4.1 Flashcards Preview

Biology AS OCR > 4.1 > Flashcards

Flashcards in 4.1 Deck (256)
Loading flashcards...

I have not included all the 'did you know' boxes in this deck.



What is the organism in which a pathogen lives called?

The host.


What does a host body create for a pathogen?

A good habit in which microorganism can live.


What is a pathogen?

A microorganism that causes disease.


How do pathogens live?

By taking nutrition from their host, but also cause damage in the process. This damage can be considerable.


Where do numerous types of microorganism live in or on?

The body of another organism.


What kingdom does bacteria belong to?

The kingdom Prokaryoate.


How does the size of eukaryotic cell's compare bacteria cells?

Bacteria cells are smaller than eukaryotic cells.


How often do bacteria reproduce?

In the right conditions, some types of bacteria can reproduce every 20 minutes. Once in the hosts body, they can multiply rapidly.


What can the presence of bacteria cause?

Their presence can cause diasease by damaging cells or by releasing waste products and/or toxins that are toxic to the host. In plants, the bacteria often live in the vascular tissues and cause blackening and death of these tissues .


What are the problems caused by fungi?

Fungi can also cause a variety of diseases in both plants and animals. There are common fungal infections where the fungus lives in the skin of an animal, and where its hyphae, which form a mycelium, grow under the skin surface.


How does fungi grow across the skin surface?

The fungus can send out specialised reproductive hyphae, which grow to the surface of the skin to release spores. This causes redness and irritation.


Where do fungi live in pants?

In plants, the fungus often lives in the vascular tissue, where it can gain nutrients.


What do fungi cause in a plant?

The hyphae release extracellular enzymes, such as cellulases, to digest the surrounding tissue, which causes decay. Leaves will often become mottled in colour, curl up and shrivel, before dying. Fruit and storage organs, such as tubers (potatoes) will turn black and decay.


How do viruses reproduce?

Viruses invade cells and take over the genetic machinery and other organelles of the cell. They then cause the cell to manufacture more copies of the virus. The host cell eventually bursts, releasing many new viruses which will infect healthy cells.


Describe protoctista.

There are a number of diseases caused by animal-like protoctists. These organisms usually cause harm by entering host cells and feeding on the contents as they grow.


What parasite feeds on haemoglobin inside red blood cells?

The malarial parasite Plasmodium has immature forms that feed on the haemoglobin inside red blood cells.


What are the characteristics of tuberculosis?

A disease that affects many parts of the body killing the cells and tissues: the lungs are most often affected.


What is the organism that causes tuberculosis?

Bacteria Mycobacterium tuberculosis and M. bovis


What are the characteristics of bacterial meningitis?

Infection of the meninges - the membranes that surround the brain and spinal cord; the membranes become swollen and may cause damage to the brain or nerves


What is the organism that causes bacterial meningitis?

bacteria Neisseria meningitidis or Streptococcus


What are the characteristics of ring rot (in plants) ?

Ring decay in the vascular tissue of a potato tuber or tomato, accompanied by leaf wilting.


What is the organism that causes ring rot (in plants) ?

bacterium Clavibacter michiganensis subsp. sepedonicus


What are the characteristics of HIV/AIDS?

attacks cells in the immune system and comprises the immune response.


What is the organism that causes HIV/AIDS?

virus; human immunodeficiency virus


What are the characteristics of influenza?

attacks respiratory system and causes muscle pains and headaches.


What is the organism that causes influenza?

virus from family Orthomyxoviridae - 'flu' viruses


What are the characteristics of tobacco mosaic virus?

causes mottling and discolouration of leaves.


What is the organism that causes tobacco mosaic virus?

virus tobacco mosaic virus.


What are the characteristics of black sigatoka (bananas)?

causes leaf spots on banana plants reducing yield