Attributes of Life - Biology

The correct order of the level of organization of an individual is as follows: cells, tissue, organs, organ systems, and organism. In other words, tissues form organs. For example, in a human being the order in the musculatory system would be: muscle cell, muscle tissue, bicep muscle, musculatory system, and human being.

The R group is a side chain connected to the central carbon atom in an amino acid. The central carbon atom of an amino acid can bind to four other groups. In an amino acid, the central carbon will always bind to a carboxyl group, and amine group, and a hydrogen atom. The fourth bond, however, will be different for each amino acid, linking the central carbon to the R group.

Waxes provide skin with a waterproof coating. Waxes are made out of fats.

Hemoglobin is a protein responsible for transporting oxygen. DNA polymerase repairs DNA molecules. Amylase is the protein that helps convert starch to glucose.

Organic compounds are defined as solids, liquids, or gases whose molecular structure includes carbon. Inorganic compounds, in contrast, do not contain carbon. Organic compounds might contain other elements, like hydrogen and oxygen, but not all compounds need these other elements to be considered organic.

In the water cycle, there are abiotic and biotic factors that contribute to the recycling of water. The process by which non-living things return water to the atmosphere is called evaporation. Plants, on the other hand, intake water through their roots and release the water as vapor through tiny openings on leaves called stomata. This process is called transpiration.

Molecules that are hydrophobic or "water fearing" will have a hard time dissolving in an aqueous solution. Lipids, which are nonpolar molecules, would not be able to dissolve in water.

Proteins are synthesized through dehydration synthesis reactions, which is the removal of water between two amino acids. In this case, two hydrogen atoms are removed from the amine group and one oxygen is removed from the carboxyl group, forming a peptide bond between the carbon atom of one amino acid and the nitrogen atom of the other amino acid.

The sequence of amino acids is called a protein's primary structure. Each protein has a unique sequence of amino acids. A difference of just one amino acid in a chain of hundreds can be deadly to the organism. For example, mutation leading to a single amino acid change is responsible for sickle cell anemia.

A helix is formed when Hydrogen bonds occur between the amino group in one peptide bond and the carboxyl group of another in the same polypeptide chain.

The cell theory has three basic parts: all living things are made of cells, the cell is the smallest unit of life, and all cells come from preexisting cells. Prokaryotic cells are indeed cells and they do not contradict any tenets of the cell theory. However, they do not contain nuclei; rather, their genetic material is contained in the cytoplasm.

The pH of a solution is defined as the the concentration of H+ ions in the solution. The pH of a solution declines as H+ concentration increases. On the pH scale, ranging from 0 to 14, 7 is neutral. Substances below 7 are more acidic, 0 being the most acidic. Substances above 7 are more basic, 14 being the most basic.

“Composed of plutonium” is not a characteristic of a living organism. The other three choices are characteristics of living organisms. Organisms use energy in their metabolic processes. Organisms reproduce either asexually or sexually to make offspring for the next generation. Organisms from the simplest prokaryote to the human species contain DNA—the universal genetic code.

All amino acids contain carbon, hydrogen, oxygen, and nitrogen. These elements create a carboxylic acid group and an amine group, which can fuse to form a peptide bond. Peptide bonds hold amino acids together and generate the primary structure of the protein.

Cysteine, a specific amino acid, also contains sulfur. Thus, the correct answer is that carbon, oxygen, hydrogen, nitrogen, and sulfur can all be found in amino acids.

Phosphorus is never found in amino acids, but plays an important role in the structure of nucleic acids, such as DNA, and in the modification and activation of proteins.

Living organisms are primarily made up of organic molecules, which contain carbon. The six most prevalent elements in living organisms are carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur, in that order.

Carbon and hydrogen are found in the basic monomer structure of all biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids). Nitrogen is found in amino acids, which form proteins, and the nitrogenous bases in nucleic acids (DNA and RNA). Oxygen is found in all biological macromolecules. Phosphorous is found in nucleic acids and lipids, such as phospholipids in the cell membrane. Sulfur is found in cysteine, a specific amino acid.

Since carbon is in group IV of the periodic table, we know that it has four valence electrons. Most elements (with the exceptions of hydrogen and helium) are most stable when they have filled their valence shell with eight electrons. For carbon to fill its valence shell, it needs to make four covalent bonds. Remember that carbon is not very electronegative and only very rarely (if ever) forms ionic bonds. This means that carbon will not donate, nor accept electrons; rather it will share them with other atoms to form molecules.

Carbon has four electrons in its valence shell which means it needs four more to have a stable octet. This means that the maximum number of bonds it can form is four when each bond only contributes one electron to the relationship.

One of the reasons carbon is so ubiquitous in biological structures is the fact that it has four valence electrons, meaning it likes to form four bonds to complete an octet in its outer shell. Being able to form four bonds means that it can bind to multiple other atoms covalently and with high stability.

Organic compounds are defined as solids, liquids, or gases whose molecular structure includes carbon. Inorganic compounds, in contrast, do not contain carbon. Organic compounds might contain other elements, like hydrogen and oxygen, but not all compounds need these other elements to be considered organic.

Water is a very important molecule in order for life to take place. It is the solvent in which chemical reactions take place, as well as a reactant for certain reactions. Water's polarity also causes polar molecules to dissolve and nonpolar compounds to aggregate. As a result, nonpolar molecules are not dissolved in water.

Water is often called the universal solvent and is one of the most important compounds on Earth. The molecular structure of water promotes intermolecular hydrogen bonding, a very strong force between molecules. The result is known as cohesion, the phenomenon of water molecules "sticking" to one another. Cohesion leads to other water properties, such as high surface tension and capillary action, which are essential to supporting life. Hydrogen bonding is only possible in water molecules because of the polarity of the bond between oxygen and hydrogen; oxygen carries a partial negative charge, and hydrogen carries a partial positive charge. Water also have a very high specific heat, which means that it requires a lot of energy to raise the temperature of water. This promotes homeostasis and temperature stability in biological organisms.

In the liquid state, cohesion promotes stability, but in the gaseous state water molecules must separate from one another to move around. Essentially, cohesion must be overcome in order for water to boil. This leads to a high heat of vaporization, rather than a low heat of vaporization.