Communicable Diseases

Question 1

Definition of communicable and non-communicable diseases

Answer 1

Communicable = caused by pathogens that can be passed from one person to another
Non-communicable = cannot be transmitted from one person to another

Question 2

Examples of factors that can make you ill:

Answer 2

Diet = do not get enough to eat/right nutrients → anaemia, too much food or wrong type → diabetes and cancer

Stress = cancer and mental health

Life situations = gender, ethnic group, financial status, sewage, how many children you have, healthcare

Question 3

How health problems interact

Answer 3

Viruses living in cells = cancer
Immune system helps destroy pathogens = defects in your immune system. not work effectively
Immune reactions = common cold, allergies
Physical and mental health
Malnutrition = diabetes, cancer

Question 4

Differences between bacteria and viruses

Answer 4

Bacteria:
Free-living cells
Live inside and outside the body
Divide and excrete toxins, damaging cells

Viruses:
Non-living
Need a host to live
Live inside cells, destroying them

Question 5

How pathogens are spread

Answer 5

Air = expel droplets full of pathogens when you cough sneeze or talk, the other breathe in droplets

Direct contact = STD’s, plant diseases, cuts scratches and shared blood

Water = salmonella, drinking water containing sewage, fungal spores

Question 6

Growing microorganisms practical

Answer 6

1) Sterilise agar gel and inoculating loop
2) Pour agar plates and allow to set fully
3) Sterilise loop in Bunsen burner
4) Dip inoculation loop into the microorganism solution and make streaks on agar
5) Quickly put lid on and secure with tape
6) Label plate and store it upside down
7) Incubate at maximum temperature of 25 degrees (room temperature in schools

Question 7

Preventing pathogens from spreading

Answer 7

Hand washing (before cooking and after using toilet)
Using disinfectants (kitchen surfaces and toilets)
Keeping raw meat ad uncooked food away from each other
Coughing or sneezing into a handkerchief
Maintaining hygiene of people and agricultural machinery
Isolated infected individuals
Destroying or controlling vectors
Vaccines

Question 8

Measles

Answer 8

Virus
Spread by water droplets in air and surfaces
Ill children
Cold, red eyes, high temperature, rash

Question 9

HIV/AIDS

Answer 9

Virus
Attacks immune cells
Remains hidden inside immune system
Spread by sexual contact and exchange of bodily fluids (blood)
No cure
No vaccine
Prevented using condoms and not sharing needles, drugs help

Question 10

Tobacco Mosaic Virus

Answer 10

Discolouration on leaves
Virus destroys the cells
Affects growth
Affected areas of the leaf and do not photosynthesise
Reduces yield of a crop
Spread by contact
Insects act as vectors
Can remain infectious in soil for about 50 yrs
No treatment
Now grow TMV resistant strains

Question 11

Salmonella

Answer 11

Bacteria
Lives in the guts of animals
Disrupts balance of natural gut bacteria
Uncooked food
Vomiting, diarrhoea = caused by bacteria and toxins they secrete
No antibiotics given
Poultry vaccinated against salmonella

Question 12

Gonorrhoea

Answer 12

Bacteria
STD
Spread by unprotected sex with infected person
Thick yellow or green discharge, pain on urination, long term pelvic pain, infertility
Some get no symptoms
Difficult to treat
Prevent spread using barrier protection (condoms)

Question 13

Bacterial disease in plants

Answer 13

Bacteria
Causes crown galls
Infects fruit trees, vegetables and garden flowering plants
Bacteria insert plasmids in to plant cells and cause mass undifferentiated genetically modified cells to grow
Scientists can manipulate bacteria so they carry desirable genes into cells they infect

Question 14

Fungal Diseases

Answer 14

Athlete’s foot
Can be fatal if some fungal diseases attack lungs and brain
Antifungal drugs used
In plants fungal diseases are common

Question 15

Rose Black Spot

Answer 15

Fungal disease
Purple or black spots develop on leaves
Weakening plant
Reduces area of leaves available for photosynthesis
Spreads by wind or water (rain)
Prevent spread by removing and burning affected leaves and stem
Cannot be prevented or cured

Question 16

Malaria

Answer 16

Protist Pathogens
Life and feed on other organisms
Cycle of protists include time in human body and time in female mosquito
Reproduce sexually and asexually in human body
Mosquitos = vectors
Need 2 meals of human blood so female can lay eggs
Affect liver and damage red blood cells
Causes recurrent episodes of fever and shaking when protists burst out of blood cells, can be fatal

Spread can be controlled by:

• insect nets
• insecticides (kill mosquitos)
• preventing vectors for breeding
• can take antimalarial drugs

Question 17

Similarities and Differences between rose black spot and tobacco mosaic virus

Answer 17

Similarities:
Both reduce rate of photosynthesis
Reduce growth of plant

Differences:
RBS is a fungal infection
RBS causes dark spots and leaves turn yellow and fall off
TMV causes mosaic discolouration on leaves

Question 18

Skin Defences

Answer 18

Prevents bacteria and viruses reaching tissue
Get cut, body restores it and forms clot
Produces antimicrobial secretions destroys pathogenic bacteria
Covered in microorganisms, extra barrier prevents entry of pathogens

Question 19

Defences of Respiratory and Digestive Systems

Answer 19

Nose hairs and mucus = trap particles and pathogens that can irritate lungs
Trachea and bronchi secretes mucus = traps pathogens, lining of tubes covered in cilia wafting mucus up to back of throat where it’s swallowed
Stomach acid = destroys microorganisms in mucus you swallow

Question 20

How white blood cells protect you against disease?

Answer 20

Some white blood cells ingest pathogens destroying them
Some produce antibodies specific to each type of pathogen
Some produce antitoxins which counteract toxins released by pathogens

Question 21

Detecting Diseases in plants

Answer 21

Stunted growth
Spots on leaves
Areas of decay or rotting
Growths
Malformed stems and leaves
Discoloration
Presence of visible pests

Question 22

Aphids

Answer 22

Penetrate into phloem vessels
Act as vectors transferring viruses, bacteria and fungi from diseases plants into the tissues of healthy plants on their mouthparts
Destroyed using pesticides
Plants fail to grow

Question 23

Non-Communicable Plant Diseases (how magnesium ions affect plants)

Answer 23

Plants take magnesium ions from soil to make chlorophyll
If level of magnesium ions in soil is low, leaves become yellow and growth slows because plants can’t photosynthesise
Known as chlorisis

Question 24

Plant’s physical barriers

Answer 24

Cellulose cell walls = resist invasion by microorganisms
Waxy cuticle = surface of leaf, barrier
Bark = layer of dead cells, hard for pathogens to penetrate, dead cells are lost or shred, pathogens fall off with bark
Leaf fall = deciduous trees lose leaves in autumn
Thorns
Hairy stems/leaves
Drooping or curling when touches
Mimicry = plants droop

Question 25

Chemical barriers in plants

Answer 25

Plants produce antibacterial chemicals, protect them against invasion of pathogens
Poisons