The fluxes are several times as great as the net movement which is their difference. ON THE PATHOGENESIS OF FATTY LIVER
|
|
- Sibyl Bradford
- 5 years ago
- Views:
Transcription
1 January 1966 EDITORIALS 137 hexose and amino acid accumulates during absorption in vitro, with development of high concentration gradients between the cell and ECF, it is unlikely that this occurs in vivo. It is more likely that nutrient molecules pass rapidly through the serosal surface of the cell to be carried away in the circulation under in vivo conditions. Membrane pore size, which regulates permeability, is susceptible to metabolic effects such as hormone action. Antidiuretic hormone (ADH) regulates pore size of relatively impermeable membranes as in the distal renal tubule cells. The kidney is an organ of water excretion and receives large volumes of solutions. During dehydration, when water retention is necessary for homeostasis, the water must be recovered from the solutions. ADH increases pore size and permeability of renal tubule cells and promotes water retention by increasing its recovery from the lumen. In contradiction to earlier work, recent studies of the effect of ADH on the intestinal epithelium show a paradoxical decrease in permeability, particularly in the proximal portion of the small intestine. 9 Although these findings require confirmation, if the same agent produces opposite effects in different organs, this may be a valuable clue as to the chemical and structural nature of the opening and closing mechanism of the pores. Finally, it should be emphasized that transport has been discussed as net movement. The net is actually the difference between mucosal to serosal and serosal to mucosal unidirectional movements (fluxes). The fluxes are several times as great as the net movement which is their difference. Harold P. Schedl, M.D., Ph.D. Department of Internal Medicine University of Iowa College of Medicine Iowa City, Iowa REFERENCES 1. Woodbury, J. W The cell membrane: Ionic and potential gradients and active transport, p. 2. In T. C. Ruch and J. F. Fulton [ed.] Medical physiology and biophysics. W. B. Saunders Company, Philadelphia. 2. Curran, P. F Na, Cl, and water transport by the rat ileum in vitro. J. Gen. Physiol. 43: Durbin, R. P Osmotic flow of water across permeable cellulose membranes. J. Gen. Physiol. 44: Parsons, D. S., and D. L. Wingate Fluid movements across the wall of the rat intestine in vitro. Biochim. Biophys. Acta 30 : Curran, P. F., and J. R. Mac Intosh A model system for biological water transport. Nature (London) 193: Soter, N. A., J. P. Kinney, J. S. Fordtran, and F. Rector Permeability characteristics of the human small intestine. J. Lab. Clin. Med. 64: Schedl, H. P., and J. A. Clifton Cortisol absorption in man. Gastroenterology 44: Schedl, H. P., and J. A. Clifton Solute and water absorption by the human small intestine. Nature (London) 199: Soergel, K. H., G. E. Whalen, and J. A. Harris Effects of antidiuretic hormone (ADH) on the human small intestine. Clin. Res. 13: 261. ON THE PATHOGENESIS OF FATTY LIVER Recent advances in our knowledge of lipid metabolism have given new insight into the mechanisms of lipid absorption, transport, and regulation in higher animals as well as in man. New approaches to the Address requests for reprints to: Dr. Emmanuel Farber, Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania study of disease, now made possible by this knowledge, give every indication of clarifying the pathogenesis of a common pathological manifestation which has intrigued students of the liver for a long time, namely, fatty liver. In the fasting organism, lipid is transported from the adipose tissue as free (F) (or nonesterified (NE)) fatty acid (FA)
2 138 EDITORIALS Vol. 50, No.1 bound to serum albumin. The various cells of the body utilize some of this FF A as a source of energy. In the liver also, some of it is oxidized but the bulk is re-esterified, predominantly to triglyceride (TG), and is then transferred to the blood mainly as,b-lipoprotein. The combination with protein, phospholipid, and other non-tg lipids appears to be essential for the transfer of the TG from the liver to the blood. The TG transported in the blood is utilized by the tissues of the body, presumably with the aid of lipoprotein lipase, which hydrolyzes the TG in the lipoprotein to free fatty acids. In the jed organism, the liver actively takes chylomicra TG coming from the intestine and again converts at least some of this lipid to plasma lipoprotein. Thus the liver plays an active role in the handling and preparation of lipid from both the diet and the storage depots for transport and utilization by the body. Important in this concept is the realization that the bulk of the free fatty acids taken up by the liver appears as blood TG and that the over-all rate of this conversion is very rapid. The first maj or breakthrough in our understanding of the pathogenesis of liver steatosis was the discovery in 1960 that the fatty liver induced by such agents as carbon tetrachloride was due to a block in the transfer of triglyceride from the liver to the plasma. 1,2 According to this formulation, the liver continues to take up FF A and dietary lipid from the blood and to esterify them to triglycerides but cannot release the newly synthesized triglyceride into the blood at a rate sufficiently rapid to balance the rate of uptake of its precursor. The second important step in our understanding was the suggestion that the underlying mechanism for such a block might be the interference with the synthesis by the liver of the protein moiety of the plasma lipoproteins. 3-5 Although some intimate relationship between fatty liver and disturbed protein synthesis was suspected some years earlier (cf. reference 6), it is now possible to formulate this in molecular terms which can be subjected to experimental test. In the case of at least four agents, CCl 4 ; phosphorus; the methionine antagonist, ethionine; and the antibiotic, puromycin, the accumulation of excess triglyceride is preceded by a significant inhibition of hepatic protein synthesis. With ethionine, this disturbance in protein metabolism in the liver is the result of a striking decrease in hepatic ATP concentration;7 while with puromycin, the amino acids, although activated normally, are prevented from being linked together to form the peptide chains of protein. 