colorimetry
As turbidity increases, absorbance increases
Counts dead cells, expensive, assumes density of cells is constant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How would dilution plating be carried out?

A

Colony is grown from a single, viable microorganism
Original culture is serially diluted and streak plating to count individual colonies.
Slow due to incubation period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are endotoxins and which bacteria secrete them?

A

Lipopolysaccharides in the outer membrane - gram negative

Salmonella

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are exotoxins and which bacteria secrete them?

A

Soluble proteins produced and released by bacteria as they metabolise and reproduce
Staphylococcus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an example of bacterial disease caused by host tissue invasion?

A

Tuberculosis

1) First infection is symptomless, infected phagocytes are sealed in tubercles as a result of the inflammatory response
2) Bacteria lie dormant in tubercles and are not destroyed by immune system
3) When immune system weakens, bacteria become active again and destroy lung tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a bactericidal antibiotic?

A

Destroy bacteria’s cell wall and cause them to burst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is a bacteriostatic antibiotic?

A

Inhibit growth of bacteria by stopping protein synthesis and production of nucleic acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How can bacterial resistance be combatted?

A

1) New patients are screened at arrival and isolated if they are infected
2) Antibiotics are only used when needed and courses are completed to minimise selection pressure to prevent resistant strains
3) Strict hygiene, antibiotic gel hand wash, suitable clothing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Describe how influenza infects and effects the host

A

Droplet infection
Infects ciliated epithelial cells- injects viral RNA, host produces new viruses, lysis of cell
Headache, sore throat, coughing, vomiting, fever

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe how stem rust infects and effects the host

A

Spores via wind/ infected fragments
Spore germinates in water- produces hyphae which enter the plant, grow into mycelium, digest plant and absorb nutrients
Weakened stem, water loss, reduced photosynthesis, pustules on epidermis burst to release more spores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe how malaria infects and effects the host

A

Female anopheles mosquito saliva
Parasite travels to liver, infect RBCs, reproduce asexually inside erythrocytes and cause lysis
Sweating, shaking, anaemia, muscle pains, headaches, liver damage

17
Q

How can influenza be treated?

A

Anti-viral medication
Antibiotics
Painkillers

18
Q

How can malaria be treated?

A
Mosquito nets
Insect repellent 
Treating still water with pesticides
Proper disposal of sewage 
Antimalarial drugs
19
Q

What are the physical barriers to infection?

A

Skin- keratin
Stomach acid
Gut and skin flora- competitive

20
Q

What are the non-specific responses to infection?

A

Inflammation- vasodilation, increase permeability of vessels, more antibodies, WBC
Fever- decreases speed of pathogen reproduction, increases rate of specific immune response
Phagocytosis- WBC engulf pathogens
Lysozyme action- found in tears and mucus, damages bacterial cell walls

21
Q

Where do B cells mature?

A

Bone marrow

22
Q

Where do T cells mature?

A

Thymus gland

23
Q

Describe the cell mediated response

A

Pathogen invades host cell

1) Host cell resents antigen on MHC protein
2) T killer cell with complimentary receptor proteins binds to Antigen-presenting cell
3) Cytokines secreted by T helper cell stimulated T killer cell to divide by mitosis
4) T killer cell divides to form active T killer cells and T memory cells
5) Active T killer cells bind to APCs and secrete chemicals which cause pores to form in cell membrane
6) Infected cell dies

24
Q

Describe the humoral response

A

1) Bacterium is engulfed by macrophage which presents antigen on MHC protein
2) Macrophage APC binds to complimentary T helper cell
3) The T helper cell is activated and divides by mitosis to form T memory cells and active T helper cells
4) T helper cell presents antigen on MHC protein and activates complimentary B cell with cytokines
5) Cytokines cause B cell to divide rapidly by mitosis to form plasma cells
6) Plasma cells secrete complimentary antibodies

25
Q

What do antibodies do?

A

They render the pathogens harmless by binding to antigen and group pathogens together so they can be engulfed by macrophages faster

26
Q

What is natural active immunity?

A

Exposed to antigen/ suffered the disease

27
Q

What is natural passive immunity?

A

Crossing of a mother’s antibodies through placenta and breast milk

28
Q

What is active artificial immunity?

A

Vaccinations

29
Q

What is passive artificial immunity?

A

Injection of antibodies into body