Edexcel CS Biology Topic 5

Define health

a state of complete physical, mental and social well-being

What is a communicable disease?

any disease that can be spread directly from one person to another and is caused by pathogens

What is a non-communicable disease?

when a disease cannot be spread from animal to animal or person to person and isn’t caused by a pathogen

What is a pathogen?

a disease-causing organism

Give 4 types of pathogens

viruses, bacteria, fungi and protists

What does cholera cause?

diarrhoea

What type of pathogen causes cholera?

bacteria

What does tuberculosis cause?

lung damage

What type of pathogen causes tuberculosis?

bacteria

What does chalara ash dieback cause?

leaf loss and bark lesions

What type of pathogen causes chalara ash dieback?

fungi

What does malaria cause?

damage to blood and liver

What type of pathogen causes malaria?

protists

What does HIV do?

destroys white blood cells, leading to the onset of AIDS

What type of pathogen causes HIV?

virus

How is cholera spread?

water

How is tuberculosis spread?

airborne

How is chalara ash dieback spread?

airborne

How is malaria spread?

animal vectors

What does STI stand for?

sexually transmitted infections

Give 2 examples of STIs

chlamydia and HIV

What type of pathogen causes chlamydia?

bacteria

how to prevent TB spread

avoid overcrowding, good hygiene

how to prevent chalara ash dieback

remove infected plant, restrict tree movement

malaria prevention

mosquito nets, insect repellent

stomach ulcers by helicobacter prevention

hygiene, clean water

what is ebola

virus

what does ebola cause

hemorrhagic fever

how is ebola and chlamidya spread

spread of bodily fluids

what does helicobacter cause

stomach ulcers, vomiting

what is helicobacter

bacteria

how is helicobacter spread

contaminated food and water

how can STIs be prevented

use protection - condom, absistence

how can presence of a disease lead to another

weakens immune system increasing chances of communicable disease. Weaken organ systems - increase chance of non-communicable disease

what does chlamidya cause

infertility

how to prevent ebola

isolation and sterilisation

what are the 2 types of antibodies

phagocytes and lymphocytes

how do phagocytes protect the body

they engulf the pathogen and break it down with enzymes

what are the 2 types of lymphocytes

antibody producing lymphocytes , anti toxin producing lymphocytes

how do antibody producing lymphocytes protect the body

they produce antibodies to bind to the antigens of pathogens to make them clump together so they can be engulfed by phagocytes

how do antitoxin producing lymphocytes protect the body

they produce anti toxins to neutralise the toxins

what are memory lymphocytes

lymphocytes that remain in the blood after the pathogen is killed so if there’s a second infection they can easily create antibodies.

what antibody is involved with specific immunity

lymphocytes

how do vaccines work

person is injected with weakened or dead version of pathogen. body produces memory lymphocytes so if they get infected again they can respond quicker with more antibodies.

physical defences of the human body against pathogens

mucus and cilia in trachea and nose, skin

chemical defences of body against pathogens

lysozymes and HCl

what are risk factors for cardiovascular disease

high-fat diet, smoking, lack of excercise

what are risk factors for malnutrition

poor diet

risk factors for obesity

lack of exercise, high fat diet

what is a risk factor for liver disease

alcohol consumption

what are measurements for obesity

bmi, waist to hip ratio

treatments for coronary heart disease

statins, stents, heart transplant , lifestyle changes

what causes coronary heart disease

buildup of cholesterol in the coronary arteries which causes lumen to narrow meaning reduced blood flow to heart muscles

how do stents work

wire mesh that is inflated to widen the artery

drawback of stents

have to take anti-coagulation drugs to prevent clots

statins

drug that lowers cholesterol production by blocking an enzyme in the liver needed to make cholesterol

statin drawback

have to be taken daily , damages kidney and liver

heart transplant drawbacks

risk of rejection for donor heart. mechanical heart doesn’t last long and uses a lot of power