8 The underlying molecular mechanisms for the inhibitions of protein synthesis by CCl 4 9 and plo remain to be clarified. If further research substantiates the essential validity of this hypothesis, one may formulate the basic defect in one group of fatty livers as an inability of the liver either to package the lipoprotein for export or to transfer it through the various membranes from the interior of the liver cell to the plasma. Since the plasma lipoproteins, including the very low density,b-lipoproteins, are composed not only of triglycerides and protein but also of phospholipids, cholesterol, cholesterol esters, and some carbohydrate, and since the decrease in the level of such lipoproteins in the plasma following CCl 4 or ethionine administration involves all lipid components,ll, 12 it naturally follows that fatty liver may result from an interference with the ability of the liver either to synthesize anyone of these component parts or to conjugate them in the appropriate manner to make the complete lipoprotein molecule. There is a growing realization that, although the delineation of the chemical alterations in cells is fundamental to our eventual understanding of the pathogenesis of most disease, such information, without due regard to intracellular compartments, will probably be insufficient per se to explain disease. The beginning elucidation of the intricate subcellular structure of cells makes it evident that complex intracellular chemical compartmentation is a phenomenon that must be integrated with the overall biochemical activities of cells and tissues in order to explain many pathological as well as physiological phenomena. This concept is well illustrated by recent information
3 139 EDITORIALS January 1966 FIG. 1. Portions of three hepatocytes (H1, H 2, and H 3) 4\12 hr after ethionine. M embranebound osmiophilic bodies are apparent in each hepatocyte. Sites of continuity between the membrane enclosing the osmiophilic bodies and the agranular and rough endoplasmic reticulum are indicated by arrows. A peg-and-socket type of contact is seen between two hepatocytes (H2 and H.). ar agranular reticulum; ER rough endoplasmic reticulum ; r ribosomes. Tissue fixed in osmium tetroxide, buffered with Veronal acetate, embedded in Epon, and stained with lead citrate (X 14,250). about ultrastructural alterations in fatty liver as observed with the electron microscope. Work from several laboratories during the past year has shown that triglyceride accumulates first inside the endoplasmic reticulum early in the genesis of several forms of fatty liver. A representative illustration of this, as seen within a few hours after ethionine administration, is given in figure 1. As more and more TG appears in the liver, these small lipid bodies fuse to form larger lipid collections which are visible under light microscopy. It now appears that small lipid bodies are easily and rapidly removed from the liver when the basic chemical defect is reversed,
4 140 EDITORIALS Vol. 50, No. 1 whereas the larger accumulations are metabolically much less labile. This is observed, for example, in animals in which an early fatty liver has been induced by the administration of ethionine 3 to 4 hi' previously. By counteracting the A TP deficiency with the administration of an A TP precursor such as adenine, the small lipid bodies rapidly disappear from the endoplasmic reticulum and appear, transitorily, in the space of Disse. 13 According to the thesis outlined above, these lipid bodies accumulate in the ~ : m d o p lreticulum a s m i c as a result of the inability of the cell to transform them into plasma lipoprotein. Since triglyceride is synthesized from FF A and glycerophosphate in the endoplasmic reticulum, the TG naturally accumulates first in this site in the cell. This hypothesis is represented diagrammatically in figure 2. If it is basically valid, TG may accumulate in the liver as a result of an interference with the production of either protein, as with ethionine, puromycm, or CCI 4 ; phospholipid, as is probably the case in choline deficiency, cholesterol, or cholesterol esters. However, one would expect that the lipid accumulating in some fatty livers might consist not only of TG but also of phospholipid or cholesterol, or both. Yet, why do the majority of fatty livers contain only or predominantly excess triglyceride? No clear-cut answer to this important problem has been presented. However, it must be pointed out that the liver plays a unique role in plasma cholesterol and phospholipid metabolism in that this organ not only synthesizes these components but plays a very active part in their removal from the blood and in their further metabolism or breakdown. Also, triglyceride is utilized as a major energy source for many cells while phospholipid and cholesterol are mainly important as components of the structure of cell membranes or other cellular components or, as in the case of cholesterol, are precursors for metabolic regulators such as the steroid hormones. In view of this, it would not be at all surprising if a PLASMA F LIPID GLYCEROPHOSPHATE \... RETICULUM ETHIONINE, CCI4.., PUROMYCIN PHOSPHORUS CHOLINE ~ { DEFICIENCY? VERY LOW ~ Y P L A S M A ~ - - ~ ' LIPOPROTEIN FIG. 2. Diagrammatic representation of the synthesis of plasma ~ - l i p o p r o t e i n by the liver cell and the possible derangements during the pathogenesis of some forms of fatty liver. The fatty acids derived either from adipose tissue or from the diet are coupled with glycerophosphate to form triglyceride (TG) in the endoplasmic reticulum. This is somehow conjugated with protein, phospholipid, cholesterol, and cholesterol esters at some place along the route between the site of synthesis and the site of transfer into the blood. It is suggested that the interference with anyone of these conjugation steps may result in accumulation of triglyceride in the liver.
5 January 1966 EDITORIALS 14 I sensitive feedback inhibition of synthesis exists for phospholipid as well as for cholesterol, and that such a mechanism may be one factor in preventing any significant increase in either of these lipid components in most fatty livers. It should be emphasized that the pathogenetic mechanism here discussed is still a working hypothesis applicable to only some forms of fatty liver. A major exception among several is the case of the ethanol fatty liver,14 the genesis of which is still unclear. A major consideration for the experimental pathologist is the applicability to human disease of information obtained in experimental animals. In the case of fatty livers, it appears likely that the hypothesis discussed above may be useful in explaining human disease because of the essential similarity between higher animals and man in their over-all handling of lipids and in their lipid metabolism. Since several tests of the hypothesis could be relatively simply set up (e.g. serum lipid and lipoprotein determinations, conversion' of radioactive fatty acid to plasma triglyceride, etc.), it is anticipated that the appropriate studies will soon be performed to observe whether any forms of human fatty liver prove to have a pathogenetic mechanism similar to those discussed here. The results of such critical tests of the usefulness of this hypothesis in human disease will be awaited with great interest. Emmanuel Farber, M.D., Ph.D. Department of Pathology University of Pittsburgh School of Medicine Pittsburgh, Pennsylvania REFERENCES 1. Recknagel, R. 0., B. Lombardi, and M. C. Shotz A new insight into the pathogenesis of carbon tetrachloride fat infiltration. Proc. Soc. Exp. BioI. Med. 104: Recknagel, R. 0., and B. Lombardi Studies of biochemical changes in subcellular particles of rat liver and their relationship to a new hypothesis regarding the pathogenesis of carbon tetrachloride fat accumulation. J. BioI. Chern. 236: Lombardi, B., and R. O. Recknagel On the pathogenesis of experimental fatty infiltration of the liver. Fed. Proc. 20: Lombardi, B., and R. O. Reeknagel Interference with secretion of triglycerides by the liver as a common factor in toxic liver injury. Amer. J. Path. 40: Harris, P. M., and D. S. Robinson Ethionine administration in the rat. 1. Effects on the liver and plasma lipids and on the disposal of dietary fat. Biochem. J. 80: Farber, E Studies on the chemical pathology of lesions produced by ethionine. Arch. Path. (Chicago) 67: Farber, E., K. H. Shull, S. Villa-Trevino, B. Lombardi, and M. Thomas The biochemical pathology of acute hepatic adenosine triphosphate deficiency. Nature (London) 203: Darken, M. A Puromycin inhibition of protein synthesis. Pharmacol. Rev. 16: Smuckler, E. A., O. A. Iseri, and E. P. Benditt An intracellular defect in protein synthesis induced by carbon tetrachloride. J. E xp. Med. 116: Seakins, A., and D. S. Robinson Changes associated with the production of fatty livers by white phosphorus and ethanol in the rat. Biochem. J. 92: Lombardi, B., and G. Ugazio. Serum lipoproteins in rats with carbon tetrachloride induced fatty liver. J. Lipid R es. In press. 12. Ugazio, G., and B. Lombardi Serum lipoproteins in rats with ethionine-induced fatty liver. Lab. Invest. 14 : Baglio, C. M., and E. F arber Ultrastructural consequences of biochemical lesions in the liver induced by ethionine. Fed. Proc. 24: Isselbacher, K. J., and N. J. Greenberger Metabolic effects of alcohol on the liver. New Eng. J. Med. 270: 351.
Name: Date: Block: Biology 12
Name: Date: Block: Biology 12 Provincial Exam Review: Cell Processes and Applications January 2003 Use the following diagram to answer questions 1 and 2. 1. Which labelled organelle produces most of the
More information1Why lipids cannot be transported in blood alone? 2How we transport Fatty acids and steroid hormones?
1Why lipids cannot be transported in blood alone? 2How we transport Fatty acids and steroid hormones? 3How are dietary lipids transported? 4How lipids synthesized in the liver are transported? 5 Lipoprotien
More information4. ABSORPTION. Transport mechanisms. Absorption ABSORPTION MECHANISMS. Active transport. Active transport uses metabolic energy
4. ABSORPTION ABSORPTION MECHANISMS Once the digestive process is completed, the nutrients have to be transferred across the digestive tract epithelium into the intracellular space and eventually into
More informationPlasma lipoproteins & atherosclerosis by. Prof.Dr. Maha M. Sallam
Biochemistry Department Plasma lipoproteins & atherosclerosis by Prof.Dr. Maha M. Sallam 1 1. Recognize structures,types and role of lipoproteins in blood (Chylomicrons, VLDL, LDL and HDL). 2. Explain
More informationB.4B Cellular Processes
B.4B Cellular Processes Picture Vocabulary homeostasis The process of maintaining a constant state of balance cell membrane Cell part surrounding the cytoplasm and is also a barrier between the inside
More informationLIFE IS CELLULAR. Cell Theory. Cells Are Small. Prokaryotic Cell 10/4/15. Chapter 7 Cell Structure and Function
Chapter 7 Cell Structure and Function The cell basic unit of life, all living things are made of a cell (unicellular) or more than one cell (multicellular). LIFE IS CELLULAR The invention of the microscope
More informationDiabetes. Albumin. Analyte Information
Diabetes Albumin Analyte Information -1-2014-05-02 Albumin Introduction Albumin consists of a single polypeptide chain of 585 amino acids with molecular weight of 66.5 kda. The chain is characterized by
More informationBIOLOGICAL MOLECULES REVIEW-UNIT 1 1. The factor being tested in an experiment is the A. data. B. variable. C. conclusion. D. observation. 2.
