Biology Reviewer 2 PDF

RESPIRATORY SYSTEM Allows gas exchange (respiration) – gets oxygen into the body and removes CO2 from the body. Functions of Respiratory System: 1. To supply the body with oxygen; 2. To remove carbon dioxide from the lungs; 3. To keep normal body temperature; 4. To protect against microorganisms b...

RESPIRATORY SYSTEM Allows gas exchange (respiration) – gets oxygen into the body and removes CO2 from the body. Functions of Respiratory System: 1. To supply the body with oxygen; 2. To remove carbon dioxide from the lungs; 3. To keep normal body temperature; 4. To protect against microorganisms by preventing entry and removing them; 5. Regulation of blood pH: Altered by changing blood carbon dioxide levels; 6. Gas exchange: Oxygen enters blood and carbon dioxide leaves. Introduction to the Human Respiratory System -The human respiratory system plays a vital role in the overall functioning of the body. It is responsible for the intake of oxygen and the removal of carbon dioxide, ensuring the body's cells receive the necessary oxygen for energy production. What are the parts of the Respiratory system involved in doing its primary function? The NOSE -Gateway for Breathing Structure and Functions of the Nose 1) External Structure -The nose is composed of the external nostrils, nasal septum, and nasal bones. It acts as a filter, warming and moisturizing the inhaled air. 2) Internal Structure -The nose is composed of the external nostrils, nasal septum, and nasal bones. It acts as a filter, warming and moisturizing the inhaled air. -Inside the nose, there are nasal passages lined with cilia and mucus-producing cells. They further filter the air and trap particles, preventing them from reaching the lungs. The PHARYNX and LARYNX -Passage and Vocalization The pharynx serves as a passage for air flowing from the nasal cavity to the larynx, while also connecting to the esophagus for the passage of food and liquids. - The larynx, also known as the voice box, is responsible for vocalization. The TRACHEA and BRONCHI: Transporting Air Trachea Bronchial Tree -The trachea, or windpipe, -The bronchial tree refers to the is a long tube connecting network of bronchi and bronchioles the larynx to the bronchi. within the lungs. It is composed of cartilage It ensures the distribution of air to all rings that prevent collapse lung segments. and allow the passage of air. Bronchi The trachea branches into two primary bronchi, which further branch into smaller bronchioles. These structures transport the inhaled air deeper into the lungs. The LUNGS: Where Gas Exchange Takes Place Structure and Function of the Lungs Anatomy of the Lungs -The lungs are a pair of sponge-like organs located in the chest cavity. They are divided into lobes and surrounded by a thin membrane called the pleura. Gas exchange -Within the lungs, millions of tiny air sacs called alveoli are responsible for the exchange of oxygen and carbon dioxide between the air and the bloodstream. Pulmonary capillaries -The alveoli are surrounded by a network of pulmonary capillaries, allowing for the efficient transfer of gases between the air and the blood. The DIAPHRAGM: Key Muscle for Breathing Function and Role of the Diaphragm Anatomy of the diaphragm -The diaphragm is a dome-shaped skeletal muscle located beneath the lungs. It separates the chest cavity from the abdominal cavity. Breathing process -During inhalation, the diaphragm contracts and moves downward, allowing the lungs to expand. During exhalation, the diaphragm relaxes and moves upward, helping to expel air from the lungs. Accessory muscle -In addition to the diaphragm, other muscles such as the intercostal muscles and abdominal muscles also play a role in the breathing process. Two phases of respiration (GAS EXCHANGE) 1. Internal respiration – exchange of gases between the blood and the body tissues. 2. External respiration – exchange of gases between the atmosphere and the blood. This involves the lungs. Breathing is a mechanical process that helps get air into and out of the lungs. It consists of two stages: inspiration – intake of air and expiration – breathing out of air. Mechanism of breathing - Carbon dioxide level in the blood controls breathing - When the concentration of carbon dioxide reaches a higher than normal level, the breathing centre of the brain is stimulated and a signal is conveyed to the diaphragm, which contracts (moves down). - The ribs and the lungs are able to expand. - Air rushes in through the nose or mouth to fill the extra volume available in the lungs. - This whole process is called breathing