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.
What are you asking? i cant help if i cant understand
1) When a star's temperature or size increases, its luminosity increases. In other words it seems more bright.
2) The electromagnetic spectrum is used to determine different types of light waves (infrared, visible light, x-rays etc.) which produced by different kinds of astronomical objects.
I
have black hair just like my father and blue eyes like my mother. The
shape of my nose also resembles the shape of my father’s nose yet I
am taller than both of them, I have less body fat index and more
hair!
<span>I
think the environmental factors are responsible from much of the
differences between me and my parents, after all I grew up, in a
sense, in a different world. The level of pollutants in the air, the
hormones in the food, ,better medical care and even the availability
of information regarding health care choices, they are all factors
that change from generation to generation and change they way we are
and a very real way. It is true that we are the product of our genes
but the environment plays a determinant role in our development as
well.</span>
Germline mutation is the types of the mutation of the respective cell can be passed to the offspring.
<u>Explanation:</u>
During the sexual reproduction somatic mutations occur in the nonreproductive cells, they are passed to the daughter cells during the mitosis but not to be the offsprings.
During the sexual reproduction, a mutation is used in large scale evolution that can be passed to the offsprings.
Its occurs in the cells such as egg and the sperm are called as the germ line mutations. A single sperms line mutation have a light effect in the gene but there is no change in the phenotype.
