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Learning Describes

Cell and it’s related science for nursing profession.

Define : A living structural and functional unit enclosed by a membrane called ‘Cell’. Study/Science of cell called “Cytology”

• Interesting Points of Cell:
• Cells are Fundamental & Smallest Function Unit of The Body.
• First Cell Organism is “Bacteria”.
• Cytology means “The Study of Cell”, Father of Cytology is “Robert Hooke”
• Prokaryotic means Single cell organism. Cell division is “Binary Fusion.”
• Eukaryotic means multiple cell organisms. Cell division is “Meiosis & Mitosis.”
• The Human Body develops from a single cell called the “Zygote” which results from the fusion of the ovum (female egg cell), and the spermatozoon (Male germ cell).
• Largest cell- Ovum (Egg).
• Longest cell- Neuron.
• Smallest cell- Sperm (Male Germ).
• Engulf cell (foreign particles)-Phagocytes
• Drinking cell (Toxic Fluid) – Pinocytes.

About Structure of the Cell:

• Plasma Membrane:
• Cell membrane forms the outer boundary of the cell and selectively allows substances to enter or leave the cell.
• Consist of 3 Components: Phospholipid (Fat), Protein, Carbohydrates.
• Phospholipids (Fat):
• The cell membrane is made by lipid bilayer of three type of lipid molecule e.g. phospholipids (75%), cholesterol (20%) and glycolipids (5%).
• The phospholipids having two molecules. Head which is electrically charged called as Hydrophilic (Water loving),Tail which has no charged called Hydrophobic (Water Hating).The Phospholipid bilayer is arranged like a “Sandwich”.
• Protein: Protein molecules give the cell its “Immunological identity”. They can act as specific receptors for hormones and other chemical messengers. Some are enzymes are involved in transport across the membrane.
• Carbohydrates: Branched carbohydrates molecules attached to the outside of some membrane.

• Cytoplasm :
• All cellular contents between cell membrane and nucleus.
• It has two broad division i.e. cytosol and organelles.
• Cytosol (Intracellular fluid) :
• The fluid portion of cytoplasm, which constitute about 55% of total cell volume.
• It contains 75 to 90% water and remaining are ions, glucose, amino acid, fatty acid, protein, fats, ATP and waste products.
• Cytosolic pH ranges between 7.0-7.4, and is usually higher if cell is growing.
• It is the site of many chemical reactions like glycolysis during oxidation of glucose (gain of two ATP molecules).
• Organelles:
• Specialized structure within a cell that has a specific shape and performs a specific function.
• Examples of some organcells are the centrosome, ribosomes, endoplasmic reticulum, the Golgi apparatus, lysosomes and mitochondria.
• Centrosome:
• An organelle near the nucleus containing two centrioles in its center.
• During mitosis the centrioles migrate to opposite poles of the cell, and each forms the center of the aster to which the spindle fibers are attached.
• Mitochondria:
• A cell organelle of rod or oval shape 0.5 pm in diameter.
• They contain the enzymes for the aerobic (oxygen requiring) stages of cell respiration and thus are the sites of most ATP synthesis.
• So, It’s “Power House” of the cell.
• Inner mitochondrial membrane contains a series of folds called mitochondrial cristae and cavities of these folds called mitochondrial matrix.
• Mitochondrial cristae and mitochondrial matrix is the Site of aerobic phase of cellular respiration
• So, It’s a Cell Respiratory part. O2 Utilizer of the cell.
• Sausage shaped organ of the cell is mitochondria.
• Mitochondria have their own DNA that inherited from mother only and contain 37 genes
• The greatest number of mitochondria such as Liver, Muscle, Spermatozoa etc
• Ribosomes:
• It’s a “Protein synthesis factory” of the cell.
• Using RNA as Template.
• Cell body of a nerve cell contains basophilic granules of Ribosomes called “Nissl’s Granules”.
• These granules appear to be cisternae of rough endoplasmic reticulum with numerous attached and free ribosomes. They probably synthesize proteins for the cell.
• Free ribosomes (not attached to endoplasmic reticulum) form protein needed for cytosol.
• Ribosomes also situated into mitochondria which synthesis mitochondrial protein.
• Reticulo-Endothelial System(RES): Store of Iron in cell.
• Endoplasmic Reticulum(ER): ER is a series if interconnecting membranes canals in the cytoplasm.
• Smooth ER- Synthesizes lipids and steroid hormones.
• Rough ER- Synthesizes enzymes & hormones. Site of protein synthesis in cell & transportation..
• Golgi apparatus: The Golgi apparatus consists of stacks of closely folded flattened membranous sacs. The proteins move from the endoplasmic reticulum to the Golgi apparatus where they are “Packer organelle” into membrane bound vesicles called “Secretory granules”. Also Exocytosis functions.
• Lysosomes:
• Lysosomes are formed by Golgi apparatus
• It’s a Suicidal Sac organelle.
• It also called as digestive (Stomach) part of the cell. Toxic fluid, microbes are engulf by lysosomes.
• It’s a execratory part of the cell.
• Lysozyme is present in granulocyte WBC and tears.
• Lysozyme absent in urine, sweat and CSF.
• It contains a number of hydrolytic enzymes capable of breaking down proteins and some of carbohydrates.
• Lysosomal enzymes contribute to the digestion of pathogens phagocytized by a cell, and also to the damaged tissue.
• Nucleus:
• The oval shaped single structure within a cell that contains the genetic material (chromosomes).
• A structure like the cell membrane known as nuclear envelop or nuclear membrane separate it with cytoplasm.
• Nucleus contains one or more spherical bodies called nucleoli which produce ribosome.
• It’s a Largest Organelle of the cell.
• RBC has “No nucleus”.
• The nucleus contains the body’s genetic material, which directs the activities of the cell.
• This is built from DNA& Proteins called Histones (Chromosomes).
• The Functional subunit of chromosomes is called “Genes” contain cell’s hereditary unit.
• Genes are situated on the chromosomes and each chromosome is a long molecule of long with several proteins (histones, positive charge protein).
• The complete genetic information present in a cell, or an organism called genome.
• Human genome contains about 30,000 genes.
• Except during cell division, the chromosomes resemble a fine network of threads called chromatin.

