Pathogens

Question 1

Viruses

Answer 1

. Non living infectious agents (50x smaller than bacteria)
. Take over cell metabolism
. The Virus generic gets into host DNA so it can make new ones which burst out the cell destroying it and spreading
. Is successful due to evolving and developing quickly

Question 2

Bacteria

Answer 2

. Classified by cell wall the basic shape (prokaryotic)

. Will produce toxins which will poison and damage host cells

Question 3

Fungi

Answer 3

. Main problem in plants
. Fungi digest living cells and destroy them and some produce toxins which affect the host cell causing disease
. Fungi which cause communicable disease are parasitic

Question 4

Protists

Answer 4

Group of Eukaryotic cells which have a wide variety of feeding methods: . Act as pathogens causing devastating communicable diseases. Uses plant and animal as host
. May need a vector to transfer hosts eg mosquitoes
. Also take over cells and break them open by digesting and using cell contents to reproduce

Question 5

Tobacco Mosaic Virus

Answer 5

. Damages leaves flower and fruit stunting growth and reducing yield
. Resistant crop stains available (no cure)

Question 6

Influenza (Virus)

Answer 6

. Infection of ciliates epithelial cells in the gas exchange system. Kills them leaving airways open for secondary infection
. No cure
. Vulnerable (eg children and elderly) given annual flu vaccine to prevent against changing strains

Question 7

HIV/Aids (Virus)

Answer 7

. Targets T helpers in the immune system gradually destroying it opening people to other infections
. Contains enzyme reserves transcriptase, which transcribes with RNA to single strand of DNA to produce a single strand in host cell
. DNA interacts with host cell material
. Passed via bodily fluids
. No vaccine but anti-retrieval drugs slow process

Question 8

Black Sigatoka (bananas) (Fungi)

Answer 8

. Attack and destroys leaves by penetrating and digesting cells turning leaves black
. Can lead to 50% yield reduction
. No cure but resistant strains are being developed which can help prevent spreading

Question 9

Ringworm (cattle, Fungi)

Answer 9

. Cause grey-white crusty, infectious, circular area of skin
. Not damaging but looks unsightly and may be itchy
. Anti-fungal cream effective cure

Question 10

Athletes foot (Fungi)

Answer 10

. Caused by form of human ringworm the grown in and digests in the warm moist skin between the toes
. Causes cap racking and scaling which is itchy and may be sore
. Anti fungal creams are an effective cure

Question 11

Malaria (Protoctists)

Answer 11

. Spread by bites of mosquitoes (vector)
. Invades RBC, liver and brain
. No vaccine and limited cure
. Key to preventing it is by controlling vector (eg mosquito nets)

Question 12

Potato/Tomato late blight (Protoctists)

Answer 12

. Caused by fungus like protist
. Hypache penetrates host cell destroying leaves, tubers and fruit causing crop damage
. No cure but resistant strains, careful management and chemical treatments reduces infection risk

Question 13

Ring Rot (Potatoes, Tomatoes) (Bacteria)

Answer 13

. Caused by gram positive bacteria
. Damaged leaves, tubers and fruit
. Can destroy up to 80% of the plant and there’s no cure
. Once infected cannot be used to grow crops for at least 2 years

Question 14

Bacterial Meningitis

Answer 14

. Infection of brain which can spread to the rest of the body causing blood poisoning and rapid death
. Antibiotics will cure disease if delivered early enough and vaccines can protect against some forms of bacterial meningitis
. Symptom would by red/purple blotchy rash

Question 15

Tuberculosis (Bacteria)

Answer 15

. Disease of humans, cows, pigs, badgers and deers
. TB destroys lung tissue and suppresses immune system so the body is less able to fight off the diseases
. Both curable via antibiotics and preventable by improving living standards and vaccination