Infection and Response in Plants and Animals- Paper 1 Flashcards
(79 cards)
1
Q
Health Definition
A
A complete state of physical, mental and emotional wellbeing.
2
Q
Key Features of Communicable Diseases
A
- Can spread to person to person or sometimes people to animals- a.k.a. infectious or contagious
- Caused by fast-spreading pathogens, and can make people sick quickly
3
Q
Key features of Non-communicable diseases
A
- Not infectious
- Lifestyle choices such as drinking, smoking and diet can increase risk of these diseases.
Can also be impacted by life situations like:
-Gender
-Part of world that you live in
-Ethnic group
-Local sewage and rubbish disposal
-Levels of free health care etc. - They are long-term and slowly get worse.
4
Q
Cellular Pathogens
A
- Protists (single-celled eukaryotic)
- Fungi (Multi-cellular eukaryotic) e.g. mould and mushrooms
- Bacteria (Single- celled prokaryotic)
5
Q
Acellular pathogen
A
Virus- an ultramicroscopic non cellular organism that can replicate inside the cells of living hosts- cannot reproduce on its own.
6
Q
How can pathogens spread?
A
- Droplet Infection
- In water
- By direct contact
7
Q
Droplet Infection
A
Pathogens spread through the air e.g. when people cough or sneeze and others breathe in the pathogens
8
Q
Examples of disease spreading through water
A
- Drinking contaminated water
- Poor sanitation
9
Q
Diseases spreading by direct contact
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- Contact with bodily fluids e.g. sexual contact/ sharing needles
10
Q
Types of non-specific defence systems
A
-
Skin: Physical, protective barrier preventing pathogens from reaching the tissue. When you cut yourself, the barrier is broken but the body restores it preventing you bleeding to death and pathogens entering through the wounded area.
It also produces antimicrobial secretions destroying pathogenic bacteria. - Nose: Cillia and mucus traps pathogens, which are removed through sneezing and blowing your nose.
- Trachea and Bronchi: Ciliated epithelial cells lines the tubes which moves mucus up to the nose or back of the throat. The mucus traps pathogens so it could be sneezed out or swallowed.
- Stomach: Produces hydrochloric acid, which destroys micro-organisms in your fod and drink, as well as the micro-organisms in the mucus that you swallow.
- Tears: Chemicals in your tears destroy micro-organisms.
11
Q
What are non-specific defence systems?
A
Physical defence systems that are always there to protect us from any pathogens.
12
Q
What happens when a pathogen makes it inside the body?
A
Immune System produces a specific response to target the pathogen and destroy it.
13
Q
Immune System Definition
A
The body’s defence system against the entry of any foreign body, including pathogens and agents such as pollen grains. The role of it, is to prevent disease.
14
Q
Three ways in which white bood cells destroy pathogens
A
- Phagocytosis
- Producing Antibodies
- Producing anti-toxins
15
Q
How does phagocytosis work?
A
*They engulf and destroy pathogens
- Macrophages are a type of phagocyte which are white blood cells that engulf and absorb waste material, harmful micro-organisms or other foreign bodies in the bloodstream and tissues.
- They have a large-lobed nucleus which allows them to stretch around bacteria, engulf them and digest them using enzymes.
- Once the phagocytes have ingested as many pathogens as possible, they die. Dead phagocytes make up mucus or puss which is often yellow or green in colour.
*Macrophages are a second line of defence and if they’re unable to cope, the third line of defence is mobilised- antibodies
16
Q
How does Producing Antibodies defend against pathogens?
A
*This is a very specific response carried out by white blood cells called lymphocytes.
- Lymphocytes are white blood cells which attacks pathogens by producing antibodies.
- Lymphocytes detect pathogens in the body due to proteins on their surface called antigens.
- Lymphocytes produce antibodies (proteins that match the shape of the antigens) and binds to them, helping to destroy the pathogen.
- Some lymphocytes become memory cells which can produce these antibodies again quickly if re-infected with the same pathogen in the future.
17
Q
How does producing antitoxins help to defend against pathogens?
A
- When bacteria enters the body, they produce toxins which damages the cells amd causes illness.
- Lymphocytes produce antitoxins which binds to the toxins made by the bacteria, preventing harm to your cells (neutralise them).
18
Q
Antibiotic Definition
A
Substance that controls the spread of bacteria in the body, killing them or stopping them reproducing
19
Q
Define antibiotic resistance
A
The ability of bacteria to survive exposure to antibiotics and reproduce, caused by mutations in their genes.
