There is no precise definition of life. However, the process of life can be explained right from how it begins to how it ends. Life has a basic, structural, and functional unit that helps to define life. The structural unit is the cell (Liljas et al., 2009). Some organisms have one cell, while others are made up of millions of cells. These cells are the ones that are involved in reproduction, homeostasis, growth and development, movement, response to the environment, evolution, and order (Prud’homme-Généreux, 2013). These seven characteristics are the properties of life (Prud’homme-Généreux, 2013). This paper integrates the properties of life in explaining the basic anatomy and physiology of the cell, discussing the Mendel’s Law and finally, explaining cancer and mechanisms of gene control.
Properties of Life, Molecules, Basic Chemical Terminology, and Compounds of a Cell Necessary for Life
The properties of life include reproduction, homeostasis, growth and development, movement, response to the environment, evolution, and order. These features begin from the cell, which is a basic unit of an organism (Liljas et al., 2009). Subsequent cells arise from the division of old cells (Heng & Koh, 2010). Consequently, an organism can grow and develop. There are various types of cells. However, these cells are mainly divided into two categories – eukaryotic and prokaryotic cells (Prud’homme-Généreux, 2013). Eukaryotic cells have membranous cell organelles, chromosomal proteins, and a prominent nucleus (Herren, 2012). They form plants and animal bodies. However, prokaryotic cells lack a prominent nucleus, and they form organisms such as bacteria and archaea (Herren, 2012).
In eukaryotic cells, the deoxyribonucleic acid (DNA) replicates within the nucleus (Herren, 2012). Additionally, there is a transcription of DNA to messenger ribonucleic acid (RNA) in the nucleus. The DNA is responsible for carrying the genetic information when the cells divide, making sure that each cell possesses a copy of the DNA contained in the old cell (Herren, 2012).
Anatomy and Physiology of the Cell, Cell Reproduction, Photosynthesis, and Respiration
Anatomy and Physiology of the Cell
A cell is covered by a cell membrane, which is semi-permeable (Herren, 2012). This cell membrane has a phospholipid layer that has proteins embedded in it (Repetto, Boveris, & Semprine, 2012). The proteins are responsible for maintaining homeostasis (Herren, 2012). On the inside, there is cytoplasm, a jelly-like fluid, in which organelles are suspended (Herren, 2012). The main organelles include lysosomes, mitochondria, Golgi apparatus, vacuoles, endoplasmic reticulum, ribosomes, and the cell nucleus (Herren, 2012). Each organelle plays a significant function in the cell.
The endoplasmic reticulum is divided into smooth endoplasmic reticulum and rough endoplasmic reticulum (Herren, 2012). Smooth endoplasmic curriculum synthesizes membrane proteins and lipids. At the same time, rough endoplasmic reticulum contains ribosomes, which are necessary for assembling proteins, and enzymes that are imperative for various body functions (Herren, 2012).
Plant cells have a cell wall covering the cell membrane. The cell wall is made up of cellulose that has protective and structural functions (Herren, 2012). Additionally, the cell wall has three layers, and each of them possesses a unique function. Although animal cells do not have cell walls, there are other cells, such as the white blood cells, that fight against disease to protect the human body (Motswaledi, Kasvosve, & Oguntibeju, 2013). The Golgi apparatus in another organelle in the cell that is responsible for sorting, modifying, and packaging proteins for secretion (Herren, 2012). Additionally, the Golgi apparatus creates lysosomes and transports lipids around the cell. Mitochondria is responsible for cell metabolism while lysosomes break down larger molecules in the cell in a process called hemolysis.
Photosynthesis and Cellular Respiration
Photosynthesis happens in plant cells. Plants have cells known as chloroplasts that utilize energy from the sun to make glucose (Herren, 2012). During photosynthesis, the light energy coming from the sun transfers electrons from water to carbon dioxide that leads to the production of carbohydrates (Herren, 2012). In the transfer, water becomes oxidized, and carbon dioxide is reduced. That is, 6CO2+ 6H20 +Sunlight= C6H12O6 + 6O2+ 6H2O (Saltveit, n.d). The C6H12O6 is called adenosine triphosphate (ATP), and it is necessary for transporting chemical energy within cells for metabolism (Herren, 2012).
Transport of substances across cells can happen in two ways – active and passive ones (Herren, 2012). Thus, passive transport does not require energy for substances to move across the cell membrane. It involves diffusion, or movement of material from high concentration to low concentration, and osmosis that happens much like diffusion but through a semi-permeable membrane (Herren, 2012). On the other hand, active transport involves the movement of substances from a region of lower concentration to a region of higher concentration (Herren, 2012). The energy (ATP) enables larger molecules to move against a concentration gradient.
Cellular reproduction is an important function of the cell because it ensures organism growth. It occurs in two main processes, namely mitosis and meiosis (Herren, 2012). Mitosis gives rise to two identical daughter cells (Herren, 2012). This process is responsible for the reproduction of somatic cells. In this process, the DNA of the nucleus of the cell splits into two equal sets of chromosomes, forming two cells (Herren, 2012). The process involves six stages – early prophase, late prophase, metaphase, anaphase, telophase, and cytokinesis (Herren, 2012). According to Herren (2012), in the prophase stage, the cells break down some structures while building others up and preparing to divide the chromosomes. In the metaphase stage, the chromosomes get ready for separation. Further, in the anaphase stage, the chromatids separate and move to the opposite ends of the cell. Next, in the telophase stage, the cell becomes ready to divide by reestablishing its normal structures. Finally, in cytokinesis, the two cells divide, and a new cell is formed (Herren, 2012). At the same time, meiosis is for sexual reproduction since in the process of meiosis, two divisions take place – meiosis I and meiosis II. Meiosis I is like the normal mitosis. However, meiosis II results into four haploid daughter cells.
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Mendel discovered three laws after observing the behavior of plants. The laws include dominance, segregation, and independent assortment (as cited in Herren, 2012). In the first law, Mendel asserted that, in parents with contrasting traits, a dominant trait would appear in the subsequent generation (Herren, 2012). For instance, tall parents and short parents will produce all tall children. In the second law, Mendel states that when gametes form, two alleles separate (Herren, 2012). The alleles are often responsible for a given trait (Herren, 2012). Then, the gametes recombine after fertilization to produce the genotype for the trait of the offspring. For instance, according to this law, some parents differ from their children. In the last law, Mendel explains that alleles that characterize different traits distribute to sex cells independently of one another (Herren, 2012). In this case, the traits are inherited independently.
DNA Structure and Function
The DNA is made up of molecules called nucleotides (Liljas et al., 2009). Each nucleotide has four nitrogenous bases, a phosphate group, and a sugar called ribose. The nitrogen bases are four in quantity, and they include guanine (G), thymine (T), Adenine (A), and cytosine (C) (Herren, 2012). DNA instruction, or the genetic code, is determined by the arrangement of these nitrogenous bases. Their order is responsible for forming genes. Significantly, the DNA has genetic instructions that lead to the function and development of organisms. It stores long-term information for living things.
Cancer and Mechanisms of Gene Control
Cancer is a condition where a massive growth of cells occurs. The cells divide uncontrollably, forming tumors, except for some cancers, such as leukemia, where normal blood function is inhibited (National Cancer Institute, 2016). If not treated early enough, the tumors grow and metastasize into other systems, altering the physiological functions of the body. Cancer is fatal, and it one of the leading causes of death. However, cancer can be managed by gene control. Gene therapy targets mutations in cancer cells, and this is a more effective mode of treatment than treating all cells in the body chemically (Gaudet et al., 2013).
Cells are the basic units of life. They carry out all the physiological processes in living organisms and plants. Plant cells differ from animal cells because of the protective cell wall. The protective cell wall gives it both structural and protective functions. The cell wall, contained in both animal and plant cells, has a double phospholipid layer. Both cells must undergo various metabolic functions to keep them functional. Additionally, plant cells and animal cells have a nucleus that contains the genetic materials that are transferred from parents to their offsprings. If these cells divide uncontrollably, they lead to cancer. However, gene control can be used to treat this cancer efficiently as opposed to chemical methods that have adverse effects.