BIOLOGICAL MOLECULES REVIEW-UNIT 1 1. The factor being tested in an experiment is the A. data. B. variable. C. conclusion. D. observation. 2. A possible explanation for an event that occurs in nature is
More informationUnit IV Problem 3 Biochemistry: Cholesterol Metabolism and Lipoproteins
Unit IV Problem 3 Biochemistry: Cholesterol Metabolism and Lipoproteins - Cholesterol: It is a sterol which is found in all eukaryotic cells and contains an oxygen (as a hydroxyl group OH) on Carbon number
More informationDraw and label a diagram to show the structure of membranes
2.4 Membranes 2.4.1 - Draw and label a diagram to show the structure of membranes Phospholipid Bilayer - This is arranged with the hydrophilic phosphate heads facing outwards, and the hydrophobic fatty
More informationCell Structure and Function Practice Exam - KEY
Biology 12 Name: Cell Structure and Function Practice Exam - KEY Cell parts and Function 1. Identify each part of the cell indicated and give one role for each structure in the secretion and/or synthesis
More informationBiology 12 Cell Structure and Function. Typical Animal Cell
Biology 12 Cell Structure and Function Typical Animal Cell Vacuoles: storage of materials and water Golgi body: a series of stacked disk shaped sacs. Repackaging centre stores, modifies, and packages proteins
More informationLipids digestion and absorption, Biochemistry II
Lipids digestion and absorption, blood plasma lipids, lipoproteins Biochemistry II Lecture 1 2008 (J.S.) Triacylglycerols (as well as free fatty acids and both free and esterified cholesterol) are very
More informationANSC/NUTR 618 LIPIDS & LIPID METABOLISM Lipoprotein Metabolism
ANSC/NUTR 618 LIPIDS & LIPID METABOLISM Lipoprotein Metabolism I. Chylomicrons (exogenous pathway) A. 83% triacylglycerol, 2% protein, 8% cholesterol plus cholesterol esters, 7% phospholipid (esp. phosphatidylcholine)
More informationCell Structure and Function
Cell Structure and Function Many Scientists Contributed to the Cell Theory! Hooke discovered cells while looking at cork under the microscope! Leewenhoek was the first to observe bacteria! Schleiden discovered
More informationKeystone Biology Remediation A4: Homeostasis and Transport
Keystone Biology Remediation A4: Homeostasis and Transport Assessment Anchors: to describe how the structure of the plasma allows it to function as a regulatory structure and/or protective barrier for
More informationCELLS and TRANSPORT Student Packet SUMMARY CELL MEMBRANES ARE SELECTIVELY PERMEABLE DUE TO THEIR STRUCTURE Hydrophilic head
CELLS and TRANSPORT Student Packet SUMMARY CELL MEMBRANES ARE SELECTIVELY PERMEABLE DUE TO THEIR STRUCTURE Hydrophilic head Hydrophobic tail Hydrophobic regions of protein Hydrophilic regions of protein
More informationPlant Cells. Chapter 3
Plant Cells Chapter 3 Major Learning Objectives Contrast prokaryotic and eukaryotic cells Describe the functions of 10 parts of a plant cell Summarize the similarities and differences between plant cells
More informationBIOL2171 ANU TCA CYCLE
TCA CYCLE IMPORTANCE: Oxidation of 2C Acetyl Co-A 2CO 2 + 3NADH + FADH 2 (8e-s donated to O 2 in the ETC) + GTP (energy) + Heat OVERVIEW: Occurs In the mitochondrion matrix. 1. the acetyl portion of acetyl-coa
More informationThe Cell. Copyright 2003 Pearson Education, Inc. publishing as Benjamin Cummings
The Cell Cell Theory The cell is the basic structural and functional unit of life The organism activity depends on individual and collective activity of cells Biochemical activities of cells are dictated
More informationLipoprotein Formation, Structure and Metabolism: Cholesterol Balance and the Regulation of Plasma Lipid Levels
Lipoprotein Formation, Structure and Metabolism: Balance and the Regulation of Plasma Lipid Levels David E. Cohen, MD, PhD Director of Hepatology, Gastroenterology Division, Brigham and Women s Hospital
More informationA small, membrane-bound compartment capable of performing all the basic functions of life
AP Biology The Cell The Cell Cell: A small, membrane-bound compartment capable of performing all the basic functions of life Discovery of Cells: - 17 th century - A Dutch clothing dealer named Antonie
More informationChapter 3 Review Assignment
Class: Date: Chapter 3 Review Assignment Multiple Choice 40 MC = 40 Marks Identify the choice that best completes the statement or answers the question. 1. Which of the following organelles produces transport
More informationHomeostatic Regulation
Homeostatic Regulation A hormone is :a Water-soluble hormones: Composed of amino acids and bind a receptor protein on the of the target cell. This starts a signal cascade inside the cell and the signal
More informationThe endoplasmic reticulum is a network of folded membranes that form channels through the cytoplasm and sacs called cisternae.