20
Q
Define Binary Fission
A
Form of cell division that prokaryotes use to reproduce.
Similarly to mitosis, the DNA and ribosomes are replicated, and the cell size increases before the cell divides to create two identical bacterial cells
21
Q
How do bacterial pathogens cause disease?
A
- Bacteria divides rapidly through binary fission, releasing toxins that make you feel ill, sometimes directly damaging your cells.
22
Q
What are two types of bacterial diseases?
A
- Salmonella- Food Poisoning
- Gonorrhoea- STD
23
Q
Symptoms of Gonnorheoa
A
*Symptoms occur in the early stages, but then becomes relatively symptomless
- Thick yellow or green discharge from the vagina or penis, and pain on urination
- Untreated/ long-term infection can cause infertility, pelvic pain and ectopic pregnancies.
- Babies born to infected mothers may have severe eye infections and become blind.
24
Q
Preventing Transmission of Gonorrheoa
A
- Bacterial Disease- can be treated with antibiotics however rise of resistant strains means that it is more difficult to treat.
- To prevent spread, barrier contraception methods like condoms can be used.
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How is Gonorrheoa spread?
It is spread by direct sexual contact.
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What are Salmonella?
* Salmonella are bacteria that lives in the guts of many different animals.
* They can be found in raw meat, poultry, eggs and egg products such as mayonnaise.
If these bacteria gets into our bodies, they disrupt the balance of natural gut bacteria and can cause salmonella food poisoning.
The bacteria and toxins they secrete causes the symptoms.
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Causes of Salmonella food poisoning
* Eating undercooked food, when the bacteria have not been killed by heating.
* Eating food prepared in unhygienic conditions where food is contaminated with Salmonella bacteria from raw meat.
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Symptoms of Salmonella
*Symptoms develop within 8-72 hours of eating infected food. It can be fatal to elderly and children due to dehydration but mostly in countries where there are high levels of malnutrition.
* Fever
* Abdominal Cramps
* Vomiting
* Diarrheoa
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# Preventing
Preventing Transmission of Salmonella
* Keep raw meat refrigerated (especially chicken)
* Food should be cooed properly to a high enough temperature to kill bacteria
* In the UK chickens are vaccinated against salmonella to control the spread.
* Avoid washing raw chicken (as it spreads bacteria around the kitchen)
* Wash hands and surfaces well after handling raw chicken.
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Types of Viral Diseases
**Animals:**
* Measles
* HIV
**Plants:**
* Tobacco Mosaic Virus (TMV)
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How do viruses cause disease?
*Viruses are acellular so they cannot reproduce on their own. They are 100 times smaller than bacteria.
Viruses enter our cells, as they need to use them to reproduce. They replicate inside until it bursts causing symptoms of illness.
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Measles Symptoms
* Fever
* Red Skin Rash
* If complications arise, it can cause blindness and brain damage, which can be fatal
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Measles treatment
NO treatment for measles- if someone catches it, they need to be isolated to stop the spread of the virus.
It's rare in the UK due to improved living conditions and a vaccination programme for young children.
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How is measles spread?
Droplet infection
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HIV stand for?
Human Immunodeficiency Virus
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Causes of HIV
Direct contact:
* **Sexual Contact**
* **Exchange of Bodily Fluids**, such as blood which occurs when drug users share needles, or unscreened blood is used for transfusions.
* Can also be spread from mother to child in breastmilk.
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Why does HIV go unrecognised for so long?
Mild flu-like illness to begin with
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How can HIV develop into AIDS?
HIV attacks the immune cells and after the initial mild illness, remains hidden insie the immune system (sometimes for years) until the immune system is so badly damaged that it can no longer deal with infections or certain cancers.
The time between infection with HIV and the onset of the final stages of AIDS is affected by factors including the level of nutrition, overall health of the person and access to antiretroviral drugs.
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How can viruses be cured?
Viruses cannot be cured because any drugs that you could potentially take to kill the viruses, will kill the cells that the virus invaded.
The body's immune system is the only thing that can fight off a virus.
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Preventing the spread of HIV's
* Using barrier methods of contraception
* Not sharing needles
* Screening blood that is used for transfusions, and HIV positive mothers breastfeeding their children.
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Preventing the development of AIDS
* Regular use of antiretroviral drugs can also prevent the development of AIDS for many years and give HIV positive people an almost normal life expectancy.
* Majority of people infected with HIV live in areas such as Sub-Saharan Africa where it is hard to get antiretroviral drugs, so life expectancy for those infected are low.
