Science Exam Study Guide PDF

▪ Chemistry: Kinetic theory o All matter is composed of very small particles called atoms. o These particles are in constant motion, with higher temperatures resulting in faster particle movement. o Temperature affects the kinetic energy of par...

▪ Chemistry: Kinetic theory o All matter is composed of very small particles called atoms. o These particles are in constant motion, with higher temperatures resulting in faster particle movement. o Temperature affects the kinetic energy of particles, which influences their behavior. o When temperature increases, gas particles move faster and occupy a greater volume, while lowering the temperature results in slower particle movement and a smaller volume. Bulk properties of matter o The space between gas particles is much greater compared to solids and liquids. o Higher temperatures lead to increased volume due to faster particle movement, while higher pressures compress gas particles, reducing volume. o Different states of matter (solid, liquid, gas) have distinct properties regarding shape, volume, and fluidity. Pure substances and mixtures o A pure substance consists of only one type of substance without impurities. o Pure substances have precise and predictable melting and boiling points. o Impurities can affect the melting and boiling points, causing them to occur over a range of temperatures. o Melting and boiling points can be used to test the purity of a substance o Mixtures consist of two or more substances that are physically combined but not chemically bonded. o The composition of a mixture can vary, with different amounts of each substance present. o No chemical reaction occurs when forming a mixture; substances retain their original properties. o Mixtures can be separated by physical methods, such as filtration, distillation, or using a magnet. Separation techniques o Mechanical/Physical Separation: Passing a mixture through a sieve to separate components based on size or physical properties. o Filtration: Passing a mixture through a filter to separate insoluble solids from liquids. o Decantation: Allowing a mixture to settle, then pouring off the top layer to separate components with different densities. o Magnetism: Using magnets to attract and separate materials with magnetic properties from non-magnetic materials.  o Evaporation: Heating a mixture to vaporize the solvent, leaving behind the solute. o Centrifugation: Spinning a mixture at high speeds to separate components based on density. o Distillation: Boiling a mixture to vaporize the more volatile component, then condensing the vapor back into a liquid. Atomic structure o Subatomic Particles - Atoms are composed of subatomic particles: protons, neutrons, and electrons. - Protons and neutrons reside in the nucleus, while electrons orbit around the nucleus in shells. - Electrons are negatively charged and virtually massless, while protons are positively charged and have a mass of 1 unit. o Protons, Neutrons, and Electrons - Protons carry a positive charge, neutrons are electrically neutral, and electrons carry a negative charge. - Protons and neutrons have almost the same mass (relative mass = 1 unit), while electrons have negligible mass. o Electron Configuration - Electrons occupy shells around the nucleus, with each shell having a specific energy level. - Electrons fill shells starting from the innermost (lowest energy level) to the outermost (higher energy levels). - The first shell can hold up to 2 electrons, while the second and subsequent shells can hold up to 8 electrons (up to atomic number 20). o Atomic Representation - The arrangement of electrons in shells, along with the numbers of protons and neutrons, determines the properties of an atom. - The electronic configuration of an element reflects its position in the Periodic Table, with group number indicating the number of electrons in the outer shell and period number indicating the number of shells.  Periodic table o Development and Structure: - Developed by Dmitri Mendeleev in 1869. - Arranges elements based on increasing atomic number (number of protons in the nucleus). - Organized into periods (rows) and groups (columns). - Periods indicate the number of electron shells an atom possesses. - Groups reflect similar chemical properties, due to the same amount of electrons in the outermost shell. o Representation of Elements - Each element is represented by its chemical symbol, proton number (atomic number), and mass number (nucleon number). - The chemical symbol is a one or two-letter abbreviation representing the element (e.g., H for hydrogen, He for helium). - Proton number (Z) indicates the number of protons in the nucleus, defining the element. - Mass number (A) represents the total number of protons and neutrons in the nucleus, determining the atom's mass. o Significance of Noble Gases - Noble gases reside in Group VIII of the periodic table. - Includes helium, neon, argon, krypton, xenon, and radon. - Known for their highly stable electron configurations with a full outer shell of electrons. - Highly unreactive due to their stable electron configurations. - Serve as benchmarks for understanding chemical reactivity and bonding in other elements.  