Answer:
one which is able to express itself outwardly in the presence of a recessive allele
Explanation:
Answer:
Because it is formed by rocky materials
Explanation:
These planets are small and of high density, mainly by transparent and rocky materials with a well differentiated internal structure and a similar size.
They tend to be more dense since it is formed of rocky and non-gaseous materials like the higher planets.
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.
The question is incomplete. The rest of the question is : Which of these is not supported by the endosymbiosis theory concerning organelles?
A) contain DNA.
B) contain ribosomes.
C) are capable of living independently.
D) are surrounded by a double membrane.
Answer:
Option C) are capable of living independently is not supported by the endosymbiosis theory concerning organelles
Explanation:
The endosymbiosis theory proves that chloroplasts and mitochondria were prokaryotic cells before due to many reasons. Some of which are:
- These organelles have their own separate DNA.
- The separate DNA present in them is capable of making their own proteins.
- They are membrane- bound organelles.
However, these organelles can now not live separately outside of the cell. This might be because of the evolutionary changes which occurred in these cells during the long period of time.
The answer is most definitely a