Nucleic acid :

• A group of chemicals of high-molecular-weight consisting of carbon, hydrogen, oxygen, nitrogen and phosphorus, which carries the genetic information during the replication of cells and the manufacturing of cellular proteins.
• It called nucleic acid because first time discovered into nuclei of cells.
• They have a complex structure formed of sugars (pentoses), phosphoric acid and nitrogen bases (purines and pyrimidines).

Types :

• Two important types of nucleic acid are ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).
• Deoxyribonucleic acid (DNA) :
• A complex nucleic acid of high molecular weight consisting of many nucleotides.
• Nucleotides are made of a deoxyribose sugar (a pentose sugar), phosphoric acid and one of four bases.
• Among four base present into DNA, two are purines (adenine and guanine) and two pyrimidines (thymine and cytosine).
• Adenine always attach to thymine (A= T) and guanine with cytosine (G=C)
• According Waston and crick (1953) model, structure of DNA is like double helix.
• The nucleotides are arranged as two long chains that twist around each other to form a double helix joined by hydrogen bonds between the complementary base pairs A-T and C-G.
• DNA, present in chromosomes, is the chemical basis of heredity unit (gene), which carries the genetic information from one generation to another.

Biological importance of DNA :

• DNA is a basic molecule of hereditary.
• Genes are the basic unit of heredity, made of DNA.
• Nucleic acid (DNA) store, express and transmit genetic information from one generation to another.
• Mutation into DNA produce abnormal cell (malignant cell).
• DNA form RNA and RNA synthesize protein.
• DNA form RNA and DNA synthesize protein.

DNA finger printing  :

• Nowadays this technique use in research, paternity identification and legal situations for individual identification.
• A spot of semen and blood is enough for DNA finger printing.
• Ribonucleci acid (RNA) :
• A nucleic acid that controls protein synthesis in all living cells.
• RNA is the sole nucleic acid in certain viruses (RNA virus).
• Except the structural differences, RNA equal to DNA.
• RNA has ribose sugar rather than deoxyribose sugar in DNA.
• RNA has uracil (pyrimidine ) base rather than thymine present into DNA (thymine absent in RNA and uracil absent in to DNA)
• RNA is single strand molecule.

Types of RNA:

RNA mainly present in three forms that are determined by the number of nucleotides

1. Messenger RNA (m-RNA) :

• It forms by transcription of DNA templates.
• Transcription is a first step in protein synthesis, the synthesis of a messenger RNA (mRNA) molecule that is a complementary copy of a DNA gene.
• It carries the code for specific amino acid sequences from the DNA present into nucleus to the cytoplasm for protein synthesis.
• It is 10 to 20% of total RNA.

2. Transfer RNA (t-RNA) or soluble RNA (s-RNA) :

• Transfer RNA (t-RNA) carries the amino acid groups from cytoplasm to the ribosome for protein synthesis.
• It is 10 – 20% of total RNA.
• Ribosomal RNA (r-RNA) :
• Ribosomal RNA (r-RNA) exists within the ribosomes and assists in protein synthesis.
• Ribosomes are the site of protein synthesis.
• It is 60 – 80% of total RNA.

Learning Describes

Relation of Biology in Nursing profession

Biology is a fundamental subject of Living Science(Bio-Science), Modern theory of biology discovered by “Aristotle“(Father of Biology & Zoology), His theory describes five major biological processes, namely

Biology>>>>>Zoology>>>>>Human Biology & Microbiology

Human Biology Includes Basic Chemistry, Anatomy & Physiology , Nutrition.

• Basic Chemistry = Atoms + Molecules.
• Anatomy = Structure of Human Body. Discovered by “Andreas Vasalius”(Father of Anatomy).
• Physiology= Function of Human Body. Discovered by ” Claude Bernard”(Father of Physiology).
• Microbiology = Study of Micro-organism. Modern /Medical Microbiology discovered by “Louis Pasteur”.

https://www.youtube.com/watch?v=H4fhK1hFcYA&t=99s

Four Key Concept to Remember about Medical Science in Nursing :

• Health= Normal Structure and function of human body , it’s co-relation with external environment called “Biological Healthy Concept”.
• Illness = Abnormal or Structural and functional disturbance within human body called ” Illness”.
• Disease= Any Cause by micro-organism or it’s toxicity within the body called as ” Disease”.
• Deficiency = Particular disturbance with specific Nutrition within the body called as “Deficiency”.