Microbes And Defence Against Disease

Question 1

What are communicable diseases

Answer 1

Diseases that can be transmitted from one person to another

Question 2

Examples of communicable diseases

Answer 2

Measles, mumps, rubella and malaria

Question 3

What are non-communicable diseases

Answer 3

Diseases that cannot be transmitted from one person to another

Question 4

Examples of non-communicable diseases

Answer 4

Cancer, heart attack, diabetes and asthma

Question 5

What are microbes

Answer 5

Tiny living things that can only be seen clearly with a microscope. Microbes can cause diseases and illnesses. Some microbes are extremely dangerous but microbes also have many useful applications that they can use to help us.

Question 6

Bacteria - structure description

Answer 6

Cocci are spherical in shape, bacilli are rod shape, spirochetes are spirals. Some may have a long filament called a flagellum attached - this allows them to move

Question 7

What are pathogens

Answer 7

Pathogens are micro-organisms that cause disease

Question 8

What are the 3 types of pathogens

Answer 8

Bacteria, viruses and fungi

Question 9

Bacteria - why is it dangerous

Answer 9

Bacteria are responsible for numerous illnesses including: MRSA, Salmonella and Tuberculosis. They also cause food to go “off”

Question 10

Bacteria - why can it be useful

Answer 10

Some are very useful to human - e.g for the production of yoghurt, treating sewage and in genetic engineering

Question 11

Bacteria - features

Answer 11

They are prokaryotes - single called organisms.
They do not have a true nucleus, but a circular strand of DNA.
They do not contain mitochondria.
They may have a tail, known as flagellum, to help it move.
They produce toxins that damage cells and tissues.
They are living cells.
The largest bacteria are 10 micrometers long.
Examples: lactobacillus, salmonella, staphylococcus.

Question 12

Viruses - features

Answer 12

They are not cells.
They are much smaller than bacteria.
They reproduce rapidly inside host cells. They consist of genetic material and a protein coat.
Once inside a cell, viruses can make thousands of copies of itself. This continues until the cell bursts open. It is this cell damage that makes humans feel unwell.
Measles, mumps, chicken pox and colds are all caused by viruses.

Question 13

Viruses - description of structure

Answer 13

Their structure is a head capsule (that contains DNA) with a long tail with an end plate attached.

Question 14

Viruses - why are they dangerous

Answer 14

Viruses cause many diseases including all flu (the influenza virus), chicken pox, mumps and AIDS (the HIV) virus. Flu viruses can change into many different forms meaning that you cannot be immune to the flu.

Question 15

Viruses - why can they be useful

Answer 15

Humans can also make use of viruses in genetic engineering.

Question 16

Fungi - features

Answer 16

Toadstools, mushrooms and moulds are examples of multi-cellular fungi.
The cell wall of fungi is made from chitin.
Fungi use saprotrophic nutrition - they secrete enzymes to digest food and then absorb it.
Fungi have thread like structures called hyphae.
Hyphae can produce spores enabling the fungus to be easily spread.

Question 17

Fungi - structure description

Answer 17

They have a spore case and a network of threads forming a structure called a mycelium.

Question 18

Fungi - why is it dangerous

Answer 18

Fungi are responsible for the athletes’ foot infection as well as ringworm and thrush. They also spoil food - e.g. bread mould

Question 19

Fungi - why can it be useful

Answer 19

Yeast is probably the best known fungus - it is used in the baking and brewing industries. Fungi are also used in the cheese industry - think of smelly ‘blue’ cheeses!

Question 20

What size are viruses in comparison to bacteria

Answer 20

Smaller

Question 21

4 ways pathogens are spread

Answer 21

Airborne, water (droplets), direct contact, indirect contact

Question 22

Aseptic technique

Answer 22

A technique used to study bacteria and other microbes effectively. It allows scientists to ensure that the bacteria they are looking at has come from one single source

Question 23

examples of when aseptic technique may be used

Answer 23

Environmental health laboratories, tattoo artists, medical equipment and ear piercers

Question 24

3 measures that must be taken when working under aseptic conditions

Answer 24

Wash hands, flame/heat to kill unwanted micro-organisms, protective clothing

Question 25

What must the equipment be when using aseptic technique

Answer 25

Sterile (equipment sterilised in an autoclave)

Question 26

What is used to grow bacteria

Answer 26

A special jelly called an agar which contains all the necessary nutrients required for the bacteria to grow.