in, inspiration or inhalation - When the signal from the breathing centre of the brain stops, the diaphragm relaxes and the rib cage is moved down and inward. - The volume of the chest cavity is reduced and air is forced out of the lungs. - This is called breathing out, exhalation or expiration. Inhalation(inspiration) (i) The diaphragm muscle contracts and moves down. (ii) The external intercostal muscles contract and pull the rib cage upwards and outwards. (iii) Therefore the volume of the chest cavity increases (and so the lung expands). (iv) This decreases the air pressure in the alveoli, so (v) Air flows IN to equalise the pressure. Exhalation (expiration) (i) The diaphragm muscles relax, allowing the diaphragm to return to its curved shape. (ii) The internal intercostal muscles contract, pulling the ribs downwards. (iii) Therefore, the volume of the chest cavity decreases (and so the lungs contract and get smaller) (iv) This increases the air pressure in the alveoli, so. (v) Air flows OUT to equalise the pressure. CHANGES ON THE COMPOSITION OF BREATHED AIR Gases Percentage inhaled Percentage exhaled Oxygen 21 16 Carbon Dioxide 0.04 4 Nitrogen 79 79 Water vapour Less More Common Respiratory Disorders and Diseases Asthma -Asthma is a chronic respiratory condition characterized by inflammation and narrowing of the airways. It can cause shortness of breath, wheezing, and coughing. Chronic Obstructive Pulmonary Disease (COPD) -COPD refers to a group of progressive lung diseases, including chronic bronchitis and emphysema. It can lead to difficulty breathing, reduced lung function, and increased risk of respiratory infections. Pneumonia -Pneumonia is an infection that inflames the air sacs in one or both lungs. Symptoms can include fever, cough, chest pain, and difficulty breathing. Lung Cancer -Lung cancer is the uncontrolled growth of abnormal cells in the lungs. 1-Simulation of breathing muscles by the breathing center of the brain 2-Contraction of the diaphragm and rib muscles 3-Outward pull of ribcage, resulting in lung expansion 4-Increase in the size of the chest cavity 5-Decrease in air pressure inside of the lungs 6-Flow of the air from higher to lower pressure Circulatory System - The circulatory system is a complex network of blood vessels, the heart, and blood. It plays a vital role in the body, delivering oxygen and nutrients to all cells and removing waste products. Components of the Circulatory System Blood Vessels, Heart, and Blood Blood vessels -including arteries, veins, and capillaries, form a vast network throughout the body. Arteries -carry oxygen-rich blood away from the heart. They have thick, elastic walls to withstand the high pressure generated by the pumping action of the heart. Arteries branch into smaller vessels called arterioles. Veins -return oxygen-depleted blood back to the heart. Unlike arteries, veins have thinner walls and contain valves that prevent blood from flowing backward. Veins merge to form larger vessels called vena cavae. Capillaries -are tiny vessels that connect arteries and veins, facilitating exchange of oxygen, nutrients, and waste products. Capillary walls are incredibly thin, facilitating efficient diffusion of substances in and out of the bloodstream. Heart -The heart is a muscular organ responsible for pumping blood throughout the body. It consists of four chambers: two atria and two ventricles. The atria receive blood, while the ventricles pump it out. The heart has its own blood supply, delivered by the coronary arteries. Blood -is a specialized fluid that carries oxygen, nutrients, hormones, and waste products. It consists of red blood cells, white blood cells, platelets, and plasma. Red blood cells carry oxygen, white blood cells fight infections, platelets help with blood clotting, and plasma is the liquid component that transports all these elements. Functions of the Circulatory System Delivering Oxygen and Nutrients, Removing Waste Delivering Oxygen and Nutrients The circulatory system ensures that oxygen and nutrients are delivered to all cells in the body. Oxygen is carried by red blood cells, while nutrients are transported in plasma. This ensures that every cell has the necessary resources for optimal functioning. Removing the waste As blood circulates through the body, it picks up waste products generated by cells. The circulatory system facilitates the removal of these waste products, such as carbon dioxide and metabolic byproducts, to organs like the lungs and kidneys for elimination. The Heart: The Pump of Life The heart is often referred to as the pump of life It contracts and relaxes