Bio Study Doc - Exam: January 24 - Unit 4: Taxonomy PDF

Bio study doc Exam: January 24 Unit 4: Taxonomy 1.1 - identifying, naming and classifying species Why does it matter that all these species have a name? ​ Farmers and gardeners - need to be able to identify wee...

Bio study doc Exam: January 24 Unit 4: Taxonomy 1.1 - identifying, naming and classifying species Why does it matter that all these species have a name? ​ Farmers and gardeners - need to be able to identify weeds that might be growing next to their crops ​ Doctors - need to know which bacteria a patient is infected with to prescribe the right medication ​ Border officials - need to check incoming goods to prevent the introduction of invasive species Identifying species ​ 3 species concepts to identify species: 1.​ Morphological species concept -​ Body, shape, size, and other structural features -​ Biologists compare measurements and descriptions of different organisms over time 2.​ Biological species concept: offspring -​ Whether 2 organisms can interbreed in nature to produce viable and fertile offspring that can also reproduce 3.​ Phylogenetic species concept -​ Smallest, distinct set of organisms that share an ancestor and can be distinguished from other such sets -​ Evolutionary history organisms -​ Includes extinct species -​ Uses DNA analysis Naming species Binomial Nomenclature ​ Carolus Linnaeus known as “the Father of Taxonomy” -​ He is responsible for coming up with this binomial nomenclature system -​ Binomial = 2 names/parts, Nomenclature = naming system ​ Taxonomy - the branch of biology that identifies, names and classifies species -​ Taxonomy = arrangement law ​ Every species has a species name or a scientific name ​ The species name includes the genus and the species -​ Written in italics or underlines (when written by hand) -​ Only the genus is CAPITALIZED Ex. Homo sapiens (human), Grizzly bear - Ursus arctos horribilis *note: organisms with a 3rd name after the species indicates a subspecies 1.2 - Classification Taxonomy VS Phylogeny ​ Linnaeus’ Taxonomy relied on organisms’ morphology (shapes, form, and structure) to group organisms  ​ Modern taxonomy groups are based on their evolutionary relatedness. This is known as: Phylogeny - the evolutionary history of a species Hierarchical classification ​ A hierarchy arranges items above, below, or at the same level as other items in the group ​ Ex. how would we arrange a single student from most general to most specific ​ class>student>16 year old> female> Jessica Taxonomic categories ​ All identifies living organisms are placed in a hierarchy ​ There are 8 taxonomic levels known as ranks while a taxon (plural: taxa) is the actual name of a group in that rank -​ Domain - most general rank, containing the most species -​ Species - most specific rank Dear ​ ​ king​ phillip ​ ​ came​ over​​ for​ good​ spaghetti Domain > kingdom > phylum > ​ class > order > family > genus > species Eukarya > animalia > chordata > mammalia > carnivora > canidae > canis > canis lupus (grey wolf) ​ Similar species are grouped in the same genus ​ Ex. the bobcat and housecat are in the same genus (plural: genera) Felis ​ Similar genera are grouped to form Families. Family Felidae ​ Families are grouped into Orders. Order Carnivora ​ Orders are then placed in Classes. Class Mammalia ​ Classes are grouped into Phyla (plural). Phylum Chordata ​ Phyla are grouped into Kingdoms. There are 6 Kingdoms (plantae, animalia, fungi, protista, eubacteria, archaebacteria) ​ Kingdoms are grouped into Domains (bacteria, archaea, eukarya) 1.3 - classifying living organisms, the kingdoms Kingdoms and domains ​ The second most general rank, kingdom, includes six different taxa. There is incredible structural diversity (internal and external forms) within the kingdoms even though species are grouped. ​ Classification at the kingdom level is based on general internal and external similarities, but it begins with the two basic cell types on Earth. 2 major cell types ​ Karyot - nucleus Prokaryotic (before nucleus) Eukaryotic (true nucleus) (us!) No membrane-bound nucleus Membrane bound nucleus  Simpler internal cell structure More complex internal cell structure Usually smaller Usually larger (up to 1000x) Unicellular multicellular Originated first 3 domains (dichotomous key) 1.​ Bacteria (eubacteria) - prokaryotic 2.​ Archaea (archaebacteria) - prokaryotic 3.​ Eukarya - eukaryotic ​ Bacteria and Archaea are their own domains and kingdoms ​ Both are prokaryotes but not grouped together due to vast cellular and genetic (DNA) differences ​ They were once lumped together as MONERA - all prokaryotes ​ Eukarya includes all species composed of eukaryotic cells: 4 kingdoms - protista, fungi, plantae, animalia ​ ​ MONERA ​ Unicellular → the individual organism consists of ONE cell (E. coli) ​ Multicellular → individual organisms are made of MANY cells (you!) ​ Autotrophe → an organism that is photosynthetic (flower) ​ Heterotrophe → an organism that eats other cells for food (kitty!) ​ Asexual reproduction → reproduces itself alone (contains both male and female DNA or splits DNA identically) (bacteria) ​ Sexual reproduction → reproduces in pairs male and female DNA (kitty + cat = O2 in blood of capillaries in lungs -​ CO2 in inhaled air < CO2 in blood of capillaries in lungs ​ So in external respiration: -​ O2 diffuses from the alveoli to the capillaries and -​ CO2 diffuses from the capillaries to the alveoli ​ Once in the bloodstream, oxygen travels throughout the body Internal respiration: the exchange of O2 and CO2 between blood and the cells of the surrounding tissue (occurs in the body tissues) ​ As blood passes body cells O2 diffuses from the capillaries to the tissue and ​ CO2 diffuses from the tissue to the capillaries 11.4 - human respiratory system Part Function Special Features Nasal Point of entry, filter, warm, moisten air Mucus, hairs, capillaries, sinus cavities, turbinates passages Oral cavity Warm and moisten air Alternate space for gas exchange, no filtration pharynx Connects nasal and oral cavity to larynx Cilia in top portion move food toward mouth to be swallowed epiglottis A flap that prevents food from entering the lungs Small, flexible by blocking the glottis (opening of trachea) larynx Contains vocal cords for sound, “voice box”, ~ 12 cm long, semi-circular cartilage rings to prevent “adam’s apple” collapse - cilia and mucus bronchus Each carries air into lungs and splits into many Full cartilage rings for support bronchioles bronchiole Many branches carry air to alveoli, able to Many branched tubes, smallest passageways to change diameter to regulate air flow increase surface area, smooth muscle walls, NO cartilage rings Alveoli Site of external respiration (gas exchange) ~150 Single cell layer thick, surrounded by capillaries, (singular: million very thin sacs (large surface area) coated with “surfactant” (a lipoprotein) to