Defence against pathogens

Question 1

Immune system

Answer 1

If a pathogen enters our body due to failure of non specific defence system:
It destroys pathogens + toxins
Protects us if same type of pathogen enters again

Question 2

What makes up the immune system?

Answer 2

White blood cells that travel in the blood

Question 3

How do white blood cells respond to an infection

Answer 3

White blood cells:
Engulf it (phagocytosis) + destroy
Release antibodies
Releases antitoxins

Question 4

How does phagocytosis work?

Answer 4

WBC detects chemicals released from pathogen and goes to it
INGESTS the pathogen
Uses enzymes to destroy them

Question 5

What white blood cells name engulf the pathogen?

Answer 5

Phagocytes

Question 6

What are antibodies and what are they made of?

Answer 6

Protein molecules
Represented by the Y shape

Question 7

How do antibodies work?

Answer 7

Released by WBCs
Stick to the pathogen
Triggers pathogens to be destroyed

Question 8

What’s special about antibodies?

Answer 8

They are very specific to each pathogen
Ie the antibodies are designed for one specific pathogen ONLY

Question 9

How long do antibodies stay in the blood for?

Answer 9

A long time

Question 10

How do antibodies protect us from future possible infections

Answer 10

If you get infected by pathogen,
The WBCs make specific antibodies against this pathogen
Which after the infection is gone still remain in the blood
So if that pathogen enters again, the pre existing antibodies will destroy the pathogen immediately

Question 11

What are antitoxins and how do they work?

Answer 11

Chemicals produced by WBCs (not antibodies!!)
That stick to toxins produced by bacteria
Prevents the antitoxins from damaging cells and making us unwell

Question 12

What is the name of the white blood cell that releases antibodies and antitoxins?

Answer 12

Lymphocytes

Question 13

What do vaccines contain

Answer 13

Dead or inactive forms of the pathogen that we are being vaccinated against

Question 14

Do vaccines cause the disease in patient?

Answer 14

No because the pathogens are DEAD or INACTIVE

Question 15

How do vaccines work?

Answer 15

Enter the dead/inactive pathogen
Stimulates WBCs to release antibodies against it
But these WBCs divide by mitosis = copies of itself
That stay in the body for decades
So if the ALIVE version of the pathogen enters
These WBCs release the specific antibody much quicker = no infection

Question 16

Herd immunity

Answer 16

If as many people possible get vaccinated, they won’t pass the disease on
So unvaccinated people won’t be infected: no one can pass the pathogen on

Question 17

Penicillin

Answer 17

An antibiotic discovered in 1940s

Question 18

What do antibiotics do?

Answer 18

Kill infective bacteria in the HUMAN BODY without harming body cells

Question 19

Antibiotic resistance

Answer 19

Some antibiotics have been overused
So bacteria evolved to be resistant to the antibiotic

Question 20

Problem with antibiotic resistance

Answer 20

In the future bacterial diseases will be more difficult to treat

Question 21

Properties of antibiotics

Answer 21

Doctors prescribe them specifically for specific bacteria
They can’t kill virus

Question 22

Why won’t doctors prescribe antibiotics for viral diseases?

Answer 22

Because they will not destroy virus
So it’s a bit pointless

Question 23

Painkillers

Answer 23

Treat symptoms of infections
By relieving pain
BUT THEY DO NOT KILL PATHOGENS SO TREAT THE DISEASE

Question 24

What drug will be prescribed for a virus?

Answer 24

Painkillers to relieve symptoms
Not antibiotics
But usually no specific antiviral drugs

Question 25

Why aren’t there many antiviral drugs?

Answer 25

Difficult to develop them without harming body tissues
As virus enters the body cells and reproduce inside