Answer:
The important events of light reaction are (i) Excitation of chlorophyll molecule to emit a pair of electrons and use of their energy in the formation of ATP from ADP + Pi. This process is called photophosphorylation. Splitting of water molecule (a) (b) End products of light reaction are NADPH and ATP.
Answer:
Cross bridge in a sarcomere of a fast fiber produce higher amounts of force as compared to a cross bridge in a sarcomere of a slow fiber
Explanation:
When a muscle contracts, a cross bridge is formed between actin and myosin. The sarcomere shortens when a muscle contracts by reforming cross bridge. In general a muscle fiber is of three types – a) slow, b) Fast and c) intermediate.
The sarcomere of fast fiber generates high force but for a short period of time. On the other hand, sarcomere of slow fiber generate lower amounts of force but this force lasts for a longer period of time. Due to this difference, fast fibers are the predominant fibers in the body
Answer:
Specifically, a glycosidic bond is formed between the hemiacetal group of a saccharide (or a molecule derived from a saccharide) and the hydroxyl group of some alcohol.
Explanation:
Answer:
True
Explanation:
CSF is produced by choroid plexus. It starts flowing from the lateral ventricles and move towards the fourth ventricle via the third ventricle. It then moves towards the subarachnoid space which is the region surrounding the brain and spinal cord. From the brain and spinal cord, CSF is absorbed through the blood vessels and passed into the bloodstream again. It then moves to the kidney and liver for filtration.
Hence, give statement is true
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.
