Viruses- topic 3 Flashcards
what are viruses? why are they not considered true cells?
-defined as particles not cells because they are very small
-they do not contain cytoplasm or any of the organelles associated with it
what is the general structure of a virus?
-they have a protein coat called a capsid that surrounds nucleic acid which can be either DNA or RNA
what are the two viruses?
-bacteriophages
-Human Immunodeficiency Virus (HIV)
do bacteriophages have DNA or RNA?
-DNA
how do bacteriophages replicate, what is the term used to describe this?
-they are parasitic and invade on bacteria
-inside the host cell the viral DNA codes for new proteins for new capsid coats
-the bacteria cell then ruptures and new viruses are released to continue the cycle
what are the host cells of bacteriophages?
-bacteria
why do bacteriophages have a base plate and tail fibers?
-it allows them to anchor onto bacteria and allows them to punch holes into the cell surface membrane, allowing viral DNA in
what are the contents/ structure of the HIV virus?
-RNA
-protein coat
-lipid bilayer containing glycoprotein
how does HIV virus replicate?
-deliver RNA into the host cell with the enzyme reverse transcriptase which speeds up (catalyzes) the synthesis of DNA from RNA
-the DNA then makes new viruses by synthesizing new protein coats and viral RNA
what type of virus is HIV and why is it known as this?
-retrovirus
-viral RNA is used as a template for DNA
what are the host cells for HIV? why is this particularly bad, what can it develop into?
-helper t cells which are important in the immune system when protecting against disease
-as more are infected the immune system gets weaker and AIDS can develop
what is one similarity between bacteriophages and HIV?
-both very small and contain their genetic material in a protein coat
what are 5 differences between bacteriophages and HIV?
-different shapes, bacteriophages have a base plate and tail fibers
-HIV protein coat is within a lipid bilayer
-HIV have glycoproteins
-HIV have RNA, bacteriophages have DNA
-HIV contain the enzyme reverse transcriptase
