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Write an Essay on the importance of bonds and bonding.
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the document is an essay consisting of 4 paragraphs on the importance of bonds and bonding in organisms written following the aqa a level biology specification.
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Write an essay on the importance of bonds and bonding in organisms.Hydrogen bonds are important in a variety of biological processes. Hydrogen bonds are bonds
that occur between polar molecules such as water and oxygen. The differences in
electronegativity between hydrogen and oxygen induce dipoles in this element. In the process of
transpiration, hydrogen bonds are extremely important. When water evaporates from mesophyll
cells in the leaf into the air space, it causes tension in the Xylem, causing the water molecules
to travel up the Xylem, followed by the other water molecules due to hydrogen bonds between
the water molecules. In addition, some hydrogen bonds form between the xylem and the water,
causing adhesion between them and thus explaining the decrease in trunk diameter. If there
were no hydrogen between the water, there would have been no cohesion, meaning there
would be an insufficient supply of water molecules to the leaves. Thus, the process of photolysis
would stop. This means that electrons, oxygen, and H+ ions are not produced. This further halts
the process of light-dependent reaction as there isn’t an electron that can be replaced in
photosystem 2. Moreover, NADP cannot be reduced to NADPH as there is no production of H+,
so the light-dependent reaction would also halt as reduced NADP is needed in that process.
Without the mass transport of water, which is due to the hydrogen bonds, the process of
photosynthesis would stop.
Peptide bonds play a great role in the formation of proteins. A peptide bond is formed between
carboxylic acid and amino acid by condensation reaction ..Peptide bonds are used to create
long chains of amino acid, these polypeptides join together to form proteins. The order of amino
acids determines the primary structure of the proteins. Proteins such as enzymes play a vital
role in biological processes. Without the presence of a peptide bond, the amino acids will not be
able to join to form the primary structure and thus will not have a tertiary structure. This means
that the enzymes will not have specific active sites that allow them to hydrolyse their specific
substrate e.g without the formation of the enzyme maltase, maltose cannot be hydrolysed to
glucose. This means that without the presence of enzymes, the breakdown of substances will
be slower so fewer nutrients will be absorbed by the blood.
The ester bond between the fatty acid and glycerol in lipids is critical in the formation of
phospholipids in cell membranes. The phospholipids' hydrophilic heads and hydrophobic tails
form a bilayer in the cell membrane. Phospholipids form barriers in cellular membranes to
protect the cell and barriers for organelles within the cells. The small, lipid-soluble molecules
can easily pass through the bilayer while larger molecules pass through channels or carrier
proteins. The lipid bilayer acts as a barrier to molecules and ions' passage into and out of the
cell. However, one important function of the cell membrane is to allow certain substances to
pass into and out of cells selectively. This is achieved by embedding various protein molecules
such as the channel and the carrier in and through the lipid bilayer. Without the formation of
ester bonds, there wouldn't be any phospholipids, and thus the crucial process of controlling the
movement of substances would not occur. Without the presence of the bilayer, the exchange of
small molecules of oxygen and carbon dioxide will be slower, meaning the respiring cells may
not receive sufficient oxygen. The cotransport of glucose and sodium will not occur as there is
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