Biology - Infetion and response

Question 1

How are infections caused

Answer 1

When a foreign pathogen invades an organism

Question 2

How do viruses make us feel ill

Answer 2

Viruses are tiny non-living particles that can reproduce rapidly within the body. They invade host cells and use them to make new virus particles. Once the new virus particles are made, they cause the cell to burst. The cell damage makes us feel ill.

Question 3

How does bacteria make us feel ill.

Answer 3

Bacteria are small living cells that either damage cells directly or by producing toxins. The toxins released by bacteria can damage the cells and tissues, making us feel ill.

Question 4

What is fungi

Answer 4

Some fungi are single celled organisms that have a body made up of hyphae. the hyphae are able to grow and penetrate tissue, such as human skin or the surface of plants. The hyphae produce spores that can spread to other plants and animals.

Question 5

How do protists make us feel ill

Answer 5

protists are single celled eukaryotes. Many are parasites, meaning they live on or inside other organisms. They are often transferred to the host organism by a vector such as insects or mosquitos. They make us feel ill by damaging our tissue.

Question 6

4 ways to stop a disease from spreading

Answer 6

Vaccination
Isolation
Disease vectors
Hygiene

Question 7

What is tobacco mosaic virus

Answer 7

Pathogen that affects plants such as tomatoes. They cause discolouration and stunt growth in plant as photosynthesis cannot take place.

Question 8

What is HIV

Answer 8

HIV is spread through sexual contact or exchange of bodily fluids. It causes flu-like symptoms however unless antiretroviral drugs are taken successfully, HIV virus enters the lymph nodes and attacks the body’s immune system.

Question 9

What is measles

Answer 9

Virus that can be spread by inhaling droplets. It causes a fever and red skin and can be fatal therefore most young children are vaccinated against it.

Question 10

What is gonorrhoea

Answer 10

Sexually transmitted disease that causes pain when urinating and a thick yellow or green discharge from vagina or penis. Barrier methods include contraception such as condoms which can stop the bacteria spreading from person to person.

Question 11

What is salmonella

Answer 11

disease we may get from food that has not been cooked properly or has been prepared in unhygienic conditions. Causes stomach pain, fever, vomiting and diarrhoea

Question 12

What is rose black spot

Answer 12

Can be spread through water or air (wind). Causes purple or black spots on leaf of rose plants and eventually the leaves discolour and fall off. Makes it harder for the leaves to photosynthesise and so plant growth is slower. Must destroy and remove the discoloured leaves and use fungicides.

Question 13

Examples of non-specific defenses of the body

Answer 13

Skin
Stomach acid
Mucus
Tears

Question 14

How does skin fulfill its purpose of a non-specific defense

Answer 14

-waterproof barrier that pathogons cannot pass through
-good bacteria permanently live on the skin which covering the surface and preventing pathogens from growing on our skin.

Question 15

How does the stomach fulfil its purpose of a non-specific defense

Answer 15

-glands in stomach wall produce hydrochloric acid, which destroys any pathogens in the stomach

Question 16

How does mucus fulfil its purpose of a non-specific defense

Answer 16

Produced in the respiratory system and traps particles and bacteria from entering our airways

Question 17

How do tears fulfil its purpose of a non-specific defense

Answer 17

contain enzymes that destroy any pathogens that make contact with our eye

Question 18

what do anti toxins do

Answer 18

the immune system responds to toxins from bacteria by producing anti-toxins which neutralize the toxins and prevent them from causing harm

Question 19

What are antibodies

Answer 19

White blood cells recognize foreign antigens (proteins) on the surface of pathogens and produce protein molecules called antibodies. antibodies are specific to particular pathogens

Question 20

what is phagocytosis

Answer 20

White blood cells find the pathogen and engulf it by changing shape. The white blood cell ingests and digests the pathogen, destroying it.

Question 21

How do memory cells work

Answer 21

Some white blood cells remain in the blood as memory cells from. If the same pathogen was to invade the body again the memory cells are able to produce antibodies faster , produce more antibodies, meaning that the antibody concentration remains in the body for longer

Question 22

Why do antibiotics not work on viruses

Answer 22

viruses stay inside host cells and are not living cells

Question 23

how do antibiotics work

Answer 23

Destroying cell membranes of the bacteria so that they cannot replicate

Question 24

how do doctors stop antibiotics resistance

Answer 24

doctors should only prescribe antibiotics if they are needed and not for minor infections or viral infections. patients should complete their course of antibiotics to ensure all bacteria are killed