prevent alveolus) sticking diaphragm Increases and decreases volume of chest cavity Dome shaped, thin, muscular Pleural Surrounds lungs and lines chest cavity, reduces Filled with fluid that reduces friction during inhalation membrane friction 11.5 - lung capacities Lung capacities ​ The full capacity of your lungs is not used up under normal conditions - consider yawning, or blowing out a candle ​ A spirometer is used to measure lung capacities and produce a spirograph Average adult: VC = 5L, TLC = 6L TV = 0.5L​ IC = 3.0L​ VC = vital capacity​ RV = 1.2L ​ TLC = total lung capacity Tidal volume: volume of air inhaled and exhaled in a normal breathing movement Inspiratory Reserve volume: the additional volume of air that can be taken in, beyond a regular or tidal inhalation Inspiratory Capacity: total volume of air that can be taken in IRV = IC - TV​ IC = TV + IRV​ TLC = TV + IRV + ERV + RV​​ TLC = VC + RV Expiratory Reserve Volume: the additional volume that can be forced out of lungs Vital capacity: the total volume of gas that can be moved in or out of the lungs -TV + IRV + ERV = VC Residual Volume: the amount of gas that remains in the lungs and passageways of the respiratory system even after full exhalation (prevents collapse; no value for gas exchange) 11.6 - simpler circulatory system *refer to diagram in notes* Open system: ​ No closed vessels ​ Sinus: body cavity surrounding ​ Interstitial fluid surrounds cells internal organs Closed system (us): ​ True blood vessels ​ Pumping system Purpose: ​ Bring O2 and nutrients to cells ​ Chemical messages ​ Take wastes away from cells ​ Maintain balance ​ Transport immune cells Cells need: ​ (get to the cell and waste removed) ​ Immune response ​ Macromolecules (DNA, lipids, carbs, ​ Chemical reactants proteins) ​ H2O ​ Micronutrients (minerals) ​ Hormone movement throughout ​ O2 (from external respiration) body 11.7 - types of circulation Arteries ​ Carry blood away from heart ​ Usually O2 rich (oxygenated) (except for pulmonary arteries) ​ Connective tissue and muscle ​ Walls elastic and thick (can stretch) ​ Precapillary sphincters control blood flow Artery problems ​ Arteriosclerosis: buildup of plaque in artery, increases blood pressure ​ Aneurysm: bulge in artery (elastic wall) Veins and capillaries: ​ Veins -​ Carry blood to the heart -​ Usually O2 poor, high in CO2 (deoxygenated) (except for pulmonary veins) -​ Valves push blood towards heart -​ Slim, low pressure -​ Smooth surface ​ Capillaries -​ Smallest blood vessels for gas exchange Blood flow in veins ​ Valves prevent backflow ​ Less pressure than arteries ​ Skeletal muscles contract and pump blood back to the heart Arterioles and venules ​ Arteries to arterioles to capillaries ​ Capillaries to venules to veins ​ Capillaries perform gas exchange at capillary bed at cells Circulation types: (systemic, pulmonary and coronary) ​ systemic circulation  -​ Oxygenated blood to tissue and deoxygenated blood to heart ​ Pulmonary circulation -​ Between lungs and heart -​ Deoxygenated blood goes to lungs and oxygenated blood goes to heart ​ Coronary circulation 1.​ Rt side of heart receives blood returning from body (deoxygenated which enters the heart through the Inferior Vena Cava/Superior Vena Cava 2.​ SVC (collects from head neck and shoulders/arms), IVC (collects from below the lower region - below heart) 3.​ Rt atrium fills with deoxygenated blood - which pushes open the tricuspid valve 4.​ Blood now fills the Rt ventricle 5.​ Blood pumped into the pulmonary trunk into the left and right pulmonary artery (NOTE - this is the only case where an artery has deoxygenated blood within it) 6.​ Blood continues to right and left lung for gas exchange (CO2 - O2) 7.​ Oxygenated blood now moves to the pulmonary veins (NOTE - only case where veins have oxygenated blood 8.​ Blood enters the left atrium, and once full pushes open the mitral (bicuspid) valve and pumps to… 9.​ Oxygenated blood fills the left ventricle. The left ventricle pumps very hard 10.​Oxygenated blood flows through the aorta and exits the heart into the body Components of blood ​ 55% of fluid = plasma -​ Electrolytes, protein for immunity and clotting ​ 45 % red cells -​ Erythrocytes, leukocytes, platelets -​ Produced in bone marrow ​ 1 % white blood cells -​ Functional immune system cells Erythrocytes ​ Red blood cells ​ No nucleus and biconcave = max oxygen ​ Hemo (red) globin and iron carry oxygen ​ White blood cells in spleen remove old RBCs - gives colour to feces (bilirubin) ​ Anemia = deficiency in hemoglobin or RBC Leukocytes ​ White blood cells ​ RBC outnumber WBC by 700:1 ​ Immune system, phago(eat)cytosis(cell) (eats bacteria) ​ Concentrated in lymph nodes ​ Pus = dead WBC and microbe ​ Neutrophils -​ Most abundant ​ Eosinophils -​ Found in mucus lining of digestive and respiratory system  ​ Basophils -​ Aids immunity by attracting pathogens (bacteria, viruses) ​ Lymphocyte (B and T cells) -​ Secrete proteins called ​ Monocyte -​ Become specialized phagocytes called macrophages that engulf bacteria Antibodies and antigen ​ Antibodies coat free virus particles. The virus envelope cannot fuse with the host cell membrane ​ The antibody - coated virus is recognized and phagocytosed by a macrophage Platelets ​ Fragmented RBC ​ No nucleus ​ Initiate blood clotting ​ Fragile - rupture over toen blood vessel Blood clotting ​ Blood vessel breaks, releases chemicals that attract platelets ​ Platelets rupture and release chemical to produce Thromboplastin ​ When calcium present thromboplastin reacts with prothrombin to produce thrombin ​ Thrombin reacts with fibrinogen to produce fibrin Functions of blood Transport ​ Transport nutrients from intestine ​ Transports fasses ​ Transports and removes waste -​ Minerals and cell waste to -​ CO2 from cells to lungs for kidneys for excretion expiration Temperature regulation ​ Balancing loss of heat from the body with the production of metabolic processes ​ Mammals control heat by changing the volume of blood in the skin ​ Controlled by autonomic branch of the nervous system Autonomic nervous system ​ Involuntary responses ​ Vasoconstriction: narrowing blood vessels (preserves heat for cold conditions) ​ Vasodilation: widening blood vessels (preserves cold for hot conditions) Homeostasis - process that regulate and maintain optimal conditions within an organism, making sure cells stay at certain temperature, body has 2 mechanisms when hot or cold: shivering and sweating (involuntary mechanism) Factors affecting constriction ​ Blood pressure -​ An increase in BP is offset by vasodilation. If BP is too low, vasoconstriction will occur ​ Metabolic activity ​ Exercise -​ vasodilation  ​ drugs -​ Alcohol and nicotine result in vasodilation 11.8 - the hearts tempo Electrical activity in the heart ​ The heart is controlled by a bundle of specialized muscle tissue known as the sinoatrial (SA) node, which stimulates the