rhythmically, creating the pressure needed to circulate blood throughout the body. This non-stop pumping action ensures that oxygen and nutrients are continuously delivered to every part of the body. Blood: Red Blood Cells, White Blood Cells, Platelets, Plasma Red Blood Cells -Red blood cells, or erythrocytes, are the most abundant cells in the blood. Their primary function is to carry oxygen from the lungs to the body's tissues and organs. They achieve this with the help of a protein called hemoglobin, which binds to oxygen and releases it where needed. White blood cells -White blood cells, or leukocytes, are an essential part of the immune system. They help defend the body against infections and diseases by identifying and destroying harmful bacteria, viruses, and other foreign substances. Platelets -Platelets are tiny cell fragments that play a crucial role in blood clotting. When a blood vessel is damaged, platelets rush to the site and form a plug, preventing excessive bleeding. They also release chemicals that promote clotting, leading to the formation of a stable blood clot. Plasma -Plasma is the liquid component of blood. It consists of water, proteins, hormones, waste products, and other molecules. Plasma serves as a transportation medium, carrying the various elements of blood, such as red and white blood cells, platelets, and nutrients, throughout the body. Circulatory System Disorders Hypertension -Hypertension, or high blood pressure, is a condition in which the force of blood against the artery walls is too high. If left untreated, it can lead to serious health complications, such as heart disease, stroke, and kidney problems. Atherosclerosis -Atherosclerosis occurs when fatty deposits, called plaques, build up on the artery walls. This narrows the arteries and reduces blood flow, increasing the risk of heart attacks, strokes, and other cardiovascular problems. Heart Failure -Heart failure refers to the heart's inability to pump enough blood to meet the body's needs. Pulmonary and Systemic Blood Circulations What is Pulmonary Circulation? Function -Pulmonary circulation facilitates the exchange of oxygen and carbon dioxide between the lungs and the blood. Components -Pulmonary artery, pulmonary veins, and capillaries form the main components of pulmonary circulation. Components of Pulmonary Circulation -Pulmonary circulation consists of several crucial components that ensure proper oxygenation of blood. These components include the pulmonary arteries, which carry deoxygenated blood from the heart to the lungs, the pulmonary veins responsible for returning oxygenated blood from the lungs to the heart, and the pulmonary capillaries where gas exchange occurs between the air sacs in the lungs and the blood vessels. What is Systemic Circulation? Function -Systemic circulation delivers oxygenated blood to various organs and tissues, supplying them with the required nutrients and removing waste products. Components -Systemic circulation includes the aorta, arteries, arterioles, capillaries, venules, and veins as its primary components. Involvement of Heart -The heart pumps oxygenated blood to the systemic circulation through the left ventricle, ensuring a continuous supply to all body parts. Exchange of Gases, Nutrients & Wastes -Systemic capillaries enable the exchange of nutrients, waste products, and gases between blood and tissues. Components of Systemic Circulation Aorta -The largest artery in the body, the aorta serves as the main channel for distributing oxygen-rich blood to the entire systemic circulation. Arteries -Arteries carry oxygenated blood away from the heart to various organs and tissues. Arterioles -Arterioles control the blood flow and regulate blood pressure within the systemic circulation. Differences Between Pulmonary and Systemic Circulations Pathway -Pulmonary circulation mainly involves blood flow between the heart and the lungs, while systemic circulation encompasses blood flow to and from all body organs. Oxygenation -Pulmonary circulation is responsible for oxygenating deoxygenated blood, whereas systemic circulation distributes oxygenated blood throughout the body. Pressure -The pressure in pulmonary circulation is lower than in systemic circulation due to the difference in resistance and distance traveled by blood. Importance and Functions of Pulmonary and Systemic Circulations Role of Pulmonary Circulation -Pulmonary circulation ensures proper oxygenation of blood, facilitating efficient respiratory function and the removal of carbon dioxide from the body. Role of Systemic Circulation -Systemic circulation