The cell membrane is a highly selective barrier that controls the movement of substances in and out of the cell. in fact, polar molecules are unable to go across unless

they pass through channels in the cell membrane

Further Explanation:

Membranes of different organisms are rich in lipids, a bio molecule, which is hydrophobic in nature. Due to this reason, amino acids which are hydrophobic in nature will become part of proteins, residing on the external surface of the membrane, so that they can interact with the membrane through hydrophobic interactions. Hydrophobic amino acids, such as leucine and phenylalanine interact with hydrophobic phospholipid and help in holding the protein together.  

And the amino acids, which are having charged side chains will become part of the proteins, present inside the cell.A trans membrane pump (transporter protein) is associated with membrane. It helps in the movement of nutrients from one side to another by some components of cells, such as vesicles. It carries out a facilitated diffusion process.

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Answer Details:

Grade: High School

Subject: Biology

Chapter: Cell Biology

Keywords:

both male and female gametes are produced by meiosis of the germ cells. therefore, both male and female gametes are haploid. one male and one female gamete unite during the fertilization to form the diploid zygote. in seed bearing plants, pollen grain is the male gametophyte, which produces sperm cells.

all matter is made up of atoms

in any element all atoms are the same

elements in a compound are always in a constant ratio: apex