Endoplasmic reticulum (ER) The endoplasmic reticulum is a network of folded membranes that form channels through the cytoplasm and sacs called cisternae. Cisternae serve as channels for the transport of
More informationChapter 2: The Chemical Level of. Organization. Copyright 2009, John Wiley & Sons, Inc.
Chapter 2: Organization The Chemical Level of Question Of the following functions, the major propose of RNA is to A. Function in the synthesis of protein. B. Transmit genetic information to offspring.
More informationStudy Guide for Biology Chapter 5
Class: Date: Study Guide for Biology Chapter 5 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Which of the following led to the discovery of cells? a.
More informationChapter 19 The Urinary System Fluid and Electrolyte Balance
Chapter 19 The Urinary System Fluid and Electrolyte Balance Chapter Outline The Concept of Balance Water Balance Sodium Balance Potassium Balance Calcium Balance Interactions between Fluid and Electrolyte
More informationUNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DIVISION OF BASIC MEDICAL SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY
1 UNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DIVISION OF BASIC MEDICAL SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY GLUCOSE HOMEOSTASIS An Overview WHAT IS HOMEOSTASIS? Homeostasis
More informationCell Cell
Go to cellsalive.com. Select Interactive Cell Models: Plant and Animal. Fill in the information on Plant and Animal Organelles, then Click on Start the Animation Select Plant or Animal Cell below the box.
More informationThe Structure and Function of Biomolecules
The Structure and Function of Biomolecules The student is expected to: 9A compare the structures and functions of different types of biomolecules, including carbohydrates, lipids, proteins, and nucleic
More informationThe Cell Organelles. Eukaryotic cell. The plasma membrane separates the cell from the environment. Plasma membrane: a cell s boundary
Eukaryotic cell The Cell Organelles Enclosed by plasma membrane Subdivided into membrane bound compartments - organelles One of the organelles is membrane bound nucleus Cytoplasm contains supporting matrix
More informationCellular control of cholesterol. Peter Takizawa Department of Cell Biology
Cellular control of cholesterol Peter Takizawa Department of Cell Biology Brief overview of cholesterol s biological role Regulation of cholesterol synthesis Dietary and cellular uptake of cholesterol
More informationUnit 2 Warm Ups. Equilibrium
Unit 2 Warm Ups Equilibrium 1. Cell wall 2. Mitochondria 3. Chloroplast 4. Vesicle 5. Vacuole 6. Rough Endoplasmic Reticulum 7. Smooth Endoplasmic Reticulum 8. Cytoskeleton 9. Lysosomes 10.Cell Membrane
More informationMolecular Cell Biology Problem Drill 16: Intracellular Compartment and Protein Sorting
Molecular Cell Biology Problem Drill 16: Intracellular Compartment and Protein Sorting Question No. 1 of 10 Question 1. Which of the following statements about the nucleus is correct? Question #01 A. The
More informationOxidation of Long Chain Fatty Acids
Oxidation of Long Chain Fatty Acids Dr NC Bird Oxidation of long chain fatty acids is the primary source of energy supply in man and animals. Hibernating animals utilise fat stores to maintain body heat,
More informationCell Structure Animal/Human
Cell Structure Animal/Human cell is basic unit of all life; structural and functional if its alive, must contain at least a single cell the function of an organism is the summation of functions of its
More informationIntroduction. Biochemistry: It is the chemistry of living things (matters).
Introduction Biochemistry: It is the chemistry of living things (matters). Biochemistry provides fundamental understanding of the molecular basis for the function and malfunction of living things. Biochemistry
More informationCell Physiology
Cell Physiology 21-10-2018 1 The two major parts of a typical cell are the nucleus and the cytoplasm. The nucleus is separated from the cytoplasm by a nuclear membrane, and the cytoplasm is separated from
More informationReview Quizzes Chapters 1-5
Review Quizzes Chapters 1-5 1.Which of the following constitutes the quarternary level of protein structure? a. bonding between side chains of amino acids b. sequence of amino acids joined by peptide bonds
More informationThe Cell. The smallest unit of life that can perform all life processes.
The Cell The smallest unit of life that can perform all life processes. Life is macromolecules that can perform unique functions because they are enclosed in a structural compartment that is separate from
More informationA. Major parts 1. Nucleus 2. Cytoplasm a. Contain organelles (see below) 3. Plasma membrane (To be discussed in Cellular Transport Lecture)
Lecture 5: Cellular Biology I. Cell Theory Concepts: 1. Cells are the functional and structural units of living organisms 2. The activity of an organism is dependent on both the individual and collective
More informationFrom Atoms to Cells: Fundamental Building Blocks. Models of atoms. A chemical connection
From Atoms to Cells: A chemical connection Fundamental Building Blocks Matter - all materials that occupy space & have mass Matter is composed of atoms Atom simplest form of matter not divisible into simpler
More information1. How many fatty acid molecules combine with a glycerol to form a phospholipid molecule? A. 1 B. 2 C. 3 D. 4
Topic 3: Movement of substances across cell membrane 1. How many fatty acid molecules combine with a glycerol to form a phospholipid molecule? A. 1 B. 2 C. 3 D. 4 Directions: Questions 2 and 3 refer to
More informationBiological molecules
Biological molecules 04-04-16 Announcements Your lab report 1 is due now Quiz 1 is on Wednesday at the beginning of class, so don t be late Review Macromolecues are large molecules necessary for life made
More informationAP Biology
Tour of the Cell (1) 2007-2008 Types of cells Prokaryote bacteria cells - no organelles - organelles Eukaryote animal cells Eukaryote plant cells Cell Size Why organelles? Specialized structures - specialized
More informationOrganelles. copyright cmassengale 1
Organelles copyright cmassengale 1 Organelles Very small (Microscopic) Perform various functions for a cell Found in the cytoplasm May or may not be membrane-bound 2 Animal Cell Organelles Nucleolus Nucleus
More informationWhat systems are involved in homeostatic regulation (give an example)?
