Infection and Response

Infection and Response

microorganisms

Living creatures that are too small to see with the naked eye, can only be seen with a microscope

pathogens

microorganisms that cause illness and disease

antiseptics

chemicals used to clean wounds or get rid of sores, eg. nappy rash

disinfectants

chemicals that are used to clean work surfaces and other places where pathogens might be found

hygiene

keeping things clean to help stop the spread of pathogens

what are the four main types of pathogens

viruses, bacteria, fungi, protists

types of bacteria

cholera, boils, MSRA, typhoid, tuberculosis

types of viruses

warts, herpes, polio, flu, mumps, measles, smallpox

how can diseases spread?

air

direct contact (eg. holding hands)

indirect contact (eg. touching surfaces)

food

liquids

vectors

vector

An organism that transmits pathogens from one host to another but doesn't show symptoms

how often do bacteria divide?

every 20 minutes

what is a property of newly divided bacterium?

each new bacterium is exactly the same as the one it came from

mutation (bacteria)

when a bacterium is produced that is slightly different to the others

what do mutations in bacteria result in?

-the bacteria being resistant to existing antibiotics, so the bacteria aren't killed by this treatment

-the non-resistant bacteria are killed but a small number of resistant bacteria remain

-the resistant bacteria survive and reproduce

why should you always complete a course of antibiotics?

some bacteria will stay alive, reproduce and come back to make you sick again

how do you prevent superbugs?

avoid overusing antibiotics

why should you avoid overusing antibiotics?

when you overuse an antibiotic, the bacteria will adapt and wont be affected by it, so when you really need to use it, it won't work

endemic

when thousands of people in a country are infected by an outbreak

pandemic

when a virus spreads very rapidly around the world

communicable diseases

diseases that can be spread between people

non-communicable diseases

diseases that develop with a person from genetic or environmental factors and cannot be spread between people

examples of communicable diseases

TB, HIV, chicken pox, cholera

examples of non-communicable diseases

diabetes, cancer, stroke, arthritis

risk factors for communicable diseases

-poor sanitary conditions

-not washing your hands

-undercooked/raw food

-dirty water

-not covering your mouth when coughing/sneezing

-lack of medical treatment to stop infection (eg. antibiotics/vaccines)

-weak immune system

-exchange of bodily fluids

-dirty medical equipment

preventable threats to health

-low weight children + mothers

-unsafe sex

-tobacco

-alcohol

-high blood pressure

-high cholesterol

-unsafe water/sanitation/hygiene

what do bacteria do?

-single-celled organisms

-divide + produce toxins which affect your body

-some are harmless and can be useful- can be used to make foods, eg. cheese or yoghurt

-once inside the body, they reproduce fast

-cause symptoms such as high temperature, headaches, and rashes

prokaryotic

what do viruses do?

-very small + have a regular shape

-take over cells to reproduce, causing damage + destroying cells

-can cause disease in a range of organisms, from people to bacteria

-once inside the body, they reproduce fast

-cause symptoms such as high temperature, headaches, and rashes

properties of bacteria

prokaryotes

plasmids

have slime capsule around cell

bacteria may produce poisons (toxins that damage tissues and make us feel ill

cell wall made from peptidoglycan

properties of fungi

some fungi, such as yeast, are very important to us

others are pathogens and cause diseases such as athletes foot

eukaryotic

bigger than bacteria but still very small (3-4 nanometres wide)

reproduce through asexual budding

properties of viruses

-even smaller than bacteria- the smallest pathogen

-all viruses are harmful- some are just unpleasant (like the common cold)

-simple organism that doesn't completely display all the characteristics of living things

-consists of protein coating and a strand of genetic material (DNA or RNA)

-live and reproduce inside cells, causing cell damage

properties of protists

-single-celled organisms

-some protists, such as amoeba, have features like an animal cell. Others, such as chorella, have chloroplasts and are more like plants

-some protists are pathogens, some are parasites; these organisms live on, or inside another organism and cause it harm

-food contaminated with protists can cause infections such as amoebic dysentary of which severe diarrhoea is a symptom

white blood cells

Blood cells that perform the function of destroying disease-causing microorganisms

what are the types of white blood cell

phagocytes and lymphocytes

What do lymphocytes do?

produce antibodies specific to the antigen

what do phagocytes do?

engulf and destroy pathogens through phagocytosis

antibody

A protein that acts against a specific antigen

antigen

a toxin or other foreign substance that induces an immune response in the body, especially the production of antibodies.

antitoxins

produced by the host body and neutralize toxins made by antigens

memory cells

General term for lymphocytes that are responsible for immunological memory and protective immunity.

how do vaccines work

The vaccine inserts dead or weakened pathogen to produce a primary immune response

what makes a medicine good

-effective (works)

-safe (no unacceptable side effects)

-stable (able to use + store it under normal condition

-must be able to reach the target in the body and must be able to remove the medicine

placebo

a fake drug used in the testing of medication

double blind trial

Neither the doctors or patient know if they are receiving a placebo or the actual drug

blind trial

Only the doctor knows whether the patient is receiving a placebo or the actual drug

pre clinical trials

Testing the drug on cells/ animals

clinical trials

healthy human volunteers and patients to identify any side effects

toxicity

side effects

efficacy

effectiveness

observer bias

doctors might accidentally give away clues to the volunteers about the drug they are testing

symptoms of plant disease

-stunted growth

-malformation

-spots on leaves

-areas of decay/rotting

-presence of visible pests

-growths

-discolouration

-wilting

How to diagnose plant disease

-garden manuals/online

-take sample of plant and send it to a lab to be tested for disease

-plant scientists/foresters/farmers/market gardeners can use testing kits which contain monoclonal antibodies to identify the presence of pathogens quickly and easily

why are nitrates needed in plants

to convert sugars made during photosynthesis into proteins which the plant needs for growth

sympoms of nitrate deficiency in plants

-stunted growth

-upper leaves pale green

-lower leaves yellow and dead

why is magnesium needed in plants

the synthesis of chlorophyll in the plant (chlorophyll is needed for photosynthesis)

symptoms of magnesium deficiency in plants

less chlorophyll being made so:

-yellowing leaves (chlorosis)

-slowed/stunted growth

why is potassium needed in plants?

for the plant to produce flowers and fruits

symptoms of potassium deficiency in plants

-poor growth of flowers and fruit

-yellowed leaves

-dead spots

plant defenses

waxy surface

thorns

hairy leaves/stems

being tall

carnivorous plants

plant releases poisons/toxins

mimicry

monoclonal antibodies

a collection of identical antibodies that interact with a single antigen site- type of treatment which relies on the immune system

How are monoclonal antibodies produced?

-mouse is vaccinated with target antigen

-B cells stimulated and the specific antibody will be produced by them against the target antigen

-this creates a higher concentration of the target antigen

-mouses spleen is then removed and they isolate and extract the specific B cells

-antibody produces is then electronically fused with a tumour cell, which is called a hybridoma cell

-the antibodies are then extracted from the hybridoma and purified for use

uses of monoclonal antibodies

pregnancy tests, diagnosis of disease,reasearch, measuring and monitoring, treating disease, cancer treatment and detection

advantages of monoclonal antibodies

1)bind to only what needs treatment

2)Healthy cells are not affected

3)Can treat a wide range of conditions

disadvantages of monoclonal antibodies

1) created more side affects than expected

2) difficult

3) not as effective and successful as they once were