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>.
That was correct. it was letter choice b
Answer:
The answer to this question is given below in this explanation section.
Explanation:
"Alternation of generation"
Alternation of generations is the type of life cycle that occurs in those plant and algae in the archaeologist and the heterokontophyta that have distinct haploid sexual and diploid asexual stages.In these groups a multicellular haploid gametophyte with n chromosomes alternates with a multicellular diploid sporophyte with 2n chromosomes made up of n pairs.A mature sporophyte produces haploid spores by meiosis a process which reduces the number of chromosomes to half from 2n to n.
Two haploid spores germinate and grow into a haploid gametophyte.At maturity ,the gametophyte produces gametes by mitosis which does not alter the number of chromosomes.Two gametes from different organism of the same species fuse to diploid zygote,which develop into a diploid sporophyte . This cycle from gametophyte to sporophyte in the way in which all land plant and many algae undergo sexual reproduction.
Two of the most important energy-carrying molecules are glucose and ATP.