1 UNIVERSITY OF PNG SCHOOL OF MEDICINE AND HEALTH SCIENCES DIVISION OF BASIC MEDICAL SCIENCES DISCIPLINE OF BIOCHEMISTRY AND MOLECULAR BIOLOGY GLUCOSE HOMEOSTASIS (Diabetes Mellitus Part 1): An Overview
More informationEXCRETION QUESTIONS. Use the following information to answer the next two questions.
EXCRETION QUESTIONS Use the following information to answer the next two questions. 1. Filtration occurs at the area labeled A. V B. X C. Y D. Z 2. The antidiuretic hormone (vasopressin) acts on the area
More informationWELCOME TO BIOLOGY 11. Mr. Gandha
WELCOME TO BIOLOGY 11 Mr. Gandha TOPICS OF BIOLOGY 11 Chemicals of life Cells Evolution Taxonomy Microbio Plants Animals BIOLOGY THIS SEMESTER Review of Biology and Processes Adaptation and Evolution:
More informationCellular Injury. Intracellular degeneration. By Dr. Hemn Hassan Othman PhD, Pathology Fall /20/2018 1
Cellular Injury Intracellular degeneration By Dr. Hemn Hassan Othman PhD, Pathology Fall 2018 10/20/2018 1 Types of cell injury Cell injury is divided into: 1. Reversible cell injury 2. Irreversible cell
More informationIntracellular Compartments and Protein Sorting
Intracellular Compartments and Protein Sorting Intracellular Compartments A eukaryotic cell is elaborately subdivided into functionally distinct, membrane-enclosed compartments. Each compartment, or organelle,
More information18. PANCREATIC FUNCTION AND METABOLISM. Pancreatic secretions ISLETS OF LANGERHANS. Insulin
18. PANCREATIC FUNCTION AND METABOLISM ISLETS OF LANGERHANS Some pancreatic functions have already been discussed in the digestion section. In this one, the emphasis will be placed on the endocrine function
More informationLecture 5: Cell Metabolism. Biology 219 Dr. Adam Ross
Lecture 5: Cell Metabolism Biology 219 Dr. Adam Ross Cellular Respiration Set of reactions that take place during the conversion of nutrients into ATP Intricate regulatory relationship between several
More informationZool 3200: Cell Biology Exam 4 Part I 2/3/15
Name: Key Trask Zool 3200: Cell Biology Exam 4 Part I 2/3/15 Answer each of the following questions in the space provided, explaining your answers when asked to do so; circle the correct answer or answers
More informationA Tour of the Cell. Ch. 7
A Tour of the Cell Ch. 7 Cell Theory O All organisms are composed of one or more cells. O The cell is the basic unit of structure and organization of organisms. O All cells come from preexisting cells.
More informationCELLS CELL THEORY. There are two types of cells: 9/26/2016 CELLULAR COMPONENTS & PROCESES. Which is more complicated? REMEMBER YOU ARE EUKARYOTIC!
CELLS CELLULAR COMPONENTS & PROCESES CELL THEORY 1. All living things are made up of one or more cells 2. The cell is the smallest unit of life. 3. All new cells come from pre-existing cells. There are
More informationMILK BIOSYNTHESIS PART 3: FAT
MILK BIOSYNTHESIS PART 3: FAT KEY ENZYMES (FROM ALL BIOSYNTHESIS LECTURES) FDPase = fructose diphosphatase Citrate lyase Isocitrate dehydrogenase Fatty acid synthetase Acetyl CoA carboxylase Fatty acyl
More informationFIRST MIDTERM EXAMINATION
FIRST MIDTERM EXAMINATION 1. True or false: because enzymes are produced by living organisms and because they allow chemical reactions to occur that would not otherwise occur, enzymes represent an exception
More informationCHM333 LECTURE 34: 11/30 12/2/09 FALL 2009 Professor Christine Hrycyna
Lipid Metabolism β-oxidation FA Acetyl-CoA Triacylglycerols (TAGs) and glycogen are the two major forms of stored energy in vertebrates Glycogen can supply ATP for muscle contraction for less than an hour
More informationTransport across the cell membrane
Transport across the cell membrane Learning objectives Body compartments ECF and ICF Constituents Lipid Bilayer: Barrier to water and water-soluble substances ions glucose H 2 O urea CO 2 O 2 N 2 halothane
More informationEndomembrane system 11/1/2018. Endomembrane System. Direct physical continuity. Transfer of membrane segments as vesicles. Outer Nuclear envelope
Endomembrane system Endomembrane System Outer Nuclear envelope Direct physical continuity Transfer of membrane segments as vesicles Endoplasmic reticulum BUT membranes are not identical in structure and
More informationHuman Epithelial Cells
The Cell Human Epithelial Cells Plant Cells Cells have an internal structure Eukaryotic cells are organized Protective membrane around them that communicates with other cells Organelles have specific jobs
More informationCell Structure. Present in animal cell. Present in plant cell. Organelle. Function. strength, resist pressure created when water enters
Cell Structure Though eukaryotic cells contain many organelles, it is important to know which are in plant cells, which are in animal cells and what their functions are. Organelle Present in plant cell
