BIOL 1111 Lecture Notes - Lecture 6: Virus, Chromosome, Dna Replication
13 Jun 2018
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Chapter 23- Viruses, Viroids and Prions: Infectious Biological Particles
What is a virus?
-oliig ifetie agets ut still lassified eause it’s ot a ell
Characteristics
-virus particle (virion) consists of a nucleic acid genome enclosed in a protein coat (capsid)
-some have envelope
-viral genome: DNA or RNA, enclosed by capsid; double or single stranded (ranges to >100 genes)
Viral Structure
1. Helical viruses
-protein subunits assemble in rodlike spiral around the genome (cylindrical structure)
-common form of plant viruses
2. Polyhedral viruses
- genome in the middle, proteins form triangular units in geodesic shape
-infect plants, animals, bacteria
-some have protein spikes for host cell recognition
3. Enveloped viruses
-helical or polyhedral virus covered by surface membrane derived from host cell
-protein spikes for host cell recognition and adhesion (to next host)
4. Complex polyhedral viruses
-polyhedral head plus complex tail
-genome in head, uses head to inject genome into host cell
Acquiring their Envelope
-the viral particle pushes up against
the cell membrane, the cell
membrane surrounds the virus (both
host proteins and viral recognition
proteins around that virus), and then
breaks off
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Document Summary
Chapter 23- viruses, viroids and prions: infectious biological particles. (cid:374)o(cid:374)li(cid:448)i(cid:374)g i(cid:374)fe(cid:272)ti(cid:448)e age(cid:374)ts (cid:271)ut still (cid:272)lassified (cid:271)e(cid:272)ause it"s (cid:374)ot a (cid:272)ell. Virus particle (virion) consists of a nucleic acid genome enclosed in a protein coat (capsid) Viral genome: dna or rna, enclosed by capsid; double or single stranded (ranges to >100 genes) Protein subunits assemble in rodlike spiral around the genome (cylindrical structure) Common form of plant viruses: polyhedral viruses. Genome in the middle, proteins form triangular units in geodesic shape. Some have protein spikes for host cell recognition: enveloped viruses. Helical or polyhedral virus covered by surface membrane derived from host cell. Protein spikes for host cell recognition and adhesion (to next host: complex polyhedral viruses. Genome in head, uses head to inject genome into host cell. The viral particle pushes up against the cell membrane, the cell membrane surrounds the virus (both host proteins and viral recognition proteins around that virus), and then breaks off.