Chemical behavior using electron structure o The arrangement of electrons in an atom's electron shells determines its chemical properties and reactivity. o The outermost shell, known as the valence shell, plays a crucial role. o The number of electrons in the valence shell determines how readily an atom will form chemical bonds. o Atoms with a full valence shell tend to be stable and less reactive. o Elements in the same group of the periodic table have similar outer electron configurations, leading to similar chemical behaviors. o Valence electrons are involved in chemical reactions, influencing an atom's ability to gain, lose, or share electrons to achieve a stable electron configuration. o The tendency of an atom to gain or lose electrons determines its reactivity and the type of chemical bonds it forms (ionic or covalent). o Understanding electron arrangement helps predict an element's behavior in chemical reactions and its ability to combine with other elements to form compounds. Isotopes o Atoms of the same element with different masses. o Have the same number of protons and electrons but different numbers of neutrons in the nucleus. o Defined by their difference in mass number. o Isotopes are named according to their mass number. (Example: Carbon has three isotopes - carbon-12, carbon-13, and carbon-14.) o Isotopes are represented using their mass number in the symbol. o Characteristics - Many elements have naturally occurring isotopes. (Example: Hydrogen has three isotopes - hydrogen, deuterium, and tritium.) - Hydrogen-1 (protium) is the most common isotope, followed by deuterium (hydrogen-2), and tritium (hydrogen- 3). - Tritium is usually artificially produced and is radioactive. ▪ Physics - Waves and Optics: Wave properties (frequency, wavelength, speed, amplitude) o Describing Waves: - Waves transfer energy through a series of back-and-forth movements or vibrations. - Examples include ripples spreading in a pond when a stone is dropped and waves traveling along a string. o Wavelength and Amplitude: - Wavelength (λ): Distance from one crest (or trough) of a wave to the next. ▪ Symbol: λ (lambda). ▪ Measured in meters (m). - Amplitude (A): Height of a crest or depth of a trough. ▪ Symbol: A. ▪ Measured in meters (m). o Frequency: - Frequency (f): Number of oscillations per second. ▪ Measured in Hertz (Hz). ▪ Represents how often a wave cycle repeats. ▪ Example: If a wave completes four cycles per second, its frequency is 4 Hz. o Wave Speed: - Wave Speed: Rate at which the crest of a wave travels through a medium.  - Measured in meters per second (m/s). o Waves and Energy: - Waves serve as carriers of energy. o Energy transfer occurs through various types of waves, such as light waves and sound waves. o The amplitude of a wave correlates with the amount of energy it transfers. - Higher amplitude waves transfer more energy. - Example: A wave with a large amplitude results in bright light or a loud sound. Longitudinal and transverse waves o Transverse Waves (mechanical wave): - Description: In transverse waves, the particles oscillate perpendicular to the direction of wave propagation. - Example: Ripples on the surface of water demonstrate transverse wave motion, where water particles move up and down as the wave moves horizontally. - Representation: Waves on a string or slinky exhibit transverse characteristics, with crests and troughs forming as the wave travels. - Characteristics: ▪ Motion: Particles move in a perpendicular direction to wave travel. ▪ Waveform: Distinct peaks (crests) and troughs are observed as the wave passes through a medium. o Longitudinal Waves (electromagnetic wave): - Description: In longitudinal waves, the particles oscillate parallel to the direction of wave propagation. - Example: Sound waves traveling through air exemplify longitudinal wave behavior, where air molecules move back and forth as the wave travels. - Representation: Similar to compressions and rarefactions seen in a spring, longitudinal waves feature regions of high pressure (compressions) and low pressure (rarefactions). - Characteristics: ▪ Motion: Particles move in the same direction as wave travel, alternating between compression and rarefaction. ▪ Waveform: Characterized by regions of high and low pressure along the direction of wave travel.  o Reflection: - Description: Reflection occurs when a wave encounters a barrier and is bounced back. - Illustration: Similar to light reflecting off a mirror, water waves exhibit reflection when they encounter a solid barrier, changing the direction of the wave. - Characteristics: ▪ Angle of Incidence: The angle at which the wave strikes the barrier determines the angle at which it reflects. ▪ Law of Reflection: The angle of incidence equals the angle of reflection. - Application: Reflection is essential in various fields, from acoustics (echoes) to optics (mirrors). o Refraction: - Description: Refraction occurs when a wave transitions from one medium to another, causing a change in speed and direction. - Example: When water waves move from deep to shallow water, they slow down and change direction, demonstrating refraction. - Mechanism: Waves bend toward the normal (perpendicular line) when entering a slower medium and away from the normal when entering a faster medium. - Impact: Refraction influences phenomena like the bending of light in lenses and the apparent depth of objects in water. o Diffraction: - Description: Diffraction refers to the spreading out of waves as they pass through an opening or around an obstacle. - Example: When waves pass through a gap in rocks, they spread out, filling the bay, showcasing diffraction. - Characteristics: ▪ Dependence on Wavelength: Diffraction is more pronounced when the wavelength of the wave is comparable to the size of the obstacle or opening. ▪ Patterns: Diffraction patterns often feature areas of constructive and destructive interference. - Applications: Diffraction plays a role in various fields, from sound engineering to the behavior of light in