What are the 4 components of a cell?
All cells share four common components: (1) a plasma membrane, an outer covering that separates the cell’s interior from its surrounding environment; (2) cytoplasm, consisting of a jelly-like region within the cell in which other cellular components are found; (3) DNA, the genetic material of the cell; and (4) …
What methods would you use to study the structure of eukaryotic cells?
Two types of electron microscopy—transmission and scanning—are widely used to study cells. In principle, transmission electron microscopy is similar to the observation of stained cells with the bright-field light microscope.
What are the four major classifications of cellular functions?
Cellular functions include such basic life processes as protein and lipid (fat) synthesis, cell division and replication, respiration, metabolism, and ion transport as well as providing structural support for tissues, protecting the body against disease or injury, and serving as selective barriers to the passage of …
What is the method of choice to view surface details of cells?
A scanning electron microscope would be the best choice for viewing very small surface structures of a cell.
What microscope is used to view bacteria?
Compound microscopes
Which should be used to observe bacteria?
Among the choices above, in viewing the bacteria we should use an objective lens that has a magnification of 600 or higher. Thus, the answer is letter A. 60x objectives with immersion oil and 10x eyepiece. Bacteria are very minute organism so we have to use a higher magnification./span>
At what magnification can you see bacteria?
1000X
What can you see with 1000X magnification?
At 1000x magnification you will be able to see 0.180mm, or 180 microns.
Which objective lens is most commonly used to observe bacteria?
Generally, objective lenses of 60X or greater might use oil — and they certainly will by the time you reach 100X. Because oculars are typically 10X, oil is necessary for viewing bacteria at a magnification of 1000X./span>
Which is the largest virus?
Mimivirus
What does a helical virus look like?
Helical Viruses The helix may have a hollow center, which makes it look like a hollow tube. This arrangement results in rod-shaped or filamentous virions. These virions can be anything from short and very rigid, to long and very flexible.
What are the major components of a virus?
The simplest virions consist of two basic components: nucleic acid (single- or double-stranded RNA or DNA) and a protein coat, the capsid, which functions as a shell to protect the viral genome from nucleases and which during infection attaches the virion to specific receptors exposed on the prospective host cell.
What are 5 characteristics of a virus?
These are: 1) attachment; 2) penetration; 3) uncoating; 4) replication; 5) assembly; 6)release. As shown in , the virus must first attach itself to the host cell. This is usually accomplished through special glycoprotiens on the exterior of the capsid, envelope or tail.
What are the 2 main categories of viruses?
There are two categories of viruses based on general composition. Viruses formed from only a nucleic acid and capsid are called naked viruses or nonenveloped viruses. Viruses formed with a nucleic-acid packed capsid surrounded by a lipid layer are called enveloped viruses (see Figure 4).
What are the steps in the virus life cycle?
The virus life cycle could be divided into six steps: attachment, penetration, uncoating, gene expression and replication, assembly, and release.
What are the 5 steps of the viral lifecycle?
The viral life cycle can be divided into several major stages: attachment, entry, uncoating, replication, maturation, and release.
How do viruses die?
Strictly speaking, viruses can’t die, for the simple reason that they aren’t alive in the first place. Although they contain genetic instructions in the form of DNA (or the related molecule, RNA), viruses can’t thrive independently. Instead, they must invade a host organism and hijack its genetic instructions.
What are the 5 steps of virus replication?
Most productive viral infections follow similar steps in the virus replication cycle: attachment, penetration, uncoating, replication, assembly, and release.
How do viruses kill cells?
The new viruses burst out of the host cell during a process called lysis, which kills the host cell. Some viruses take a portion of the host’s membrane during the lysis process to form an envelope around the capsid. Following viral replication, the new viruses may go on to infect new hosts.
Why do cells let viruses in?
When it comes into contact with a host cell, a virus can insert its genetic material into its host, literally taking over the host’s functions. An infected cell produces more viral protein and genetic material instead of its usual products.
What is it called when the viral DNA is injected into a bacteria host cell?
Viral DNA that becomes embedded in a bacterial host cell’s DNA is called a prophage.
How do you viruses attach to cells?
A virus attaches to a specific receptor site on the host cell membrane through attachment proteins in the capsid or via glycoproteins embedded in the viral envelope.
Do viruses kill bacteria?
Bacteriophages (phages) are viruses of bacteria that can kill and lyse the bacteria they infect. After their discovery early in the 20th century, phages were widely used to treat various bacterial diseases in people and animals.
Can a bacteriophage make a human sick?
When the phage infects a new bacterium, it introduces the original host bacterium’s DNA into the new bacterium. In this way, phages can introduce a gene that is harmful to humans (e.g., an antibiotic resistance gene or a toxin) from one bacterium to another….
What diseases are caused by bacteriophage?
These include diphtheria, botulism, Staphylococcus aureus infections (i.e. skin and pulmonary infections, food poisoning, and toxic shock syndrome), Streptococcus infections, Pasteurella infections, cholera, Shiga toxing-producing Shigella and Escherichia coli infections, and Pseudomonas aeruginosa infections.
How do phages die?
Bacteriophages have two life cycles In the bacteriophage lytic cycle, the virus replicates within the host. The host is killed when the newly replicated viruses break open or lyse the host cell and are released….
Are phages good or bad?
Bacteriophage means “eater of bacteria,” and these spidery-looking viruses may be the most abundant life-form on the planet. HIV, Hepatitis C, and Ebola have given viruses a bad name, but microscopic phages are the good guys of the virology world.
Why is phage therapy not used?
Lack of cross-resistance with antibiotics. Because phages infect and kill using mechanisms that differ from those of antibiotics, specific antibiotic resistance mechanisms do not translate into mechanisms of phage resistance.
What do phages look like?
A bacteriophage, or phage for short, is a virus that infects bacteria. Like other types of viruses, bacteriophages vary a lot in their shape and genetic material. The capsid of a bacteriophage can be icosahedral, filamentous, or head-tail in shape.
Will phage therapy replace antibiotics?
Bacteriophage treatment offers a possible alternative to conventional antibiotic treatments for bacterial infection. It is conceivable that, although bacteria can develop resistance to phages, the resistance might be easier to overcome than resistance to antibiotics.