Biology Past Paper PDF

## Extracellular Fluid: - _The internal environment that supplies the cell with nutrients, ions, and oxygen, which is necessary for cells._ - __Composed of:__ 1. Plasma - Fluid inside blood cells. 2. Interstitial Fluid - Fluid between cells. 3. Transcellular Fluid - Fluid in the body c...

## Extracellular Fluid: - _The internal environment that supplies the cell with nutrients, ions, and oxygen, which is necessary for cells._ - __Composed of:__ 1. Plasma - Fluid inside blood cells. 2. Interstitial Fluid - Fluid between cells. 3. Transcellular Fluid - Fluid in the body cavities. ### Distribution of ions in ICF, ECF | | ICF | ECF | |-------------|-----|-----| | Cation (+ve ions) | | | | Na+ | 14 | 140 | | K+ | 140 | 2.4 | | Ca+2 | 0.0001 | 1.04 | | Anions (-ve ions) | | | | Cl- | 4 | 9.6 | | HCO3- | 10 | 28 | | Phosphate | 75 | 21 | | Protein | 40 | 1 | ## Body Fluid: - _About 60% of the adult human body is Fluid_. - **Body Fluid are solution of water containing:** 1. **Organic molecules:** - Carbohydrates - Lipids - Proteins - Nucleic Acid 2. **Inorganic molecules:** - Ions ### Total Body Fluids (TBF): - **Intracellular Fluid (ICF)**: _2/3 of TBF_ - **Extracellular Fluid (ECF)**: _1/3 of TBF_ ## To release the energy required for Cell function: - **All cells deliver end product for their chemical reaction into surrounding fluid.** ## Cell Membrane: - _Keep the cell intact._ - _Regulate the passage of substance into and out of the cells._ - _Maintain the physical integrity of the cell._ - _Detect chemical messengers arriving at the cell surface._ - _Link adiacent cells together by membrane junction._ ## Cell Function: - _Each type of cell is adapted to perform one or a few particular functions._ - **For example:** _The red blood cells about 25 trillion cells in each human being transport oxygen from the lungs to the tissue. _ - _Although the many cells of the body often differ markedly from one another all of them have certain basic characteristics that are alike. For example all cells carry out oxygen react with carbohydrate, fat and protein._ ## Golgi Apparatus: - * The Golgi apparatus function is association with endoplasmic reticulum - Small transport vesicles also called endoplasmic reticulum vesicles or ER vesicles, continually pinch off from endoplasmic recticulum and shortly thereafter fuse with Golgi apparatus. - In this way, substances entrapped in ER vesicles are transported from ER to the Golgi apparatus and then form lysosomes. ## Lysosomes: - _Provide an intracellular digestive system (enzyme), which digest unwanted matter, damaged cellular structure, food particles that have been ingested by the cell._ # Mitochondria: - _Called the Power house of the cell, Help in production of energy._ ## Ribosomes and the granular endoplasmic reticulum: - Attached to the outer surfaces of many parts of the endoplasmic reticulum are large numbers of minute granular particles called ribosomes where these are present, the reticulum called granular endoplasmic reticulum. - The ribosomes are composed of a mixture of ribonucleic acid (RNA) and proteins and they function in the synthesis of new protein molecule in the cell. - A granular endoplasmic reticulum part of the endoplasmic reticulum has no attached ribosomes, this part called granular or smooth endoplasmic reticulum. - A granular reticulum function in the synthesis of substance and in many enzymatic processes. ## Cytoplasm: - The cytoplasm is filled with both minute and large dispersed particles and organelles. - The clear fluid portion of the cytoplasm in which the particles are dispersed is called cytosol. - This contain mainly dissolved protein electrolytes and glucose. - Dispersed in the cytoplasm five important organelles: 1. Endoplasmic Reticulum 2. The Golgi Aparatus 3. Mitochondria 4. Lysosomes 5. Peroxisomes ## The different substances that make up the cell are collectively called (Protoplasm) - Protoplasm is mainly composed of five basic structures: - Water - Electrolytes - Proteins - Lipids - Carbohydrates ## Components of the cell and its function: - The Nucleus. - The Control center of the cell, which contains the genes. - Large quantities of DNA which are the genes, determine the characteristics of the cell’s protein including the structural proteins, as well as the intracellular enzyme that control cytoplasmic and nuclear activities. - The genes also control reproduction of the cell itself. - *Genes control.* - Others the integral proteins act as Carrier proteins for transporting substance which could not penetrate the lipid bilayer. - Peripheral proteins: That are attached only to one surface of the membrane and don’t penetrate. These protein Function almost entirely as enzyme or as other types of controllers of intracellular function. ## The phosphate end of phospholipid that is hydrophilic and the fatty acid portion that is hydrophobic - **Cell Membrane Proteins:** - Two Types of protein - Integral Protein - *That protrude all the way through the membrane, many of it provide structural channel (or pores) through which water molecules and water soluble substances especially ions, can diffuse between extracellular and intracellular fluid.* - *These protein channels also have selective properties that allow preferent all diffusion of some substances more than others.* - **Cell Membrane:** - *It is composed almost entirely of protein and lipid. It is basic structure a lipid bilayer.* - *The lipids of the membrane provide a barrier that prevents movement of water and water soluble substances from one cell compartment to the other, because the water is not soluble in the lipid.* - *The basic lipid bilayer is composed of phospholipids, one end of each phospholipid molecules is soluble in water it is hydrophilic. The other end is only soluble in fats, it is hydrophobic.* ## Cell Organization - *The cells are surrounded a cell membrane, which allow selective communication between intracellular and extracellular compartment.* - *These cells contain two major parts: - The nucleus and the cytoplasm. - Numerous other membrane-bound structures called cell organelles (little organs) e.g. mitochondria and ribosomes. These organelles are suspended in cytoplasm.* - *Each part of the cell perform specific function, these function contribute to the cell’s survival. Most organelles of the cell are covered by membranes. ## The cell - The Plasma membrane ( ) - Plasma membrane is a phospholipid bi-layer structure surround the cytoplasm and cell organelles. ## Cells as the living units of the body - *The basic unit of the body is cell.* - *The number of cells is very large, in an adult person contain approximately 100 trillion of cells.* - *Each type of cell is specially adapted to perform one or a few particular function.* - *The group of many cells usually have the same function form tissue [ epithelial - connective - muscle and nerve tissue].* - *Groups of different tissue form organ. Each organ in the body composed from four different tissue (epithelial - connective - muscle and nerve tissue).* - *Groups of organs form system as: Nervous - endocrine - cardiovascular... * - *Cell → tissue → organ → system → body. * ## Human Physiology: - *Is the concerned with function of the entire human body.* ## Cellular Physiology: - *Concerned with the mechanism of transport of nutrient, ions, and water in to and out of the cell, and how cells communicated with each other through signaling pathways or respond to external effects.* ## Definition of physiology: - *Is the study of normal function of living organism.* - **Goal of physiology:** - *Is to explain the physical and chemical factors that are responsible for the origin, development and progression of life.* - **Type of physiology:** - *Each type of life, from the very simple virus to the largest tree, or to the complicated human has its own functional characteristics. Can be divided in to Viral Physiology, Bacterial Physiology, Cellular Physiology, Plant physiology and many more subdivision.*