Biology 5- Communicable diease

Describe Aseptic technique.

* Wash hands thoroughly and disinfect the work area
* Flame the neck on the bottle before putting the lid on
* Heat the inoculating loop for a few seconds
* Lift the lid of the petri dish never fully removing it

What 3 factors do bacteria need to grow?

* Nutrients (glucose)
* Warmth
* Oxygen

How do viruses cause disease?

Viruses live and reproduce rapidly inside an organisms cells. this can damage or destroy the cells.

Name 2 bacterial diseases.

* Salmonella
* Gonorrhoea

How does TMV affect the plant?

Reduces the plants ability to photosynthesise, affecting growth.

How does HIV affect the body?

The virus attacks the bodys immune cells,which can lead to AIDS where the immune system is so damaged that it cannot fight off infections or cancers.

What are the symptoms of TMV?

* Mosaic patterns of discolouration on the leaves- where chlorophyll has been destroyed.

What are the symptoms of HIV?

Flu-like symptoms at first.

What are the symptoms of Measles?

* Fever
* Red-skin rash
* Complications can be fatal

How is TMV spread?

* Direct contact of plants with infected plant material
* Animal and plant vectors
* Soil: the pathogen can remain in soil for decades

How is HIV spread?

* Sexual contact
* exchange of bodily fluids (eg. blood)

How is Measles spread?

Inhalation of droplets produced by infected people when sneezing or coughing.

Name 3 viral diseases.

* Measles
* HIV
* TMV (Tobacco mosaic virus)

How do antitoxins kill pathogens?

* Bacteria can produce toxins that are harmful to the human body
* White blood cells detect the toxins and produce antitoxins
* the antitoxins neutralise the effects of toxins by counteracting the effect

Describe how a Lymphocyte (Antibodies) kills pathogens

* Pathogens contain antigens on their surface
* When white blood cells detect these antigens, they produce complementary antibodies in response
* The antibodies lock onto the antigens rendering them useless, whilst other white blood cells can destroy them
* Antibodies are specific to the pathogen and can be produced very quickly

What is an antigen?

A unique molecule that pathogens contain on their surface.

Describe how a phagocyte kills pathogens.

* Identifies the pathogen and attaches itself to it
* Cytoplasm surrounds and engulfs the pathogen
* The pathogen is killed and digested
* Indigestible residue is removed

Name the three types of white blood cell.

* Phagocytes
* Antibodies/ Lymphocytes
* Antitoxin

What is a communicable disease?

Diseases that can be passed from one organism to another.

What is a non-communicable disease?

Disease that cannot be passed from one organism to another.

What is a vaccine?

Dead or inactive pathogenic material used in a vaccination to develop immunity to a disease in a healthy person.

What is a protist?

Single celled organisms. Can be pathogenic.

What is fungus?

Resemble plant cells but without chloroplasts. can be pathogenic.

What is bacteria?

Single celled prokaryotic organisms. Live outside the cell. Produce toxins that damage tissues and make us feel ill.

What is a virus?

Pathogens that reproduce inside living cells of other organisms, causing cell damage.

What are pathogens?

Micro-organisms that cause disease.

How does the immune system defend against pathogens?

Destroys pathogens using white blood cells.

How does the stomach defend against pathogens?

Produces hydrochloric acid which kills pathogens.

How does the trachea and bronchi defend against pathogens?

* Secretes mucus
* Covered in cilia

How does the nose defend against pathogens?

Full of hairs and produces mucus which traps pathogens.

How does the skin defend against pathogens?

Creates a barrier and produces antimicrobials in the oil it secretes.

Name 4 types of pathogens.

* Bacteria
* Fungus
* Virus
* Protists

How do health problems interact

* Viruses can trigger changes in cells that lead to cancer


* Immune reactions caused by pathogens can trigger allergies such as asthma
* Severe physical ill health can lead to depression and other mental health problems
* Malnutrition can be linked to obesity, weakened immune system, type 2 diabetes and cancer

How can life situations affect health?

* Gender
* Financial situation
* Where you live
* Health care provided
* Children
* Air pollution

How can stress affect health?

