Can affect an organism by changing its physical characteristics (or phenotype) or it can impact the way DNA codes the genetic information (genotype). they can cause termination (death) of an organism or they can be partially lethal.
One risk for accessing carbon from the ground is that it may cause soil contamination. Soil when exposed to large amount of gases and other organically decaying materials can absorb these into their make-up. Fossil fuels are extracted from the ground through drilling processes. When the drilling is unsuccessful, pockets created within the soil can create areas for contamination. When soil is contaminated by fossil fuels, it can no longer be use for agricultural purposes.
Answer:
Lipid insoluble hormones/Peptide hormones
Explanation:
Hormones produce their effect by binding to speific receptor. These receptors may be intracellular or membranal.
Membrane receptors;
The lipid insoluble hormones cannot cross the plasma membrane thus their receptors are found on plasma membrane. These are usually peptide hormones.
Examples; Insulin.
Intracellular receptors;
The lipid soluble hormones can cross the plasma membrane thus their receptors are found in cytoplasm. These are usually steroidal hormones.
Example; Testosterone.
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>.
