Answer:
"As a molecule moves through the plasma membrane it passes through <em>a hydrophilic layer of phospholipid heads then a hydrophobic layer of phospholipid tails and then another hydrophilic layer of phospholipid heads".</em>
Explanation:
Biological membranes are formed by two lipidic layers, proteins, and glucans.
Lipids characterize for being amphipathic molecules, which means that they have both a hydrophilic portion and a hydrophobic portion at the same time. These molecules have a lipidic head that corresponds to a negatively charged phosphate group, which is the polar and hydrophilic portion. They also have two lipidic tails that correspond to the hydrocarbon chains -the apolar and hydrophobic portion- of the fatty acids that esterify glycerol.
Membrane lipids are arranged with their hydrophilic polar heads facing the exterior and the interior of the cells, while their hydrophobic tails are against each other, constituting the internal part of the membrane.
Through this lipidic bilayer, some molecules can move from one side of the cell to the other, which happens because of concentration differences. When this occurs, molecules must pass through the hydrophilic layer of phospholipid heads then through the hydrophobic layer of phospholipid tails and then again through another hydrophilic layer of phospholipid heads.
Answer:
Transcription
Explanation:
Transcription is the first process of gene expression involving the synthesis of a mRNA molecule from a segment of DNA (gene). Transcription is key to the production of proteins, which bring about biochemical activities, in every living organism. The process of transcription is catalyzed by an enzyme called RNA polymerase.
According to the question that describes a chemical found to be produced by a tropical tree that kills insects. The chemical is discovered to deactivate RNA polymerase enzyme in the insect. This utterly means the chemical is interfering with the process of transcription of genes in the insect because transcription cannot occur without RNA polymerase.
Answer:
Sand particles are the largest and range from 2.0 to 0.05 mm in diameter. Silt particles are smaller, ranging from 0.05 to 0.002 mm. Clay particles are smaller than 0.002 mm. Texture affects other soil properties such as bulk density, water holding capacity, permeability, and porosity.
Explanation:
