It's an assignment on cellular respiration. It discusses the definition of cellular respiration, why it’s important for the body, the process and making of ATP, and much more. Very detailed, includes references. A grade
Cellular Respiration
We exhale and inhale air every day and night with the goal of bringing oxygen to our
body. Many people assume we need oxygen to breath when the fact is that we
breathe to get oxygen. Oxygen is the main ingredient for the production of energy in
the process known as cellular respiration. This paper will discuss the definition of
cellular respiration, why it’s important for the body, the process and making of ATP
and much more. (Khan Academy, 2012)
Cellular respiration occurs in three distinct processes which are glycolysis, the Krebs
cycle, and the electron transport chain. Throughout these cycles, our bodies turn
oxygen and glucose into carbon dioxide, water, and energy. Every living organism
needs cellular respiration to survive. These processes are the key to how life has
evolved and become as diverse as it is today. (Cheriyedath et al. 2019)
ATP
Adenosine triphosphate (ATP) is an organic molecule that carries the energy within
cells and is the end product of cellular respiration. The structure of ATP includes the
molecule adenosine which is made up of adenine and five-carbon sugar ribose that
is linked to three phosphate groups that are labelled as alpha, beta and gamma. The
two bonds between the phosphates are equal high-energy bonds that release
sufficient energy to power a variety of cellular processes and reactions. The bond
between beta and gamma phosphate is considered as ‘’high-energy’’ because the
when the bond breaks, the products Adenosine diphosphate (ADP) and the inorganic
phosphate group (Pi) have lower free energy than ATP and water molecules which
are the reactants here. The process where ATP breakdown into ADP and (P i) is
known as Hydrolysis, with hydro-, meaning “water”, and lysis, meaning “separation”.
The hydrolysis reaction equation can be shown as:
ATP+H2O→ADP+Pi+free energy
The hydrolysis reaction of ATP and ADP is also reversible. The reaction to reverse it
would need to combine ADP + Pi to regenerate ATP from ADP. The reaction
equation for this would be:
ADP+Pi+free energy→ATP+H2O
This was the ATP and ADP conversion that takes place in the substance between
the cell membrane and the nucleus, known as the cytoplasm, or in special energy-
producing structures called mitochondria. (Lumen Learning, 2019)
There are two types of cellular respiration, one is aerobic respiration and the other
one is anaerobic respiration.
, Aerobic Respiration
Aerobic respiration occurs in the cytoplasm and in the mitochondria. Aerobic
respiration is located in all higher animals and plants. It can be defined as the set of
reactions that only occur with the presence of Oxygen. This type of respiration
breaks down food in order to produce energy in the form of ATP. It produces 36 ATP
molecules in total from a single glucose molecule. There are three steps involved in
Aerobic respiration, Glycolysis, The Citric Acid Cycle and the Electron Transport
Chain. The substrate in this process would be the glucose and the inorganic end
product is carbon dioxide and water. Henceforward, the aerobic respiration is the
reverse process of photosynthesis. (Li, 2020)
The chemical equation for aerobic respiration is:
C6H12O6+ 6O2 → 6CO2 + 6H2O
Glucose + Oxygen → Carbon Dioxide + Water
Anaerobic Respiration
Anaerobic respiration proceeds the absence of Oxygen. In this type of respiration,
the glucose breaks down without Oxygen and produces energy with it’s given
sources. The energy that is produced in the anaerobic respiration is beneficial when
there is a high energy requirement in tissues when the oxygen produced by aerobic
respiration is not capable to achieve the required demand. However, it is produced in
more limited amount as compared to aerobic respiration. (Baker, 2017)
The equation for anaerobic respiration is:
(BBC Bitesize, 2020)
Glycolysis
Glycolysis is the first step in both Aerobic and Anaerobic respiration as it occurs
without the presence of Oxygen. Glycolysis occurs in the cytosol of the cytoplasm.
Glycolysis literal meaning is ‘’to split sugar’’ as it involves the breakdown of sugar
into more manageable compounds that produce energy. The first step is that glucose
is broken down into two pyruvate molecules which consist of three carbon atoms and
two functional groups known as carboxylate and a ketone group. The energy that is
released in the breakdown of glucose and other organic fuel molecules such as
carbohydrates, lipids and proteins are carried and then stored in ATP. NAD + also
known as Nicotinamide Adenine Dinucleotide which is a cofactor that is found in all
living cells is converted to NADH during this step of the process. If oxygen is present,
the two pyruvate molecules enter a reaction known as the Link reaction. The
pyruvates move from the cytosol to the matrix of the mitochondrion. A carbon dioxide
molecule is then broken off from each pyruvate in the matrix, NAD + strips off some
more electrons and H+. This results in the end product of the two-carbon molecule
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