supplies oxygenated blood and nutrients to all tissues for their proper functioning, while simultaneously removing metabolic waste products. Order Right atrium Bicuspid valve Tricuspid valve Left ventricle Right ventricle Aortic valve Pulmonary valve Aorta Pulmonary veins Systemic arteries Lung capillaries Body tissues Pulmonary arteries Systemic veins Left atrium Superior/inferior vena cava Non-Mendelian Patterns of Inheritance -These laws describe the inheritance of traits linked to single genes on chromosomes in the nucleus. Genetics -Genetics is the study of heredity, the process in which a parent passes certain genes onto their children Genetic Terms allele: different forms of a gene, which produce variations in a genetically inherited trait genes: Genes are parts of DNA and carry hereditary information passed from parents to children. dominant:Dominant version (allele) of a gene shows its specific trait even if only one parent passed the gene to the child recessive: Recessive gene shows its specific trait when both parents pass the gene to the child. homozygous: Two of the same form of a gene—one from mother and the other from father heterozygous: Two different forms of a gene— one from mother and the other from father genotype: Internal heredity information that contain genetic code. phenotype: Outwardly expressed traits or characteristics Incomplete dominance -A heterozygote shows a phenotype that is intermediate between the two contrasting homozygous phenotype.Neither allele is dominant over the other. Genotypic ratio also becomes the phenotypic ratio. Codominance -Occurs when both alleles are expressed equally in the phenotype of the heterozygote. A cross between organisms with two different phenotypes produces offspring with a third phenotype in which both of the parental traits appear together. Multiple alleles -more than two alleles control the inheritance for a single given trait (e.g. the ABO blood group system) Polygenic -two or more gene pairs that are located in several loci in one or more chromosomes controls the inheritance of a trait. Two types of chromosomes : - autosomes (22pairs) - sex chromosomes(1pair) What are sex chromosomes? In humans, they are the X and Y chromosomes There is a pair in every somatic cell. Females have two complementary sex chromosomes: XX Males have 2 non complementary sex chromosomes: XY chromosomes that determine the sex of an individual. Sex Related Inheritance Other patterns of non-Mendelian inheritance involve the sex chromosomes. expression of traits depends on whether one is male or female Three types of inheritance of sex traits: sexlinked, sex-influenced and sex-limited. Pedigree Analysis – one way to study the inheritance of human traits A pedigree is a genetic family tree that shows how prevalent a trait is in a family unit from generation to generation. They are often used to track the expression of genetic conditions and disorders. Karyotyping – another method to study inheritance of a trait -Karyotype/karyogramphotograph of all chromosomes in a nucleus of a cell that are arranged in pairs (homologous chromosomes) and accdg to size Sex-linked Genes -genes found in the sex chromosomes -Genes located in the same chromosomes are said to be linked together so they are called linked genes. X –linked genes - genes on the x chromosomes, found in both sexes but more likely to be expressed in the heterogametic sex (male) Y-linked genes or holandric genes - found in Y chromosomes, found only in males and there is no skipping among male generation. Only males are affected, affected males pass the disease gene to all their sons and to none of their daughters. Sex-Influenced Inheritance -Autosomal genes in which the expression is affected by the sex of the individual -Appear more frequently (although not exclusively) in one of the sexes -Pattern baldness is dominant in males but recessive in females. Sex-limited Traits -Autosomal genes in which the expression is manifested in one sex only because of the sex hormones. (Autosomes carry the genetic coding for everything except sex determination) (46 chromosomes) Photosynthesis and Cellular Respiration -Photosynthesis and respiration are complementary processes in the living world. Photosynthesis uses the energy of sunlight to produce sugars and other organic molecules. Introduction to photosynthesis - From the Greek PHOTO = produced by light SYNTHESIS = a whole made of parts put together. Definition: PHOTOSYNTHESIS is the process whereby plants, algae, some bacteria, use the energy of the sun to synthesize organic compounds (sugars) from inorganic compounds (CO2 and water). WHY IS PHOTOSYNTHESIS SO IMPORTANT? PHOTOSYNTHESIS is one of the most important biological process on earth Provides the oxygen we breathe Consumes much of the CO2 Food Energy Fibers and materials GENERAL FORMULA FOR PHOTOSYNTHESIS light 6 CO2 + 12 H2O ---------> C6H12O6 + 6 O2 + 6 H2O pigments, enzymes Oxygen on earth allowed for the evolution of aerobic respiration and higher life-forms. Respiration: extracting energy from compounds (sugars) C6H12O6 + 6O2 6 CO2 + ATP + 6H2O PROPERTIES OF LIGHT Light moves in waves, in energy units called PHOTONS Energy of a PHOTON inversely proportional to its wavelength Visible light (between UV and IR) occurs in a spectrum of colors Chlorophyll a is the primary photosynthetic pigment that drives photosynthesis. Accessory pigments absorb at different wavelengths, extending the range of light useful for photosynthesis. Absorption spectrum of chlorophyll a: BLUE & RED Action spectrum of photosynthesis closely matches absorption spectrum of chlorophyll a, but not perfectly (due to accessory pigments) Chloroplast Membrane Structure The thylakoid is the structural unit of photosynthesis containing photosynthetic chemicals. Thylakoids are stacked like pancakes in stacks known collectively as grana. The areas between grana are referred to as stroma. Chloroplast Structure & Function The chloroplast has three membranes: inner, outer, and thylakoid. It has three compartments: stroma, thylakoid space, and inter-membrane space. These compartments and the membranes that separate them serve to isolate different aspects of photosynthesis. – Dark reactions take place in the stroma. – Light reactions take place on the thylakoid membranes. The Light and “Dark”or Carbon reactions happen at different sites in the chloroplast The Light Reactions 1. Light dependent 2. Occur in the thylakoid membrane of chloroplast 3. Water is split into oxygen gas (O2 ) and H+ The“Dark” 4. Use light energy (photons) to generate two chemical energy compounds: ATP & NADPH The“Dark” or Carbon Reactions 1. Light independent (can occur in light or dark; some enzymes require activation by light) 2. Occur in the stroma of chloroplasts 3. Use the chemical energy produced in Light Reactions (ATP; NADPH) to reduce CO2 to carbohydrate (sugar). 4. CO2 is converted to sugar by entering the Calvin Cycle Summary of Photosynthesis: 1. Light energy absorbed by chlorophyll drives the reactions of photosynthesis. 2. Converts light energy into chemical energy to make organic compounds. 3. CO2 and H2O used to produce C6H12O6 (glucose) and O2 (gas). 4. Light Reactions occur in thylakoids of the chloroplasts; ATP and NADPH are formed; water is split to O2 (gas) and protons. 5. Carbon Reactions occur in stroma – Calvin Cycle fixes CO2 to produce C6H12O6 (glucose). 6. Low efficiency, about 1- 7% RESPIRATION Process of making energy of food available in the cell… Involves breaking down Complicated molecules into simple molecules (C6H1206, sugars) (CO2, water) The energy held by complicated molecules is held temporarily as ATP (energy currency) C6H12O6 + 6 O2 6CO2 + 6 H2O + 36 ATP -Respiration occurs mainly in Mitochondria and Cytoplasm Stages of Respiration Cellular Respiration 3 Stages of cellular respiration Glycolysis: Splitting of glucose – 2 net ATP generated Krebs Cycle: Energy of glucose molecule is harvested as ATP (2) – it occurs in the mitochondria (matrix) Electron Transport System: also happens in the mitochondria, more ATP are generated (32). For each glucose molecule, total ATP = 36 BIODIVERSITY -species diversity is a measurement of richness and evenness. Population Species -group of organism of the -a group of living organisms consisting same species. Of similar individuals capable Interbreeding Biosphere Biotic community –consists of the entire earth -Made up of all living organisms Where all ecosystems that share a common environment. Function. Ecosystem -several communities living together in a particular region, along with the physical environment form an ecosystem. Includes abiotic components. Biodiversity index -Way of measuring biodiversity Species richness -total number of species in an area Species evenness -how evenly the species are represented in the area Threats to biodiversity Extinction -total disappearance of all the members of a certain species. Local extinction – certain population of organisms cease to exist in an area, but some continue to exist elsewhere Background extinction – gradual process of becoming extinct Mass extinction - a large percentage of all living species become extinct in a relatively short period of time