Humans cannot convert the sun's energy into glucose for themselves because humans lack <span>chlorophyll.</span>
All of the cells within a complex multi-cellular organism such as a human being contain the same DNA; however, the body of such an organism is clearly composed of many different types of cells.
<u>What, then, makes a liver cell different from a skin or muscle cell</u> is <em>the way each cell deploy (utilizes) its genome</em>. In other words, the particular combination of genes that are turned on (expressed) or turned off (repressed) dictates cellular morphology (shape) and function. This process of gene expression is <em>regulated by cues</em> from both within and outside cells, and the<em> interplay </em>between these cues and the genome <u>affects essentially all processes</u> that occur during embryonic development and adult life.
Outside/Environmental cues include small molecules, secreted proteins (growth factors or signaling molecules), temperature, and oxygen.
The signaling molecules trigger intercellular signaling cascades (series of chemical reactions) that ultimately cause semipermanent changes in expression of genes. Such changes in gene expression can include turning genes completely on or off.
This process is thought to regulate a vast number of cell behaviors, including cell fate decisions during embryogenesis, cell function, and chemotaxis (i.e. cell movement in response to concentration gradient of a particular substance.)
The answer is true.
<span>Antigens are molecules capable to induce an immune response, "targeted" by antibodies. Antigens are usually proteins, peptides, or polysaccharides but they can combine with lipids and nucleic acids and form more complex antigens (lipopolysaccharide). Usually, antigens are exogenous (foreign substances), but sometimes are part of the host itself (in an autoimmune disease). All of them contain an epitope which is a part of an antigen that can be recognized and bound by an antibody.</span>
It depend some plants have the waxy layer because of their cuticles and to make sure the leaf doesn't dry out or to protect it againts the harmful sun rays when directly shined on its good to have sun but not too much. HOPE THIS HELPS