muscle cells to contract and relax rhythmically via electric signals ​ The SA node is referred to as the pacemaker, because it sets the pace for cardiac activity. It is located in the wall of the right atrium ​ As atria contract, the signal from the SA node reaches the atrioventricular (AV) node, which transmits the signal through specialized fibers called bundle of His. These fibres relay the signal through 2 bundle branches that divide in to the fast - conducting Purkinje fibres ​ contraction: right atrium, left atrium, right ventricle, left ventricle Setting the heats tempo ​ Myogenic muscle = not attached to nerve ​ Sinoatrial (SA) node = pacemaker ​ Atrioventricular (AV) node = impulse passed to ventricles Conducting the signal ​ Purkinje fibres -​ pass through the septum to create rhythm Autonomic nervous system ​ Involuntary responses ​ Sympathetic = stress, increase heart rate ​ Parasympathetic = relaxation, decreased rate Electrocardiograph ​ P wave = atrial contractions ​ QRS wave = ventricular contraction (closes) ​ T wave = ventricular reconvers (reopens) Blood pressure ​ Diastole # = atrial relaxation, fill with blood ​ Systole # = ventricular contraction, blood going out ​ Normal = 120/80 mmHg Systolic/Diastolic pressure ​ Pressure in arteries during these events Regulating heart rate ​ Sympathetic: fight/flight -​ Release -​ Increase -​ Constrict epinephrine cardiac arteries output ​ Parasympathetic: rest and digest -​ opposite Raise BP  1.​ Sympathetic response 2.​ Narrowed blood vessels (vasoconstriction) -​ plaque in vessels (poor -​ Stress (good/bad) lifestyle) Cardiac output and stroke volume ​ Cardiac output is the amount of blood pumped out by the heart in mL/mm. Cardiac output = heart rate x stroke volume ​ Stroke volume - the volume of blood pumped out of the heart with each heartbeat Cardiovascular fitness ​ Capacity of heart, lungs, and blood vessels to deliver oxygen to working muscles ​ Enlarges ventricles ​ Increases elasticity ​ Strengthening the ventricle walls ​ Cardiovascular charges increase the stroke volume ​ Good indication of fitness is how long it takes the heart to return to resting heart rate after strenuous exercise Factors affecting cardiac output ​ Cardiovascular can improve stroke volume ​ Genetics Disorders Tonsillitis ​ a bacterial infection of the tonsils, located in the pharynx at the back of the throat ​ The function of the tonsils is to help prevent bacteria and other harmful substances from entering the respiratory system. ​ Symptoms of tonsillitis include red and swollen tonsils, a sore throat, fever, and swollen glands in the neck. ​ Severe tonsillitis may be treated by surgically removing all or part of the tonsils. Laryngitis ​ is an inflammation of the larynx caused by an infection or allergy, or by overstraining the voice, such as by prolonged yelling. ​ The larynx contains the vocal cords. When the larynx is inflamed, the vocal cords cannot vibrate as they usually do. ​ People with laryngitis may “lose” their voice, or speak in a hoarse whisper. This condition is usually not serious Pneumonia ​ When the alveoli in the lungs become inflamed and filled with fluids ​ It interferes with gas exchange, and the body becomes starved for oxygen. ​ There are two main types of pneumonia: lobular pneumonia and bronchial pneumonia. ​ Lobular pneumonia affects a lobe of the lung, and bronchial pneumonia affects patches throughout both lungs. Bronchitis ​ The bronchi becomes red, inflamed, and filled with mucus ​ A short-term form of bronchitis, called acute bronchitis, is caused by a bacterial infection and can be treated with antibiotics. ​ Chronic bronchitis is a long-term disorder caused by regular exposure to concentrations of dust or chemicals. Because the exposure takes place over a long period of time, the cilia lining the bronchi are gradually destroyed. Without the cleansing action of the cilia, the bronchi grows increasingly inflamed. Mucus accumulates in the bronchi, causing the person to develop a cough to try to clear it. Asthma ​ inhaled irritants such as pollen, dust, and smoke can often trigger an inflammation of the bronchi and bronchioles, known as asthma. The inflammation narrows the air passages of the bronchi and bronchioles, thus reducing airflow. ​ People with asthma experience wheezing, coughing, tightness in the chest, and shortness of breath. ​ During an asthma attack, muscles around the airways contract and cells in the airways may increase mucus production, which further blocks airflow Emphysema ​ A respiratory disorder in which the walls of the alveoli lose their elasticity ​ This loss of elasticity reduces the respiratory surface for gas exchange and causes an oxygen shortage in the tissues. ​ Exhaling becomes difficult because the small airways collapse during exhalation, trapping air in the lungs and blocking the airflow. Cystic fibrosis ​ The mutation of a single gene causes a multisystem disease. ​ This genetic condition causes cells lining the airways to release thick, sticky mucus that clogs the lungs, leading to difficulty in breathing. The mucus traps disease-causing agents, making it difficult to clear bacteria that cause lung infections. ​ There is no cure Unit 2 - Digestive System 10.1 - the function of digestion and human digestive system Obtaining and processing food ​ All organisms, regardless of their size or complexity, must have a way of obtaining essential nutrients ​ Essential nutrients - basic raw materials organisms need to make their own structures, perform their life functions and obtain energy for survival ​ Metabolism - all of the chemical processes carried out by cells to maintain life Macromolecules ​ Organic molecules - contain carbon bonded to hydrogen as well as to other atoms such as oxygen, sulfur and nitrogen ​ Macromolecules - large, more complex assemblies of organic molecules, AKA nutrients ​ These are the raw materials that our bodies need to provide energy, to regulate cellular activities and to build and repair tissues ​ Often grouped into 4 major categories 1.​ Carbohydrates (C1H2O1) 2.​ Lipids (CHO) (triglycerides, phospholipids, sterols)  3.​ Proteins (CHON) 4.