Cells viruses

54 %
46 %
Information about Cells viruses
Health & Medicine

Published on March 27, 2014

Author: mprasadnaidu

Source: slideshare.net


cell biology

M.Prasad Naidu MSc Medical Biochemistry, Ph.D.Research Scholar

What is the importance?  Division of labor  Increased Surface Area  Regulation

Prokaryotes  Simplest  No organelles  No nucleus  No membrane bound organelles  DNA uncomplexed by histones


Prokaryotes  Prokaryotes can live in the coldest, hottest, most acidic and most highly pressurized environments.  They can live in places such as beneath the earth in bare rock, under glaciers, floating around in clouds and miles down on the sea floor at temperatures greater than 100 C.


Bacteria  Bacteria live mostly on the surfaces of objects where they grow as colonies.  Bacteria are important in making soil, feeding cows, controlling insects, making medicines, making bioplastics, making plants grow, degrading pollutants such as oil and plastics as well as in causing disease.

Bacteria  Most bacterial species are un-named and unidentified  Tens of thousands of species have been isolated  There are more than 15,000 known species of bacteria living in the sea  Most famous is E.coli (Escherichia coli)

E. coli

E.coli  well studied  cell envelope  plasma membrane constitutes #2  pili (for adherence to cells)  flagella (for propulsion through aqueous environment)  chemistry similar to ours

E.coli  Some strains frequently cause diarrhea in travelers, and it is the most common cause of urinary tract infections  One strain, designated O157:H7, is particularly virulent and has been responsible for several dangerous outbreaks in people eating contaminated food (usually undercooked hamburger).  Several important drugs (insulin, for example) are now manufactured in E. coli

Eukaryotes  More complex  More DNA  Has to be folded  histones (positively charged proteins)


Plasma membrane  compartmentalization  huge number of proteins  transporters (nutrient carriers)  receptors (signal transduction)  lipids and protein  semi-permeable (polar and charged ions cannot cross freely)

Nucleus  double membrane  contains DNA  genetic material  chromatin vs. chromosomes  nucleolus has RNA  histones: proteins that are positively charged that wind up DNA

Endoplasmic Reticulum  Rough ER:  ribosomes  protein synthesis occurs here for those proteins that will be routed out of cell  Smooth ER  lipid synthesis  metabolism of drugs and toxic substances

Golgi  Cellular post office  Proteins synthesized in the ER are packaged with extras such as  SO4 2-, carbohydrates, lipid moieties  Then, the proteins are directed to either the cell membrane to outside the cell or within the cell.  In other words, the proteins are flagged for their next destination

Mitochondria  ATP production  has its own DNA  uses nutrients to make energy  In plants, chloroplasts makes sugar from sunlight  Endosymbiotic theory

Lysosomes (Animal Cells)  Recycling centers can breakdown proteins  in plant cells these are vacuoles

Peroxisomes  Breakdown H2O2

Cytoskeleton  internal organization, assists the plasma membrane in retaining cell shape, and allows the cell to move  microtubules  rods from tubulin  arrangement  motion  Actin: protein filament for cell rigidity  Myosin: moves along actin using ATP


Viruses  Contains nucleic acid surrounded by protective shell or capsid  Uses host cells enzymes and ribosomes for replication  Lysogenic phase: viruses may remain dormant inside host cells for long periods. There is no obvious change in their host cells  Can enter the lytic phase: new viruses are produced, assemble, and burst out of the host cell.  The cell is killed and other cells are infected

Famous Viruses Smallpox, common cold, chickenpox, influenza, shingles, herpes, polio, rabies Ebola AIDS

Bacteriophages  Viruses that infect bacteria  Commonly used in molecular biology  DNA isolated from tissue---> Packaged into bacteriophage DNA---> Bacteria culture grown and infected with bacteriophage---> DNA of interest is replicated and studied either on DNA level or protein level

Add a comment

Related presentations

Related pages

Viruses: Structure, Function, and Uses - Molecular Cell ...

A virus is a small parasite that cannot reproduce by itself. Once it infects a susceptible cell, however, a virus can direct the cell machinery to produce ...
Read more

Molecular Expressions Cell Biology: Structure of Cells and ...

Explore the structure of animal, plant, and bacteria cells along with their associated viruses with our three-dimensional graphics.
Read more

Molecular Expressions Cell Biology: Virus Structure

Virus Structure. Viruses are not plants, animals, or bacteria, but they are the quintessential parasites of the living kingdoms. Although they may seem ...
Read more

The Origins of Viruses - Nature

The evolutionary history of viruses represents a fascinating, albeit murky, topic for virologists and cell biologists. Because of the great diversity among ...
Read more

Are Viruses Alive? - Scientific American

Are Viruses Alive? Although viruses challenge our concept of what "living" means, they are vital members of the web of life
Read more

Introduction to the Viruses (UC - Berkeley) - UCMP

Introduction to the Viruses. In 1898, Friedrich Loeffler and Paul Frosch found evidence that the cause of foot-and-mouth disease in livestock was an ...
Read more

Viruses - MicrobeWorld

Viruses exist for one purpose only: to reproduce. To do that, they have to take over the reproductive machinery of suitable host cells. Upon landing on an ...
Read more

DSMZ: Virus Testing

Detection of EBV sequences in human cell lines of the B cell lineage by PCR. a, sample only; b, sample with internal control DNA
Read more

Virus | ASU - Ask A Biologist

Capsid: a protective shell around the genome of a virus. Cell membrane: the outside layer of a cell that separates it from its environment. Envelope: ...
Read more

Cells and Viruses - Biology with Ms. Martinez

TEKS Covered •4A. Compare and contrast prokaryotic and eukaryotic cells. •4C. Compare the structures of viruses to cells, describe viral
Read more