Question 27

Why must we work close to a Bunsen burner when working under aseptic conditions

Answer 27

It creates a convection current to remove any unwanted micro-organisms

Question 28

Why is it necessary to flame the neck of the bottle of agar

Answer 28

Gets rid of/destroys any unwanted microbes on the glass bottle

Question 29

Why must you incubate your Petri dish upside down

Answer 29

Stops the agar drying out and also stops condensation from gathering on the lid and washing away bacterial colonies

Question 30

Why would it be dangerous to incubate the growth plates at 37°C

Answer 30

This is body temperature and could increase the likelihood of growing pathogenic microorganisms that could cause illness

Question 31

Outbreak

Answer 31

An outbreak is a sudden rise in the number of cases of a disease. It may occur in a community or geographical area or may affect several countries. It may last for a few days or weeks or even several years. E.g. Covid or flu

Question 32

Epidemic

Answer 32

An epidemic occurs when an infectious disease spreads rapidly to many people. Epidemic = 1 region or country

Question 33

Pandemic

Answer 33

A pandemic is a global disease outbreak. It differs from an outbreak or epidemic because it affects a wider geographical area first, often worldwide or continental and it infects a greater number of people than an epidemic. It’s often caused by a new virus or a strain of virus. Humans usually have little or no immunity against it. The virus spreads quickly from person to person worldwide

Question 34

Who developed the first vaccination

Answer 34

Edward Jenner

Question 35

What disease did milk maids get from the cows they worked with

Answer 35

Cowpox

Question 36

What was Jenners theory when he noticed that the milkmaids never seemed to get smallpox

Answer 36

If people got cowpox, they were immune to smallpox

Question 37

Who did Jenner choose to carry out his experiment on and why?

Answer 37

He carried the experiment out on a young boy called James Phipps. He was the son of Jenners servant

Question 38

How did Jenner treat the boy and what was the outcome of his treatment

Answer 38

Jenna took cowpox from the udder of a cow and infected the boy with it. The boy was sick for a few days but recovered soon after. Then six weeks later he infected the boy was smallpox and he wasn’t affected by it

Question 39

What was the name of the person who produced the first antibiotic

Answer 39

Alexander Fleming (produced penicillin)

Question 40

What did Fleming notice on his bacterial growth plates when he returned from holidays

Answer 40

There was an area of the plate that was no longer covered in bacteria; this area seemed to radiate from an area of mould that had settled on the plate

Question 41

What conclusion did he draw from his observation

Answer 41

He concluded that the mould must be killing the bacteria

Question 42

Where did Fleming think the mould had come from?

Answer 42

Fleming had said that the plates were left close to an open window and this is how the mould had got into the lab

Question 43

What happened in the experiment carried out by Florey and Chain to show the life-saving effects of penicillin

Answer 43

The experiment involves injecting mice with a lethal dose of bacteria and then injecting the half of the mice with penicillin. The mice that were injected with penicillin survived and the others did not.

Question 44

Why do doctors not prescribe as many antibiotics as they used to

Answer 44

As more antibiotic are prescribed, the bacteria will come resistant and you will not be able to be treated

Question 45

Phagocytes

Answer 45

Phagocytes are the type of white blood cells responsible for mopping up infected cells and pathogens that have entered the body. These cells go around ingesting and then digesting microbes

Question 46

Lymphocytes

Answer 46

These are the cells that produce antibodies. When a lymphocyte encounters a microbe it will produce antibody molecules – these join onto a specific part of the microbe called the antigen. This can instantly cause the microbe to rupture. Rupturing of the cells cause them to die.

Question 47

Antibodies

Answer 47

Antibodies attach to multiple antigens so the pathogens clump up. They send out a signal to the white blood cell. The white blood cell comes and engulfs the pathogens

Question 48

Memory cells

Answer 48

Memory cells can remain in your body for life meaning that if you are infected for a second time your immune system can respond much more quickly – so fast that you do not have any symptoms.

Question 49

Superbugs

Answer 49

These are bacteria that are very hard to stop with antibiotics and are thought to have developed as they mutated to produce new genes that allow them to be resistant to most antibiotics.