​ Nucleic acids (CHONP) ​ Energy released from these macromolecules, and matter supplied by them, is used to maintain the body’s metabolism (all of the chemical processes carried out by cells to maintain life) ​ Together, the 4 major categories of macromolecules are known as essential nutrients Carbohydrates ​ Macromolecules that always contain carbon, hydrogen, and oxygen ​ Ex. bread, pasta, rice, fruits, vegetables, wheat, corn based ​ Almost always 1C: 2H: 1O ​ Provide short term or long-term energy storage for organisms ​ 3 main types: simple sugars (monosaccharides) and polysaccharides Monosaccharides (simple sugars) -​ Carbohydrate molecules with 3-7 carbon atoms -​ Ex. glucose (the sugar found in blood) and fructose (sugar found in fruit) Disaccharides -​ Made up of 2 simple sugars (di=2) -​ Ex. sucrose (table sugar), and lactose (sugar in dairy) Polysaccharides -​ Complex carbohydrates that consist of many linked simple sugars (poly=many) -​ Ex. starch (stores energy in plants) and glycogen (stores energy in animals) Lipids (fats) ​ Ex. oil, butter, lard, avocados, dairy, meats ​ Insoluble in water ​ Basic structure of lipids is a molecule of glycerol ​ 3 carbon atoms each attached to a fatty acid chain ​ Stores 2.25 times more energy per gram than other biological molecules; function as energy storage molecules ​ Make up skin, brain, coats nerves ​ Phospholipids - form cell membranes, polar, barriers Proteins ​ Ex. meat, nuts, eggs, beans, lentils, fish, dairy ​ Assembled from amino acids ​ Polypeptides - chains for hundreds of amino acids joined together by peptide bonds ​ Most enzymes are proteins, and so are antibodies, which combat disease ​ They have nitrogen ​ Ex. hair, skin, muscles, enzymes Nucleic acid ​ Direct growth and development of all organisms using a chemical code ​ 2 types of nucleus acid are ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) ​ Has nitrogen AND phosphate group Hydrolysis (decomposition) ​ A water molecule (H2O) is added to the macromolecule ​ This breaks the chemical bonds that hold together the smaller molecules from which the macromolecule is made ​ Digestive enzymes help to speed up the process of hydrolysis Minerals and vitamins ​ Macromolecules  ​ Inorganic and organic substances that enable chemical reactions to occur and aid in tissue development, growth, and immunity ​ Needed by a healthy, functional human body ​ Minerals -​ Calcium - forming bone, conducting nerve signals, contracting muscle, clotting blood, derives from dairy products -​ Iron - producing hemoglobin, derives from red meat -​ Magnesium - supporting enzyme functions, producing protein, derives from dark leafy greens -​ Potassium - conducting nerve signals, contracting muscles, derives from grains -​ Sodium - conducting nerve signals, balancing body fluids, derives from salt ​ Vitamins -​ A (carotene) - good vision, healthy skin and bones, derives from fruits -​ B1 (thiamine) - metabolizing carbohydrates, growth and muscle tone, derives from beans -​ C (ascorbic acid) - boosting immune system, healthy bones, teeth, gums, and blood vessels, derives from fruit -​ D - absorbing calcium, forming bone, derives from fish -​ E - strengthening red blood cell membranes, derives from fruit Water ​ Needed for the proper functioning of all cells and organs ​ Makes up ⅔ of body mass Functions include ​ Transporting dissolved nutrients into the cells that line the small intestine ​ Flushing toxins from cells ​ Lubricating tissues and joints ​ Forming essential body fluids, such as blood and mucus ​ Regulating body temperature (by sweating) ​ Eliminating waste materials (in urine and sweat) Digestive tracts in herbivore vs. carnivore ​ most herbivores have relatively longer digestive tracts, because cell walls in plants are harder to digest Types of secretion Names Names of each one Where they come from What they do Acids Nucleic acid Nucleus Store genetic information Fatty acid Lipids Energy storage Amino acid proteins Break down food Liquids saliva Salivary glands Moistens mouth Juices Pancreatic juices The pancreas reduce the acidity of the chyme Gastric juices (HCl) a mixture of stomach acid and enzymes Breaks down food 10.2 - Types of digestion Intracellular digestion: -​ Digestion inside the cell -​ Ex. single cell organisms -​ Phagocytosis - cell engulfs (amoeba) the food Extracellular digestion: -​ Digestion outside the cells -​ Ex. most animals, human -​ Food enters a tube and exits digestive tract from the other end Mechanical digestion ​ Physical breakdown of larger food particles into smaller ones ​ Achieved through chewing, chopping, mashing, etc. ​ Increases the surface area of food, allowing more enzymes to come into contact with food Chemical digestion ​ Chemical breakdown of large molecules into smaller ones -​ Carbohydrates: polysaccharides (starch) are broken into monosaccharides (simple sugars) -​ Proteins: broken down into amino acids -​ Lipids: (mainly triglycerides) are broken down into fatty acids and glycerol ​ Note: food particles are broken down by enzymes. Each enzyme has a pH at which it performs best Types of feeders ​ Autotrophs -​ Do photosynthesis -​ Ex. plants use sun + H2O + -​ Can feed themselves from CO2 to form organic inorganic molecules compounds -​ Self-sufficient ​ Heterotrophs -​ Depends on organic -​ Not self sufficient compounds made by other -​ Ex. animals, fungi, bacteria, living things etc ​ Filter feeders -​ Siphons water into its mouth -​ Ex. whales, clams, flamingos and filters it to get small organisms to digest ​ Fluid feeders -​ Obtain food by sucking or licking nutrient-rich fluids from live plants or animals -​ Mouth parts are adapted to pierce or rip skin or leaf tissue and are used to suck or lick the blood or sap -​ Ex. mosquitos or spiders ​ Substrate feeders -​ Live in or on food -​ Caterpillars eat their way -​ Ex. caterpillars through green tissues of leaves  ​ Bulk feeders -​ Include many animals and most vertebrates -​ Bulk feeders ingest fairly large pieces of food or swallow food whole -​ Use teeth to tear pieces of meat The digestive system ​ The digestive system is used for breaking down food into nutrients which then mass into the circulatory system and re taken to where they're needed in the body Digestion → macromolecule to monomer Sugars -ose i.e. lactose, Enzyme -ase i.e. lactase 4 stages to food processing 1.​ Ingestion - taking in food 2.​ Digestion - breaking down food into nutrients 3.​ Absorption - taking in nutrients by cells 4.​ Egestion/excretion - removing leftover waste Human digestive system ​ Food enters the mouth (through the oral cavity) ​ Physically broken down by teeth (mechanical digestion) ​ Chemically broken down by enzymes released from salivary glands ​ Tongue moves food around until it forms a ball called bolus ​ Bolus is passed to the pharynx (throat) and the epiglottis makes sure the bolus passes into the esophagus and not down the trachea ​ Bolus passes down the esophagus by peristalsis ​ Peristalsis - wave of muscular contractions that push the bolus down towards the stomach ​ To enter the stomach, the bolus must pass through the lower esophageal sphincter, a tight muscle that keeps stomach acid out of the esophagus ​ The stomach has folds called rugae and is a big muscular pouch which churns the bolus (physical digestion) ​ The bolus is mixed with gastric juice, a mixture of stomach acid and enzymes (chemical digestion) ​ Stomach does do some absorption too (alcohol, aspirin) ​ The bolus is called chyme, leaves stomach by passing through the pyloric sphincter ​ Food is now in the small intestine ​ Majority of absorption occurs here ​ The liver and pancreas help the small intestine to maximize absorption ​ The small intestine is broken down into 3 parts: 1.