immune systems/defences + vaccines

Signs of disease in plants (7)

Stunted growth

Discolouration

Spots on leaves

Presence of pests

Abnormal growths

Areas of decay (rot)

Malformed stem and leaves

Identification of plant diseases (4)

field → reference books and websites, tissue analysed in detail, use testing kits

laboratory→ diagnostic monoclonal antibodies identifying pathogen

Insects and plant diseases (3)

Eat and destroy plants

Act as vector for other pathogens

Aphids are a pest (sap sucking insects)

E.g. greenfly, blackfly

Mineral deficiencies (2)

Nitrate ions: needed for proteins to make it grow → leaves pale/yellow

magnesium ions: needed to make chlorophyll for photosynthesis→ can’t grow

Physical plant defences (3)

Cellulose in cell walls to stop pathogen

Tough waxy cuticle on leave surface as a barrier

Bark on trees sheds as made of dead cells

Chemical plant defences (2)

Produce anti microbial chemicals that can protect against pathogens

Some produce poisons (e.g. foxglove) to deter animals from eating them

Mechanical plant defences (3)

Hairs and thorns deter from eating or laying eggs on them (e.g. roses)

Mimicry to trick animals (e.g. passion flower has dots like butterfly eggs)

Leaves can curl up or droop when touched → scares bigger animals and dislodges smaller ones

Non specific defences

Does not distinguish between pathogens, defends against all

Specific defences

Does distinguish between pathogens, defends against specific one e.g. antibodies

Tears(ns)

Washes out pathogens + contains lysosomes

Skin(ns)

Tight cell junctions firm strong barriers + anti microbial compounds in sweat + commensal bacteria + scabs when breached

Large intestines(ns)

Contains ‘good’ bacteria to stop pathogens from growing (peristalsis)

Nose(ns)

Internal hairs + stops pathogens from entering + produces mucus + physical bacteria

Stomach(ns)

Contains hydraulic acid (chemical) to kill bacteria

Mouth(ns)

Contains ‘good’ bacteria to stop pathogens growing

Trachea + bronchi(ns)

Lined with cilia (hairs) to help sweep them away + mucus (goblet cells) traps microbes

Reproductive system(ns)

Vagina and urethra are acidic

Memory cells(s)

Remember the pathogens the body has been infected with before

Non specific defences (4)

Physical (barriers), biological (organisms), chemical (chemicals), mechanical (motion)

Vaccines step 1

Harmless pathogen is injected (dead or weakened or a small part)

Vaccines step 2

Antigens trigger a response

It can take days for a lymphocytes making complimentary antibodies to be activated

Vaccines step 3

Lymphocytes able to produce complimentary antibodies, multiply and release them

Vaccines step 4

Memory cells (lasting years) are produced

Vaccines step 5

If antigen is encountered again, antibodies produced much faster = long lasting immunity