Biological Science Assignment Sample

Running head: BIOLOGICAL SCIENCES 1
Biological sciences
Name
Date of Submission

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Topic two
1.
Nucleus- storage of the hereditary material (DNA) and controls various cell functions.
Golgi body- sorts and transports proteins, and the synthesis of lipids.
Vesicles- transportation of materials from one organelle to another.
Mitochondria- synthesis of energy (Picard et al., 2016).
Ribosomes- protein synthesis
Nucleolus-synthesis of ribosomal subunits from the proteins and rRNA for the assembly
of complete ribosomes.
Nuclear membrane- lipid bilayers containing pores that protects the DNA molecules.
Nucleolus-found in the nucleus and are involved in the fabrication of ribosomes.

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Rough ER-contains many ribosomes for protein synthesis
Smooth ER- contains vesicles for carrying lipids and proteins.
Vacuoles- storage of water and holding of waste materials
Cytoplasm- maintenance of the cell shape, transport of materials
Centrosome-microtubule organizing centers
Lysosome- contains degradative enzymes.
2. eukaryotic cell membranes have lipids (40%), proteins (50%) and carbohydrates in
form of glycolipids and glycoproteins (10%).
Non-polar- lipid bilayer containing a hydrocarbon oriented inwards to form a
hydrophobic portion.
Polar ends- made u of hydrophilic portions oriented outwards in the hydrophobic phase
(Ray et al., 2016).
Peripheral proteins-these collects the water soluble materials of proteins during protein
purification
Integral proteins- offer structural roles, transport of materials and binding to receptors

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3. Eukaryotic protein synthesis

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Important for the cell to copy its genetic materials and takes place in the nucleus and in
the following stages; initiation, elongation and termination (Plaschka et al., 2016). The DNA is
transcribed to form the messenger RNA (mRNA) which is transported to the ribosomes for
protein synthesis via translation (Sakatani et al., 2015).
4. Meiosis and mitosis have some similarities and differences as well. The two cell
division types give rise to daughter cells from the parents after cytokinesis. The sequence of
events is the same, only that it occurs twice in meiosis. However, the differences in that while
meiosis has two rounds of cell decision, mitosis has one round. Moreover, in meiosis the
homologous chromosomes separate to form daughter cells which are not identical (Griswold,
2015). On the other hand, in mitosis, the resulting daughter cells are identical to the parent cell.
Mitosis

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Mitosis

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Topic 3
1.
2. Connective tissues-involved in transport of materials in the cells, and holds other body
components including other tissues together to offer supportive roles.

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Epithelial tissues-these covers the outer surface of organs like the skin and allows
selective absorption of materials, offers protection and is involved in secretion of substances. An
example includes the stratifies squamous epithelia cells found on the skin.
Adipose tissues- this is a layer of fats which offers cushion or insulation properties of the
skin. An example is the fatty adipose tissue of the skin. Examples include the loose and dense
connective tissues found on various skin parts.
Topic 4
1. The skin microvasculature is affected by either the acute or chronic effects of
smoking. The cigarette smoke has some negative effects to the circulatory system especially the
coronary endothelial system. This is because nicotine in cigarette smoke raises the proliferation
of endothelial cells, while high amounts of carbon monoxide in the serum leads to increased
circulating endothelial cells. Thus the cigarette smoking causes the dysfunction of the cutaneous
microvascular system, whose severity is independent of the duration of cigarette smoke exposure
(Rossi et al., 2014). The impacts of smoking are felt on the cutaneous vasculature by causing
them to dilate instead of maintaining the vascular tone. Thus the human cutaneous system in
circulation is very important in the determination of the microvascular functions. Smoking
causes a reduces response to the vascular endothelial systems.

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2.

