Biology Notes PDF

Digestion of Carbohydrates - Only monosaccharides can be absorbed - Large chains have to be broken down 1. Large chain 2. Broken down by amylase (in saliva) and pancreatic juices 3. Into disaccharides such as lactose, maltose and sucrose 4. Broken down by enzymes in the brush border of...

Digestion of Carbohydrates - Only monosaccharides can be absorbed - Large chains have to be broken down 1. Large chain 2. Broken down by amylase (in saliva) and pancreatic juices 3. Into disaccharides such as lactose, maltose and sucrose 4. Broken down by enzymes in the brush border of enterocytes 5. Into monosaccharides such as glucose, fructose and galactose 6. Absorbed by intestinal epithelial cells via active transport (apical side) and diffusion (basal membrane) into capillaries Energy Production Cellular respiration: energy from food is captured to form ATP in cells - Energy can also be stored in glycogen and fats to be broken down later Phosphorylation: enzymes shift high energy phosphate groups of ATP to other molecules - Phosphorylated molecules become activated to perform cellular functions Metabolism 1. Digestion, absorption and transport to tissues 2. Cellular Processing - Synthesis of lipids, proteins and glycogen 3. Oxidative breakdown of intermediate products into CO2, water and ATP Metabolism Regulation 1. Absorptive Stage - Lasts 4 hours after eating - Anabolism exceeds catabolism - Excess nutrients stored as fat 2. Postabsorptive Stage - GI tract empty - Energy sources supplied by breakdown of body reserves - Catabolism of fat, glycogen and protein exceeds anabolism Anabolism: synthesis of large molecules from small ones Catabolism: hydrolysis of complex structures to simpler ones Glucose: ATP production, storage in liver and muscles (glycogen) and made from other nutrients in liver Lipids: ATP production, storage in adipose tissue (triglycerides), made from glucose Proteins -- building material, can be used for ATP (keto acids), can be converted into fat for storage, ammonia by-product is converted into urea (liver) and excreted (kidney) Amino Acids - 20 different types - Smallest building blocks of protein - The human body can't produce essential amino acids or can't be produced in sufficient amounts - Essential amino acids must be provided by diet Diabetes The body can't maintain BGLs 1. Insulin deficiency -- insufficient/no release by pancreas 2. Insulin resistance -- cells react ineffectively to insulin Types: 1. Autoimmune -- destruction of pancreatic islet cells 2. Insulin resistance (may progress to Type1) 3. Gestational -- presents during pregnancy (is a risk factor for type2) Type 2 Risk factors - Obesity/increased BMI - Metabolic syndrome - Physical inactivity - Unhealthy diet - Tobacco smoking - Genetic factors Genetics Gene: sequence of DNA that contains information for making a specific protein Allele: two versions of a genetic sequence, an individual inherits two alleles from each parent Homozygous dominant: an individual inherits two sets of a dominant gene (BB) Homozygous recessive: an individual inherits two sets of a recessive gene (bb) Heterozygous: an individual inherits two different versions of the same gene (Bb) Phenotype: observable characteristics Genotype: unique sequence of DNA Autosomal Dominant Eye Colour: Bb (Brown) vs bb (blue) +-----------------+-----------------+-----------------+-----------------+ | | B | b | Phenotype: 2:2 | | | | | | | | | | Genotype: 2:2 | +=================+=================+=================+=================+ | B | BB | Bb | | +-----------------+-----------------+-----------------+-----------------+ | b | Bb | bb | | +-----------------+-----------------+-----------------+-----------------+ Autosomal Recessive - The abnormal gene is recessive - The condition will only show if 2 alleles are present e.g. cystic fibrosis (nn) N (Normal alleles) vs n (cystic fibrosis) +-----------------+-----------------+-----------------+-----------------+ | | N | n | Phenotype: 3:1 | | | | | | | | | | Genotype: 1:2:1 | +=================+=================+=================+=================+ | N | NN | Nn | | +-----------------+-----------------+-----------------+-----------------+ | n | Nn | Nn | | +-----------------+-----------------+-----------------+-----------------+ - Humans have 23 pairs of chromosomes - Numbers 1-22 are autosomal chromosomes - Number 23 are sex chromosomes DNA is double-stranded, one strand is the template, and the second is the complimentary. A binds to T -- Apples in Trees C binds to G -- Cars in Garage - A strand forms a gene - The gene is read in sets with 3 letters per set, each set making up an amino acid. Cystic Fibrosis - 1 in 2800 and 1:25 of carrying the defective allele - Treatment 1. Replacement of pancreatic enzymes 2. Treat muscus build up in lungs 3. Prophylactic antibiotics 4. Improvement of live function STIs - 70000 reported cases in Aus - Reporting not mandatory for all types - Preventable with barrier conception - Gonorrhea: caused by microorganisms - Chlamydia: caused by small intracellular bacterium causing infections. Most common STI - Genital herpes: Two types, transmitted through contact via shedding from a secretion from a lesion/mucosal surfaces, travels to dorsal root ganglion, persists for life. Endometriosis - Functional endometrial tissue/implants outside uterus - Responds to hormone fluctuations of menstrual cycle - Can cause infertility/pain ECG : the electrical signal of action potential moving through the heart muscle P-wave: atrial depolarisation P-R interval: atrial depolarisation followed by contraction QRS complex: depolarisation of ventricles S-T segment: ventricular depolarisation to repolarisation T-wave: ventricular repolarisation Cardiac Cycle/Mechanical Events: 1. Ventricular filling -- Heart in diastole, ventricles fill with blood, semilunar valves are closed, atria contract. At the end of atrial contraction, the amount of blood in the ventricles is called EDV (End Diastolic Volume), pressure in the ventricles slightly increases. Ventricular filling = P-wave 2. Isovolumetric contraction -- Atrial diastole, ventricular systole, AV valves close all 4 valves are closed. (Lub sound is heard) Associated with = QRS complex 3. Ventricular ejection -- Ventricular systole, semilunar valves open, AV valves remain closed, blood pumps out of heart. Blood pumped out is called Stroke Volume (SV) blood left in the heart is called the ESV (End Systolic Volume). 4. Isovolumetric relaxation -- Ventricular diastole, semilunar valves close, AV valves still closed, blood volume is constant, atria fill with blood Heart Rate (HR) = average 72 beats per minute Stroke Volume (SV) = 1 beat/contraction Cardiac Output (CO) = amount of blood from the heart in a minute HR x SV = CO Factors that affect SV 1. Preload -- EDV is part of preload affected be venous return and ventricular filling time 2. Contractility -- the force of contraction at any given EDV 3. Afterload -- is the aortic pressure Intrinsic Pathway 1. Pacemaker cells in the SA node produce AP which spreads out to both atria 2. This causes depolarisation of Atria, this is called P-wave 3. This is followed by contraction of both atrium 4. The AP then spreads out to AV Node. Here the Ap is delayed for 0.1 seconds (this allows the atria to fully contract) 5. The AP then goes to the bundle of HIS, then to left and right branches and to the Purkinje fibres 6. This causes depolarisation of the ventricles 7. This is the QRS complex 8. This is followed by contraction of the ventricles 9. The ventricles repolarise and this is called the T-wave 10. This causes the ventricles to relax ABG Interpretation Rules: 1. Check the pH 2. Check the partial pressure for CO2 (paCo2) 3. Check the bicarbonate levels (HC03) 4. Is there compensation Compensation = pH is in normal range Metabolic = HC03 is out of normal range Respiratory = PaCo2 is out of normal range Normal Ranges pH Acidosis 7.35 - 7.45 Alkalosis paCO2 Alkalosis 35 -- 45 Acidosis HCo3 Acidosis 22 -- 26 Alkalosis +-------------+-------------+-------------+-------------+-------------+ | Values | Acid | Normal | Alkaline | Interpretat | | | | | | ion | +=============+=============+=============+=============+=============+ | Ph = 7.31 | pH | paCo2 | | = Metabolic | | | | | | acidosis | | paCO2 = 37 | HCO3 | | | with no | | | | | | compensatio | | HCO3 = 20 | | | | n | +-------------+-------------+-------------+-------------+-------------+ | pH = 7.3 | pH | | paCO2 | = metabolic | | | | | | acidosis | | paCO2 = | HCO3 | | | with | | 30.8 | | | | partial | | | | | | compensatio | | HCO3 = 13 | | | | n | +-------------+-------------+-------------+-------------+-------------+ | pH = 7.42 | paCO2 | pH | HCO3 | = metabolic | | | | | | alkalosis | | paCo2 = 46 | | | | with full | | | | | | compensatio | | HCO3 = 32 | | | | n | +-------------+-------------+-------------+-------------+-------------+