Answer:
The correct answer is option - d. Production of primary spermatocytes.
Explanation:
The accessory cells or supporting cells present within the seminiferous tubules of reproductive system termed as the Sertoli cells. They play various roles in the body and reproductive system.
Sertoli cells make blood-testis barrier in adjacent Sertoli cells in the seminiferous tubules. These cells secrete different types of enzymes and hormones such as inhibin which are also secreted by ovary and placenta in females. Sertoli cells produce seminiferous tubular fluid to provide nutrition to the sperm. Apoptotic germ cells are timely eliminated by these cells.
Thus, the correct answer is option D. Production of primary spermatocytes.
A monocot<span> seed has an embryo with a single cotyledon, and a </span>dicot<span> seed has an embryo with two cotyledons. </span>Monocots<span> have stem vascular systems with their bundles scattered, and </span>dicots<span> have their stem vascular systems with their bundles in a ring.</span>
<em>Cone-Bearing Plants</em> also known as <em>Conifers, </em>are classified as Gymnosperms
Answer:
Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living things. All known cellular life and some viruses contain DNA. The main role of DNA in the cell is the long-term storage of information.
Explanation:
-Eijiro <3
<h2>Transportation across the membrane</h2>
Explanation:
(a) Simple diffusion; Faciliated diffusion-Directions in which two transported solutes move
- In simple diffusion diffusion of non polar compounds across the membrane and along the concentration gradient without the involvement of protein whereas in case of facilitated diffusion membrane transport proteins that facilitate movement pf molecules across the membrane down its concentration gradient
- Both the diffusions does not require energy
(b) Facilitated diffusion; active transport-Direction the solute moves relative to its concentration gradient
- In facilitated diffusion membrane transport proteins that facilitate movement of molecules across the membrane down its concentration gradient without the expenditure of energy
- Active transport drives transportation of solute against the concentration gradient across the membrane
(c) Simple diffusion; Active transport-Directions in which two transported solutes move and Direction the solute moves relative to its concentration gradient
- In simple diffusion diffusion of non polar compouds across the membrane and along the concentration gradient without the involvement of protein and energy
- Active transport drives transportation of solute against the concentration gradient across the membrane;secondary active transporters coupled with transportation of two solute molecules
(d) Direct active transport; Indirect active transport-Direction the solute moves relative to its concentration gradient or its electrochemical potential
- Direct active transport use direct energy such as ATP hydrolysis,oxidation and sunlight energy
- Indirect active transport use indirect energy such as chemical gradient,electrochemical gradient established by direct active transporters;one solute moves along the concentration gradient while other moves against the concentration gradient
(e) Symport; Antiport-Direction in which two transported solutes move
- In symport both the solute molecules move in same direction;coupled with primary active transport(direct transport)
- In antiport both the solutes moves in opposite direction;coupled with secondary active transport(indirect transport)
(f) Uniport; coupled transport-Directions in which two transported solutes move
- Uniport is the transport of single solute across the membrane
- Coupled transport is the transport of two solute molecules across the membrane;it may be symport or antiport
(g) P-type ATPase; V-type ATPase-Kinetics of solute transport
- P-type ATPase always transport cations and undergoes phosphorylation
- V-type ATPase(here V stands for vacuole) transport protons and no phosphorylation occurs;catalytic activity is not reversible
- Both are types of primary active transporters