* Heart disease → Heart attack
* Certain cancers
* Mental health problems → Insomnia

→ Anxiety

How can diet affect health?

* Not eating enough →Starvation

→Defiency diseases
* Eating too much → Obesity

→ Some cancers

→ Diabetes (type 2)

What 3 factors have an effect on health?

* Diet
* Stress
* Life Situations

What is health?

A state of physical and mental wellbeing.

Name 4 ways we can control the spread of disease and give an example for each.

* Hygiene- cleans away/kills pathogens
* Isolating infected individuals- reduces the spread by limiting contact
* Destroying/controlling vectors- reduces the spread of pathogens
* Vaccination- Strengthens immune system defences against the disease

What mechanical adaptations help plants defend against disease?

* Thorns and hairs stop animals eating plants
* Leaves that droop or curl when touched to scare herbivores or dislodge insects
* Some plants mimic the apperance of unhealthy or poisonous plants to deter insects or herbivores

What chemical barriers do plants use to prevent disease?

* Many plants produce antibacterial chemicals
* Poison production stops animals eating plants

What physical barriers do plants use to prevent disease?

* Cellulose walls
* Tough waxy cuticle
* Bark on trees

How is malaria prevented?

* Prevent mosquito vectors from breeding
* Mosquito nets to prevent bites
* Vaccinations

What is the treatment for malaria?

Anti-malarial medicine

What are the symptoms of malaria?

* Recurrent episodes of fever
* Can be fatal

How is malaria spread?

Mosquitos feed on the blood of infected people and spread the protist pathogen when they feed on another person.

What is the treatment for rose black spot?

* Fungicides
* Affected leaves removed and destroyed

How does rose black spot affect the plant?

Reduces the plant's ability to photosynthesise affecting growth.

What are the symptoms of rose black spot?

Purple or black spots on leaves, which turns yellow and drops early.

How does rose black spot spread?

Water and wind.

How is gonorrhoea treated?

Antibiotics (many antibiotic-resistant strains have appeared)

How is gonorrhoea prevented?

* Barrier methods such as condoms
* Monogamous partner

What are the symptoms of gonorrhoea?

* Thick yellow or green discharge from the vagina or penis
* Pain when urinating

How is gonorrhoea spread?

Direct sexual contact.

How is salmonella prevented?

Poultry are vaccinated against salmonella bacteria.

What are the symptoms of salmonella?

* Diarrhoea
* Fever
* Abdominal cramps
* Vomiting

How is salmonella spread?

Bacteria in or on food that is being ingested.

What is a toxin?

A harmful chemical produced by microorganisms

Name 3 positive effects of bacteria.

* Assist in digesting food


* Some bacteria produce vaccines, antibiotics and/or drugs
* Act as decomposers

How can pathogens enter the body?

* Water (eg drinking contaminated water)
* Air (eg breathing in droplets)
* Direct contact (eg touching an infected person)

What is a droplet infection?

An infection spread from one person to another by droplets of water released from the upper respiratory tract by sneezing/coughing. Can be prevented by wearing masks.

What are the features of a bacteria cell?

* Single celled organisms
* Have a circular strand of DNA rather than a nucleus
* Do not contain mitochondria
* May have a flagellum
* Living cells

What are the physical features of a virus?

* NOT cells
* Smaller than bacteria
* Consist of genetic material and a protein coat

How do bacteria cause disease?

Reproduce rapidly by splitting in 2 (binary fission) and produce toxins which can damage cells and tissues.

How do viruses cause disease?

Live and reproduce rapidly inside host cells, continuing until the cell bursts. Cell damage is what causes people to feel unwell.

What did Louis Pastuer develop?

Developed the germ theory of disease, showing that it was caused by living microorganisms.

What did Joseph Lister develop?

Introduced the use of carbolic acid to sterilise instruments and to clean wounds in surgeries.

What did Ignaz Semmelweis prove?

Proved that hand-washing could dramatically reduce the number of deaths during childbirth

What did Florence Nightingale introduce?

Introduced handwashing and other hygienic practices into hospitals.