optical instruments. Velocity (v) = Frequency (f) X wavelength ( Human ear and eye structures o Ear - Pinna  ▪ Collects sound waves and channels into ear canal - Ear canal ▪ Entryway for sound waves - Eardrum ▪ Movement of the three bones in the middle ear, also protects the middle ear - Middle ear bones ▪ Connect tympanic membrane to the inner ear allowing transmissions of sound waves ▪ Hammer/ malleus ▪ Anvil/ stapes ▪ Stirrup/ incus ▪ English/ Latin - Cochlea ▪ Auditory transduction, receives middle ear bones and transmits to auditory nerve - Auditory nerve ▪ Transform vibrations to electronic impulses - Semicircular canals ▪ Help keep balance - Eustachian tubes ▪ Opens intermittently t equalize the intratympanic air pressure with the pressure in the external auditory canal  o Eye Name of structure Description cornea Tough white protective outer layer  Initially refracts light towards lens, protects pupil from dust etc conjuctiva Mucus membrane that covers sclera, produces fluid to lubricate and protect eyeball Eyelid Protects eye from dust Aqueos humor Clear jelly that fills section of eye behind cornea Pupil Hole that allows light into the eye Lens Focuses light onto retina Iris Ring of muscles that controls size of pupil Vitreous humor Clear jelly that fills main part of eye, maintaining pressure Retina Location of photoreceptors (rods and cones) Fovea Area with highest concentration of colour photoreceptors (cones) Optic nerve Sensory neuron linking photoreceptors to visual cortex of brain Optic disk (blind spot) No photoreceptors at place where optic nerve leaves retina Electromagnetic spectrum o Introduction: ▪ The electromagnetic spectrum encompasses a wide range of electromagnetic waves, including those with wavelengths longer than visible light (infrared) and shorter than visible light (ultraviolet, X-rays, and gamma rays). ▪ Our eyes are adapted to detect only a small portion of this spectrum, known as the visible spectrum, which consists of colors from red to violet. o Properties of Electromagnetic Waves: ▪ Transverse Nature: All electromagnetic waves are transverse waves, meaning they oscillate perpendicular to the direction of propagation, transferring energy. ▪ Reflection and Refraction: Like other waves, electromagnetic waves can undergo reflection and refraction when encountering barriers or transitioning between mediums. ▪ Speed: Electromagnetic waves travel at the speed of light in a va cuum o Components of the Electromagnetic Spectrum: - Radio Waves: ▪ Used for broadcasting radio and television signals. ▪ Employed in radar systems for navigation and speed measurement. - Microwaves:  ▪ Utilized in satellite television broadcasting and mobile phone communication. ▪ Form the basis of microwave ovens, which heat food through absorption. - Infrared Radiation: ▪ Employed in remote controls, grills, toasters, and security alarms. ▪ Used in medicine for therapeutic and diagnostic purposes. - Visible Light: ▪ Provides sensory information and enables visual observation through optical instruments. ▪ Crucial for photosynthesis in plants. - Ultraviolet (UV) Light: ▪ Used in forensic investigations for detecting invisible evidence. ▪ Applied for security marking and detecting counterfeit items. - X-rays: ▪ Penetrate solid materials, used in security scanners and medical imaging. ▪ Can cause cell mutations and pose hazards if not used cautiously. o Hazards of Electromagnetic Waves: ▪ Infrared and UV Radiation: Can cause burns and damage to skin and eye cells. ▪ X-rays and Gamma Rays: Pose the highest risk, capable of causing cell mutations and cancer. Law of reflection o Definition: The Law of Reflection states that the angle of incidence is equal to the angle of reflection, measured from the normal (a line perpendicular to the surface at the point of incidence). o Angle of Incidence: The angle between the incident ray and the normal line drawn perpendicular to the surface at the point of incidence. o Angle of Reflection: The angle between the reflected ray and the normal line drawn perpendicular to the surface at the point of reflection. o Reflection: When light (or any wave) strikes a surface and bounces back, it's called reflection. This can occur on smooth, shiny surfaces like mirrors or even on rough surfaces where light scatters. o Normal Line: An imaginary line perpendicular to the surface at the point where the incident ray strikes. It helps measure the angles of incidence and reflection.  Refraction and lenses o Refraction: Refraction is the bending of light as it passes from one medium to another of different optical density. This bending occurs due to a change in the speed of light as it moves from one medium to another. o Optical Density: The optical density of a medium determines how much it can bend light. Materials with higher optical density, like glass or water, cause more refraction compared to less dense materials like air. o Refraction in Lenses: Lenses are transparent optical elements that refract light to form images. There are two main types of lenses: convex lenses, which converge light, and concave lenses, which diverge light. o Convex Lenses: Convex lenses are thicker in the middle than at the edges. When light passes through a convex lens, it converges or focuses to a point on the opposite side of the lens, forming a real or virtual image depending on the object's distance from the lens. o Concave Lenses: Concave lenses are thinner in the middle than at the edges. When light passes through a concave lens, it diverges or spreads out, causing the light rays to appear to come from a virtual focus point on the same side as the object. Concave lenses can only produce virtual images.  