B3/Infection and Response

Question 1

define a pathogen

Answer 1

a microorganism that can cause a disease

Question 2

name 4 pathogens

Answer 2

bacteria
virus
protists
fungi

Question 3

bacteria and viruses multiply rapidly inside the body, describe how they may make us feel ill

Answer 3

damage to cells

produce toxins

Question 4

describe the symptoms of measles

Answer 4

fever and a red skin rash

Question 5

how is measles spread?

Answer 5

inhalation of droplets from sneezes and coughs

Question 6

how is HIV spread?

Answer 6

sexual contact or exchange of body fluids such as blood which occurs when drug users share needles

Question 7

what are the symptoms of HIV?

Answer 7

initially causes a flu-like illness. unless successfully controlled with antiretroviral drugs the virus attacks the body’s immune cells. late stage HIV occurs when the body’s immune system becomes so badly damaged it can no longer deal with other infections or cancers.

Question 8

describe the symptoms of the tobacco mosaic virus

Answer 8

pattern of discolouration on the leaves which affects the growth of the plant due to lack of photosynthesis

Question 9

what type of pathogen causes salmonella food poisoning?

Answer 9

bacteria

Question 10

what are the symptoms of salmonella food poisoning?

Answer 10

fever, abdominal cramps, vomiting and diarrhoea are caused by the bacteria and the toxins they secrete

Question 11

why are poultry in the UK vaccinated against salmonella?

Answer 11

to control the spread of the bateria

Question 12

what type of pathogen causes the sti gonorrhoea?

Answer 12

bacteria

Question 13

what are the symptoms of gonorrhoea?

Answer 13

thick yellow or green discharge from the vagina or penis and pain on urinating

Question 14

how can the spread of gonorrhoea be controlled?

Answer 14

treatment with antibiotics or use a condom

Question 15

what type of pathogen causes rose black spot?

Answer 15

fungal disease

Question 16

what are the symptoms of rose black spot?

Answer 16

purple or black spots develop on leaves, which often turn yellow and drop early.
it affects the growth of the plant as photosynthesis is reduced

Question 17

how is rose black spot spread?

Answer 17

in the environment by water or wind.

Question 18

how is rose black spot treated?

Answer 18

using fungicides and/or removing and destroying the affected leaves

Question 19

what pathogen causes malaria?

Answer 19

protists

Question 20

what vector do the protists use to reproduce?

Answer 20

mosquitos

Question 21

what methods can be used to control the spread of malaria?

Answer 21

preventing the vectors, mosquitos from breeding and by using mosquito nets to avoid being bitten

Question 22

what are the defence systems in the human body that protect against pathogens?

Answer 22

skin
nose
trachea and bronchi
stomach

Question 23

name 3 ways that white blood cells defend against pathogens

Answer 23

photocytosis
antibody production
antitoxin production

Question 24

what does a vaccination contain?

Answer 24

small quantities of dead or inactive forms of pathogen

Question 25

explain how a vaccination prevents infection from a particular pathogen?

Answer 25

introducing small quantities of dead or inactive forms of a pathogen into the body to stimulate the white blood cells to produce antibodies. if the same pathogen re-enters the body the white blood cells respond quickly to produce the correct antibodies, preventing infection

Question 26

what do antibiotics such as penicillin kill?

Answer 26

bacteria

Question 27

what do antibiotic NOT kill?

Answer 27

viruses

Question 28

what do painkillers do?

Answer 28

treat the symptoms but do not kill the pathogen

Question 29

why is it difficult to develop drugs that kill viruses?

Answer 29

viruses multiply inside the body cells, it is difficult to develop drugs that kill viruses without also damaging the body's tissues

Question 30

traditionally drugs were extracted from plants and microorganisms. give 3 examples

Answer 30

the heart drug digitalis originates from foxgloves, the painkiller aspirin originates from willow. penicillin was discovered by Alexander Fleming from the penicillium mould

Question 31

what is the starting point for many drugs synthesised by chemists in the pharmaceutical industry?

Answer 31

a chemical extracted from a plant

Question 32

what are new drugs tested for?

Answer 32

toxicity, efficiency and dose

Question 33

describe the main stages in a drug trial

Answer 33

pre-clinical testing is done in a laboratory using cells, tissues and live animals. clinical trials use healthy volunteers and patients. very low doses of the drug are given at the start of the clinical trial if the drug is found to be safe, further clinical trials are carried out to find the optium dose for the drug in double blind trials, some patients are given a placebo

Question 34

how are monoclonal antibodies produced?

Answer 34

stimulating mouse lymphocytes to make a particular antibody the lymphocytes are combined with a particular kind of tumour cell to make a cell called a hybridoma cell the hybridoma cells can both divide and make the antibody. single hybridoma cells are cloned to produce many identical cells that all produce the same antibody, a large amount of the antibody can be collected and purified

Question 35

give examples of the use of monoclonal antibodies

Answer 35

for diagnosis such as in pregnancy tests in labs to measure levels of hormones and other chemicals in the blood, or to detect pathogens in research to locate specific molecules in a cell or tissue treat some diseases for cancer the monoclonal antibody can be bound to a radioactive substance, a toxic drug or a chemical which stops cells growing and dividing it delivers the substance to the cancer cells without harming the other cells in the body.

Question 36

how can plant diseases be detected ?

Answer 36

``` stunted growth spots on leaves areas of decay growths malformed stems or leaves discolouration the presence of pests ```

Question 37

how can people identify plant diseases?

Answer 37

reference to gardening manuals taking infected plants to the lab using tests kits

Question 38

what deficiency causes stunted growth in plants?

Answer 38

nitrate deficiency

Question 39

why does nitrate deficiency cause stunted growth?

Answer 39

nitrates are needed to make proteins

Question 40

chlorosis is a condition where leaves produce little chlorophyll. what ion deficiency causes this?

Answer 40

magnesium deficiency

Question 41

name the physical defences in plants to rest invasion from microorganisms

Answer 41

cellulose cell walls tough waxy cuticle on leaves layers of dead cells around stems which fall off

Question 42

name the chemical defences in plants

Answer 42

antibacterial chemicals | poisons to deter harbivores

Question 43

name the mechanical adaptations in plants

Answer 43

thorns and hairs deter animals laves which droop or curl when touched mimicry to trick animals