The Cell Chapter 2 Anatomy and Physiology of the Cell Farm Animal Biosystems ANSC 113 Fall 2022 Chemical Composition of the Cell Chemical composition of the cell plays a key role in cellular function 85 water 10 protein 2 lipid 1 5 inorganic matter 1 5 other substances Chemical Composition of the Cell 2 1 5 1 5 10 carbohydrates 85 Water Inorganic Matter Protein Other Substances Lipid Water Largest constituent of protoplasm Acts as a solvent for inorganic substances and enters many biochemical reactions Most body water is within cells and known as intracellular fluid 40 of body weight Water found outside of cells is referred to as extracellular fluid 20 of body weight Most extracellular fluid surrounds cells and is known as interstitial fluid Cerebrospinal fluid joint fluid Water Blood plasma an additional extracellular fluid is about 5 of total body weight Fluid content varies from animal to animal an is impacted by a variety of factors Condition fat Age Hydration Species Water Water is constantly lost from the body Must be replenished for the animal to remain in water balance Most is lost via urine but also lost in feces and evaporation from body surfaces Replacement is done almost entirely through drinking Proteins Proteins are the next largest constituent of protoplasm Complex high molecular weight colloidal molecules Consist of amino acids that are polymerized into polypeptide chains A peptide linkage bond between amino NH2 and carboxyl COOH group of another Proteins Peptide a small chain of amino acids Polypeptide a chain of more than 50 amino acids Protein a chain of more than 100 amino acids Proteins Peptide linkages are somewhat flexible Permits the chain to bend into 3D structures 3D shape is important determines biological function Shape determines what protein segments are exposed for interaction with other molecules https depositphotos com 99013092 stock photo molecular structure of collagen html Proteins Most proteins can be classified into two categories Structural Proteins Reactive Proteins https www sinobiological com resource c reactive protein proteins Structural Proteins Include fibrous proteins Collagens major protein of connective tissue Make up about 30 of the total protein in the animal body Elastins present in elastic tissue such as the ligamentum nuchae arteries and abdominal tunic Keratins proteins of wool hair horn and hoof https pressbooks umn edu largeanimalanatomy chapter thorax Reactive Proteins Enzymes Protein hormones Histones Contractile proteins of muscle Actin Myosin Barrington et al Lipids Fatty substances consisting of primarily carbon hydrogen and oxygen Some contain minor amounts of phosphorous nitrogen and sulfur Most are nonpolar molecules insoluble in water Four primary chemical lipid types in animals Fatty Acids Fatty Acids chains of covalently bound carbon atoms with hydrogens attached If each carbon has four single covalent bonds it is saturated If any carbon has fewer than four single bonds it is unsaturated Monounsaturated 1 double bond Polyunsaturated more than 1 double bond Animal tissues tend to have more saturated fatty acids than vegetable oils Fatty Acid Derivatives Prostaglandins and leukotrienes are derived from fatty acids and produced from various cells throughout the body Serve as local messengers that permit one cell to impact the function of a nearby cell Both are local messengers in the inflammation process Prostaglandins regulate ovarian function in some species https www zoetisus com products dairy lutalyse injection aspx Triglycerides Consist of a glycerol molecule with three fatty acids attached Glycerol Backbone Primary form of lipid storage in adipose tissue Fatty acids must be detached from glycerol before they can undergo further metabolism Detached be enzymes known as lipases Triglycerides Combined with lipids and other proteins for transport resulting in a large particle called a lipoprotein Glycerol and the fatty acids derived from triglyceride breakdown are all sources of energy Triglycerides Glycerol can serve as a substrate in the Glycolytic Pathway in the cytosol Fatty acids enter the mitochondria Ultimately broken down into Acetyl CoA to produce ATP Phospholipids Similar to triglycerides except a phosphate group containing molecule replaces a fatty acid Creates variation in water solubility Phospholipid bilayer impacts membrane structure Cell membranes throughout the body consist of a phospholipid Steroids Lipids in which carbon atoms are connected in ring structures Cholesterol is a steroid and most steroids found in animals are derived from Cholesterol Bile salts Hormones Essential constituent of cell membranes Cholesterol Can be obtained from dietary sources Synthesized in the liver Inappropriate rates of synthesis are responsible for elevated rates when diet is cut back Carbohydrates Composed of carbon oxygen and hydrogen Simple sugars or monosaccharides contain 3 7 carbon atoms Glucose is most prevalent monosaccharide in the body Two simple sugars can combine to form a disaccharide Multiple molecules of glucose can polymerize to form a polysaccharide glycogen Glycogen Two major sites of glycogen synthesis in the body Liver Skeletal Muscle Stored glycogen can be broken down to glucose and metabolized by liver cells or secreted as glucose in the blood Glycogen stores in skeletal muscle can be used for immediate energy cannot be a source of glucose for blood release Review What are the chemical components of a cell Why is protein shape important What are the four main lipid classifications What are the general carbohydrate structures Where can glycogen be stored What are the differences among the locations and their ultimate use of glycogen
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