o Focal Point and Focal Length: The focal point of a lens is the point at which light rays converge (for convex lenses) or appear to diverge (for concave lenses) after passing through the lens. The focal length is the distance between the lens and its focal point. Diseases of the eye o Nearsightedness (Myopia): - Description: Myopia occurs when the eyeball is too long or the cornea is too steep, causing light rays to focus in front of the retina instead of directly on it. This results in distant objects appearing blurry, while close objects can be seen clearly. - Symptoms: Blurry vision when looking at distant objects, squinting, eye strain, headaches, difficulty seeing while driving or in a classroom. - Treatment: concave (minus) lenses, which diverge light before it enters the eye o Farsightedness (Hyperopia):  -Description: Hyperopia occurs when the eyeball is too short or the cornea is too flat, causing light rays to focus behind the retina rather than on it. This results in difficulty seeing close objects clearly, while distant objects may be seen more clearly. - Symptoms: Blurry vision when reading or performing close-up tasks, eye strain, headaches, difficulty focusing on nearby objects. - Treatment: Corrected with convex (plus) lenses, which converge light before it enters the eye o Astigmatism: - Description: Astigmatism occurs when the cornea or lens has an irregular shape, causing light rays to focus unevenly on the retina. This results in distorted or blurry vision at all distances. - Symptoms: Blurred or distorted vision, eye strain, difficulty seeing fine details. Stimuli and the human brain o Neurons and Reaction: - Neurons carry signals. - Sensory neurons: from senses to brain. - Relay neurons: within the brain. - Motor neurons: from brain to muscles. - Example: Touch hot stove → sensory neurons → relay neurons process → motor neurons react. o Integration and Interpretation: - Brain combines signals, understands them. - Compares with past experiences. - Example: Doorbell sound = someone at the door. o Response and Behavior: - Brain tells body how to react. - Makes us respond to surroundings. - Example: Feeling thirsty = get a drink. ▪ Biology - Cells, Digestion, and Energy: Digestive system o Function: Breaks down food for nutrient absorption and waste elimination. o Organs Involved: Alimentary canal, liver, pancreas. Processes Involved: 1. Ingestion: Food and drink intake via lips, teeth, and tongue. 2. Digestion: Mechanical and chemical breakdown of food. 3. Absorption: Nutrient molecules move into bloodstream. 4. Assimilation: Nutrients used by body cells for energy or building. 5. Egestion: Removal of undigested material as feces. Alimentary Canal: o Structure: Long tube from mouth to anus. o Muscles: Peristalsis moves food; sphincter muscles control passage. o Mucus: Lubricates food, secreted by goblet cells. Main Organs and Functions: o Mouth and Salivary Glands: - Teeth grind food; tongue mixes with saliva. - Saliva contains water, mucus, and amylase enzyme. o Oesophagus: - Passage for food from mouth to stomach. o Stomach: - Muscular walls mix food with enzymes and mucus. - Enzymes digest proteins; hydrochloric acid kills microbes. - Food storage; sphincter releases food into duodenum. o Small Intestine: - Duodenum receives food from stomach; ileum absorbs nutrients. - Pancreatic juice from pancreas aids digestion. - Absorption of digested nutrients and water into blood. o Large Intestine and Anus: - Colon absorbs water from remaining food. - Rectum stores undigested material (faeces) until elimination.  Accessory Organs: o Pancreas: Stashes enzymes for digestion. o Liver and Gall Bladder: Produce bile for fat digestion and neutralization of stomach acids. Nutrients (macro and micro) o Macronutrients: - Carbohydrates: Serve as the primary source of energy for the body, providing fuel for cellular processes and physical activities. Found abundantly in staple foods like potatoes, rice, bread, and pasta, as well as sweet foods containing sugars. - Fats and Oils: Essential for energy storage, insulation, and protection of vital organs. Sources: cooking oils, nuts, seeds, fatty fish, and dairy products. - Proteins: Comprised of amino acids, proteins are fundamental for building and repairing tissues, synthesizing enzymes and hormones, and supporting immune function. Sources: meat, fish, poultry, eggs, dairy products, legumes, nuts, and seeds. o Micronutrients: - Vitamins: Organic compounds necessary for various metabolic reactions and overall health. ▪ Vitamin C: Acts as an antioxidant, supports immune function, and aids in collagen synthesis for skin, tendons, and blood vessels. Found in citrus fruits, strawberries, bell peppers, and leafy greens. ▪ Vitamin D: Essential for calcium absorption and bone mineralization, crucial for bone health and immune function. Sun exposure triggers vitamin D synthesis in the skin, while dietary sources include fatty fish, fortified dairy products, and egg yolks. - Minerals: Inorganic elements vital for physiological processes and structural integrity. ▪ Calcium: Integral for bone and teeth formation, muscle contraction, and nerve transmission. Found abundantly in dairy products, leafy greens, fortified foods, and calcium-set tofu. ▪ Iron: Critical for oxygen transport as part of hemoglobin in red blood cells, also involved in energy metabolism and enzyme function. Dietary sources include red meat, poultry, fish, beans, lentils, fortified cereals, and leafy greens. o Other Nutrients:  - Water: Fundamental for hydration, nutrient