Answer:
<u>d. Transport proteins within the membrane serve as a tunnel for molecules to enter the cell.
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Explanation:
Solutes are typically moved across the cell through either passive or active transport. The cells, surrounded by a bilipid layer or plasma membrane is amphiphlic- its polar, hydrophilic lipid heads face outwards, while their non-polar hydrophobic lipid tails face inwards towards each other.
While lipid-soluble molecules move across the layer easily, it is also difficult for charged and also large molecules to move across its surface, into the cell. Transmembrane channels, <u>embedded within the membrane</u>, help to maintain selective permeability as transport proteins, pores and gated channels. Simple diffusion happens as a method of passive transport in cells through plasma membranes.
The solutes travel through the plasma membrane in the process of diffusion from regions of high concentration to regions of low concentration; this occurs without the use of energy. <u>Molecules moving against their concentration require active transport mechanism to cross the membrane</u>.
Answer:
2. have no negative particle
Explanation:
Helium atoms contains 2 neutrons and 2 protons (or 2 electrons). Thus, it has a mass number of 4 and atomic number of 2.
Alpha particles are heavy and positively charged, which make them to be deflected in a magnetic or electric charge. So, the helium atoms used as alpha particles for the gold foil experiment must have no negative particle.
Answer:
a. Because it offers the greatest improvement in environmental conditions, sufficient to match the damage caused by CEP, for the least expense.
Explanation:
The businesses are required to restore the land to their original condition once they are with their business activities. The business operations often causes damage to the site and nearby land, for this reason restoration is mandatory in many countries. Vancouver Fraser Port Authority selects Maplewood Flats for the restoration activity because it offers the restoration at cheap cost. This will save company's cost and the land will be to its original condition with least possible damage to environment.
Explanation:
Both Darwin and Mendel proposed their theory at the same time but they never communicated with each other. They both explained the population and studied the variation between them and in them.
The variation within a population could be of two types: the discontinuous traits and the quantitative trait.
A discrete trait refers to a trait that is usually controlled by only one gene that is only two alleles or two variants are observed in the population whereas the quantitative trait is a trait that can be determined by more than one gene like the variation in height.
