Cell summary


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Cell summary

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  2. 2. BIOMOLECULES and the CELL The cell speaks: “I am the unit of biological activity; Organized into subcellular organelles; Assigned to each are specific duties; Thus, I truly represent life!”
  3. 3. The living matter is composed of mainly six elements: carbon hydrogen oxygen nitrogen phosphorous sulfur These elements together constitute about 90% of the dry weight of the human body. Several other functionally important elements are also found in the cells. It includes: Ca K Na Cl Mg Fe Cu Co I Zn F Mo Se
  4. 4. Carbon - a unique element of life Carbon is the most predominant and versatile element of life. It possesses a unique property to form infinite number of compounds. This is attributed to the ability of carbon to form stable covalent bonds and C - C chains of unlimited length. It is estimated that about 90% of compounds found in living system invariably contain carbon.
  5. 5. The Major Complex Biomolecules of Cells Biomolecule Building Block (repeating unit) Major Functions 1. Protein Amino Acids Fundamental basis of structure and function of cell (static and dynamic functions). 2. Deoxyribonucleic acid (DNA) Deoxyribonucleotides Repository of hereditary information. 3. Ribonucleic acid (RNA) Ribonucleotides Essentially required for protein biosynthesis. 4. Polysaccharide (glycogen) Monosaccharides (glucose) Storage form of energy to meet term demands. 5. Lipids Fatty acids, glycerol Storage form of energy to meet long term demands; structural components of membranes.
  6. 6. Chemical Composition of a Normal Man (weight 65kg) Constituent Percent(%) Weight (kg) Water 61.6 40 Protein 17.0 11 Lipid 13.8 9 Carbohydrate 1.5 1 Minerals 6.1 4
  7. 7. THE CELL - is the structural and functional unit of life. - it may be also regarded as the basic unit of biological activity. Prokaryotic and eukaryotic cells The cells of the living kingdom may be divided into two categories: 1.Prokaryotes - lack a well defined nucleus and possess relatively simple structure. These include the various bacteria. 2. Eukaryotes - possess a well defined nucleus and are more complex in their structure and function. The higher organisms (animals and plants) are composed of eukaryotic cells.
  8. 8. Comparison between prokaryotic and eukaryotic cells Characteristics Prokaryotic Cell Eukaryotic Cell 1. Size Small (generally 1 - 10 μm) Large (generally 10 - 100 μm) 2. Cell membrane Cell is enveloped by a rigid wall Cell is enveloped by a flexible plasma membrane 3. Sub - cellular organelles Absent Distinct organelles are found (e.g., mitochondria, nucleus, lysosomes) 4. Nucleus Not well defined;DNA is found as nucleoid,histones are absent Nucleus is well defined, surrounded by a membrane;DNA is associated with histones 5. Energy metabolism Mitochondria absent, enzymes of energy metabolism bound to membrane Enzymes of energy metabolism are located in mitochondria 6. Cell division Usually fission and no mitosis Mitosis 7. Cytoplasm Organelles and cytoskeleton absent Contains organelles and cytoskeleton (a network of tubules and filaments)
  9. 9. BIOCHEMICAL/CLINICAL CONCEPTS •A living cell is a true representative of life with its own organization and specialized functions. • Accumulation of lipofuscin, a pigment rich in lipids and proteins, in the cell has been implicated in ageing process. • Leakage of lysosomal enzymes into the cell degrades several functional macromolecules and this may lead to certain disorders (e.g. anthritis)
  10. 10. SUMMARY 1. Life is composed of lifeless chemical molecules. The complex biomolecules, proteins, nucleic acids (DNA and RNA), polysaccharides and lipids are formed by the monomeric units amino acids, nucleotides, monosaccharides and fatty acids, respectively. 2. The cell is the structural and functional unit of life. The eukaryotic cell consists of well defined subcellular organelles, enveloped in a plasma membrane. 3. The nucleus contains DNA, the repository of genetic information. DNA, in association with proteins (histones), forms nucleosomes which, in turn, make up the chromosomes.
  11. 11. 4. The mitochondria are the centres for energy metabolism. Thy are the principal producers of ATP which is exported to all parts of the cell to provide energy for cellular work. 5. Endopalsmic reticulum (ER) is the netweok of membrane enclosed spaces that extends throughout the cytoplasm. ER studded with ribosomes, the factories of protein biosynthesis, is referred to as rough ER. Golgi apparatus are a cluster of membrane vesicles to which the newly synthesized proteins are handed over for further processing and export.
  12. 12. 6. Lysosomes are the digestive bodies of the cell, actively involved in the degradation of cellular compounds. Peroxisomes contain the enzyme catalase that protects the cell from the toxic effects of H2O2 . The cellular ground matrix is referred to as cytosol which, in fact, is composed of a network of protein filaments, the cytoskeleton.