​ Duodenum - bile enters through the bile duct and breaks down fats. -​ The pancreas secretes pancreatic juice to reduce the acidity of the chyme 2.​ Jejunum - where majority of absorption takes place -​ Tiny finger-like projections called villi lining it, which increases the surface area for absorbing nutrients -​ Each villi has tiny finger-like projections called microvilli, which further increases surface area 3.​ Ileum - has fewer villi, compacts leftovers to pass in cecum into large intestine ​ The large intestine (or colon) is used to absorb water from waste material leftover ​ All leftover waste is compacted and stored at the end of the large intestine called rectum ​ When full, the anal sphincter loosens and the feces, leaves the body through the anus Accessory organs in digestion The liver  ​ If we ingest toxins or poisons in our food and drink (alcohol), the liver processes nutrients and filters toxins then releases the blood into the main arterial system to feed the rest of the body ​ The filtered toxins and excess blood by-products are turned into urea and bile. ​ The bile goes to the gall bladder where its secreted into the intestines to break down fats and the digestive process starters all over again Function of the bile ​ Bile salts are released into the small intestine when needed to break up fat into smaller droplets so they can be mixed with water ​ The fat droplets in the small intestine are further broken down by the enzyme lipase, which the bile also activates The pancreas ​ The pancreas is the source of several enzymes that act on carbohydrates, fats and peptides (subunits of proteins) ​ Most valuable accessory organ ​ It also releases a solution that changes the pH of chyme (strom strongly acidic to basic) after it enters the duodenum (alkaline) ​ Pancreatic duct empties in the duodenum of small intestine ​ Produces insulin to regulate blood glucose levels The gallbladder ​ The gall bladder serves as the storage site for bile ​ The releases of bile from the gallbladder is stimulated by a hormone that makes the sphincter muscle relax and the bile enters the duodenum via bile duct ​ As lipids are absorbed in the small intestine, so is the bile, however it gets recycled back to the liver Salivary glands ​ Salivary glands make saliva and empty it into your mouth through openings called ducts ​ Saliva helps with swallowing and chewing ​ It can also help prevent infections from developing in your mouth or throat ​ Has enzymes ​ Chemical digestion but helps with mechanical digestion 10.4 - chemical digestion Enzymes ​ Special proteins made at ribosomes ​ Specific to the substrate (molecule it acts on) ​ There are different classes of enzymes: 1.​ Carbohydrases - break downs carbs 2.​ Proteinases.protease - breaks down proteins 3.​ Lipases - break down lipids 4.​ Nucleotidases, nuclease - break down DNA ​ These enzymes are secreted into the digestive system by special groups of secretory cells called glands ​ Glands are usually connected to the digestive system through special tubes called ducts ​ The item that an enzyme breaks down is called a substrate ​ The enzyme is not changes at all during this process ​ Every enzyme performs best under its own optimal conditions ​ This depends on temperature, pH and the presence of certain ions or vitamins and minerals The mouth  ​ 3 salivary glands produce saliva which contains -​ Water and mucus: lubricates the food -​ Sodium bicarbonate: reduces the acidity of the bolus -​ Salivary amylase: enzyme that begins to break down carbohydrates The stomach ​ Hydrochloric acid (HCl) kills off any invading bacteria or viruses ​ The enzyme pepsin breaks down proteins ​ The enzyme lipase breaks down lipids ​ Mucus protects the lining of the stomach from being eaten away by the acid The pancreas ​ Produces and releases into the small intestine: -​ Enzymes that act on proteins, fats and carbohydrates -​ Bicarbonate solution to raise the pH of the chyme ​ Produces and releases into the bloodstream: -​ Insulin that converts glucose to glycogen, which gets stored in the body cells for later use The liver ​ Makes bile, which aids in fat digestion ​ Most of the glycogen is stored here ​ Vitamins A, D, E, K are stored here ​ Detoxifies poisons that are ingested including ethanol -​ Cirrhosis: breakdown of liver cells due to high levels of poisons The gallbladder ​ Illnesses of the gallbladder include: -​ Gallstones: crystals of bile salts around cholesterol -​ Jaundice: collection of bile pigment in blood (yellow skin) Digestion and homeostasis ​ A large meal activates receptors that churn the stomach and empty it faster ​ If the meal was high in fat, digestion is slowed, allowing time fo the fat to be broken down ​ Hence why we feel fuller after eating a high fat meal ​ The endocrine, nervous digestive and circulatory systems all work together to control digestion ​ Before we eat, smelling food releases saliva in our mouths and gastrin in our stomachs which prepares the body for a snack Hormones ​ Chemical regulators, they also help control digestive enzymes ​ The hormone gastrin stimulates the digestive glands around the stomach ​ The hormone secretin stimulates the pancreas to release its enzymes which helps neutralize the stomach contents as they enter the small intestine  10.5 - digestive system disorders Digestive system Part of the What is happening/symptoms treatment disorder digestive system involved Inflammatory Intestines Causes inflammation in the intestines Since it is chronic, it Bowel Disease cannot be cured but it Main forms: can be treated with a ​ Crohn's special diet and Disease medication ​ Ulcerative Colitis Constipation Colon (large Little to no bowel movement, stools are Consume more fibres intestine) dry, small, and difficult to eliminate. and water Caused by inadequate waste intake, lack of good nerve & muscle function hepatitis liver - inflammation Type A: no vaccine, but Type A: from drinking contaminated water body will recover Type B: spread sexually Type B: vaccination Type C: from contact with infected wood Type C: no vaccine cirrhosis liver - liver tissue is replaced with scar tissue - liver can heal itself - can't function properly - extreme cases: it - causes alcoholism and hepatitis c enough regeneration, - blood tests can help diagnose liver failure occurs and a transplant is needed diabetes pancreas The pancreas isn’t creating enough Chronic, insulin vaccines insulin/body doesn't use the insulin and medication available properly Peptic ulcers Stomach or - Unprotected tissue comes in contact with lifestyle changes like no duodenum, where gastric acid. alcohol, no smoking, HCl and pepsin are - abdominal pain, bloating, nausea, and and losing weight present loss of appetite Endoscopy Through the mouth It allows a surgeon to visually inspect the to the stomach