Question 25

How were drugs extracted before

Answer 25

before most drugs were extracted from plants and microorganisms

Question 26

how are drugs extracted nowadays

Answer 26

nowadays most drugs are synthesised in the pharmaceutical industry

Question 27

what are painkillers used for

Answer 27

used or relieve pain caused by an infection but do not cure diseases or kill pathogens

Question 28

What is carried out in preclinical testing

Answer 28

Scientists carry out early stage testing on cells and tissues. They also carry out stage testing on live animals which is useful for working out toxicity

Question 29

What is carried out in clinical testing

Answer 29

Scientists test drugs on health volunteers or patients to check how safe the drug is. The dose is usually low

Question 30

how can plants suffer from ion deficiency

Answer 30

most plants gain their minerals from the soil. But if the soil quality is poor , plants can suffer from ion deficiency

Question 31

magnesium deficiency

Answer 31

magnesium is required for the production of chlorophyll. If there is a lack of magnesium then the plant cannot photosynthesise well. This means that it cannot produce the glucose needed for healthy growth. When magnesium is absent plant leaves are yellow

Question 32

Nitrate deficiency

Answer 32

Nitrates are needed for the production and synthesis of proteins. Without proteins plants cannot grow. This means that a nitrate deficiency causes stunt growth

Question 33

plant defences

Answer 33

mechanical defences chemical defences physical defences

Question 34

signs of plant disease

Answer 34

presence of pests spots on leaves growths malformed stems or leaves areas of decay discolouration stunted growth

Question 35

Monoclonal antibodies are specific to

Answer 35

one binding site on one protein antigen

Question 36

what are some uses of monoclonal antibodies

Answer 36

treating cancer testing for HIV testing for pregnancy

Question 37

How can the spread of disease be reduced or prevented

Answer 37

- Being hygienic - Destroying vectors - Isolation - Vaccination

Question 38

What do vaccinations involve

Answer 38

Injecting small amounts of dead or inactive pathogens. These carry antigens which cause your body to attack them - even though the pathogen is harmless.

Question 39

How do vaccinations prevent infection

Answer 39

White blood cells know how to fight of the pathogen and therefore next time it enters the blood stream, white blood cells can massively reproduce antibodies to kill off the pathogen.

Question 40

Pros of vaccinations

Answer 40

- Helped to control lots of communicable diseases that were once common in the UK - Big outbreaks of disease can be prevented if a laege percentage of people are vaccinated - Provides herd immunity

Question 41

Herd immunity

Answer 41

Even people who aren't vaccinated are unlikely to catch the disease because there are fewer people passing it on

Question 42

Cons of vaccination

Answer 42

- Doesn't always work - Can have a bad reaction to a vaccine

Question 43

What does it mean if a bacteria is resistant to antibiotics

Answer 43

When you treat the infection only the none resistants strains will be killed.

Question 44

How does antibiotic resistance work

Answer 44

Bacteria can mutate - sometimes cayuse them to be resistant to an antibiotic. The individual resistant bacteria will survive and reproduce, and the population of the resistant strain will increase.

Question 45

What is Asprin used for

Answer 45

Painkiller to lower fever. Developed from a chemical found in willow.

Question 46

What is Digitalis

Answer 46

Used to treat heart conditions. Was developed from a chemical found in foxglove

Question 47

What is the difference in how drugs are made now compared to before

Answer 47

They are now made on a large scale in the pharmaceutical industry. Before they were extracted from a lab

Question 48

Why do plants need nitrates

Answer 48

To make proteins and therefore for growth a lack of nitrates leads to stunted growth

Question 49

Why do plants need magnesium ions

Answer 49

Needed for making chlorophyll which is needed for photosynthesis. Plants without enough magnesium suffer from chlorosis and have yellow leaves

Question 50

Common signs of plant diseases

Answer 50

- Stunted growth - Abnormal growths - Spots on leaves - Malformed stems or leaves - Patches of decay - Discolouration

Question 51

How can plant diseases be identified

Answer 51

- Looking up signs in a gardening manual - Taking the infected plant to a laboratory - Using testing kits that identify the pathogen using monoclonal antibodies

Question 52

Physical defences of plants

Answer 52

- Waxy cuticle - provides a barrier to stop pathogens entering - Plant cells have cell walls that form a barrier against pathogens that make it past the waxy cuticle - Layers of dead cells around their stems, for example the outer part of the bark on trees

Question 53

Chemical defences of plants

Answer 53

- Some produce antibacterial chemicals which kill bacteria - Other plants produce poisons which can deter herbivores

Question 54

Mechanical defences of plants

Answer 54

- Thorns and hairs which stop animals from touching and eating them - Droop or curls which knock inserts away Some plants can mimic other organisms