Diabetes, Digestion, and Enzymes

• These notes cover topics including diabetes, digestion, enzymes, macromolecules, cell structure and transport, endocrine system, hormone action, cellular respiration, and reproductive cycles.

Diabetes

• Diabetes is characterized by the body's impaired ability to produce or respond to insulin.
• This leads to abnormal carbohydrate metabolism and elevated glucose levels.
• Diabetes is a major health concern, being the tenth leading cause of death and the fastest-growing chronic disease in the US.
• It affects how the body obtains energy.

Digestion

• Digestion involves chemical processes in the stomach (acids and enzymes) and mechanical processes in a mouth.

Enzymes

• Enzymes are proteins that bind molecules to facilitate product formation, acting as catalysts to speed up reactions and are reused.
• Enzyme functionality is temperature and pH-sensitive; deviation can cause enzyme denaturation.
• Enzymes have specific binding sites that correspond to specific substrates.
• They lower activation energy, resulting in faster reactions.
• The induced-fit model explains that enzymes change shape upon substrate binding to facilitate the reaction.
• Digestive enzymes include amylase (acting in the mouth and pancreas), protease (acting in the stomach), lipase, and nuclease (acting in the pancreas).
• Enzymes split polymers into smaller units (monomers or dimers) that can be absorbed.

Macromolecules

• The four main macromolecules are carbohydrates, proteins, fats, and nucleic acids.
• All are polymers which are made up of monomers.
• Carbohydrates consist of carbon, oxygen, and hydrogen.
• Polymer examples include starch, cellulose, and glycogen.
• Monomer examples include glucose and fructose.
• Dimer examples include sucrose and maltose.
• Carbohydrate enzymes include amylase and lactase.
• Carbohydrates are always polar.
• Nucleic acids are made of a phosphate/sugar backbone and a nitrogenous base.
• Examples of nucleic acids are DNA and RNA.
• Fats (lipids) are fatty acids, sometimes include sugar or phosphate.
• Saturated fats have only single bonds, resulting in higher melting points.
• Unsaturated fats have double or single bonds.
• Proteins are polypeptides composed of amino acids and are polar.

Polar and Nonpolar Molecules

• Polar molecules have charged regions and they dissolve in water.
• Nonpolar molecules do not dissolve in water and have long carbon-hydrogen chains.
• A chain of at least five carbons without a partial charge makes a molecule nonpolar.

Movement of Molecules

• Molecules cross into intestinal lining cells for nutrient absorption.
• The small intestine, with its large surface area, facilitates this process.
• Phospholipid bilayers are selectively permeable.
• Phospholipids have a polar phosphate head and a nonpolar fatty acid tail.
• The polar head is hydrophilic (water-loving), and the nonpolar tail is hydrophobic (water-hating).
• Nonpolar and neutral molecules can pass through the membrane.
• Nonpolar characteristics create a non-polar barrier.
• Carbohydrates and proteins are polar and hydrophilic, and they do not easily pass through membranes.
• Fats/lipids are nonpolar and hydrophobic, and they do pass through membranes.

Transmembrane Proteins

• Transmembrane proteins help move polar molecules across the membrane and aid in cellular communication and structure.
• Transport can be passive or active.
• Facilitated diffusion is a passive process that involves channel and carrier proteins.
• Channel proteins allow molecules to move through channels or pores.
• Carrier proteins bind specific molecules and change shape to transfer them.
• "Pumps" are active transport mechanisms.
• During diffusion, only nonpolar molecules can move from high to low concentration.
• Facilitated transport involves ATP synthases, channels, or carriers, moving molecules from high to low concentration, and it's unique to each molecule.
• Active transport uses proteins and ATP to move molecules from low to high concentration, using pumps.
• Molecules leave the way they enter (“like dissolves like”).
• Blood is polar, so fatty acids do not dissolve directly in it.
• Blood carrier proteins help move nonpolar molecules through the blood.
• Membrane carrier proteins transport polar molecules through the phospholipid bilayer.

Signal Transfer

• Signal transfer is carried out by the nervous and endocrine systems.
• The endocrine system sends signals through the bloodstream.

Endocrine System

• The endocrine system is a network of glands that secrete hormones into the blood.
• Hormones are chemical messengers that travel through the blood.
• Hormones bind to receptors on target cells to cause a response.
• Receptors are hormone-specific proteins and will eventually breakdown.
• Extracellular receptors are on the outside of the cell (transmembrane proteins) and bind to polar hormones.
• This binding initiates signal transduction.
• Intracellular receptors are inside the cell and bind to nonpolar hormones.
• Hormone Receptor Complex (HRC) formation leads to gene regulation by affecting gene expression.
• Transduction is the movement of a message.

