Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A Level Biology > [OLD] The Immune System > Flashcards

[OLD] The Immune System Flashcards

1
Q

what is a pathogeN?

A

a microorganism that causes disease e.g virus, bacteria, fungus

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

what is the body’s first line of defence?

A 
tears
skin
large intestine
saliva
respiratory tract 
bladder
stomach
earwax
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is an antigen?

A

a molecule that triggers an immune response

always large complex molecules

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

what is an antibody?

A

a protein which binds to antigens, they are specific

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

what are antibodies made by?

A

white blood cells

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

what is a toxin?

A

a substance released by pathogens, they are toxic

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

what do antitoxins do?

A

neutralise toxins

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

what makes antitoxins?

A

white blood cells

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

what is an antibiotic?

A

a substance that kills bacteria or prevents its growth

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

describe phagocytosis

A

pathogens release chemical products that attract phagocytes
the phagocyte engulfs the pathogen in a phagosome
the phagosome fuses with a lysosome already within the phagocyte to form a phagolysome
lysosyme from the lysosome is released which hydrolysed the pathogen, breaking it down
debris is released by exocytosis

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

Why do mutations cause antibiotic resistance?

A

If you Change the DNA sequence resulting in a different amino acid, the shape of the protein i.e the tertiary structure will change, giving rise to a new strain of bacteria.

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

how does antibiotic resistance happen so quicklY?

A

the short generation time of bacteria mean there are more opportunities for mutations to be passed on

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

how are t-cells activated?

A

they have receptor proteins on their surface that bond to complementary antigens presented to them by phagocytes

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

what do helper T cells do?

A

release chemical signals that activate and stimulate phagocytes and cytotoxic T cells, which kill abnormal and foreign cells.
they also activate B cells, which secrete antibodies.

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

name 3 types of white blood cells

A

phagocytes
T cells
B cells

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

what are B cells covered with?

A

antibodies - proteins that bind antigens to form an antigen-antibody complex

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

why do different B cells bind to different shaped antigens?

A

each B cell has a different shaped antibody on its membrane.

18
Q

how do B cells work?

A

1) when the antibody on the surface of a B cell meets a complementary shaped antigen, it binds to it.
2) this, together with substances released form helped T cells, activates the B cell. this process is called clonal selection.
3) the activated B cell divides into plasma cells.

19
Q

what do plasma cells do?

A

secrete monoclonal antibodies

20
Q

what are monoclonal antibodies?

A

antibodies specific to the antigen

21
Q

what do monoclonal antibodies do?

A

bind to the antigens on the surface of the pathogen to form lots of antigen-antibody complexes.

22
Q

how many binding sites does an antibody have?

A

2

23
Q

why can agglutination occur?

A

an antibody can bind to two pathogens at the same time as it has two binding sites.

24
Q

what is agglutination?

A

when pathogens become clumped together

25
Q

what forms the cellular response?

A

the T cells and other immune system cells that they interact with, e.g phagocytes

26
Q

what forms the humoral response?

A

B cells, clonal selection and the production of monoclonal antibodies.

27
Q

what is the primary immune response?

A

when an antigen enters the body for the first time and activates the immune system

28
Q

why is the primary immune response slow?

A

there aren’t many B cells that can make the antibody needed to bind to it

29
Q

what happens while the body is producing enough of the right antibodies to overcome an infection?

A

the infected person will show symptoms of the disease

30
Q

what happens after being exposed to an antigen?

A

t and B cells produce memory cells, which remain in the body for a long time.

31
Q

what do memory T cells do?

A

remember the specific antigen and will recognise it a second time around

32
Q

what do memory B cells do?

A

record the specific antibodies needed to bind to the antigen

33
Q

what is being immune?

A

when a persons immune system has the ability to respond to a second infection

34
Q

what is the secondary response?

A

the quicker, stronger immune response produced by the immune system if the same pathogen enters the body for the second time

35
Q

what happens during the second immune response?

A

clonal selection happens faster
memory B cells are activated and divide into plasma cells that produce the right antibody to the antigen.
memory T cells are activated and divide into the correct type of T cells to kill the cell carrying the antigen.

36
Q

what is active immunity?

A

the type of immunity you get when your immune system makes own antibodies being stimulated antigen

37
Q

name the two types of active immunity

A

natural

artificial

38
Q

what is natural active immunity?

A

when you immune after catching a disease

39
Q

what is artificial active immunity?

A

when you become immune after you’ve been given a vaccination containing a harmless dose of antigen

40
Q

what is passive immunity

A

the type of immunity you get from being given antibodies made by a different organism - your immune system doesn’t produce any antibodies of their own

41
Q

what is natural passive immunity?

A

when a baby becomes immune due to the antibodies it receives from its morgen through the placenta and in breast milk

42
Q

what is artificial passive immunity?

A

when you become immune after being injected with antibodies from someone else.
e.g if you contract tetanus you can be injected with antibodies against the tetanus toxin, collected from blood donations.

A Level Biology (75 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions