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
Luda [366]
3 years ago
13

A) How does HIV bind to a host cell?

Biology
1 answer:
Taya2010 [7]3 years ago
7 0

1. The correct answer is: The viral envelope proteins interact with CD4 and a co-receptor on the cell membrane.

Binding and entering the host cell are the first steps of the HIV virus infection. So, these steps play a major role in determining the ability of HIV to degrade the human immune system. Binding of HIV to CD4+ T lymphocytes (express chemokine receptors CCR5 and CXCR4 called co-receptors) triggers the fusion of the viral and host cell membranes, initiating infection (viral core gets into the cytoplasm).

Attachment of the virion can be:

• Nonspecific-envelop protein of the virus (Env) binds to cell-surface heparan sulfate proteoglycans

• Specific-Env binds to integrin.

2. The correct answer is: Activation of the host cell by cytokines, growth factors, or antigens.

After the viral capsid enters the cell, single-stranded RNA genome is released from the attached viral proteins and copied it into a complementary DNA (cDNA) molecule thanks to an enzyme called reverse transcriptase. Next step is the integration of the viral DNA into the host cell's genome. This process is done by another viral enzyme called integrase. The integrated DNA  is transcribed into RNA and then translated into proteins that will help the package of new viruse particles.

3. The answer is: false

Reverse transcriptase is an enzyme that catalyzes the formation of DNA from an RNA template. Since the genome of the virus (HIV) is single stranded RNA, reverse transcriptase copies it into a complementary DNA (cDNA) molecule. Thanks to this enzyme, formed cDNA can be integrated into host’s genome. Because of this proprety, antiretroviral drugs used to treat HIV infection work as reverse-transcriptase inhibitors.

You might be interested in
The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the A) atrial systole. B) early d
KengaRu [80]

The phase in the cardiac cycle when the mitral valve is closed and the aortic valve is open is the systolic ejection phase (Option D). It is the second phase of the ventricular systole.

The cardiac cycle is a sequence of contraction and relaxation of the atria and ventricles to pump blood throughout the body.

This cycle (cardiac cycle) can be divided into two major periods: diastole and systole.

The diastole is when the heart relaxes and refills with blood, while the systole is when the heart contracts and pumps blood.

The systolic ejection phase is the second phase of the ventricular systole where blood is pumped from the ventricle.

Learn more in:

brainly.com/question/4224481

5 0
3 years ago
What is greenhouse gas?
Ksju [112]

Answer:

d

Explanation:

I don't know, I'm just assuming

5 0
2 years ago
What is the Difference between DNA & RNA?
Travka [436]
DNA is deoxyribonucleic acid while RNA is ribonucleic acid !

DNA has base pair of adenine guanine thymine and cytosine.....while RNA has adenine guanine cytosine and uracil !

DNA is always double helix while RNA is mainly single helix !

DNA contains genetic info for 99℅ of organism while RNA is being catalytic and unstable than DNA is only present as genetic information holder in 1℅ !

DNA does not involve in protein synthesis directly but RNA has to !

for more difference, comment !
8 0
3 years ago
Determine how tRNA is used when cells build proteins ...?
alexdok [17]
<span>tRNA carries a single amino acid to the ribosome. 
It fits the codon on the mRNA in the ribosome with it's anti-codon. 

The ribosome has peptidyl-transferase activity which catalyses the peptide bond between 2 amino acids on 2 tRNAs in the ribosome. 

One tRNA is released and then picks up another amino acid depending on its anti-codon.


I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
</span>
3 0
2 years ago
Remnants of osteons, which have been almost completely recycled by osteoclasts, are known as __________
Alex

Answer:

Lamellae

Explanation:

These lamellae are remnants of osteons whose matrix components have been almost completely recycles by osteoclasts. growth of the bone.

3 0
1 year ago
Other questions:
  • What are organisms whose cells lack a membrane-bound nucleus called?
    5·1 answer
  • Which is the last step that occurred in the speciation of the galápagos finches?
    12·2 answers
  • Why is the structure above important in maintains homeostasis
    14·1 answer
  • As part of an experiment on circadian rhythms, a laboratory rat’s brain has been lesioned. The animal is now falling asleep and
    10·1 answer
  • NEED HELP WITH DIS ASSSAAAPPP PLEASEEEE
    5·1 answer
  • What is an inflammatory disease of the arteries with clot formation, usually in the legs, leading to occlusion of arteries and i
    9·1 answer
  • A government website?, reliable or unreliable
    5·2 answers
  • ¿cuales son las ventajas y desventajas del uso de antibióticos?​
    7·1 answer
  • Explain why the cell membrane is the brain of the cell, as opposed to the nucleus.
    12·2 answers
  • Is a 8.1 pound bass good for a first bass? My friend caught one off the dock.​
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!