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Tobacco Mosaic Virus Symptoms
* A distinctive 'mosiac' pattern of discolouration on leaves as the virus destroys cells
* White or yellow patches appear on the leaves and the leaves can wrinkle and curl up.
*May also infect tomatoes, peppers and other closely related plant species.*
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How do pathogens stunt the growth of a plant?
It affects the cells such as chloroplasts inside the leaves, which is necessary for photosynthesis. Less photosynthesis taking place means that less glucose is present to provide energy to the plant through respiration. This means less cell division can take place and the plant has less energy for protein synthesis and production of cellulose, which contributes to healthy growth of a plant.
44
How is TMV spread?
* Contact between diseased plant material and healthy plant material.
* Insects can also act as vectors.
* On gardeners' hands, clothing and tools.
* Viral diseases in plant travels inside the plant through the xylem (up) and phloem (up and down) so they can be indirectly transmitted by insects and mites which feed on plants. (When they feed on the plants, the sugar solution is taken in depriving the plant from sugar and transmitting the virus)
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Which pathogen causes Rose Black Spot?
Fungus (eukaryotic + microscopic including moulds and yeast)
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Symptoms of Rose Black Spot
* Affects roses
* Affects the leaves causing black spots to appear on the leaves.
* The remaining leaf can turn yellow and fall off the plant weakening the plant because it reduces the area of leaves available for photosynthesis, and the plant doesn't flower well.
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How is Rose Black Spot transmitted?
1. The spores of fungus are spread through the air (carried by wind).
2. After it rains, it is spread over the plat in drips of water that splash from one leaf to another.
3. The spores stay dormant over dead winter leaves and on the stems of rose plants.
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Preventing the spread of plant diseases
* Insect Vectors can be killed using insecticides
* Tools should be disinfected, and hands cleaned before working on other plants.
* Removing and **burning** diseased plants.
* Rose Black Spot- Fungicide spray used on leaves and tools.
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Type of diseases spread by protists
Malaria
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How is malaria caused?
*Potentially Fatal disease
* Malaria is caused by a protist pathogen that are parasites- they live and feed on other organisms. The life cycle of a protists includes time in the human body and time in the body of a female Anopheles mosquito.
* Protists reproduce sexually in the mosquito and asexually in the human body.
* The mosquitoes acts as vectors of the disease.
* The female mosquito needs two meals of human blood before she can lay any eggs and this is when the protists are passed into the human bloodstream.
* The protists travel around the body in the circulatory system, affecting the liver and damaging red blood cells.
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Symptoms of Malaria
* Affects the liver and damages red blood cells
* Recurrent episodes of fever and shaking when the protist bursts out of the cell.
* If it doesn't kill them, it weakens the person over time.
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How can malaria be treated?
Using a combination of drugs, but it isn't always available in countries most affected by malaria, and protists have become resistant ot some of the most commonly used medicines.
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How can the spread of malaria be controlled?
*Most ways target the mosquito vector*
* Using insecticide-impregnated nests to prevent mosquitoes biting humans and passing on the protists.
* Using insecticides to kill mosquitoes in offices and homes
* Preventing the vectors from breeding by removing standing water, and spraying water with insecticides to kill the larvae
* Travellers can take antimalarial drugs that kill the parasites in the blood if they are bitten by an affected mosquito.
54
How do vaccinations work?
1. Small amounts of dead or inactive form of the pathogen are put into your body (often by injection).
2. The antigens in the vaccine are detected by T-lymphoctes and stimulate your B-lymphocytes to produce antibodies.
3. The antibodies bind to the antigens and helps kill the pathogen. This is the **Primary Immune Response**.
4. Some lymphocytes become memory cells which are able to produce the specific antibody much faster if you are re-infected with the same pathogen in the future, preventing infections.
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Immunisation definition
Giving you a vaccine made from a daed or inactivated form of disease-causing pathogen. It stimulates your body's natural immune response to invading pathogens.
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Define Pathogens
Micro-organisms that causes disease
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What is herd immunity?
If a large proportion of the population is immune to a disease, the spread of the pathogen in the population is very much reduced and the disease may even disappear. This also prevents those who are unable to take the vaccine, from becoming infected.
If however, the number of people taking the vaccine falls, the pathogen can resurface and herd immunity is lost.
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How to prevent the spread of diseases
**Hygiene**:
* Hand Washing
* Using disinfectants
* Keeping raw meat away from food that is eaten uncooked
* Coughing or sneezing into a tissue
* Maintaining the hygiene of people and agricultural machinery to help prevent the spread of plant diseases
**Isolating Infected Individuals**
**Destroying or Controlling vectors**
**Vaccination**
59
How do antibiotics work?