transport, temperature regulation, and waste removal. - Fibre: Essential for digestive health, promoting regular bowel movements, preventing constipation, and lowering the risk of certain diseases like heart disease and diabetes. Found in: whole grains, fruits, vegetables, nuts, seeds, and legumes. - o Balanced Diet: - Balancing macronutrients and micronutrients optimizes metabolic function, promotes satiety, and reduces the risk of nutritional deficiencies and chronic diseases. Diffusion o Definition: - Process whereby particles (atoms, molecules, ions) move from an area of high concentration to an area of low concentration, resulting in their even distribution. - Occurs in gases, solutions, and mixtures of liquids where particles can move freely. o Example: - Imagine a room with a rotten egg emitting hydrogen sulfide gas. Initially, the gas concentration is high near the egg and low elsewhere. - Over time, hydrogen sulfide molecules spread evenly throughout the room due to random movement, a process known as diffusion. o Mechanism: - Particles move randomly, changing direction upon collisions. - Net movement involves particles moving from regions of high concentration to regions of low concentration.  - o Concentration Gradient: - Defined as the difference in concentration between two areas. - Plays a crucial role in driving diffusion: particles move from areas of higher concentration to areas of lower concentration. - Greater the concentration gradient, faster the rate of diffusion o Factors Affecting Diffusion Rate: - Temperature: ▪ Higher temperatures increase particle kinetic energy, leading to faster random movement and diffusion.  - Surface Area: ▪ Greater surface area facilitates more particle movement, accelerating diffusion. - Concentration Gradient: ▪ Larger differences in concentration result in faster diffusion as more particles move towards areas of lower concentration. - Diffusion Distance: ▪ Smaller membrane thickness allows particles to traverse shorter distances, enhancing diffusion rate. o Significance: - Essential process in biological systems, including cellular transport and gas exchange in organisms. - Understanding diffusion aids in the design of experiments, development of technologies, and comprehension of natural phenomena. Food tests o Carbohydrates: - Test: Iodine Test (starch) ▪ Procedure: Add iodine solution to the food sample. ▪ Result: If starch is present, iodine solution changes from brown to blue-black, indicating the presence of starch. ▪ - Test: Benedict's Test ▪ Procedure: Heat the food sample with Benedict's solution.  ▪ Result: If reducing sugars (e.g., glucose) are present, Benedict's solution changes color depending on the concentration of sugar. Low concentrations turn it green, medium turn yellow, and high concentrations turn it orange-red. ▪ o Fats and Oils (Lipids): - Test: Ethanol Emulsion Test ▪ Procedure: Shake the food sample with ethanol, then pour it into water. ▪ Result: If fats are present, they form tiny droplets in the water, giving it a milky appearance. ▪ o Proteins: - Test: Biuret Test ▪ Procedure: Add biuret reagent to the food sample. ▪ Result: If proteins are present, biuret reagent changes from blue to violet (purple). This indicates the presence of polypeptides or proteins.  ▪ o Significance: - Carbohydrates: Crucial for energy, starches (polysaccharides) are detected to ensure sufficient energy sources in the diet. - Fats and Oils: Lipids are essential for cell structure and energy storage; their detection aids in monitoring fat content for balanced nutrition. - Proteins: Vital for growth and repair, protein presence is assessed to ensure adequate intake for tissue development and repair. Energy from food o Carbohydrates: - Function: Broken down into glucose during digestion, providing readily available energy for cellular functions and physical activities. - Sources: potatoes, wheat (bread, pasta), rice, and maize, as well as sweet foods containing sugars. - Metabolism: Glucose is metabolized in cells through glycolysis, yielding ATP for energy production. - Role in Energy Balance: Rapidly metabolized, carbohydrates offer quick bursts of energy o Fats and Oils (Lipids): - Function: Serve as a concentrated source of energy, providing long-term fuel storage for the body. - Sources: cooking oils, meat, eggs, dairy products, and oily fish. - Metabolism: Lipids are broken down into fatty acids and glycerol during digestion, entering the bloodstream and being stored in adipose tissue for later energy use. - Role in Energy Balance: Due to their high energy density, fats and oils provide sustained energy, essential for prolonged activities o Proteins:  - Function: Primarily used for tissue repair and growth, proteins can also be converted into energy when carbohydrate and fat stores are depleted. - Sources: meat, fish, eggs, dairy products, legumes, nuts, and seeds. - Metabolism: Proteins are broken down into amino acids during digestion, which are then used for protein synthesis or converted into glucose or fatty acids for energy. - Role in Energy Balance: While not the body's preferred energy source, proteins contribute to overall energy balance and are crucial for maintaining muscle mass and supporting metabolic functions. o Caloric Intake: - The total energy content of food, measured in calories, determines the amount of energy available o Energy Balance: - Achieving a balance between caloric intake and energy expenditure is essential for maintaining optimal weight and energy levels. o Nutrient-Dense Foods: - Foods rich in carbohydrates, fats, and proteins provide essential energy for bodily functions, supporting overall health and vitality. Photosynthesis and respiration o Energy Production: - Photosynthesis: ▪ Converts solar energy into chemical energy stored in glucose through a series of complex biochemical reactions. ▪ Solar energy absorbed by chlorophyll in chloroplasts excites electrons, initiating the light-dependent reactions. ▪ Light-independent reactions (Calvin cycle) utilize ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide into glucose. - Respiration: ▪ Releases stored energy from glucose for cellular activities such as ATP synthesis. ▪ Occurs in three main stages: Glycolysis, Krebs cycle (citric acid cycle), and Electron Transport Chain (ETC). ▪ Glycolysis takes place in the cytoplasm, producing pyruvate and a small amount of ATP.  ▪ Krebs cycle occurs in the mitochondrial matrix, generating high-energy electrons and additional ATP. ▪ ETC takes place in the inner mitochondrial membrane, using the high-energy electrons to produce a large amount of ATP via oxidative phosphorylation. o Substrate and Product: - Photosynthesis: ▪ Substrates: Carbon dioxide and water. ▪ Products: Glucose and oxygen. - Respiration: ▪ Substrate: Glucose. ▪ Products (Aerobic Respiration): Carbon dioxide, water, and a large amount of ATP. ▪ Products (Anaerobic Respiration): Lactic acid (in animals) or ethanol (in plants), carbon dioxide, and a small amount of ATP. o Location: - Photosynthesis: ▪ Chloroplasts are the primary site, with the highest concentration in mesophyll cells of leaves. - Respiration: ▪ Aerobic respiration primarily occurs in mitochondria, with glycolysis in the cytoplasm. ▪ Anaerobic respiration takes place in the cytoplasm. o Oxygen Requirement: - Photosynthesis: ▪ Oxygen is produced as a byproduct during the light-dependent reactions, originating from the splitting of water molecules. - Respiration: ▪ Aerobic respiration requires oxygen. ▪ Anaerobic respiration occurs in the absence of oxygen o Energy Yield: - Photosynthesis: ▪ Stores energy in glucose molecules and other carbohydrates synthesized during the Calvin cycle. - Respiration: ▪ Aerobic respiration yields a large amount of ATP  ▪ Anaerobic respiration yields much less ATP compared to aerobic respiration (typically 2 ATP molecules per glucose molecule in fermentation). o Purpose: - Photosynthesis: ▪ Produces organic compounds (glucose) that serve as the primary energy source for plants and other organisms. ▪ Generates oxygen as a byproduct, maintaining atmospheric oxygen levels. - Respiration: ▪ Provides ATP for cellular processes essential for growth, metabolism, movement, and other physiological functions. ▪ Facilitates the breakdown of organic molecules to release energy required for various cellular activities. o Product Utilization: - Photosynthesis: Glucose is utilized for energy production through respirationboth aerobic and anaerobic - Respiration: Glucose is metabolized to produce ATP, which powers cellular activities, including biosynthesis, transport, and mechanical work. Cell structures (animal and plant) Animal Cells: o Cell Membrane: - Thin layer of proteins and fats surrounding the cell. - Regulates passage of substances in and out of the cell. o Cytoplasm: - Gel-like substance filling the cell's interior. - Houses organelles and facilitates cellular processes. o Nucleus: - Central organelle containing genetic material (DNA). - Controls cell activities and coordinates cell functions.  o Mitochondria: - Powerhouse of the cell, generates ATP through cellular respiration. - Converts glucose and oxygen into energy (ATP) for cellular activities. o Endoplasmic Reticulum (ER): - Network of membranous tubules and sacs. - Involved in protein synthesis, lipid metabolism, and detoxification. o Golgi Apparatus: - Membrane-bound organelle responsible for packaging and processing proteins. - Modifies, sorts, and packages proteins for transport within or outside the cell. o Lysosomes: - Membrane-bound vesicles containing digestive enzymes. - Breaks down cellular waste, foreign particles, and worn-out organelles. o Centrioles: - Pair of cylindrical structures involved in cell division (mitosis and meiosis). - Form spindle fibers during cell division, aiding chromosome movement.  - Plant Cells: o Cell Membrane: - Thin layer of proteins and fats surrounding the cell. - Regulates passage of substances in and out of the cell. o Cell Wall: - Rigid outer layer composed of cellulose. - Provides structural support, shape, and protection to plant cells.  o Cytoplasm: - Gel-like substance filling the cell's interior. - Facilitates cellular processes and organelle movement. o Nucleus: - Central organelle containing genetic material (DNA). - Controls cell activities and coordinates cell functions. o Chloroplasts: - Organelles containing chlorophyll, responsible for photosynthesis. - Convert light energy into chemical energy (glucose) for the plant. o Mitochondria: - Powerhouse of the cell, generates ATP through cellular respiration. - Produces energy (ATP) from glucose and oxygen for cellular activities. o Endoplasmic Reticulum (ER): - Network of membranous tubules and sacs. - Involved in protein synthesis, lipid metabolism, and calcium storage. o Golgi Apparatus: - Membrane-bound organelle responsible for packaging and processing proteins. - Modifies, sorts, and packages proteins for transport within or outside the cell. o Vacuole: - Large membrane-bound sac filled with cell sap. - Stores water, nutrients, and waste products, maintaining turgor pressure.  