Diseases and the Immune system

Question 1

what is a disease

Answer 1

condition that impairs the normal functioning of an organism

Question 2

what are the types of pathogen

Answer 2

• bacteria
• proctista
• virus
• fungi

Question 3

what are the types of bacteria

Answer 3

Cocci
- small surface area to volume ratio
- survive in dry conditions
- cause acne

Bacilli
- large surface area and take up nutrients
- causes food poisoning

Vibrio
- large surface are and takes up nutrients
- causes cholera

Spirillum
- corkscrew motion
- stomach ulcers

Question 4

how do bacteria reproduce

Answer 4

• chromosomes duplicate
• cells grows
• cell divides into two

quick reproduction can cause spoiled food and spread disease

Question 5

how do bacteria cause disease

Answer 5

• antigen on bacterium
• produce toxins
• damage cell membranes, enzymes, genetic material

Question 6

what are the bacterial diseases

Answer 6

Tuberculosis
- caused by droplet infection
- dry cough, fever, fatigue, weight loss

Bacterial meningitis
- spread or respiratory and throat secretions
- fever, vomiting

Ring Rot
- discolouration
- leaf curling

Question 7

what is protoctista

Answer 7

• unicellular
• nucleus

Question 8

what is plasmodium

Answer 8

• live as a parasite inside a female mosquito
• mosquito secretes saliva into bloodstream that contains sporozoites
• attack liver cells
• merozoites reproduced asexually and attack red blood cells
• maturation and production of parasites
• female mosquito pregnant with parasite
• infects human

Question 9

what are the protozoan diseases

Answer 9

Blight in potatoes/tomatoes
- fungus like organism that spreads rapidly through potato in warm wet conditions
- leaves collapse, shrivel, turn brown

Malaria
- caused by a parasite
- fever, chills, discomfort, headache, nausea

Question 10

Bacteriophage

Answer 10

• attaches to a specific host cell
• injects genetic material into the host cell
• viral gene causes the host cell to reproduce new viruses
• host cell splits open to release the new virus and the process repeats

Question 11

what is retrovirus replication

Answer 11

• virus attaches to the host cell
• virus fuses with cell surface membrane and enters cell by endocytosis
• virus injects RNA
• RNA used as a template to make DNA
• DNA inserted into chromosomes by protein integrase
• viral RNA synthesised by host cell by transcriptase
• leaves nucleus and cell

Question 12

what are viral diseases

Answer 12

HIV/AIDS
- sexually transmitted
- fever, night sweats, weight loss

Influenza
- droplet inflection
- fever, aching, dry cough, sore throat

Tobacco mosaic virus
- direct contact with plants
- reduce crop yield, yellow spotting, mosaic pattern, malformation

Question 13

what are fungal diseases

Answer 13

Cattle ringworm
- infection of hair and surface layers of the skin
- itchy skin, cracked skin, hair loss

Athlete’s foot
- fungi living on skin, hair, nails called dermophytes that favour warm humid conditions
- sore flaky patches, blisters, itchy skin

Black sigatoka
- airborne
- streaks or leaf spots

Question 14

what is indirect transmission

Answer 14

Fomites
- inanimate objects
- bedding, socks

Vectors

Question 15

what is indirect transmission

Answer 15

Direct Contact
- contact with bodily fluids
- skin to skin

Inoculation
- break in the skin
- puncture wound

Ingestion
Droplet infection

Question 16

what are factors that increase the transmission of communicable diseases in animals

Answer 16

• overcrowded populations
• poor waste disposal
• compromised immune system
• culture
• climate change

Question 17

what are primary defences

Answer 17

Blood clotting = thromboplastin causes blood to clot
Skin = produces sebum that inhibits the growth of pathogens
Expulsive reflexes = coughing and sneezing
Nose = hair and mucus trap and destroy microbes
Eye = tears and REM
Ear = ear wax traps pathogens
Cilia = trap microbes and swallowed
Eating = stomach acid kills microbes

Question 18

types of phagocytes

Answer 18

Neutophils
- lobed nucleus
- engulf and destroy pathogens

Macrophages
- round nucleus
- pathogens antigens combined with glycoproteins to make the antigen and antigen presenting cell

Question 19

what are non-specific defences

Answer 19

Inflammation
- damaged tissues release histamines to make vessels dilate and leaky
- prevents pathogens from reproducing

Question 20

what is phagocytosis

Answer 20

• phagocyte recognises antigens of invading bacterium as foreign
• cell membrane of the phagocyte fuses around the bacterium and engulfs it
• lysosome fuses with vacuole and digestive enzymes hydrolyse microorganisms
• antigens presented on cell surface membrane