how to prepare a Petri dish to grow bacteria

wash hands and clean area with antibacterial soap

use bunsen burner to create sterile updraft

take a sterile petri dish and pour molten agar into the dish and let it set

heat an inoculating loop and use it to transfer bacteria in zig zag manner

secure lid with tape and incubate at 25 degrees for 48 hours

investigating antiseptic

wash you hands and workspace and work near a bunsen burner

divide the plate of Petri dish with nutrient agar with permanent marker and mark 4 dots

soak paper disks in antibiotics and carefully place them on the dots , ensuring the lid is away from your face

use a paper disk with no antibiotics as a control

secure the lid and incubate at 25 degrees for 48 hours

calculate area of circle to see its effectiveness. larger inhibition zone means more effective

what are the 2 stages of developing new drugs

pre clinical and clinical trials

what are the stages of pre clinical

test on computer models

test on cells, tissues, organs

test on animals

stages of clinical

test on healthy volunteers

test on small group with illness

test on large group with illness

the clinical trials are double blind. What does this mean?

both the volunteers and the testers don’t know which is placebo and which is drug

what do pre clinical trials test

safety and effectiveness

what do clinical trials test

safety, effectiveness, dosage, side effects and long term effects

physical defences of plant

waxy cuticle and cell wall - prevent entry into cell

what can the waxy cuticle also do

prevents fungal spores

chemical defences of plants

pest repellants, poisons, antiseptics

mechanical defences of plants

hairs , thorns, leaves that curl , mimicry

methods of diagnosis of plant disease

observations, microscopy , DNA analysis, Test kits, distribution of disease

susceptibility

likelihood of contracting disease

immunity

the body’s ability to resist or defend against infections

how does chalara ash die back spread long distances

fungal spores are carried on the wind

how is cholera prevented

hygiene, clean water

what could HIV cause

colds

how is HIV transmitted

bodily fluids

microorganism

a living thing that is so small it can only be seen with a microscope

how do mucus and cilia act as a physical defence

mucus traps organisms and cilia beat to move it out and for it to be removed by coughing . they also act as a physical barrier

how do lysozymes and stomach acid act as a chemical defence

kills micro-organism by dissolving organisms

where are lysozymes found

sweat and tears

what do lysozymes have

antimicrobial properties

what type of immunity do phagocytes form

non-specific immunity as the response is the same for any pathogenic cell

why do antibodies have a specific immune response

antibodies only fit one type of antigen on a pathogen

how do antibodies signal to phagocytes that there are cells present that need to be destroyed

release chemicals

immune response

• pathogen enters blood and releases toxins

• phagocytes enguld pathogens

• B-lymphocytes detect antigen

• B-lymphocytes make antibodies

• antibodies clump pathogen and phagocyte engulfs it

• lymphocytes release antitoxins

• memory lymphocytes stay in blood

what are antibody producing lymphocytes known as

B-lymphocytes

what is true about a secondary infection immune response and why

the secondary immune response produces more antibodies and faster because they already have memory lymphocytes that can make the correct antibody

herd immunity

most people in a population is immune so people that aren’t immune are indirectly protected

advantages of vaccines

prevents epidemics, slows down spread of disease

disadvantages of vaccines

may not always give immunity, there can be side-effects

aseptic technique

method used to prevent contamination by unwanted micro-organisms when working with bacteria

name some aseptic techniques

sterilise Petri dish in autoclave, heat inoculating loop, use a lid and lightly tape it on, store Petri dish upside down , work near bunsen burner

how does working near the bunsen burner prevent unwanted microorganisms

creates a sterile updraft . Creates convection current meaning unwanted microorganisms move to cooler regions - preventing them falling onto agar plate

how does heating inoculating loop prevent unwanted microorganisms

kills unwanted microorganisms due to heat

how does using a lid that is lightly taped on prevent unwanted microorganisms

it stops unwanted microorganisms from entering from the air

how does storing the Petri dish upside down prevent

drops of condensation falling that could be contaminated

how can you sterilise Petri dishes and what does it do

place in autoclave. uses steam at high pressure and temperature to kill microorganisms

what are the 2 types of medicine

medicine to treat causes of disease, medicine to treat symptoms of disease

antibiotics

medicine that kills bacteria by inhibiting processes such as cell wall production.