o ▪ Energy and Climate Change: Types of energy (kinetic, gravitational) o Kinetic Energy: Energy of motion. Calculated as KE = 1/2 * mass * velocity^2. (anything that moves) o Gravitational Potential Energy: Energy stored in an object due to its position relative to the Earth's surface. Calculated as GPE = mass * gravitational field strength * height. (anything above the ground has it) o Mechanical Energy: Sum of kinetic and potential energy in an object. o Electrical Energy: Energy associated with the flow of electric charge. (wherever there is a current)  o Thermal Energy: Energy associated with the movement of particles in a substance. (anything above temp. of absolute zero (-273ºC)) o Chemical Energy: Energy stored in the bonds of chemical compounds.(anything with stored energy) o Nuclear Energy: Energy stored in the nucleus of an atom. (fusion/ fission) (fision sperate) (fusion fuses (combines) atoms) o Radiant Energy: Energy carried by electromagnetic waves. (anything luminous) o Sound/ Acoustic Energy: Energy produced by vibrations traveling through a medium. (anything noisy) - Types of Energy, including Calculation of Kinetic and Gravitational: o Kinetic Energy (KE): Energy of motion. Calculated as: KE=1/2×mass×velocity^2 o Gravitational Potential Energy (GPE): Energy stored in an object due to its position relative to the Earth's surface. Calculated as: G.P.E=mass×gravitational field strength×height Energy can neither be created nor destroyed Sources of energy (renewable/non-renewable) ▪ Renewable Energy: Resources replenished naturally (e.g., solar, wind, hydro, geothermal, biomass). Benefits: sustainable, low greenhouse gas emissions. ▪ Non-renewable Energy: Finite resources (e.g., coal, oil, natural gas). Drawbacks: high greenhouse gas emissions, contributes to climate change. Energy generation (turbines) o Turbines convert kinetic energy (wind, steam, water) into mechanical energy. They then turn this to electricity through generators Energy transfer (conduction, convection, radiation) ▪ Conduction: Heat transfer through a material without movement of the material itself (e.g., metal pan getting hot). ▪ Convection: Heat transfer through fluid movement (e.g., boiling water). ▪ Radiation: Transfer of energy by electromagnetic waves (e.g., sunlight).  Thermal conductors and insulators ▪ Conductors: Materials that transfer heat effectively (e.g., metals like copper, aluminum). ▪ Insulators: Materials that resist heat transfer (e.g., wood, foam, fiberglass). Climate change connections (CO2, greenhouse effect) CO2 and Greenhouse Effect: Carbon dioxide traps heat in Earth's atmosphere, contributing to global warming. o Major sources of CO2: ▪ Burning fossil fuels ▪ Deforestation ▪ Industrial processes. o Impacts: rising temperatures, melting ice caps, extreme weather events. Thermal energy and temperature (specific heat capacity) ▪ Specific Heat Capacity: Amount of energy needed to raise 1 kg of a substance by 1°C. ▪ Formula: Q=mcΔT ▪ Q= heat energy, m= mass, c= specific heat capacity, ΔT = change in temperature. Homeostasis of temperature regulation in humans o Maintains stable body temperature (around 37°C). o Mechanisms: ▪ Sweating: Evaporative cooling. ▪ Vasodilation: Blood vessels widen to release heat. ▪ Shivering: Muscle contractions generate heat. ▪ Forces and Chemical Bonding: Contact and non-contact forces ▪ Contact Forces: Interaction requiring physical touch (e.g., friction, tension, normal force). ▪ Non-contact Forces: Interaction at a distance (e.g., gravity, magnetic forces, electrostatic forces).  Electrical forces and fields (static electricity) o Static Electricity: Charge buildup due to friction. Opposite charges attract like charges repel. o Electric Fields: Region where electric force acts on a charge. Solenoids and electric motors o Solenoids: Coiled wire that generates a magnetic field when current flows. o Electric Motors: Convert electrical energy into mechanical energy using magnetic fields. Periodic table (electronic structure) o Electronic Structure: Arrangement of electrons in shells. E.g., Sodium (Na): 2,8,12, 8, 12,8,1. o Elements in the same group have similar properties due to identical valence electrons. Simple ions and formulae o Depending of group of ion it will want to either give away (making it positive) or receive (making it negative) a certain amount of electrons. Ionic, covalent, and metallic bonding o Ionic Bonding: Transfer of electrons (e.g., NaClNaClNaCl). o Covalent Bonding: Sharing of electrons (e.g., H2OH_2OH2O). o Metallic Bonding: Delocalized electrons in a "sea" around metal ions (e.g., CuCuCu). Polyatomic ions o Groups of atoms bonded together with an overall charge. o Main polyatomic ions:  o 7. Circulatory System Main Function: o Transportation of substances o Protection against disease Heart Structure: o Valves: Prevent backflow of blood (e.g., tricuspid, bicuspid).  Blood Vessels: Arteries  Usually carry oxygenated blood from the heart to the rest of the body (Pulmonary artery is the exception as it carries deoxygenated blood to lungs) Thick walls (with muscle and elastic fibres) to withstand high pressure. Muscle and elastic fibres within the walls also allow the artery to expand and recoil with each surge of blood. Veins Usually carry deoxygenated blood from the body back to the heart (except from lungs to heart) The lumen is large and reduces friction as the blood moves through. Blood is moving at a low pressure so the walls are thin. Very few muscle and elastic fibres because blood does not surge through veins. Valves are present to prevent the backflow of blood. Capillaries Allow the diffusion of substances (e.g. oxygen, carbon dioxide, dissolved food and urea) between the blood and the body’s