1. Different groups or classes of antibiotics have different actions on bacteria.
2. Some will damage the bacterial cell wall, causing the cell to burst
3. Others interfere with genetic material in a bacterial cell and cause it to stop the bacterial cell from dividing into two and multiplying (binary fission)
4. Some antibiotics will selectively act on a few specific bacteria. These are known as narrow spectrum antibiotics. Others will target wider range of bacteria. These are known as broad spectrum antibiotics.
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Define Antibacterial
Antibody that kills bacteria
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Define Antibiotic
Type of medicine that can kill bacteria and fungi, but not viruses
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Define antifungal
Antibiotic that kills fungi
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Antiseptic Definition
Kills pathogens- used outside of the body in cleaning products and soaps, some killing viruses
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Antimicrobial
Kills pathogens, medicines used inside the body
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Explain bacterial resistance to antibiotics
There is variation amongst bacteria in a colony.
2. When bacteria are treated with antibiotics, some cells contain mutations which allows them to survive and reproduce, causing the number of resistant bacteria to increase.
3. Antibiotic resistance strains are an example of evolution, as they are more adapted to their environment to survive.
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What is MRSA?
MRSA (methicillin-resistant staphylococcus aureus):
This bacteria is known as a superbug. It is very dangerous because it’s resistant to most antibiotics. It can be fatal if it enters the bloodstream.
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Why are resistant bacteria problematic?
It is a slow and expensive process to develop new antibiotics that can fight them, without damaging bodily cells.
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Three ways we can prevent the the spread of bacteria and the development of antibiotic resistance?
* Avoid the overuse of antibiotics- doctors should only prescribe these when they need to.
* Complete the full course of antibiotics so all bacteria are killed and so none survive to mutate and form resistant strains.
* The agricultural use of antibiotics should be restricted as some bacteria can affect humans and animals.
* If given to animals too often, and then the bacteria becomes resistant to antibiotics, the bacteria can spread to humans e.g. during meat preparation and consumption
69
What are painkillers?
Painkillers are drugs that relieve symptoms caused by toxins, but they don't actually cure the disease because they don't kill the pathogen.
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Aspirin: What drug is it made from and what is it used for?
* Made from Willow Tree Bark
* Used as a painkiller to reduce temperature if you have a fever.
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Digitalis Drug
* Made from foxgloves
* Used to treat heart conditions as it can be used to regulate and control heart rate
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Penicillin
* Discovered by Alexander Fleming.
* Made from Penicillium mould
* Can be made on a large scale by culturing the penicilium mould in a fermenter- similar to the process of yeast production in making alcohol.
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Define Peer Review
Testing processes and results of drug trials need to be reviewed by other scientists before they are published in order to prevent false claims, and avoid bias.
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What does drug testing check for?
* Toxicity: Will it kill humans or damage cells (have unnaceptable side effects)
* Efficacy: Does it prevent/ cure the disease? (Stable (Able to use under normal conditions) + storage for long time)
* Dosage: How much will you need to take for it to work properly.
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Drug Testing
Pre-clinical Testing:
1.Tested using computer models and human cells and tissues in the laboratory, used to determine toxicity (do they kill or damage cells?) However they cannot tell you if the drugs will work in the body as you are not using the whole organism.
2.Animal testing- Getting a known dosage, and monitoring it for toxicity and efficacy.
Clinical Trials:
3.The drug is tested in low doses on healthy volunteers (because it wouldn't be fair to make sick patients work) to see if it causes any harmful side effects at these low doses. If so, they need to be rare or not serious to pass to the next stage.
4.Drugs are tested on patients with the illness. These trials are designed to test efficacy and dosage of the drug needed to treat people with the illness. Optimum dosage is those most effective, with the least side effects. (Often double-blind stage)
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Human Trials
Volunteers divided into two groups: those who recieve the drug and those who don't.
Blind Trials: Volunteers don't know if they are getting the real drug- researchers do.
Double Blind Trials- Volunteers and researchers don't know who is recieving the placebo and the drug.
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Why is a control group used in human clinical trials?
In order to compare between the patients who recieve the drug and patients who don't.
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What is a placebo?
A substance that appears to be the same as the drug but doesn't have any effect.
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How does the placebo effect work?
A patient thinks they have been given the actual drug and expects it to work so report feeling better even though the treatment isn't doing anything.
The patient will have an expectation of the benefits, releasing hormones like endorphins or dopamine, actually making them feel the benefits.
