Answer:
i wish there was an answer here i needed it
The
correct answer is reverse transcriptase.
<span>
Reverse
transcriptase is an enzyme used to generate complementary DNA (cDNA) from an
RNA. This enzyme is often inserted together with eukaryotic mRNA into bacteria,
so that mRNA could be inserted into the bacteria's genome.</span>
Answer:
They help to stop harmful germs from entering the body
Explanation:
- The skin can prevent bacteria and microorganisms from entering the body (unless it is damaged)
- Mucous membranes line the mouth and nose and are coated with secretions that fight microorganisms and harmful bacteria
- Tears help to clear debris from the eye to prevent infection
The movement of substances (as by diffusion) across a cell membrane without the expenditure of energy.
Answer:
have curved protofilaments at their plus ends
Explanation:
Microtubules are polymers of tubulin proteins that function as the cytoskeleton of eukaryotic cells. Microtubules are dynamic structures that can grow and shrink at a rapid rate. During this process, tubulin subunits can associate and dissociate at the plus end of the protofilament. Tubulin subunits bind to two GTP molecules, one of which is hydrolyzed to GDP after assembly. When microtubules are unstable, protofilaments curl outwards because GDP-bound tubulin has a weak affinity (thereby curving it) and disassemble. The dynamic stability of microtubules is regulated by a feedback loop: when microtubules shrink, free tubulin concentration increases and microtubules start to grow. As microtubules grow, free tubulin concentration decreases and the rate of GTP-tubulin addition also decreases.
