Infection is the attack and multiplication of microorganisms such as bacteria, viruses, fungi and parasites that are not normally present within the body.
There are four causes of infection which are:
Bacteria - a single-celled microorganism that can exist either as free-living organisms or dependent on another organism for life.
Virus - a microorganism that is smaller than bacteria that can’t grow or reproduce apart from a living cell. A virus invades living cells and uses its chemical machinery to keep itself alive and to replicate itself. It can change itself slightly in each infected person, which makes treatment difficult.
Fungi – there are millions of different fungal species but only around 300 cause ill health. Fungi can be true pathogens that cause infections in healthy people or they can be opportunistic pathogens that cause infection.
Parasites – they are either plant or animal organisms that live in or on another and take their nourishment from that other organism.
The table below identifies some of the differences between all four sources of infection:
| Bacteria | Virus | Fungi | Parasites | |
|---|---|---|---|---|
| Cell membrane | Yes, they have a cell membrane below the cell wall. | No cell membrane. | Yes, they have a cell membrane. | Yes, they have a cell membrane. |
| Genetic Material | DNA. | DNA and RNA. | DNA. | |
| Size | Medium. | Small. | Large. | All different sizes. |
| Type | Intercellular organisms. | Intercellular organisms. | Either unicellular or multi-cellular. | |
| Host | Can grow on non-living surfaces. | Needs a living host, like a plant or animal. | Can live on its own. | |
| Usefulness | Some bacteria can be useful. | Mostly are harmful. | Many fungi are beneficial. | |
| Antibiotics | Kill bacteria. | Cannot kill viruses. | Have no effect. | |
| Source of Energy | Get energy from the same sources as humans. | Get materials and energy from host cells. | They use pre-existing carbon sources in their environment and use the energy from chemical reactions. | |
| Living | Yes. | Characteristics of both living and non-living. | Yes. | Yes. |
| How they are transmitted |
Direct contact with an infected person. Contaminated food or water. Dirty objects or infected animals. |
By direct contact with infected individuals. By contact with contaminated objects. By inhalation. By animals that act as hosts. |
Transmitted through a number of ways, which include transmission by air and contact. | |
| Reproduction | Reproduce by splitting into two cells. | Virus injects itself into a living cell to take over the cell. | Reproduction can take place in multiple ways. | Reproduce asexually and sexually. |
| Mobility | There are several types of bacteria movement. | Viruses do not have structures and thus cannot move on their own. | Typically, fungi are non-mobile organisms. | These move by cilia or flagella. Animal like parasites have false feet. |
Mae haint yn golygu ymosodiad a lluosogrwydd micro-organebau fel bacteria, firysau, ffyngau a pharasitiaid nad ydynt fel arfer yn bresennol yn y corff dynol.
Mae pedwar achos o haint, sef:
Bacteria - micro-organeb un gell sy'n gallu bodoli naill ai fel organebau sy’n byw yn rhydd neu sy’n ddibynnol ar organeb arall am fywyd.
Firws - micro-organeb sy'n llai na bacteria nad yw’n gallu tyfu neu atgynhyrchu ar wahân i gell byw. Mae firws yn ymosod ar gelloedd byw ac yn defnyddio ei beirianwaith cemegol i gadw ei hun yn fyw ac i ddyblygu ei hun. Gall newid ei hun ychydig ym mhob person sydd wedi'i heintio, sy'n gwneud triniaeth yn anodd.
Ffyngau – mae miliynau o wahanol rywogaethau ffwngaidd, ond dim ond tua 300 sy’n achosi afiechyd. Gall ffyngau fod yn bathogenau gwirioneddol sy’n achosi heintiau mewn pobl iach neu gallant fod yn bathogenau manteisgar sy'n achosi haint.
Parasitiaid – maen nhw naill ai'n organebau planhigion neu anifeiliaid sy'n byw yn, neu ar, un arall ac yn cymryd eu maeth gan yr organeb arall honno.
Mae'r tabl isod yn nodi rhai o'r gwahaniaethau rhwng pob un o'r pedwar ffynonell o haint:
| Bacteria | Firws | Ffyngau | Parasitiaid | |
|---|---|---|---|---|
| Cellbilen | Oes, mae ganddynt gellbilen o dan wal y gell. | Dim cellbilen. | Oes, mae ganddynt gellbilen. | Oes, mae ganddynt gellbilen. |
| Deunydd Genetig | DNA. | DNA ac RNA. | DNA. | |
| Maint | Canolig. | Bach. | Mawr. | Meintiau gwahanol i gyd. |
| Math | Organebau rhyng-gellol. | Organebau rhyng-gellol. | Naill ai ungellog neu aml-gellog. | |
| Organeb letyol | Gall dyfu ar arwynebau nad ydynt yn fyw. | Angen organeb lletyol fyw, fel planhigyn neu anifail. | Gall fyw ar ei ben ei hun. | |
| Defnyddioldeb | Gall rhai bacteria fod yn ddefnyddiol. | Mae’r rhan fwyaf yn niweidiol. | Mae llawer o ffyngau yn fuddiol. | |
| Gwrthfiotigau | Maen nhw'n lladd bacteria. | Methu lladd firysau. | Dim effaith. | |
| Ffynhonnell Egni | Cael ynni o'r un ffynonellau â phobl. | Cael deunyddiau ac ynni o gelloedd lletyol. | Maen nhw’n defnyddio ffynonellau carbon sydd eisoes yn bodoli yn eu hamgylchedd ac yn defnyddio'r ynni o adweithiau cemegol. | |
| Byw | Ydynt. | Nodweddion byw a difywyd. | Ydynt. | Ydynt. |
| Sut maen nhw’n cael eu trosglwyddo |
Cysylltiad uniongyrchol â rhywun sydd wedi'i heintio. Bwyd neu ddŵr halogedig. Gwrthrychau budr neu anifeiliaid sydd wedi'u heintio. |
Trwy gysylltiad uniongyrchol ag unigolion sydd wedi’u heintio. Trwy gysylltiad â gwrthrychau wedi'u halogi. Trwy anadlu. Gan anifeiliaid sy'n gweithredu fel organebau lletyol. |
Cael eu trosglwyddo trwy nifer o ffyrdd, gan gynnwys trosglwyddo drwy’r awyr a chyswllt. | |
| Atgynhyrchu | Atgenhedlu trwy rannu yn ddwy gell. | Firws yn chwistrellu ei hun i mewn i gell fyw i gymryd y gell drosodd. | Gall atgynhyrchu ddigwydd mewn sawl ffordd. | Atgynhyrchu yn anrhywiol ac yn rhywiol. |
| Symudedd | Mae sawl math o symudiad bacteria. | Nid oes gan firysau strwythurau ac felly ni allant symud ar eu pen eu hunain. | Yn nodweddiadol, mae ffyngau yn organebau nad ydynt yn symudol. | Mae'r rhain yn symud drwy cilia neu fflagela. Mae gan barasitiaid tebyg i anifeiliaid draed ffug. |
How can microorganisms be defined?
Drag the microorganism to match the correct definition
Sut y gall micro-organebau gael eu diffinio?
Llusgwch y ficro-organeb i gyd-fynd â'r diffiniad cywir
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Rhybudd! Ni ellir defnyddio’r adnodd yma ar ffonau symudol neu dabled.
Well done. You have matched them all correctly.
Da iawn. Rydych wedi paru pob un yn gywir.
Microorganism Micro-organeb |
Definition Diffiniad |
Correct answers Atebion cywir |
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