Chapter 23-27-28 Flashcards
Nucleic acid can be
DNA or RNA ; circular or linear; single or double stranded
Nucleic Acid core surround by capsid (protein cover: repeats of 1 to a few proteins)
No cytoplasm
Some virus also have an envelop ( lipids + protein)
Structures of virus
Virus are classified by their genome
DNA viruses
RNA viruses
Retroviruses ( genes encoded by RNA but include DNA intermediates in those replication)
Virion
Name that recieve the viruses when they are outside of a cell, then they are metabolically inert
Virus hijacks
A cells transcription and translation machine ties to express genes needed to make additional copies of the virus… The virus tricks host cell into making viruses
Bacteriophage
Virus that affects bacteria
Attachment: Virus only attacks
CD4+ cells, viral gp120 glycoproteins attaches to CD4 protein on macrophages and Cd4 cells . Correceptors like CCR5 protein affect likelihood of entry located on cd4 surface. People with a mitigation for the protein are resistant
Replication: Reverse transcriptase
Converts virus RNA to double stranded DNA
Enzyme is extremely error prone
Mutations common in the process
Assembly:
Making copies of virus
Release:
New viruses exit by budding
Aid treatment targets 4
Viral entry
Genome replication
Intervention of viral DNA
Maturation of HIV proteins
Combination theory
Use combination of drugs to lower death rate
Prokaryotes
Oldest, structurally simplest, and most abundant forms of life and fall into two domains bacteria and archae
Molecular classification of prokaryotes
- Amino acid sequences of key proteins
- Percent guanine-cytosine content
- Nucleic acid hybridization (closely related species will have more base pairing)
- Gene and RNA sequencing
Especially RNA - Whole genome sequencing
Characteristics of prokaryotes
1) Unicellularity and variable is size
2) chromosome
3) cell division: binary fission
4) single replication origin mechanism
5) genetic recombination
6) no internal compartmentalization
7) cell walls different layers
8) flagella simple
9) metabolic diversity: photo and chemosynthesis
Prokaryotes have
Chromosome Cell wall Plasma membrane Capsule or slime later Cytoplasm Plasmid (DNA) Food granule Proka-flagellum Ribosomes Pili
DNA replication of prokaryotes
Single replication origin mechanism
Prokaryotes gene expression
Bacteria- only one RNA polymerase
Archae- two or mor RNA polymerases and these enzymes are similar to those of eukaryotes
Prokaryotes genetic recombination
Occurs through Horizontal gene transfer, not a form of reproduction
Archea have an ___ link and bacterial has an ____ link. Archea hydrophobic tail — branched with h3ch3 and bacterial — branched with h3ch3
Ether;Esther; is branched; is not branched
Gram positive
Thick network of peptidoglycan
Also contain lipoteichoic and technic acid (bacterial polysaccharides)
Gram negative
Thin layer
Second outer membrane with lipopolysaccarides
Resistant to many antibiotics
Endospores and internal membrane are not found on? What are each?
Archea; develops thick wall around genome when exposed to environment stress and highly resistant to stress like heat. When Conditions improve can germinate and return to normal cell division; function in reputation or photosynthesis
Types of horizontal gene transfer
Conjugation- cell to cell contact
Transduction- by bacteriophages
Transformation- from the environment