More informationTitle: Sep 10 7:59 PM (1 of 36) Ch 3 Cell Organelles and Transport
Title: Sep 10 7:59 PM (1 of 36) Ch 3 Cell Organelles and Transport Title: Sep 10 8:02 PM (2 of 36) Cell organelles Nucleus: contains DNA Title: Sep 10 8:03 PM (3 of 36) Nuclear envelope double membrane
More informationMembrane Structure and Function
BIOL1040 Page 1 Membrane Structure and Function Friday, 6 March 2015 2:58 PM Cellular Membranes Fluid mosaics of lipids and proteins Phospholipids - abundant Phospholipids are amphipathic molecules (has
More informationThe principal functions of the kidneys
Renal physiology The principal functions of the kidneys Formation and excretion of urine Excretion of waste products, drugs, and toxins Regulation of body water and mineral content of the body Maintenance
More informationInitially, the patients did not receive extra vitamin E except for a very
EFFECT OF VITAMIN E ON MEMBRANES OF THE INTESTINAL CELL BY I. MOLENAAR, F. A. HOMMES, W. G. BRAAMS, AND H. A. POLMAN CENTER FOR MEDICAL ELECTRON MICROSCOPY AND DEPARTMENT OF PEDIATRICS, UNIVERSITY OF GRONINGEN,
More informationPrinciples of Anatomy and Physiology
Principles of Anatomy and Physiology 14 th Edition CHAPTER 25 Metabolism and Nutrition Metabolic Reactions Metabolism refers to all of the chemical reactions taking place in the body. Reactions that break
More information/ The following functional group is a. Aldehyde c. Carboxyl b. Ketone d. Amino
Section A: Multiple Choice Select the answer that best answers the following questions. Please write your selected choice on the line provided, in addition to circling the answer. /25 1. The following
More informationFirst discovered in 1665 since then every organism observed with microscopes shows cells
The Cell Cell theory (1838): 1. All organisms are composed of one or more cells, and the life processes of metabolism and heredity occur within these cells. 2. Cells are the smallest living things, the
More information23.1 Lipid Metabolism in Animals. Chapter 23. Micelles Lipid Metabolism in. Animals. Overview of Digestion Lipid Metabolism in
Denniston Topping Caret Copyright! The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 23 Fatty Acid Metabolism Triglycerides (Tgl) are emulsified into fat droplets
More informationBIOLOGICAL CHEMISTRY Prof. J.H.P. Bayley, Dr. R.M. Adlington and Dr. L. Smith Trinity Term First Year. Lecture 2 Hagan Bayley
BIOLOGICAL CHEMISTRY Prof. J.H.P. Bayley, Dr. R.M. Adlington and Dr. L. Smith Trinity Term 2007 - First Year Lecture 2 Hagan Bayley Introduction to the macromolecules of life and cell structures. Introduction
More informationMULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Exam Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) All of the following are synthesized along various sites of the endoplasmic reticulum
More informationEndomembrane system, *Chloroplasts, *Mitochondria. *Learn these from text/connect1. Fertilization of a human cell
Key Concepts: - Cells are the Basic Unit of Life Cell Theory, Surface to Volume - 2 Cell Types Prokaryotic, Eukaryotic - Cell Membrane Membrane Structure - Cell Organelles Endomembrane system, *Chloroplasts,
More informationCell Structure Text Ref Pg 4-7, 63-81
Cell Structure Text Ref Pg 4-7, 63-81 The Cellular Basis of Life Before people had a scientific explanation for where life came from, they believed in the theory of spontaneous generation, where organisms
More information/searchlist/6850.html Tour of the Cell 1
http://www.studiodaily.com/main /searchlist/6850.html Tour of the Cell 1 2011-2012 Cytology: science/study of cells To view cells: Light microscopy resolving power: measure of clarity Electron microscopy
More informationActivity: Biologically Important Molecules
Activity: Biologically Important Molecules AP Biology Introduction We have already seen in our study of biochemistry that the molecules that comprise living things are carbon-based, and that they are thought
More informationIntegration Of Metabolism
Integration Of Metabolism Metabolism Consist of Highly Interconnected Pathways The basic strategy of catabolic metabolism is to form ATP, NADPH, and building blocks for biosyntheses. 1. ATP is the universal
More information3UNIT. Photosynthesis and. Cellular Respiration. Unit PreQuiz? General Outcomes. Unit 3 Contents. Focussing Questions
3UNIT Photosynthesis and Cellular Respiration General Outcomes In this unit, you will relate photosynthesis to the storage of energy in organic compounds explain the role of cellular respiration in releasing
More informationBasic Structure of a Cell. copyright cmassengale
Basic Structure of a Cell 1 Review Facts About Living Things 2 What Are the Main Characteristics of organisms? 1. Made of CELLS 2. Require ENERGY (food) 3. REPRODUCE (species) 4. Maintain HOMEOSTASIS 5.