lining of any part. Camera on a tube that enters through the mouth Colonoscopy Through the rectum Same as endoscope but through the other to the colon end Gastroesophageal stomach to the - Stomach acid goes back up the antacids Reflux Disease esophagus esophagus when the lower esophageal sphincter loosens nausea, bloating, stomach contents enter mouth, sour taste Unit 1 - Genetics 4.1 - Genetic Processes ​ All living things contain DNA ​ Located in nucleus (for eukaryotic cells) ​ Organized in packets called “chromosomes” Watson and Crick ​ Discovered DNA, its structure (double helix) ​ nitrogenous bases (code for what DNA is making) Nucleotide ​ Building blocks ​ 4 nucleotides, 3 structures each (held together by hydrogen bonds, phosphate group, nitrogenous base) Types of Nucleotide ​ Purine (double ring) - adenine (a) and guanine (g) ​ Pyrimidines (single ring) - thymine (t) and cytosine (c) Base pairing ​ Purine bonds with pyrimidines (only one) ​ Causes double helix in DNA ​ A and T (apple in tree) ​ C and G (car in garage) Sugar Phosphate Backbone ​ Covalent bond (phosphate + five ring sugar) ​ Protects what’s inside Packaging ​ The DNA is coiled around protein structures call histones ​ DNA wrapped around a group of histones form a bead-like structure called nucleosomes ​ Nucleosome prevents the DNA from tangling and being damaged Semi-conservative replication ​ Newly synthesized DNA molecule composed of one original and one new Chromosomes  ​ 46 chromosomes, 23 pairs (from each parent) ​ MOST cells in the body have a normal number of chromosomes - Diploid (double) (skin cells) ​ SOME cells have half the number of chromosomes - haploid (half) (ex. Eggs and sperm) ​ 23 similar chromosomes ​ 22 pairs are autosomes that contain genes ​ Last one is sex chromosomes (X and Y), influence on sex ​ Female: XX​ Male: XY ​ Genes on chromosomes - code for protein, aid in maintenance of an organism's cells, controle a particular trait ​ 3 nucleotides = 1 protein ​ Alleles - genes that control visible traits or variations ​ 2 copies of each gene, 2 alleles for a trait, each prevent ​ Gregor Mendel discovered alleles ​ Homologous - same chromosome, men sex (XY) - non homologous ​ Homologous chromosomes - chromosome pairs similar in length, gene position, centromere location, position is the same but may contain different alleles ​ Karyotype - looking at chromosomes present ​ Gene - section, all one colour, stripes, varying in sizes ​ Allele - sections of the gene ​ Genes are made of MANY alleles Mitosis ​ Process where cells reproduce ​ All cells except sex cells (meiosis) ​ For growth, repair, reproduce, development ​ Produces IDENTICAL daughter cells ​ Important because, ensures genetic continuity within an organism Interphase ​ 90% of the cell’s life ​ 3 stages: G1, S, G2 1.​ G1 - rapid growth and cell activity, synthesize any needed organelles 2.​ S - synthesis, DNA synthesizes, copies DNA 3.​ G2 - Prepares for division, does its job, optimal ​ The mitotic phase (mitosis, cytokinesis - 10% of the time) ​ Prophase - prepare, mitosis begins, chromosomes coil and take shape ​ Metaphase - chromosomes align themselves along equator ​ Anaphase - chromosomes split at centromere, spindle fibers contract to opposite poles of the cell, pull away ​ Telophase - chromosomes uncoil and decondense, cleavage furrow forms near middle, one cell becomes 2 ​ Cytokinesis - cell membrane moves, 2 daughter cells, own nuclei, identical chromosomes 4.2 - Protein synthesis transcription and translation ​ DNA - deoxyribonucleic acid, covalent name for compound  ​ Mutation - change in the nucleotide sequence of DNA Genes ​ Organized sections of DNA that code for protein, aid in maintenance and function of cells, control traits, regulate gene expression ​ Blueprint or instructions ​ Many genes make a specific protein ​ These can be structural proteins like nails, hair or could be enzymes (molecules that help speed up reactions) ​ Proteins (polypeptides) - chains of amino acids held together by peptide bonds (a lot of different amino acids) ​ Protein synthesis - transfer of genetic information from DNA to RNA to protein occurs in 2 steps: 1.​ Transcription - the synthesis of DNA from an RNA template 2.​ Translation - the synthesis of protein from an mRNA template ​ DNA (in nucleus) → (transcription - same language, different form) → RNA (made in nucleus, goes to cytoplasm (ribosomes)) → (translation - change of language) → protein (at ribosomes) ​ RNA - ribonucleic acid (composed of nucleotides), single stranded ​ Thymine replaced with Uracil (A+U) ​ mRNA - goes to ribosomes Genetic code ​ Rules to determine genetic info in the form of a nucleotide sequence, converted to amino acid of a protein ​ Triplet hypothesis - 3 nucleotide bases at a time (codon) ​ If a code is missing something it becomes a mutation 4.3 - Meiosis In mitosis ​ Parent and daughter cells have the same number of chromosomes ​ Homologous chromosomes (male and female) ​ diploid Meiosis ​ Similar to mitosis, replicates nuclear material ​ TWO cell divisions, 4 gametes with haploid number of chromosomes -​ Ex. each cell has ONE copy of each chromosome ​ Each cell is different ​ Gametes - sex cells (sperm and egg) ​ 23 sperm chromosomes (haploid) + 23 egg chromosomes (haploid) = 46 (diploid) ​ Unite to form a zygote (fertilized egg) ​ Reduces chromosomes from diploid to haploid ​ 2 stages: meiosis l and meiosis ll (PMAT for each stage - reduction division) ​ Only happens in gonads (organ where sperm and eggs are made, gametes in gonads) ​ Gonads go through interphase prior to meiosis ​ Chromosome # doubles prior to meiosis ​ Meiosis produces 4 non-identical haploid cells Meiosis l ​ Prophase l: -​ Nuclear membrane dissolves -​ Chromosomes are attached to their copy by the centromere -​ Centrioles appear and move to poles -​ All homologous chromosomes form tetrads ​ Tetrads - bundle of 4 chromosomes (2 father, 2 mother) ​ Synapsis - pairing of homologous chromosomes to form tetrads ​ Crossing over - Non-sister chromatids exchange genes to create a unique allele combination ​ Metaphase l: -​ Tetrads align themselves at the equator with their maternal pair of chromosomes facing 1 pole and paternal pair facing the other -​ They align and perform independent assortment -​ Once aligned, tetrads are held in place by spindle fibers released from centrioles -​ Spindle fibres attach to centromeres of sister chromatids ​ Independent assortment - Tetrads align independently of one another, reason for varying offspring ​ Anaphase l: -​ Spindle fibers contract and pull apart the tetrad so that one pair of sister chromatids goes to one pole and the other goes to the other pole -​ Centromere DOES NOT split apart -​ It still holds sister chromatids together ​ Telophase l and cytokinesis l: -​ Nuclear membrane reforms around new nucleus -​ Cytoplasm is divided by cytokinesis creating 2 non-identical cells -​ They immediately proceed into next round of meiosis -​ NO second interphase Meiosis ll ​ Stages are identical to mitosis ​ There are 2 cells (produced after meiosis l) doing it, 4 cells produced (non-identical, haploid) ​ Different in males and females ​ Prophase ll: -​ Nuclear membrane dissolves -​ Chromosomes - more visible, attached to their copy by centromere -​ Centrioles move towards poles ​ Metaphase ll: -​ sister chromatids line up at equator -​ Spindle fibers emerge from centrioles and attach centromere of each chromosome pair ​ Anaphase ll: -​ Spindle fibers contract, breaking centromere -​ This pulls apart sister chromatids  -​ One copy to one pole, other copy to other pole ​ Telophase ll: -​ Nuclear membrane reforms around chromosomes -​ 2 nuclear in each cell -​ Cell membrane pinches inward at equator (end of meiosis) -​ 4 non-identical, haploid cells are produced Gametogenesis ​ Gametogenesis - production of gametes through meiosis Spermatogenesis ​ Meiosis in males ​ Occurs in testes ​ Starts with a diploid cell “spermatogonium” ​ Produces 4 non-identical haploid cells ​ n = # of chromosomes in a species, haploid number ​ 2n = diploid, # can change ​ Produced from puberty until death ​ Approximately 68-74 hours for a sperm to be created ​ Meiosis produces 250 million sperm a day Oogenesis: ​ Meiosis in females ​ Occurs in ovaries and oviducts ​ Starts with diploid cell “oogonium” ​ Egg production starts before female is born, pauses in meiosis l before cells divide ​ Meiotic process resumes at puberty with ovulation (and fertilization) for 1 cell every month ​ After telophase l and ll, only 1 cell receives majority of cytoplasm, resulting in 1 egg and 2 polar bodies ​ This is to allow the egg to have sufficient nutrients to support a zygote immediately after fertilization 4.4 - genetic disorders and errors Genetic disorders ​ Clinical health problems visible at birth “congenital defects” (from birth) ​ Caused by mutations in genes or environmental agents -​ Ex. alcohol during pregnancy, viruses while pregnant ​ When chromosomes line up in meiosis differently -​ Ex. chromosomes don't split - “meiotic non-disjunction” -​ Down syndrome - extra chromosome 21, 24 chromosomes Errors in Meiosis ​ Changes, mutations in chromosomes ​ Severe consequences ​ If chromosomes are copied during interphase l, all daughter cells will carry the mutation ​ If it’s part of fertilization, new organism carries that error ​ If in meiosis ll, half the resulting cells would be affected Non-disjunction  ​ Non-disjunction - failure of chromosomes or tetrads to separate properly during anaphase l or ll ​ Results in the addition or deletion of chromosomes in a gamete ​ If a gamete with an extra chromosome is fertilized by a normal gamete, the zygote will have an extra chromosome “trisomy” ​ If a gamete missing a chromosome is fertilized by a normal gamete, the zygote will have only 1 copy of a chromosome “monosomy” Trisomy examples ​ Trisomy 21 - down syndrome, one parent gave 2 of chromosome 21 ​ Klinefelter’s syndrome - an individual receives 2X chromosomes and a Y chromosome ​ Result - infertile male with secondary sex characteristics Monosomy examples ​ Turner syndrome - individual gets 1 X chromosome ​ Result - infertile female with a broad chest, low ears, short, poor hearing, less breast development Prenatal Testing ​ Needle inserted into uterus to retrieve amniotic fluid ​ Catheter through the birth canal Changes in chromosomal structures ​ Can occur from radiation or exposure to chemicals ​ 4 means of chromosomal change: deletion, duplication, inversion, translocation (all happens only in interphase) ​ Deletion -​ Part of the chromosome is lost -​ Viruses, radiation, and chemicals can cause a piece of a chromosome to become dislocated -​ This piece may carry a specific gene which may have an effect on host ➔​ Ex. cri du chat - deletion of chromosome 5 ​ Small at birth, breathing problems, small head, round face ​ Duplication -​ A gene sequence is repeated 1 or more times within a chromosome -​ At some point, too many reapers can affect the function of the gene ➔​ Ex. fragile X syndrome = most common form of autism and inherited intellectual disabilities in males ​ Inversion -​ A gene segment momentarily becomes free from its chromosome and then reinserts in the opposite order (codon is backwards) -​ Can completely alter the genes activities ➔​ Ex. FG syndrome on X chromosome - affects males, intellectual disabilities ​ Translocation -​ Part of a chromosome changes place with a non-homologous chromosome ➔​ Ex. Can result in chronic myelogenous leukemia Unit 1: Genetics (part 2)  Test: Thursday, October 10 5.1 - Understanding Inheritance ​ Inheritance = breeding Gregor Mendel (1822-1884) ​ Austrian monk ​ “Father of genetics” (mendelian genetics) ​ Used pea plants to study genetics, hereditary and variation ​ Pea plants reproduce sexually, but usually self fertilize ​ True breeding - organisms that exhibit the same traits generation after generation ​ Parent or P generation - generation of given traits ​ Homozygous - having 2 similar alleles ​ Heterozygous - having 2 different alleles ​ First Filial or F1 generation - offspring of parental generation ​ Second Filial or F2 generation - offspring of First Filial ​ Mendelian Ratio - 3:1 ratio, 75%:25% ​ Mendel concluded each plant in the F1 gen carried an allele from the P generation, making it hybrid ​ Hybrid - individuals that contain more than 1 variation of a trait, therefore can pass on more than one variation to future generations (heterozygous) ​ Traits are dominant or recessive, if a dominant trait is inherited, it will be expressed ​ Phenotype - the appearance of traits in an organism ex. Short or tall (visible) ​ Genotype - the specific combination of 2 alleles for any trait in an organism ex. PP or Pp or pp ​ Law of Segregation: when any individual produces gametes, the copies of a gene separate so that each gamete receives one copy of a gene and therefore only one allele for all possible traits (diploid → haploid) (independent assortment) 5.2 - How to solve Genetic problems What makes an allele dominant and recessive? ​ Commonly, the dominant allele codes for a working protein while the recessive allele does not ​ For example, M represents dominant allele and codes for production of melanin ​ The recessive “m” allele is unable to code for the production of melanin (albinism) Procedure for solving Genetic Problems 1.​ Define the letter that represents the genes 2.​ Show the genotypes of the parents 3.​ Show the gametes produced by each parent 4.​ Draw a Punnett Square using gametes produced by each parent ​ Punnett Square - diagram that summarizes every possible combination of each allele from each parent 5.