Viruses Flashcards
Are viruses true cells?
No
What is the structure of viruses?
They consist of a nucleus acid core(RNA or DNA) and are surrounded by a protein coat
What is the function of viruses?
They are organisms that cause disease
Define pathogenic
Organisms that cause disease
Can viruses reproduce on their own?
No
State some examples of diseases that viruses can cause
AIDS and Haemorrhagic fevers in humans
Foot and mouth disease in cattle
Rabies in dogs
Leaf-curl in plants
Why are viruses considered to be quasi-living?
They cannot function outside the body of a host living organism
What suggests that have some things in common with living cells?
They contain the same nucleic acids found in the nuclei of living cells
What are viruses also considered to be?
Pathogenic
How are viruses spread?
By air, fluid, or transported from one host to the next by a vector
Define a vector
An organism that carries a disease without itself being affected by it
What other groups can be invaded by viruses?
Bacteria
Fungi
Protista
Insects
How does a virus infect a host cell?
The virus looks for a cell receptor it can fit into and attaches itself to it
The virus then enters the body by endocytosis
The host cell then removes the viruses protein coat and releases the viral nucleic acid into the cytoplasm
Once the host cell is infected, the viral RNA is then synthesised into DNA by the reverse transcriptase
The viral DNA is then incorporated into the host cells DNA
The viral DNA has now taken control over the host cells DNA, amino acids and ribosomes to make replicas of its own RNA and protein coats, the viral DNA then assembled the RNA and proteins coats together
The new virus then escaped the host cell by bursting out of the cell killing it in the process or by budding where the virus is contained in a vesicle
What type of plants do viruses attack?
Plants with plants cells that have damaged cell walls
How can plant cell walls be damaged?
Pruning
Wind blown sand
Chewing and sucking insects
State three examples of different types of viruses
Influenza virus
Tobacco mosaic virus
Bacteriophage virus
What does the tobacco mosaic virus attack?
Plants especially tobacco
What does the TMV do to plants?
It causes characteristic patterns on the leaves such as mottling and discoloration
What does the bacteriophage do?
Infects bacteria
What disease does HIV cause?
Acquired Immune Deficiency Syndrome
What is AIDS?
A viral disease that attacks the body’s immune system
What are some causes of HIV?
Body fluids such blood, semen and vaginal fluids
Infected needles, blood transfusions and pregnancy and childbirth
How can you manage HIV?
- People have to know if their status therefore taking a HIV test is vital in managing the disease
- Then counsellors educate patients on the right kind of healthy lifestyle in order to prevent acceleration of the virus(education is important)
- Antiretrovirals can the be used to treat the virus
What are antiretrovirals?
Medicines that doctors use to prevent HIV from replicating in the body
What is combination therapy?
A method that doctors use to treat HIV positive patients and it means that they use more than one antiretroviral to treat the infection
What is the function of ARV’s?
To slow down the progression of AIDS
What does combination therapy allow?
It allows for the ARV’s to attack the virus in more then one way
State 3 ways the HIV affects the economy
HIV related illnesses affect the labour market as people who are ill cannot work-productivity is affected
The labour force is reduced by deaths from HIV related illnesses
If the family breadwinner is ill because of HIV they cannot work and that results in no income for the family
What are 3 ways that viruses are used for the benefit of humans?
Biological control
Production of vaccines and anti-sera
Genetic engineering
Underneath biological control what way can viruses be used for human benefit?
Viral diseases can be used to reduce pest populations
Underneath the production of vaccines and anti-sera what ways can viruses be used for human benefit?
Inoculating animals are with a weakened strain of a virus causes them to develop anti-bodies and build up active immunity against the disease, the anti bodies can then be used to produce an anti-serum to treat patients in danger from viral infection
Underneath genetic engineering what ways can viruses be used for human benefit?
Viruses that infect bacteria are used to introduce a gene to make bacteria produce useful substances such as insulin to treat diabetes