More informationRegulating Hepatic Cellular Cholesterol
Under circumstances of cholesterol deficiency, Sterol Regulatory Element Binding Proteins (SREBPs) via binding to DNA nuclear response elements set off genomic production of proteins and enzymes that induce
More informationanabolic pathways- Catabolic Amphibolic
METABOLISM Introduction The fate of dietary components after digestion and absorption constitute metabolism regulated by metabolic pathway 3 types: anabolic pathways- Synthesis of compound e.g. synthesis
More informationUnit 2: More on Matter & Energy in Ecosystems. Macromolecules to Organelles to Cells
IN: Unit 2: More on Matter & Energy in Ecosystems Macromolecules to Organelles to Cells Where are cells on the biological scale? Sub-Atomic Particles Atoms Molecules Macromolecules (proteins, lipids, nucleic
More informationLesson Overview. 7.2 Cell Structure
7.2 Cell Organization The eukaryotic cell can be divided into two major parts: the nucleus and the cytoplasm. The cytoplasm is the fluid portion of the cell outside the nucleus. Prokaryotes do not have
More informationReview Session 1. Control Systems and Homeostasis. Figure 1.8 A simple control system. Biol 219 Review Sessiono 1 Fall 2016
Control Systems and Homeostasis Review Session 1 Regulated variables are kept within normal range by control mechanisms Keeps near set point, or optimum value Control systems local and reflex Input signal
More informationEukaryotic Cell Structures
Comparing the Cell to a Factory Eukaryotic Cell Structures Structures within a eukaryotic cell that perform important cellular functions are known as organelles. Cell biologists divide the eukaryotic cell
More informationChapter (5) Etiology of Low HDL- Cholesterol
Chapter (5) Etiology of Low HDL- Cholesterol The aim of this chapter is to summarize the different etiological factors mainly the role of life-style and different disease conditions contributing to the
More informationWeek 3 The Pancreas: Pancreatic ph buffering:
Week 3 The Pancreas: A gland with both endocrine (secretion of substances into the bloodstream) & exocrine (secretion of substances to the outside of the body or another surface within the body) functions
More information4/12/17. Cells. Cell Structure. Ch. 2 Cell Structure and Func.on. Range of Cell Sizes BIOL 100
Ch. 2 Cell Structure and Func.on BIOL 100 Cells Fundamental units of life Cell theory All living things are composed of one or more cells. The cell is the most basic unit of life. All cells come from pre-existing
More informationCell Structure and Function. Biology 12 Unit 1 Cell Structure and Function Inquiry into Life pages and 68-69
Cell Structure and Function Biology 12 Unit 1 Cell Structure and Function Inquiry into Life pages 45 59 and 68-69 Assignments for this Unit Pick up the notes/worksheet for this unit and the project There
More information- Most nutrients are absorbed before reaching the ileum. - Colon is responsible for final removal of electrolytes and water.
University of Jordan Department of physiology and Biochemistry Gastro-Intestinal physiology, Medical, Pt III. ---------------------------------------------------------------------------- Academic year:
More informationchange of free fatty acids during incubation was
EFFECT OF GLUCOSE AND INSULIN ON THE ESTERIFICATION OF FATTY ACIDS BY ISOLATED ADIPOSE TISSUE* By M. S. RABEN AND C. H. HOLLENBERG t (Fromn the Ziskind Research Laboratories, New Englantd Centter Hospital,
More informationCellular Structure and Function. Chapter 7
Cellular Structure and Function. Chapter 7 Cell Discovery and Theory. A cell is the basic structural and functional unit of all living organisms. The human body is made of trillions of cells that are too
More informationComprehensive and Easy Course Notes for BIOL1040 Exams and Assessment
Comprehensive and Easy Course Notes for BIOL1040 Exams and Assessment MODULE 1: PRINCIPLES OF CELL FUNCTION Membrane Structure & Function Cellular membranes are fluid mosaics of lipids and proteins Phospholipids
More informationGENERAL CHARACTERISTICS OF THE ENDOCRINE SYSTEM FIGURE 17.1
GENERAL CHARACTERISTICS OF THE ENDOCRINE SYSTEM FIGURE 17.1 1. The endocrine system consists of glands that secrete chemical signals, called hormones, into the blood. In addition, other organs and cells
More informationTypes of cells. Cell size comparison. The Jobs of Cells 10/5/2015. Cells & Cell Organelles. Doing Life s Work
Types of cells Prokaryote Cells & Cell Organelles bacteria cells Doing Life s Work Eukaryotes 2009-2010 animal cells plant cells Cell size comparison Animal cell Bacterial cell most bacteria (prokaryotic)
More informationCIE Biology A-level Topic 14: Homeostasis
CIE Biology A-level Topic 14: Homeostasis Notes Communication is essential for the survival of organism as all living organisms must be able to detect and respond to changes in both their internal and
More informationBIOLOGY 111. CHAPTER 3: The Cell: The Fundamental Unit of Life
BIOLOGY 111 CHAPTER 3: The Cell: The Fundamental Unit of Life The Cell: The Fundamental Unit of Life Learning Outcomes 3.1 Explain the similarities and differences between prokaryotic and eukaryotic cells
More informationThursday, October 16 th
Thursday, October 16 th Good morning. Those of you needing to take the Enzymes and Energy Quiz will start very soon. Students who took the quiz Wednesday: Please QUIETLY work on the chapter 6 reading guide.
More information