physio lab2

Question Answer
=Monosaccharides (glucose +glucose)
Peptide (portion of protein molecule) + Water
=amino acid + amino acid
Fat + Water
=fatty acids + glycerol
Characteristics of Enzymes: •Not changed by reaction
•Active site specific for particular substrate
•Will not make reactions occur that don’t already happen in their absence
•Increases rate of reaction in both directions
•Lowers (Ea)without any net change in total E of rxn
Enzyme Activity: • As measured by the rate at which its substrates are converted to products
• Factors that influence enzyme activity:
– Temperature
– pH
– Enzyme & Substrate concentration
Effects of Temperature on enzyme activity: Increasing the temp will increase the rate of reaction up to a certain point, after going past optimal temperature for the enzyme, the reaction is actually DECREASED
Effects of pH on enzyme activity: Each enzyme has a specific optimal pH level where it performs catalytic functions most efficiently yielding the greatest increase in rate of reaction
Effect of substrate concentration on the rate of an enzyme-catalyzed reaction: Rate of product formation will increase as the substrate concentration increases up to a point where additional substrate concentration does not result in comparable increases in reaction rate.
The solution is said to be saturated when? relationship between substrate concentration and reaction rate reaches a plateau
Albinism: Dopa: product produced by conversion Phenylalanine, Dopa is precursor of pigment molecule MELANIN, albinisim is an inherited defect in the enzyme that catalyzes the formation of melanin from DOPA
Gastrointesinal (GI) tract: “ alimentary canal ” Mouth
Most of pharynx
Small and Large Intestines
Accessory Digestive Organs Teeth
Salivary glands
Function of Digestive system:
taking food into the mouth
Function of Digestive system:
Mixing and Propulsion
churning and propulsion of food through the GI tract
Function of Digestive system:
mechanical and chemical breakdown of foodstuffs
Function of Digestive system:
passage of digested products from the GI tract into the blood and lymph
Function of Digestive system:
the elimination of feces from the GI tract
Function of Digestive system:
release of water, acid, buffers, and enzymes into the lumen of the GI tract.
Homeostasis and digestion Transferring nutrients and elctrolytes from external environment to internal environment, cells need constant supply of these nutrients to synthesize new cell parts and secretory products, nutrients help support energy generating chemical reactions
Homeostasis and digestion: first part -when food enters stomach, it disrupts homeostasis
-pH of gastric juice, stretching of stomach walls
-chemo receptors and stretch receptors in stomach detect pH increase and distention
-message is sent to submucosal plexus(control center)
Homeostasis and digestion: second part -effectors are the parietal cells which then secrete HCL and the smooth muscle in the stomach wall contracts more vigorously leading to an increase in acidity of stomach chime; mixing of stomach sat_flash_1s; emptying of stomach

Homeostasis and digestion: last part -return to homeostasis when response brings pH of gastric juice and distention stomach walls back to normal (pre-eating status)
Gastroenterology deals with the structure, function, diagnosis, and treatment of diseases of the stomach and intestines
• Carbohydrate digestion begins in the ? mouth.
Enzyme: salivary amylase (Ptylin)?
• Protein digestion begins in the ? stomach
Enzyme: pepsin
• Lipid digestion begins in the? small intestine
Enzyme: lipase
Gastric Glands:
I. Mucous neck cells
– Secrete mucous
Gastric Glands:
II. Chief or zygomatic cells
– Secrete pepsinogen and gastric lipase
– Inactive enzyme pepsinogen is activated to pepsin by HCl and by pepsin itself (positive feedback mechanism)
Gastric Glands: – Secrete HCl
– Secrete intrinsic factor, which is a glycoprotein required for absorption of Vitamin-B12 in small intestine
Gastritis: inflammation caused by anything that breaches the mucosal barrier
Peptic or gastric ulcers erosion of the stomach wall
• Most are caused by Helicobacter pylori bacteria
Bile emulsification of lipids 1. Emulsification of fat droplets by bile salts
2. Hydrolysis of triglycerides in emulsified fat droplets into fatty acid and monoglycerides
3. Dissolving of fatty acids and monoglycerides into micelles to produce “mixed micelles”
Causes of Gallstones: 1.too much absorption of water from bile
2. too much absorption of bile acids from bile
3. too much cholesterol in bile
4. inflammation of epithelium

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