Pollen tubes are produced by the male gametophytes of seed plants. They act as conduits to transport the male gamete cells from the pollen grain—either from the stigma (in flowering plants) to the ovules at the base of the pistil or directly through ovule tissue in some gymnosperms
The functions of certain cells or organs are regulated by hormones, which circulate in the circulation.
Some basic characteristics of a hormone are:
- They are substances generated chemically by certain endocrine gland cells.
- Circulation carries them to the desired cells, tissue, or organ.
- They act according to their kind.
- They are present in incredibly small numbers. Most of them are soluble in water.
- They have a light molecular structure.
- After acting, they are destroyed.
- They are heterogeneous substances in terms of composition.
- They can't be kept for a very long period; typically, they are synthesized and secured as needed.
- Typically, they create hormone receptor complexes in target cells to activate them.
Learn more about the characteristics of hormones here:
brainly.com/question/26151637
#SPJ4
Less than 300 mg of cholesterol is synthesized by the liver every day.
All cells have selectively permeable membranes, which means that only they let certain important molecules inside the cell, while the others stay outside the cell.
This occurs by the process of diffusion or osmosis.
Each time a new ATP is created, ATP synthase must process 5 protons.
<h3>Where is ATP synthase found and what does it do?</h3>
- ADP and phosphate are converted into ATP by the mitochondrial enzyme ATP synthase, which is located in the inner membrane.
- Protons are transported over a gradient created by electron transfer from the chemically positive to the negative side of the proton, which drives the flux of protons.
<h3>How does photosynthesis's ATP synthase function?</h3>
- The light-driven production of ATP is catalyzed by the chloroplast ATP synthase, which is activated in the light and deactivated in the dark by redox-modulation via the thioredoxin system.
- This down-regulation is thought to be crucial for minimizing wasted ATP hydrolysis at night.
<h3>What makes ATP synthase so crucial?</h3>
All cellular functions are powered by ATP, which is constantly used by cells and required for production. About 100 ATP molecules can be produced by each ATP synthase every second.
learn more about ATP synthase here
<u>brainly.com/question/893601</u>
#SPJ4