  13. 13. Primary Recommendations to promote Good Health through Proper Nutrition 1. Eat a variety of foods every day. 2. Breast - feed infants exclusively from birth to 4-6 months, and hen, give appropriate foods while continuing breast -feeding. 3. Maintain children’s normal growth through proper diet and monitor their growth regularly. 4. Consume fish, lean meat, poultry or dried beans. 5. Eat more vegetables, fruits and root crops. 6. Eat foods cooked in edible oil/cooking oil daily. 7. Consume milk, milk products or other calcium - rich foods such as small fish and dark green leafy vegetables everyday.
  14. 14. 8. Use iodized salt, but avoid excessive intake of salty foods. 9. Eat clean or safe food. 10. For healthy lifestyle and good nutrition, exercise regularly, do not smoke, and avoid drinking alcoholic beverages.
  15. 15. Nutritional Status or Nutriture - condition of health of body as a result of ingestion and utilization of food. Classification: Normal Nutriture = + or - 10% of Desirable Ideal Body Weigth Overweight = Actual Weight is 11 to 20% above the DBW. Obese = Actual weight is more than 20% of the DBW. Undernutrition - 1st degree - actual weight is 75.90% of DBW.
  16. 16. NUTRIENTS I. MACRONUTRIENTS Carbohydrates Fat Proteins II. MICRONUTRIENTS Vitamins Minerals Desirable Proportion of Fats, Protein and CHO in the Diet Filipino Diet CHO - 55.70 % 74% Fat - 20.30% 15% Sat fat < 10% Protein - 10 - 15% 11.3%
  18. 18. Carbohydrate Proteins Fats ATP Ethanol BODY Structure BODILY Processes Fuels are oxidized to generate ATP. Energy release from ATP drives bodily processes. Some of the available energy from fuels is lost as heat during the generation.
  19. 19. What is Energy? - Energy is the capacity to do work. - Commonly expressed in Kilocalories or cal Kilojoules Components of Energy Requirement Basal metabolism Thermic Effect of Exercise (Physical Activity) Thermic effect of food
  20. 20. Energy 1. Basal metabolic Rate (BMR) Energy needed to maintain life when a body is at complete rest after a 12 hour fast. 2. Basal Metabolism Energy expended to maintain metabolism during complete physical & mental rest
  21. 21. Components of Energy Expenditure Basal energy is needed to: Heat or cool the body normal organ functions maintenance of tissues metabolic homeostasis Computation of BMR Krause and Mahan Method ( for normal weight and height Adult Male = 1 kcal E/kg desirable body wt./hr. Female = 0.9 kcal E/kg desirable body wt/hr. BMR = 1kcal x body weight (kg) x 24 hrs.
  22. 22. Sample Calculation: 1. For a 24 year old Filipino who is confined at the hospital and is 5’2” tall DBW = 157 cm - 100 = 57 kg - 5.7 = 51 kg. Thanhausser’s Formula: Height(cm) - 100 = weight(kg) for Western Standard (Deduct 10% for Filipinos)
  23. 23. 1 inch = 2.54cm. 62 inch x 2.54 cm = 157.4 cm For a 29 year old Filipino and is 5’2” tall 5 x 12 = 60 inch + 2 = 62 inch 62 x 2.54cm = 157.48 cm. DBW = 157 cm - 100 = 57 - 5.7 = 51.3 or 51 kg. BMR = 1cal x w + kg x 24 hrs. = 1 x 51 x 24 = 1224 cal.
  24. 24. Basal Metabolic Rate Determinants •Body size •Sex •body Temperature •State of Nutrition/body condition •climate •Relaxation of muscle tension •hormone secretions •hyperthyroidism •hypothyroidism
  25. 25. Water, bone and fat do not actively participate in energy metabolism since the seat of energy exchange is in the active protoplasm or in the muscles. •Thus, women usually have a lower basal metabolic rate than men. •Non - athletes lower than athletes by about 5% •The skeletal muscles expend almost 1/5 of the resting metabolism.
  26. 26. Women have 6 - 10% lower basal metabolic rates than men because of sex differences in body mass and hormones. Women usually have more adipose tissue. Adipose tissue is much less metabolically active than in lean tissue SEX
  27. 27. BODY SIZE A tall, lean man will have higher basal metabolism than a stout, short person of the same weight because of the greater surface in the former. BODY TEMPERATURE ºTemp as in fever •will cause 13% rise for each degree above 37 ºC. º Temp •shivering results and as response, BMR increases
  28. 28. GROWTH The growth hormone stimulates cell metabolism and raises BMR 15% - 20% Thus, the BMR slowly rises during the first 5 years of life, levels off somewhat, rises again just before and during puberty, and then gradually declines into old age.
  29. 29. CLIMATE The adjustment is based more on the amount of physical activity performed on account of climate. AGE BMR declines during old age due to the slowing down of body processes. There is a decrease of 5% for each decade between 40 - 58 years. For decades 60 - 69 and 70 and above, the decrement is increased to 10% per decade.
  30. 30. PREGNANCY AND LACTATION During pregnancy and lactation, the BMR is increased by 20 - 25% because of the development of the fetus and placenta or an increase in metabolic activity of the maternal tissues. Energy expended during lactation.
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