The importance of bonds and bonding in organisms
One important bond is the bond formed in ATP synthesis via a condensation reaction where
ADP and Pi make ATP, this is catalysed by ATP synthase forming a covalent bond between the
two phosphate groups. ATP consists of adenine attached to a ribose sugar attached to 3
phosphate groups. It can also be hydrolysed to ADP and Pi, releasing heat energy in a
hydrolysis reaction. This is what makes ATP so essential in metabolic pathways; the one step
hydrolysis releasing immediate energy makes it easier to manage in small quantities. ATP
cannot be stored so it is constantly made in mitochondria through respiration. In aerobic
respiration, glucose and oxygen are converted into water and carbon dioxide. 2 molecules of
ATP are formed in glycolysis, one from the Krebs cycle and 3 more from oxidative
phosphorylation. ATP hydrolysis releases energy essential for a plethora of biological
processes including active transport – providing energy to change the shape of carrier
proteins in plasma membranes so molecules can be moved across a concentration gradient –
activation of molecules (as Pi can be used to phosphorylate other molecules triggering
subsequent reactions) and muscle contraction as ATP provides energy for the sliding
filament theory where ATP hydrolysis allows for movement of myosin heads and is also used
for reabsorption of calcium ions after the contraction. This highlights the importance of ATP
and the bonds within it as without it active transport would not occur so movement of many
substances would be inhibited, for example the sodium/potassium pump which is essential
in many processes, but in particular co-transport of glucose and amino acids from the ileum
eventually into the bloodstream. As the sodium/potassium pump begins the process,
pumping Na+ out of epithelial cells into capillaries decreasing Na+ concentration in the cell
so causing an influx of Na+ ions into the cell and co-transporting glucose and amino acids
with it. Then glucose and amino acids diffuse into capillaries by facilitated diffusion. Without
ATP the process could not begin so insufficient glucose uptake into blood causes fatigue due
to less respiration so less ATP produced for muscle contraction. Low blood glucose levels
would trigger glucagon release from alpha cells in the islets of Langerhans in the pancreas
and they would attempt to increase it back to the normal level but overall, it would cause
chronic fatigue if left untreated. Lack of amino acid uptake means less muscle formation as
amino acids join to form proteins for muscle, so less able to exercise for long periods of time
and in animals predators would chase them easier as they may run slower – less of a survival
advantage so would not survive. Also, less proteins to make carrier and channel proteins,
reducing transport of substances leading to even more deficiencies which will severely affect
an individual’s health. Therefore, the bonds in ATP are important in a variety of ways with
major consequences without them.
Another important type of bond is glycosidic bonds. They form between carbohydrate
molecules via a condensation reaction. An example is glycogen – a polymer of alpha glucose
used as a storage molecule in animals. The alpha glucose molecules are joined by glycosidic
bonds in condensation reactions releasing water. The bonds can also easily be broken in a
One important bond is the bond formed in ATP synthesis via a condensation reaction where
ADP and Pi make ATP, this is catalysed by ATP synthase forming a covalent bond between the
two phosphate groups. ATP consists of adenine attached to a ribose sugar attached to 3
phosphate groups. It can also be hydrolysed to ADP and Pi, releasing heat energy in a
hydrolysis reaction. This is what makes ATP so essential in metabolic pathways; the one step
hydrolysis releasing immediate energy makes it easier to manage in small quantities. ATP
cannot be stored so it is constantly made in mitochondria through respiration. In aerobic
respiration, glucose and oxygen are converted into water and carbon dioxide. 2 molecules of
ATP are formed in glycolysis, one from the Krebs cycle and 3 more from oxidative
phosphorylation. ATP hydrolysis releases energy essential for a plethora of biological
processes including active transport – providing energy to change the shape of carrier
proteins in plasma membranes so molecules can be moved across a concentration gradient –
activation of molecules (as Pi can be used to phosphorylate other molecules triggering
subsequent reactions) and muscle contraction as ATP provides energy for the sliding
filament theory where ATP hydrolysis allows for movement of myosin heads and is also used
for reabsorption of calcium ions after the contraction. This highlights the importance of ATP
and the bonds within it as without it active transport would not occur so movement of many
substances would be inhibited, for example the sodium/potassium pump which is essential
in many processes, but in particular co-transport of glucose and amino acids from the ileum
eventually into the bloodstream. As the sodium/potassium pump begins the process,
pumping Na+ out of epithelial cells into capillaries decreasing Na+ concentration in the cell
so causing an influx of Na+ ions into the cell and co-transporting glucose and amino acids
with it. Then glucose and amino acids diffuse into capillaries by facilitated diffusion. Without
ATP the process could not begin so insufficient glucose uptake into blood causes fatigue due
to less respiration so less ATP produced for muscle contraction. Low blood glucose levels
would trigger glucagon release from alpha cells in the islets of Langerhans in the pancreas
and they would attempt to increase it back to the normal level but overall, it would cause
chronic fatigue if left untreated. Lack of amino acid uptake means less muscle formation as
amino acids join to form proteins for muscle, so less able to exercise for long periods of time
and in animals predators would chase them easier as they may run slower – less of a survival
advantage so would not survive. Also, less proteins to make carrier and channel proteins,
reducing transport of substances leading to even more deficiencies which will severely affect
an individual’s health. Therefore, the bonds in ATP are important in a variety of ways with
major consequences without them.
Another important type of bond is glycosidic bonds. They form between carbohydrate
molecules via a condensation reaction. An example is glycogen – a polymer of alpha glucose
used as a storage molecule in animals. The alpha glucose molecules are joined by glycosidic
bonds in condensation reactions releasing water. The bonds can also easily be broken in a
