1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
In-s [12.5K]
3 years ago
7

If a virus can't attach to a cell it can't inject its genetic material.

Biology
2 answers:
Lemur [1.5K]3 years ago
8 0

Answer:

I beleive its true

Explanation:

Zinaida [17]3 years ago
7 0

Answer:

True...

Explanation:

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. The specificity of this interaction determines the host (and the cells within the host) that can be infected by a particular virus. This can be illustrated by thinking of several keys and several locks where each key will fit only one specific lock.

The nucleic acid of bacteriophages enters the host cell naked, leaving the capsid outside the cell. Plant and animal viruses can enter through endocytosis, in which the cell membrane surrounds and engulfs the entire virus. Some enveloped viruses enter the cell when the viral envelope fuses directly with the cell membrane. Once inside the cell, the viral capsid is degraded and the viral nucleic acid is released, which then becomes available for replication and transcription.

The replication mechanism depends on the viral genome. DNA viruses usually use host cell proteins and enzymes to make additional DNA that is transcribed to messenger RNA (mRNA), which is then used to direct protein synthesis. RNA viruses usually use the RNA core as a template for synthesis of viral genomic RNA and mRNA. The viral mRNA directs the host cell to synthesize viral enzymes and capsid proteins, and to assemble new virions. Of course, there are exceptions to this pattern. If a host cell does not provide the enzymes necessary for viral replication, viral genes supply the information to direct synthesis of the missing proteins. Retroviruses, such as HIV, have an RNA genome that must be reverse transcribed into DNA, which then is incorporated into the host cell genome.

To convert RNA into DNA, retroviruses must contain genes that encode the virus-specific enzyme reverse transcriptase, which transcribes an RNA template to DNA. Reverse transcription never occurs in uninfected host cells; the needed enzyme, reverse transcriptase, is only derived from the expression of viral genes within the infected host cells. The fact that HIV produces some of its own enzymes not found in the host has allowed researchers to develop drugs that inhibit these enzymes. These drugs, including the reverse transcriptase inhibitor AZT, inhibit HIV replication by reducing the activity of the enzyme without affecting the host’s metabolism. This approach has led to the development of a variety of drugs used to treat HIV and has been effective at reducing the number of infectious virions (copies of viral RNA) in the blood to non-detectable levels in many HIV-infected individuals.

The last stage of viral replication is the release of the new virions produced in the host organism. They are then able to infect adjacent cells and repeat the replication cycle. As you have learned, some viruses are released when the host cell dies, while other viruses can leave infected cells by budding through the membrane without directly killing the cell.

You might be interested in
What is the kitakami river criteria
erastovalidia [21]

Answer:

The Kitakami River is located in Japan. It is the fourth largest river in Japan and in the Tohoku Region.

Explanation:

There really isnt a explanation.

3 0
2 years ago
What is the meaning of transpiration?
disa [49]
Evaporation of water from plants:)
7 0
2 years ago
Read 2 more answers
Land ___1___ includes human activities such as agriculture and construction. The modification of the Earth’s surface due to thes
MakcuM [25]
The correct options are as follows:
1. USE, B.
Land use refers to the function of a particular land, that is, what the land is been used for. For instance land can be used for agriculture, construction of roads, residential apartments, hotels, zoos, etc. Land use differs in the urban and rural settings. In the rural settings, land is usually used for farming and forestry while in the urban setting, land is usually used for construction purposes. 
2. LUC, OPTION B.
The modification of the earth's surface due to land use is called LAND USE CHANGE, LUC. A lot of changes occur when man use lands for different purposes. For instance, examples of land use change include: reduction in forest biomass, conversion of forest and grassland to pasture, etc,
6 0
3 years ago
Read 2 more answers
What is meant by aseptate coenocytes​
spayn [35]

Answer:Filamentous fungi may contain multiple nuclei in a coenocytic mycelium. A coenocyte functions as a single coordinated unit composed of multiple cells linked structurally and functionally, i.e. through gap junctions. Fungal mycelia in which hyphae lack septa are known as "aseptate" or "coenocytic".

Coenocytic cells are present in diverse and unrelated groups of algae, including Xanthophyceae, red algae and green algae.

In the siphonous green algae Bryopsidales and some Dasycladales the entire thallus is a single multinucleate cell, which can be many meters across. However, in some cases, crosswalls may occur during reproduction.

Explanation:The green algal order Cladophorales is characterized by siphonocladous organization, i.e., the thalli are composed of many coenocytic cells.

In contrast to the Cladophorales where nuclei are organized in regularly spaced cytoplasmic domains, the cytoplasm of Bryopsidales exhibits streaming, enabling transportation of organelles, transcripts and nutrients across the plant.

6 0
2 years ago
Your brain and neurons are in constant action, sending billions of ___________and________messages each day to keep everything, f
Leviafan [203]

Answer:

Until recently, most neuroscientists thought we were born with all the neurons we were ever going to have. As children we might produce some new neurons to help build the pathways - called neural circuits - that act as information highways between different areas of the brain. But scientists believed that once a neural circuit was in place, adding any new neurons would disrupt the flow of information and disable the brain’s communication system.

In 1962, scientist Joseph Altman challenged this belief when he saw evidence of neurogenesis (the birth of neurons) in a region of the adult rat brain called the hippocampus. He later reported that newborn neurons migrated from their birthplace in the hippocampus to other parts of the brain. In 1979, another scientist, Michael Kaplan, confirmed Altman’s findings in the rat brain, and in 1983 he found neural precursor cells in the forebrain of an adult monkey.

These discoveries about neurogenesis in the adult brain were surprising to other researchers who didn’t think they could be true in humans. But in the early 1980s, a scientist trying to understand how birds learn to sing suggested that neuroscientists look again at neurogenesis in the adult brain and begin to see how it might make sense. In a series of experiments, Fernando Nottebohm and his research team showed that the numbers of neurons in the forebrains of male canaries dramatically increased during the mating season. This was the same time in which the birds had to learn new songs to attract females.

Why did these bird brains add neurons at such a critical time in learning? Nottebohm believed it was because fresh neurons helped store new song patterns within the neural circuits of the forebrain, the area of the brain that controls complex behaviors. These new neurons made learning possible. If birds made new neurons to help them remember and learn, Nottebohm thought the brains of mammals might too.

Other scientists believed these findings could not apply to mammals, but Elizabeth Gould later found evidence of newborn neurons in a distinct area of the brain in monkeys, and Fred Gage and Peter Eriksson showed that the adult human brain produced new neurons in a similar area.

For some neuroscientists, neurogenesis in the adult brain is still an unproven theory. But others think the evidence offers intriguing possibilities about the role of adult-generated neurons in learning and memory.

if wrong report me

5 0
2 years ago
Other questions:
  • At which trophic level do decomposers work
    8·1 answer
  • 15 POINTS + BRAINLIEST AND THANKS
    5·1 answer
  • The dinosaurs were dominant by which geologic period oceanography
    12·1 answer
  • The cookie cutter shark feeds by taking a bite of flesh out of whales and large fish. The shark does not kill the larger fish it
    5·1 answer
  • PLEASE HELP ILL GIVEE BRAINLIEST ASAP PLEASEE
    6·1 answer
  • Which of Mendel’s laws states that alleles for different traits are sorted into sex cells separately?
    12·1 answer
  • Importance of pollination to the environment​
    8·2 answers
  • A scientist conducting an experiment quickly saw that she was not getting the results she expected. Instead of continuing to col
    5·2 answers
  • Frameshift mutation are the result of what occurrence?​
    10·1 answer
  • The fundamental unit of life
    9·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!