University Biology: Unit 7 - Body Chemistry and Molecular Components

This report provides an overview of the role of molecular components in sustaining human life, focusing on proteins, carbohydrates, lipids, and nucleic acids. It explains how motor proteins, structural proteins, and immunoglobulins contribute to movement, structure, and defense. The report also discusses the function of carbohydrates and lipids as energy sources and structural components, including the role of glucose and fatty acids. Furthermore, it details the roles of DNA and RNA in cellular activities and protein synthesis. The report then examines the function of biological molecules, such as enzymes, antibodies, and hormones, in digestion, energy production, and cellular communication. Finally, it explores the role of proteins in homeostasis, particularly in thermoregulation, highlighting the function of thermoreceptors.

UNIT 7: BODY CHEMISTRY AND ORGANISATION
Explain the role of molecular components to the sustainability of human life
Motor proteins like myosin and dyneinsare involved in the movement, since they have the
ability to convert chemical energy into movement. Myosin is found in muscles and is
responsible for the contraction of muscle fibres in muscles. Dyneins are involved in the
movement of flagella, which are attached to outside of certain cells such as sperm cell and are
responsible for their mobility. There are also proteins who are responsible for providing
structural support. One of such example is keratin, which is found in the outer layers of skin,
nails and heir. Keratin is involved in making skin, nails and hair both strong and
protective(Pollard et al. 2016).
Immunoglobulin proteins are antibody molecules that bind to specific foreign particles like
virus and bacteria to help protect the body (Bona and Bonilla, 2019). The enzyme molecules
carry out almost all of chemical reactions that take place in cells, they also assist with
formation of new molecules by reading the genetic information stored in DNA. Growth
hormone are messenger protein that transmit signals to coordinate biological processes
between different cells, tissues and organs. Actin are proteins that provide structural support
for cells allowing body to move. Ferritin are proteins that bind and carry atoms and small
molecules within cells and throughout the body.
Monosaccharides are simple sugars such as glucose and fructose. They are the building
blocks for larger carbohydrates and are used in the cells to produce proteins and lipids.
Sugars which are not used for their energy are stored as lipids or more complex
carbohydrates. They are mostly used by cells to get energy. Glucose is an important
molecule, since it is directly involved in the ATP production.ATP is the principle energy
currency for a cell and complete oxidation of a glucose molecule yield 38 molecules of ATP.
Lipids in the body are essential for proper digestion and absorption of food and nutrients. Bile
acids produced from lipids in your liver allow fat and water to mix in your intestines and aid
in the breakdown and absorption of food. Lipids are then needed for the transport of fat-
soluble vitamins, A, D, E and K, from your intestines to your blood stream. The cells use
these vitamins to maintain the health of your vision, skin, bones, teeth and blood (Buchanan,
Gruissem and Jones, 2015).
Nucleic acid molecules that is DNA and RNA are involved in the regulation of various
cellular activities such as cell division and protein synthesis. DNA can be considered as the
genetic blueprint of the cell, which stores various genetic information and which can also be
transferred from parent to offspring. RNA is involved in the synthesis and the regulation of
proteins. There are mainly three types of RNA molecules, which are mRNA, tRNA and
rRNA. The first one is a direct transcribed product of DNA, the second one is involved in
carrying the amino acids for protein synthesis and the third one is present in the ribosome and
also involved in the protein synthesis. Another type of RNA is microRNA, which is involved
in the splicing process for the modification of mRNA molecules(Pollard et al. 2016)
.

Explain the function of biological molecules in the human body
The biomolecule protein includes enzymes, antibodies and hormones, which help in speeding
up the chemical reactions, defending against diseases and regulating the activity of cells.
They play a role in the movement, digestion and transport of substances around body. In
digestion, digestive enzymes, which are also proteins in nature drive digestion by speeding up
the chemical reactions. Digestion is the breakdown of food from large insoluble molecules
into smaller molecules that can dissolve into water. As the smaller molecules are water
soluble they enter blood and be transported around body. Digestive enzymes breaks down the
complex molecules in the food into smaller water soluble molecules. Some examples of
digestive proteins include:
 Amylase – enzyme in saliva that breaks down starch into soluble sugars
 Lipase – breaks down fats and other lipids
 Pepsin – breaks down proteins in food
Carbohydrates can be considered as important sources of energy. They also provide structural
support for the cells and help with communication between cells. Glucose in blood is taken
up into body’s cells and used to produce a fuel molecule called adenosine triphosphate
through cellular respiration. Cells can then use ATP to perform the metabolic reactions from
various sources including the dietary carbohydrates and fats (Hütter and Lepenies, 2015).
Lipids are the main component of cell membranes. Phospholipid is a type of lipid molecule
and it is the primary molecule found in the membranes of cells. Other important functions
lipids have include the insulation of heat, storing energy, protection and cellular
communication. Storage lipids are triacylglycerol molecules, which are made of three fatty
acids and a glycerol. Fatty acids are released from triacylglycerol during fasting to provide a
source of energy and to form structural components to cells. Dietary fatty acids of short and
medium chain size are not esterified but are oxidised rapidly in tissues as a source of fuel.
Longer chain fatty acids are esterified first to triacylglycerol or structural lipids (Buchanan,
Gruissem and Jones, 2015).
There are two nucleic acid molecules, which are DNA (deoxyribonucleic acid) and
RNA (ribonucleic acid). DNA is a long term storage of genetic information and is involved in
the transmission of genetic information to make other cells and new organisms. DNA is self-
replicating and is susceptible to UV damage. C-H bonds in DNA make it fairly stable, body
destroys enzymes that would attack DNA. Small grooves in helix serving as protection,
providing minimal space for enzymes to attach. RNA is used to transfer code from the
nucleus to the ribosomes to make proteins and transmits genetic information in some
organisms. RNA is synthesized from the DNA template and is resistant to UV damage. O-H
bond in ribose of the RNA molecules makes the molecule more reactive and unstable under
alkaline conditions. The large grooves in the molecule makes it susceptible to attack. RNA is
constantly produced, used, degraded and recycled(Pollard et al. 2016)

.
Describe the role of biological molecules in homeostasis
The only biomolecule involved in the homeostasis process is the protein molecule.
Role of Proteins in Homeostasis
Thermoreceptors are receptor proteins which senses the increase or decrease inthe
externaltemperature. The proteins sends signal to the brain via a feedback loop in case of a
serious rise or drop in the temperature that will cause a serious difference between the
internal and external temperature. As a result there is various actions triggered, such as
sweating or shivering in order to decrease or increase the body temperature (Morris and
Jay, 2017).

References:
Morris, N.B. and Jay, O., 2017. Staying warm in the cold with a hot drink: the role of
visceral thermoreceptors. Temperature, 4(2), pp.123-125.
Pollard, T.D., Earnshaw, W.C., Lippincott-Schwartz, J. and Johnson, G., 2016. Cell Biology
E-Book. Elsevier Health Sciences.
Hütter, J. and Lepenies, B., 2015. Carbohydrate-based vaccines: an overview.
In Carbohydrate-Based Vaccines (pp. 1-10). Humana Press, New York, NY.
Bona, C.A. and Bonilla, F.A., 2019. Textbook of immunology. CRC Press.
Buchanan, B.B., Gruissem, W. and Jones, R.L. eds., 2015. Biochemistry and molecular
biology of plants. John Wiley & Sons.