Hormone Characteristics

• Hormones vary in polarity, receptor type, use of blood transporters, size, and HRC formation.
• Amine hormones are polar, use extracellular receptors, do not need a blood transporter, do not create HRC, and are small in size.
• Protein/peptide hormones are polar, use extracellular receptors, do not need a blood transporter, do not create HRC, and are large.
• Steroid hormones are nonpolar, use intracellular receptors, use a blood transporter, create HRC, and are small in size.
• Glucoregulation involves glucose transport and signal transduction via negative feedback.
• Blood glucose metabolism in cells is necessary for fuel.

Homeostasis

• Receptors receive information.
• The control center processes information and orders a response.
• Effectors are organs that change the variable.
• Hypoglycemia is low blood sugar.
• Hyperglycemia is high blood sugar.
• The control center is the pancreas.
• Insulin opens glucose channels.
• An effector is a muscle or body cells.
• Insulin moves glucose to reduce blood sugar and the liver.

Diabetes and Insulin

• Glucagon is a hormone and glycogen is a polysaccharide.
• Insulin lowers blood glucose by opening GLUT4 channels, allowing glucose to enter body cells and binds to extracellular receptors.
• Diabetes is identified by elevated glucose levels resulting from issues with glucose transport into cells.
• Type 1 diabetes is the inability to produce insulin, often due to genetic mutation, requiring monitoring of carbs and sugar as well as insulin injections.
• Type 2 diabetes is the inability to respond to insulin, caused by too much insulin, desensitizing receptors.
• Dose response is crucial.

Hormone Response

• The amount of hormone affects blood proteins.
• Some hormone amounts are positively correlated as the presence of one stimulates the production of the other
• Some hormone amounts are negatively correlated, which means one hormone suppresses the production of the other.
• Up-regulation increases the number of receptors, amplifying hormone effects.
• Down-regulation decreases the number of receptors, dampening hormone effects.
• Inhibitors prevent or reduce how frequently hormones bind.
• Competitive inhibitors are similar to normal blockage binding sites.
• Allosteric modulators bind to alternate sites and dentures the binding site, which will increase the binding of the hormones.
• Additive hormones work together to contribute to an outcome.
• Synergistic hormones amplify the effect of a single outcome when combined.
• Permissive hormones will only happen due to the presence of another process.
• Antagonistic hormones oppose the action of another hormone.

Cellular Respiration

• Cellular respiration releases energy from glucose and occurs in the mitochondria.
• Its goal is to metabolize glucose.
• The main steps include Glycolysis, Pyruvate processing, Citric Acid Cycle, and Oxidative phosphorylation.
• Glycolysis occurs in the cytoplasm.
• Glucose is broken down into 2 pyruvate.
• Pyruvate is converted to acetyl CoA through oxidation and is transported from the cytoplasm to mitochondrian.
• The citric acid cycle occurs in the matrix of cells, where GNADH, ATP, and FADH2 are formed.
• Oxidative phosphorylation occurs on the inner membrane, where energy and H+ are established to produce water.

ATP

• 34 ATP is created through phosphorylation.
• Total ATP has a max of 38.
• Aerobic is oxygen present.
• Anaerobic no oxygen.
• Lactic acid fermentation occurs in cells with no oxygen.
• Alchol fermentation occurs in yeast.

Reproductive Cycles

• The ovarian cycle involves the maturation and release of eggs from the ovary.
• The uterine cycle prepares the uterus for the implantation of a fertilized egg: menstrual, proliferative, and secretory phase.

Female Hormones

• GnRH levels can be regular, become faster during certain parts of the cycle, and then return to regular again with slow negative feedback.
• FSH see slight gains during the luteal phase.
• LH levels are low, then get higher during ovulation, and then return to normal.
• Estrogen levels will increase to help trigger ovulation, drop during the cycle, and increase to mid-luteal during the cycle.
• Progesterone levels will remain low during ovulation and increase to their peak in the mid-luteal phase.

Male Hormones

• GnRH levels are pulsatile.
• LH levels are pulsatile.
• FSG level is stable.
• Testosterone peaks early but is present throughout the day.
• Inhibin is stable.