Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

A-level Biology > Immunity, forensics and infection > Flashcards

Immunity, forensics and infection Flashcards

1
Q

what is a pathogen?

A

a microorganism that can cause disease

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

name 3 ways to determine how old a corpse is?

A
  • rigamortis stage
  • presence of species
  • body temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is in the core of a virus?

A

nucleic acid

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

what is a virion?

A

virus before it enters the host cell

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

what is a capsid?

A

protien coat of a virus

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

what surrounds a capsid on a large virus?

A

an envelope

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

which type of nucleic acid in a virus is more dangerous and why?

A

RNA, as it mutates much more

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

what do spike protiens do?

A

help the virus to attach to specific receptors on the host cell

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

how many ways of viral entry are there?

A

2

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

describe both methods of viral entry?

A
  1. virus injects nucleic acid into cell
  2. plasma membrane of host cell surrounds virus and produces a virus filled vacuole in cytoplasm, the virus bursts out, releasing nucleic acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are introns?

A

non-coding regions of DNA, used in DNA profiling

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

what is satellite DNA?

A

large arrays of repeating, non-coding DNA

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

what does PCR do?

A

amplifies DNA sample

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

what 5 things does PCR require?

A
  • target DNA
  • primers
  • DNA polymerase
  • free nucleotides
  • buffer solution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are the 3 stages of PCR?

A
  • denaturation
  • annealing
  • elongation/extension
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

describe the PCR stage denaturation?

A

DNA is heated to 95C to break hydrogen bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

describe the PCR stage annealing?

A

temperature decreased to 50-60C so primers can anneal to the ends of single stranded DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

describe the PCR stage elongation/extension?

A

temperature increased to 72C for 1 minute, this is the optimum temperature for taq polymerase to build complementary DNA strands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

name 4 features of bacteria?

A
  • no membrane bound organelles
  • no nucleus
  • genetic material in cytoplasm
  • cell wall + membrane
  • ribosomes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what do primary defences do?

A

stop pathogens entering the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

are primary defences specific?

A

no

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

name 4 primary defences?

A
  • stomach acid
  • gut flora
  • inflamation
  • mucus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how does inflamation stop pathogens?

A

vasodilation increases permeability of blood vessels, so more white blood cells can enter

24
Q

name 3 ways the skin is adapted as a primary defence?

A
  • strengthened by keratin
  • covered by flora
  • antimicrobial secretions
25
where can tuberculosis affect?
mainly lungs, can be kidney spine and brain
26
what type of phagocyte engulf tuberculosis bacteria?
macrophage
27
how can tuberculosis bacteria survive macrophages?
- overpower and encase macrophage in tubercles - stops formation of lysosomes
28
what are the 3 stages of tuberculosis infection?
- primary infection - latent infection - active disease
29
is HIV RNA or DNA?
RNA
30
describe the 4 stages of HIV replication?
- Virus enters T helper cells by attaching to a CD4 receptor - reverse transcriptase enzyme produces a complementary RNA strand - virus uses host cells enzymes to make new viral components - Host cell lyses, viruses enter the blood, cycle repeats
31
name the 3 stages of HIV infection?
1 - accute HIV syndrome 2 - Chronic or asymptomatic stage 3 - advanced AIDS
32
how does HIV avoid antibodies?
- frequently mutates, to change antibodies - uses host cell plasma membranes to hide antigens
33
what is the lymphatic system responsible for?
complex transport of immune cells
34
name the 2 types of phagocyte?
- neutrophyls - macrophages
35
name 3 features of neutrophylls?
- most common phagocyte - made in bone marrow - short acting, for immediate response
36
name 3 features of macrophages?
- biggest phagocyte - made in bone marrow - adaptive, specific immune response
37
name the 5 stages of phagocytosis?
1 - detects pathogen by unique antigen and recognises by its pathogen recognition receptors on cell membrane 2 - phagocyte activates, pathogen is covered in opsinins, helps to bind 3 - engulfs, encases in phagosome 4 - phagosome fuses with lysosome, lysozyme breaks down pathogen 5 - phagocyte absorbs products, some products are discarded, some are used in the antigen presentation process to activate T-helper cells
38
define antibody?
glycoprotien with specific antigen binding site
39
name 2 ways antibodies kill pathogens?
- agglutination - neutralising the toxins they produce
40
where do B cells form?
bone marrow
41
where do T cells mature?
thymus
42
what are the 2 specific immune responses?
- cell mediated immunity - humoral immunity
43
what type of pathogen does cell mediated immunity mainly affect?
viruses
44
describe the 4 steps of the cell mediated response?
1) Macrophages engulf and digest pathogens, presenting their antigens 2) Specific T helper cells with complementary receptors bind 3) T helper cell produces interloukins 4) Cloned T cells may become T killer, T memory or T helper cells
45
define antigen?
specific protiens on every cells surface
46
describe the 4 steps of the humoral response?
1) T helper cells bind to antigens on presenting b cells 2) T helper cells produce interloukins 3) B cells divide rapidly into plasma and memory cells 4) Plasma cells produce antibodies to bind to and kill pathogens
47
what type of pathogen does the humoral response affect?
bacteria and fungal
48
what happens after a B cell engulfs a pathogen?
presents antigens, becoming an antigen presenting cell
49
what are the 2 types of antibiotics?
- bactericidal - bacteriostatic
50
what do bactericidal antibiotics do?
kill bacteria
51
what do bacteriostatic antibiotics do?
slow bacterial growth and reproduction
52
name 4 ways antibiotics can affect bacteria?
- inhibit cell wall synthesis - inhibit DNA synthesis - disrupt cell membrane - disrupt protien synthesis - inhibit metabolic enzymes
53
what is MRSA?
causes wound infections
54
what is clostridium difficile?
- infects digestive system - when gut flora is killed by antibiotics, it can colonise
55
name 3 ways hospitals prevent superbugs?
- hand hygiene - isolations - stricter prescriptions
56

A-level Biology (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions