Running head: BASIC BIOLOGY &nbsp&nbsp 1


October13, 2014.


Thecell is the basic functional biological unit in all living thingsbody systems. The cells are small units whose role is to replicatethedifferent functional roles in the body independently.Biologically, the cells are viewed as small ‘rooms’ through whichallow biological mechanisms to take place for the living organismsurvival (Simon,Dickey&ampReece,2012).Cells also help in the categorization of living organisms insingle-celled and multi-celled living things. In multi-cellarorganisms the cells serve many functions such as organizing andholding other biological components that have different biologicalpurpose in the living things body(Lodish, 2007).

Thereare several types of cells with the main cells been animal and plantcells. Plant cells are easily identified due to their characteristicprotective structure plant cells have cell walls while animal cellsdo not. In addition, plant cells have the green coloring matter thechloroplast that is absent in animal cells. Cells are also uniquedepending on organisms for instance, in simple organisms, there isno defined nucleus while some organisms have cells with numerousnuclei. The human body has hundreds of different cells types. Thefocus of this easy lies on the properties of the cell that makes itfunctional, the cell anatomy and physiology, cell respiration,photosynthesis and their production in the cell. In addition, theessay will focus briefly on Mandela’s law, the structure andfunction of DNA, cancer and gene control.

Thecell Anatomy

Theanatomy of the cells can be explained simplistically in relation tothe presence or absence of the nucleus. Eukaryotes cells have nucleuswhile the prokaryotes do not have a cell nucleus. The cell nucleus issignificant as an important source of information for the cell.However, all cells have cell membranes whose task is to regulate orenhance cell permeability as well as maintaining the cell electricpotential. Inside the cells is the cytoplasm that occupies most ofthe cells volume. All cells have subcellular components known asorganelles except the blood cells in animals. The organelles arecomposed of the DNA that carries the heredity components of the cellsuch as the RNA and the genes. The organelle holds the cell’snucleus in most eukaryotic cells (Simon,Dickey&ampReece,2012).

Inaddition, the cell nucleus contains the chromosomes that enhance DNAreplications as well as RNA synthesis. The nucleus has a sphericalshape and is separated from the cytoplasm by its double membrane.During DNA synthesis, it is copied to special RNA messengers’ nRNAand transported to the nucleus. Inside the nucleus, there is anucleolus that is tasked with the assembling of ribosome subunits.Furthermore, eukaryotic cells have the mitochondria and thechloroplast. Mitochondria are located in the cytoplasm of cells andplay a significant role in energy production for the cell. Cellrespiration takes place in the mitochondria for energy productionthrough oxidation process (Simon,Dickey&ampReece,2012).Mitochondria are replicate by themselves through binary diffusion.Chloroplast is only found in algae and plant cells and unlike themitochondria, the chloroplast absorbs the sun energy to make theAdenosinetriphosphate(ATP)(Lodish, 2007).

Thecell respiration

Cellularrespiration refers to a series of metabolic processes that takesplace in most cells of living organism in which biochemical energy isconverted to Adenosinetriphosphate(ATP).Cell respiration is one way through which the cells get energy. Inanimal cells, respiration takes place in the mitochondria whereoxygen is used to breakdown stored biochemical energy (Adenosinetriphosphate(ATP).


Photosynthesisprocess enables plants and other organisms such as the algae utilizethe suns light energy and convert it to chemical energy. Thischemical energy is stored as carbohydrates molecules. Duringphotosynthesis carbon dioxide, water and light energy are used up toprelease chemical energy and oxygen. As such, through photosynthesisthe atmospheric levels of oxygen are maintained. The process ofphotosynthesis takes different forms in different species. However,the general photosynthesis process takes place when light energy isabsorbed by proteins in the green chlorophyll pigments found in thechloroplast of plants (Lodish,2007).This light energy then combines with carbon dioxide and water to makeenergy and release oxygen. This is slightly different for somebacteria that have photosynthesis process but do not release oxygen.During photosynthesis, carbon dioxide is changed to sugars through aprocess of carbon fixation endothermic redox reaction.


Thecell goes through a series of the reproduction process throughsubdivision or development to enhance its exponential growth.However, there are controlled mechanisms through which this processtakes place to avoid over population that is risky for the survivalof other cells (Mitchison,2003).Cell growth is limited to a maximum figure that is twice as the firstgeneration. When this maximum figure is attained no cell developmenttakes place in normal living organism bodies (Lodish,2007).Cell reproduction takes place through asexual and a continuousprocess.

Cellreproduction takes place through four stages in the cell cycle(Simon,Dickey&ampReece,2012).The first stage is called the G1 phase marked by DNA replication, andthe second phase is the S phase in which the DNA produce two similarsets of Chromosomes. The third stage is the G2 phase in which proteinsynthesis takes place. The last phase is the M phase which ischaracterized by nuclear divisions (karyokinesis), as well as thecytoplasmic division (cytokinesis). Cell reproduction is complex ineukaryotes cells than in Prokaryotic cells. In prokaryotic cells,reproduction is through binary diffusion while in the Eukaryoticcells reproduction is through mitosis or meiosis in more complexprocess (Campbell,Williamson&amp Heyden, 2006).

TheMendel Laws

Mendel’slaw is also known as the law of segregation in which biologicalfeatures are biologically transmitted or inherited from onegeneration to the next. In his study of cross-breeding Mendeldiscovered the idea of heredity genes or the alleles that carrybiological characteristics from one generation to the other (Lodish,2007).He further discovered that, in most organisms during fertilizationgametes or alleles may pair separately or segregate. As such, Mendelintroduced the law of segregation that states that duringfertilization (gamete formation) alleles from each gene segregatesand each gene carries only one allele (Mitchison,2003).For instance, during fertilization the egg and the sperm unite witheach contributing one allele, and this restores the paired conditionof the offspring. In his law of independent assortment, Mendel arguedthat genes from different traits may segregates independently duringthe formation of gametes. Mendel observed that when only two pairs ofinherited alleles differ and only one allele determines theorganisms’ appearance, that allele is the dominant this is the lawof dominance. (Lodish, Berk, Matsudaira, Kaiser, Krieger, Scott,Zipurksy &amp Darnell, 2004).

DNAstructure and function

DNAis also referred to as the Deoxyribonucleicacid molecules that carry genetic traits. The Deoxyribonucleic acid(DNA) is generally a nucleic acid that consists of carbohydrates andproteins. In addition, the DNA has biopolymer strands that are coiledand have simpler units known as the nucleotides. The nucleotides arethen joined together by covalent bonds. The strands run in oppositedirections and help in encoding biological information to the RNA.DNA occurs in the form of linear chromosomes and a different set ofchromosomes in the cell make-up the genome. The DNA carriesbiological information transmission of genetic information in cells.In other cases, cells copy genetic information through DNAreplication process (Lodish,2007).

Cancerand the mechanisms of gene control

Canceris adversely known as a condition characterized by malignant tumorthis is an abnormal cell growth that invade particular parts of thebody. However, not all tumors are cancerous like the benign tumor.There are various possible causes of cancers such as smoking,heredity, hormones obesity, poor diet and alcoholic drinks. Otherfactors are infections, exposure to ionizing radiations and otherenvironmental pollutants. Cancer results from the inability toregulate tissues growth. As such, cancerous cells results when genesregulating abnormal cell growth are altered. Cancer affects theoncogenes which are responsible for cell growth and reproduction(Mitchison,2003).Gene control refers to mechanisms through which cell production isdecreased or increased. Gene control process has been applied invarious biological aspects that involve the regulation of cellsgenetic traits. In this way the abnormal or normal cell activitiesare controlled to produce the desired genetic traits (Campbell,Williamson&amp Heyden, 2006).


Thecell is an important biological subunit in the body of any livingorganisms. It is through the cells that most bodily functionsoriginate or are synthesized. Cells have various subcomponents whichserve various functions such as respiration, photosynthesis,transmitting genetic information during fertilization and regulatingcell reproduction in the body.These cellular subcomponents are the nucleus, the cell membrane,mitochondria, cytoplasm, chlorophyll, vacuoles and DNA among othersubunits. DNA carries biological information transmission of geneticinformation in cells.Cancer is an abnormal cell growth that invades particular parts ofthe human body. There are various possible causes of cancers such assmoking, heredity, hormones obesity, poor diet and alcoholic drinks.Gene control refers to mechanisms through which cell production isdecreased or increased and is used to regulate the genetic traits inthe cell of a living organism.


Campbell,Neil A. Brad Williamson Robin J. Heyden (2006). Biology:Exploring Life.Boston, Massachusetts: Pearson Prentice Hall.

SimonEricJ., DickeyJeanL. &amp ReeceJaneB. (2012).CampbellEssential Biology, Books a la Carte Edition (5th Edition).Boston, Massachusetts: Pearson Prentice Hall.

Lodish(2007). MolecularCell Biology.New York, NY: W.H.Freeman and Company Press

LodishH, Berk A, Matsudaira P, Kaiser CA, Krieger M, Scott MP, Zipurksy SL,Darnell J (2004). MolecularCell Biology(5th Ed.). New York, NY: WH Freeman Press.

MitchisonJM (2003). Growth during the cell cycle. Int.Rev. Cytol.International Review of Cytology 226:165–258