​ Show the genotypic and phenotypic summary of the offspring Example: Purple (dom.) - B White (rec.) - b ♂ - purple (Bb)​ ♀ - purple (Bb)  B​ b B BB Bb b Bb bb Genotype:​ ​ ​ ​ ​ ​ Phenotype: F1: BB 25%​ (homo. dom) (homo. rec)​​ Purple 75% Bb 50%​ OR​ 1 : 2 : 1​ ​ ​ White 25% bb 25%​ ​ (hetero)​ ​ ​ OR 3:1 (mendel's ratio) Monohybrid Cross ​ Considering only one trait when breeding 2 organisms Test Crosses ​ When geneticists want to know if an individual is heterozygous or homozygous for breeding purposes ​ Cross between unknown phenotype and homozygous recessive individual (Pp or PP) x pp 5.3 - Dihybrid crosses and patterns of inheritance ​ A dihybrid cross can be treated as 2 separate monohybrid crosses ​ Law of independent assortment - the inheritance of a seed shape has no influence over the inheritance of seed colour -​ 2 characters are inherited INDEPENDENTLY -​ The pairs of alleles that control these 2 characteristics assort themselves independently Mendel and Meiosis ​ Pairs of chromosomes could orientate in different ways at Anaphase I EXAMPLE: N - normal (dom.) ​ n - vestigial (rec.)​ B - black (dom.)​ b - colourless (rec.) 1.​ Heteronormal black body = NnBb 2.​ Heteronormal colourless body = Nnbb FOIL each combination NnBb - Nb, Nb, nB, nb (P1) Nnbb - Nb, Nb, nb, nb (P2) ​ NB​ ​ Nb​ ​ nB​ ​ nb Nb NNBb NNbb NnBb Nnbb Nb NNBb NNbb NnBb Nnbb nb NnBb Nnbb nnBb nnbb nb NnBb Nnbb nnBb nnbb Genotype:​ ​ ​ ​ Phenotype: NNBb - 2:16 (12.5%)​ ​ ​ Normal wing + black body - 6:16 (37.5%) NnBb - 4:16 (25%)​ ​ ​ Normal wing + colourless body - 6:16 (37.5%) NNbb - 2:16 (12.5%)​ ​ ​ vestigial wing + black body - 2:16 (12.5%) Nnbb - 4:16 (25%)​ ​ ​ vestigial wind + colourless body - 2:16 (12.5%) nnBb - 2:16 (12.5%) nnbb - 2:16 (12.5%) 5.4 - Beyond Mendel’s Laws Complete Dominance - Mendel’s Ratio ​ Phenotype is the dominant allele (BB or Bb) ​ When we see a recessive phenotype, the individual has 2 recessive alleles (bb) Incomplete dominance ​ Neither trait is dominant or recessive ​ A heterozygous individual is a blend of the 2 traits ​ Instead of using R and r, we use FR and FW to show incomplete dominance ​ Red = FRFR, Pink = FRFW, White = FWFW Co-dominance ​ BOTH alleles for a trait are dominant, a heterozygous individual expresses both traits ​ 3 phenotypes: white, black, white AND black Multiple Alleles ​ In humans a single gene controls a person’s ABO blood type ​ This gene determines what type of an antigen protein is attached to membrane of a red blood cell ​ Combination of 3 alleles make 4 different blood types: AB, A, B, O ​ A antigen, B antigen, AB antigen, No antigen (O) (rec) Type % of Canadians Can receive from Can donate to Genotype A 42% A, O A, AB IAIA OR IAi B 9% B, O B, AB IBIB OR IBi AB 3% A, B, AB, O AB IAIB O 46% O A, B, AB, O ii AB - universal recipient O - universal donor Polygenic Inheritance: ​ More than one (poly) ex. Skin colour ​ Display continuous variation, in which phenotypes vary gradually from one extreme to another ​ Variation is controlled by more than one gene polygenic trait Sex-linked Inheritance: ​ Using fruit flies as test subjects, Thomas Morgan studied eye colour using simple monohybrid crosses ​ Red eyes (R) are dominant over white eyes (r) ​ When he crossed pure-bred white-eyed males with red-eyed females, he was unable to produce a female with white eyes ​ He concluded that the gene must be located on the X chromosome ​ Some traits are located on the sex chromosomes, so the inheritance of these traits depends on the sex of the parent carrying the trait ​ Sex of baby is determined by the father  ​ Most sex-linked traits are X-linked (carried on X) ​ This is because the X chromosome is much larger than the Y chromosome ​ Some sex-linked traits are associated with disorders ​ Most are found on the X chromosome, Y-linked disorders are rare ​ Males are at a much greater risk for inheriting sex-disorders because they only inherit one X chromosome, so if the X chromosome has the allele for the disorder, they will suffer from the disorder ​ Recessive lethal X-linked traits result in death ​ Ex. Red-green colorblindness, hemophilia, X-linked severe combined immunodeficiency Hemophilia ​ Conditions that affect the body’s ability to produce proteins involved in blood clotting ​ X-linked recessive ​ “Royal Disease” (result of inbreeding) ​ Symptoms: uncontrolled bleeding Punnett Squares ​ Always assume that a trait is X-linked unless told otherwise 5.5 - Patterns of inheritance (pedigrees) ​ Pedigree - genetic family tree that shows how prevalent a trait is in a family unit from generation to generation ​ Often used to track the expression of genetic conditions and disorders ​ Autosome - somatic cell, on chromosomes 1-22, NOT X or Y Anatomy of a pedigree ​ Squares represent males, circles represent females ​ Coloured shape means that the person is carrying the trait in question ​ Half coloured in or lightly shaded means they are carrying the allele for a recessive trait ​ Squares or circles with Xs through them means they are deceased individuals ​ A diamond is an unspecified sex (continue to show if they are affected) Autosomal Dominant Inheritance ​ Refers to situations in which a single copy of an allele is sufficient to cause expressions of a trait ​ Every generation is affected ​ Male and female are equally affected ​ An affected person has at least 5% chance of transmitting the dominant allele to each offspring ​ Every affected person should have at least 1 affected parent Characteristics of a dominant pedigree ​ An affected individual has at least 1 affected parent ​ As a result, dominant traits show a vertical pattern of inheritance (trait shows up in every generation) ​ 2 affected people may have unaffected children Autosomal Dominant Inheritance Examples ​ Progeria (caused by mutation) - person ages rapidly, die by the time they can reproduce ​ Huntington’s Disease - causes the central nervous system to break down around the age of 30 Autosomal Recessive Inheritance ​ 2 recessive alleles result in a trait being expressed ​ An affected person may not have affected parents, parents can be carriers ​ Affect both sexes equally, can skip generations ​ 2 affected parents will have 100% of affected children Characteristics of recessive pedigree ​ In pedigrees involving rare traits, a horizontal (recessive) pattern occurs ​ Trait may not appear in all generations ​ Individuals affected may have parents who are not affected, result of consanguineous (relatives) mating ​ Children of 2 affected parents will be affected Autosomal Recessive Examples ​ Albinism - loss of pigment in hair, skin, and eyes ​ Tay Sachs - build up of fatty deposits in the brain, fatal ​ Cystic Fibrosis - most common fatal genetic disorder, mutation in chloride transport protein that causes thick mucus to build up in lungs Solving pedigrees ​ Is it autosomal dominant or recessive (do not look at gender) ​ Affected individuals only require 1 allele ​ Individuals coloured in should have 1 allele ​ Define letters (let A rep dom., let a rep rec., aa - unaffected, AA or Aa - affected)