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Topic 5
1.
The blood which gets to the skin comes from the deep vessels which feeds the
interconnected perforate blood vessels that supply the vascular plexus. Therefore, the skin
system gets perfused with blood by either the septocutaneous or the musculocutaneous

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perforators. The pattern via which blood flows in and out of the skin is very important for
thermoregulation to maintain the required body temperatures during hemostasis (Murray et al.,
2016). When the body is heated or warm, the skin dilation rises, while during local body cooling
he lowers the blood flow to the skin (Tang et al., 2017). The impairment of blood flow to the
skin to, probably due to a disease condition can lead to high risks of heat illnesses when there are
some elevated temperatures.
2. The hormones play a great role in the initiation of protein synthesis in the body. Based
on this diagram, once certain hormones are released from various tissues and organs, they are
transported in the blood to the cells whereby they are coupled to the transport proteins. At the
cell membrane, the hormone is de-coupled from the transport whereby the hormone diffuses
through the cell membrane while the transport protein remains in blood circulation. The hormone
binds to its receptor in the nucleus to form an activated receptor-hormone complex which in turn
alters gene expression and hence the gene or protein product. Thus this complex initiates the
DNA transcription to form the mRNA which is in turn transferred out of the nucleus to the
ribosomes, the site for protein synthesis in the cytosol. The mRNA thus drives the manufacture
of specific proteins based on the hormone type and functions which initiated this process. the
new protein is then released into the circulatory system to perform specified roles which affects
the overall activities of the cells. Therefore, the water soluble hormones take long to act since
they cause DNA transcription to make proteins.

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3. The water soluble hormones do not need to enter the cell for them to alter the activities
of the cell, since they work using the second massagers. Once the water soluble hormones are
released by the transport proteins on the surface of the target cell, they interact with the hormone
receptor on the cell membrane leading to the transmittance of a signal into the cell. Since the
water soluble hormones are not permeable to the cell membrane, the interact with the membrane
receptors leading to the activation of the G-protein. The activated G-protein then activates the
adenylyl cyclase which leads to the conversion of ATP to form cAMP, a second messenger. The
signal is transported in form of second messengers which also interacts with the transcription
factors in the nucleus hence making the specified proteins which affect the cell activities. The
cAMP leads to the activation of protein kinases which phosphorylates various proteins in the
cytoplasm leading to their activation and hence alteration of cell activities.

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References
Griswold, M. D. (2015). Spermatogenesis: the commitment to meiosis. Physiological reviews,
96(1), 1-17.
Murray, A. K., Moore, T. L., Manning, J. B., Dinsdale, G., Wilkinson, J., Bhushan, M., ... &
Herrick, A. (2016). Non-invasive Imaging of Localised Scleroderma for Assessment of
Skin Blood Flow and Structure. Acta dermato-venereologica, 96(5), 641-644.
Picard, M., Wallace, D. C., & Burelle, Y. (2016). The rise of mitochondria in medicine.
Mitochondrion, 30, 105-116.
Plaschka, C., Hantsche, M., Dienemann, C., Burzinski, C., Plitzko, J., & Cramer, P. (2016).
Transcription initiation complex structures elucidate DNA opening. Nature, 533(7603),
353.
Ray, S., Kassan, A., Busija, A. R., Rangamani, P., & Patel, H. H. (2016). The plasma membrane
as a capacitor for energy and metabolism. American Journal of Physiology-Cell
Physiology, 310(3), C181-C192.
Rossi, M., Pistelli, F., Pesce, M., Aquilini, F., Franzoni, F., Santoro, G., & Carrozzi, L. (2014).
Impact of long-term exposure to cigarette smoking on skin microvascular function.
Microvascular research, 93, 46-51.
Sakatani, Y., Ichihashi, N., Kazuta, Y., & Yomo, T. (2015). A transcription and translation-
coupled DNA replication system using rolling-circle replication. Scientific Reports, 5,
10404.
Tang, Y., Mizeva, I., & He, Y. (2017, April). A modeling study on the influence of blood flow
regulation on skin temperature pulsations. In Saratov Fall Meeting 2016: Laser Physics

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and Photonics XVII; and Computational Biophysics and Analysis of Biomedical Data III
(Vol. 10337, p. 1033716). International Society for Optics and Photonics.