Question 21

what is cellular immunity by T Lymphocytes

Answer 21

• surface covered with receptors
• receptors bind to antigens
• receptor on T lymphocyte meets complementary antigen
• activates T-Lymphocyte (clonal selection)
• matures in bone marrow
• clonal expansion (clones of plasma and memory cells)

Question 22

what is humoral immunity by B lymphocytes

Answer 22

• covered with antibodies
• antibodies bind with antigen to form antigen-antibody complex
• antibody on the surface of a B-lymphocyte meets and complementary antigen binds
• helper t cell release interleukins to activate B lymphocytes
• clonal expansion

Question 23

what are the types of T-Lymphocytes

Answer 23

T Helper Cells
- secrete interleukins to activate T and B cells

T regulatory cells
- supress immune response from attacking host cells

T memory cells
- remain in lymph nodes to respond rapidly if the same pathogen invades again

Killer T cells
- protein binds to non-self antigen
- perforin released
- foreign cell identified
- lysis
- non-self cell splits and destroyed

Question 24

what are the types of antibodies

Answer 24

Opsonin’s
- bind to antigen and act as a marker for phagocytes

Agglutin’s
- bind to antigens to cause clumping to prevent them from entering body cells

Anti-Toxins
- bind to toxins to prevent harm

Question 25

what is the structure of an antibody

Answer 25

• glycoproteins with 4 polypeptide chains
• variable regions from antigen binding sites
• hinge region allows for flexibility when antibody binds to an antigen
• constant region allows binding receptors on immune system cells

Question 26

what is the primary response

Answer 26

• pathogen enters the body for the first time
• not many B lymphocytes can make the correct antibody quickly
• shown symptoms
• memory cells produced
• T - lymph record antigen on the pathogen
• B - Lymph remember antibodies

Question 27

what is the secondary response

Answer 27

• same pathogen enters the body
• clonal selection happens faster
• memory B divide into plasma cells to produce correct antibody
• memory T divide and kill pathogen with antigen
• may not show symptoms

Question 28

what is active immunity

Answer 28

• happens naturally when a pathogen enters the body for the first time

Natural
- antigens on pathogen trigger immune response

Artificial
- vaccine contains weakened pathogen that triggers antibody production

Question 29

what is passive immunity

Answer 29

• transfer of antibodies from outside of the body

Natural
- babies drink mothers breastmilk

Artificial
- blood transfusions

Question 30

what is herd immunity

Answer 30

unvaccinated people are protected because the occurrence of the disease is reduced by the number of people who are vaccinated

Question 31

what are autoimmune diseases

Answer 31

• organisms immune system is unable to recognise self-antigens
• treats self-antigens as foreign and launches an immune response

Lupus
- immune system attacks cells in connective tissues
- damage tissues and causes painful inflammation
- affects skin, joints, organs

Arthritis
- immune system attacks cells in the joints

Question 32

what are the routine vaccinations

Answer 32

MMR
- at 1 and before school starts

Meningitis C
- 3 months, 1 year, booster as teen

HPV
- lead to cervical cancer
- year 8 girls

Question 33

how do bacteria develop resistance to antibiotics

Answer 33

• mutation
• bacteria that are resistant survive
• surviving bacteria reproduce passing resistance gene on
• whole population becomes resistant

Question 34

Antibiotic resistance

Answer 34

Causes
- overuse
- not finishing a course

Problems
- resistant strains are hard to treat (MRSA)

Prevention
- complete full dose
- only take when needed

Question 35

what are possible sources of medicines

Answer 35

Penicillin - mould, inhibits synthesis of bacterial cell walls
Docetaxel - treat breast cancer as it induces cell death
Aspirin - willow bark, pain killer
Vancomycin - soil fungus, antibiotic
Digoxin - atrial fibrillation and heart failure

Question 36

what are pharmacogenetics

Answer 36

• test peoples genomes to detect whether or not a drug will work
• replaces ‘one fits all’ approach
• tailored to individual

Question 37

What is synthetic biology

Answer 37

• develop of molecules that mimic aspects of biology
• enzymes
• pigments - pigment in blueberries has health benefits
• genetic engineering

Question 38

transmission of disease between plants

Answer 38

Direct contact = healthy plant touches infected plant
Indirect contact = soil contamination, infected plants leave pathogens in the soil
Vectors

Question 39

factors that increase the transmission of communicable diseases in plants

Answer 39

• overcrowding
• poor mineral nutrition
• damp and warm conditions
• climate change

Question 40

what are chemical defences of plants

Answer 40

Terpenoids
- antibacterial and antifungal properties
- can create a scent

Alkaloids
- nitrogen containing compounds with a bitter taste
- stops herbivores from feeding
- less grazing = less pathogen exposure

Question 41

what are physical defences of plants

Answer 41

Cellulose cell wall
- lignin thickens
- waterproof

Waxy cuticle
- prevents water from collecting on the surface

Guard cells
- closes stomata