infection and response topic 3

what is a bacteria cell

unicellular, prokaryote, only causes some disease many harmless

how big are bacteria cells

approx 1 nanometre in size (larger than viruses)

how do bacteria cells reproduce

binary fission eg mrsa

what is a virus

always cause disease even smaller than bacteria, usually have regular shapes

are viruses alive or not

not as they do not respire

example of a virus

measles

what is a fungi cell

uni and multicellular eukaryotic cells. cell walls are made of chitin

how do fungi reproduce

via spores, as they grow they extend thread-like structure called hyphae

example of fungi

athletes foot

what is a protista

eukaryotic organism and large group of dissimilar organisms, all are uni or multicellular with no tissues

example of protista

malaria

what is the life cycle of infection

spread to a new host, infect a host, reproduce/replicate

how does droplet infection spread disease

cough, sneeze, breathe out, talk you expel tiny pathogens from your breathing system which are then breathed in by someone else

how does direct contact spread disease

diseases can spread by skin to skin contact

how does contaminated food and drink spread disease

eating or drinking substances that contain large number of bacteria

how do breaks in skin spread disease

pathogens enter the bloodstream through cuts, scratches or needle punctures

how can disease be spread through other organisms

organisms that spread disease from host to host are called vectors

how does bacteria make you feel ill

splits in two to reproduce through binary fission and produce toxins

how do viruses make you feel ill

invade and take over your cells to reproduce and when they leave the cell it damages and destroys the cell

what are the symptoms of bacteria and viruses

high temperature, headaches and rashes

what are viruses made of

a strand of nucleic acid, either dna or rna, surrounded by a protective protein coat (capsid) they sometimes have a further membrane envelope, surrounding the protein

what are the symptoms of measles

fever and red skin rash

what is the mortality rate for measles

generally low, but high in LEDCs

how is measles transmitted

droplet

how can measles be prevented

vaccination

how can measles be treated

bed rest and fluid intake

what kind of pathogen is HIV

virus

what does HIV stand for

human immunodeficiency virus

what are the symptoms of HIV

failing immune system, pneumonia, lesions

what is the mortality rate for HIV

medium but high in countries with no anti-aid drugs

how is HIV transmitted

bodily fluids, often during sex or sharing of needles, can also be passed from mother to child in pregnancy

how can HIV be prevented

using protection (condom) during sexual intercourse

how does HIV become AIDS

the virus will attack the body’s immune cells, this means they are less likely to be able to fight off tuberculosis and pneumonia

what does AIDS stand for

acquired immune deficiency syndrome

what are the first lines of defence

skin, tears and saliva, and hairs, cilia and stomach acid

what is the second line of defence

phagocytes

what is the third line of defence

lymphocytes and antitoxins

how does the skin defend

insulator, waterproof, regrows

what happens when the skin is cut

platelets in the blood stick together and form a scab

how does the skin kill some pathogens

secretes antimicrobial compounds

how do tears and saliva defend

tears keep the eyes lubricated, contains anti-bacterial enzymes called lysozymes (tears) and break down the cell walls of bacteria

how do tears defend

wash away dust, dirt and other microbes and contain antibodies

where are ciliated cells

inside of trachea and bronchi

what do goblet cells do

produce mucus that is pumped into the airway

what does stomach acid do

creates the right pH for enzymes to digest protein

what are lymphocytes and antitoxins

type of white blood cells

what do lymphocytes do

recognise the antigen on the pathogen as foreign which stimulates them to produce large numbers of anitbodies

what do antibodies do

clump pathogens together so they can be engulfed by pathogens more easily

what is a memory lymphocyte

if you are infected with the same pathogen twice, memory lymphocytes will recognise the antigen and be able to produce larger numbers of antibodies quicker

what does a antitoxin do

bind and neutralise the toxin

what do vaccinations do

injected with an inactive form of pathogen, virus or toxin which causes wbc to use memory cells to reproduce antibodies to be produced rapidly and in higher concentration so the pathogen can be killed quickly

what is an antiseptic

kills microorganisms outside of the body

what does an antibiotic do

kills bacteria inside the body

what does an antibody do

made by wbc to destroy pathogens

what are antibiotics used to treat

bacterial infections

how do antibiotics act on the bacteria

stops the bacteria from reproducing or alter bacterial enzymes