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.)
Sustainability has three main pillars: economic, environmental, and social
Answer: Option D) all of these options
Explanation:
Yes! Neurotransmitters are chemical compounds that are produced from the terminal of a neuron and bound by specific protein in the adjacent neuron where it helps to transmits a nerve impulse.
Neurotransmitters can be:
- Excitatory such as acetylcholine that cause muscle to contract and gland cells to produce secretions (i.e neuron will fire)
- Or inhibitory such as glycine which inhibits the contractions of muscles (i.e neuron did not fire)
Thus, neurotransmitters do all of the functions provided
Answer:
A. amount of food available
Explanation:
An experiment consists of two types of variables, independent and dependent. Value of independent variable is decided by the person doing the experiment and is independent of experimental conditions. Value of dependent variable is dependent on the independent variable. It can not be altered by the person doing experiment.
Here, it is given that mice receive variable amount of food each day and their lifespan is recorded. Since the amount of food is decided already it is the independent variable. The lifespan is expected to depend on the amount of food hence it is the dependent variable.