B, as far as we know humans aren't from space
Answer: Hypothalamus
The brain coordinates the physical changes that occur during puberty and the hypothalamus plays an especially important role in this process.
Explanation:
Since the hypothalamus controls the secretion of hormones from the pituitary gland, and the pituitary gland, also known as master gland, controls the activities of all other glands like the following:
- gonads (ovaries and testes), responsible for producing many of the sex hormones and hence, development of sexual characterictics
- thyroid, responsible for producing thyroxine, responsible for body metabolism and development.
Thus, hypothalamus plays important role in puberty
Explanation:
B) protein channel
Lipids are composed of fatty acids which form the hydrobic tail and glycerol which forms the hydrophilic head; glycerol is a 3-Carbon alcohol which is water soluble, while the fatty acid tail is a long chain hydrocarbon (hydrogens attached to a carbon backone) with up to 36 carbons.
Their polarity or arrangement can give these non-polar macromolecules hydrophilic and hydrophobic properties. Via <em>diffusion,</em> small water molecules can move across the phospholipid bilayer acts as a semi-permeable membrane into the extracellular fluid or the cytoplasm which are both hydrophilic and contain large concentrations of polar water molecules or other water-soluble compounds. The hydrophilic heads of the bilayer are attracted to water while their water-repellent hydrophobic tails face towards each other- allowing molecules of water to diffuse across the membrane along the concentration gradient.
Transmembrane proteins are embedded within the membrane from the extracellular fluid to the cytoplasm, and are sometimes attached to glycoproteins (proteins attached to carbohydrates) which function as cell surface markers. Carrier proteins and channel proteins are the two major classes of membrane transport proteins.
- Carrier proteins (also called carriers, permeases, or transporters) bind the specific solute to be transported and undergo a series of conformational changes to transfer the bound solute across the membrane. Transport proteins spanning the plasma membrane facilitate the movement of ions and other complex, polar molecules which are typically prevented from moving across the membrane.
- Channel proteins which are pores filled with water versus enabling charged molecules to diffuse across the membrane, from regions of high concentration to regions of lower concentration. This is a passive part of facilitated diffusion
Learn more about membrane components at brainly.com/question/1971706
Learn more about plasma membrane transport at brainly.com/question/11410881
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A and B can react to form C and D or, in the reverse reaction, C and D can react to form A and B. This is distinct from reversible process in thermodynamics.
Weak acids and bases undertake reversible reactions. For example, carbonic acid: H2CO3 (l) + H2O(l) ⇌ HCO−3 (aq) + H3O+(aq).
The concentrations of reactants and products in an equilibrium mixture are determined by the analytical concentrations of the reagents (A and B or C and D) and the equilibrium constant, K. The magnitude of the equilibrium constant depends on the Gibbs free energy change for the reaction.[2] So, when the free energy change is large (more than about 30 kJ mol−1), then the equilibrium constant is large (log K > 3) and the concentrations of the reactants at equilibrium are very small. Such a reaction is sometimes considered to be an irreversible reaction, although in reality small amounts of the reactants are still expected to be present in the reacting system. A truly irreversible chemical reaction is usually achieved when one of the products exits the reacting system, for example, as does carbon dioxide (volatile) in the reaction