cells or vice versa. Walls are 1 cell thick providing a thin, permeable surface for diffusion. Main Blood Components 8. Blood Pressure Definition: Force exerted by blood against vessel walls. Measured: using a sphygmomanometer. It measures two values: systolic value – blood pressure while the heart is squeezing diastolic value – blood pressure while the heart is relaxing Factors Affecting Blood Pressure: o poor diet – eating more saturated fat tends to increase cholesterol levels o stress and smoking – increases blood pressure o salt – eating too much causes high blood pressure o lack of exercise o genetic factors 9. Transport in Plants Xylem: o Transports water and minerals from roots to leaves. o Made of dead cells forming tubes. o Vessels become strengthened by lignin Phloem: o Transports sugars from leaves to the rest of the plant. o Made of living cells. o Moves food substances that the plant has produced by photosynthesis to where they are needed for processes Transpiration and Translocation Transpiration: o When the plant opens its stomata to let in carbon dioxide, water on the surface of the cells of the spongy mesophyll and palisade mesophyll evaporates and diffuses out of the leaf. o Evaporation of water from leaves through stomata. o Crucial for plant water balance and helps cool plant, also supports photosynthesis  Translocation: o Movement of sugars through phloem, from leaves to plant. o both upward and downward directions within the stem o Translocation is crucial for plant growth and development, as it delivers nutrients to developing seeds and fruits o Occurs at night o Needs energy o Translocation can also use xylem cells o Distribution of nutrients and energy throughout plant. Food Security: access to enough affordable and healthy food Challenges to food security: -poverty -lack of recources -distribution -Climate -Lack of water -Lost of production -Food waste/ spoilage GMO: genetically modified organism -DNA has been altered through genetic engineering. Modifying its genes to give new traits -This process allows to make organisms with specific features that wouldn’t naturally occur DNA: Shape: Double Helix 4 diff. nucleotides Chromosome: Giant piece of DNA contains coded info -DNA is the instruction manual for cellular respiration DNA -> Proteins -> Cellular function -Proteins execute cellular tasks Specialized cells in an organism have the same DNA but different proteins Genome: -Entire set of genes in an organism -human genome consists of approx. 20000 genes DNA is made of nucleotides (phosphate, deoxyribose sugar, base) There are four types of bases: A-U(T) C-G G-C T-A Proteins: Proteins are long molecules made from chemical units called amino acids Protein synthesis has two parts: 1) Transcription (DNA to RNA) 2) Translation (RNA to assemble chain of amino acids) Restriction Enzymes: Special enzymes that can cut DNA of the bacteria and the DNA from the human cell Steps: 1-extract human DNA 2-Restriction enzymes cut insulin gene out 3- insert insulin gene 4- insert back into bacteria 5- bacteria grow and multiply Genetic modification vs selective breeding Transgenic= an organism that contains genes from another species due to genetic modification Protein Synthesis 1. Steps: o Transcription: 1. DNA unzips in the nucleus. 2. mRNA copies the DNA sequence. 3. mRNA exits the nucleus. 4. Instead of A pairing with T it pairs with U o Translation: 1. mRNA attaches to ribosome. 2. For every three mRNA bases the ribosome lines up one complementary molecule of tRNA. We call every three bases a codon.  3. tRNA molecules transport specific amino acids to the ribosome which they leave behind shortly after lining up opposite the DNA. 4. For every codon there is one amino acid, these combined amino acids form into a polypeptide 5. Polypeptide is finally folded into the correct shape and becomes a protein Transcribing and Translating Genes Transcription: Convert DNA sequence to mRNA (replace T with U). Translation: Use codon chart to determine the amino acid sequence. Genetic Code and Codons The genetic code consists of codons (triplets of mRNA bases). Each codon corresponds to an amino acid. Example: AUG is the start codon for methionine. These amino acids together then form a protein Atomic number: Z -represents number of protons -always constant for a given element -different elements have different numbers Mass number: A -represents the total nr. of protons + neutrons in an elements -electrons excluded Neutrons= A-Z Law of conservation of mass: -Atoms cant be created or destroyed -After reaction still the same amount of atoms, though may rearrange Chemical Reactions: Number of atoms must be the same on both sides -Reactants= Products Balancing: -Adjust big numbers (coefficients) in front of molecules to balance the equations -Small numbers (Subscripts) only apply to elements they directly follow 3O2 -> 2O3 Balanced If an element has no subscripts assume it has 1 atom Using table to balance: -List number of atoms for each element on left and right sides of equation -Compare atoms to see if match, if not adjust coefficient in front of compound -Never break bonds only coefficient Charges: -when there are charges you also need to balance them -Matter cannot be created or destroyed -Both atoms and charges balanced Ions: -Charged particles formed when atom gains/ loses electrons Loss of electron -> Positive atom (cation) Gain of electrons -> Negative atom (anion) Sodium: 2,8,1 loses electron -> NA+ Oxygen: 2,6 gains 2-> O^2- Valance electrons= electrons on outer shell -Atoms have the same structure as nearest noble gas Acids and Bases (alkaline) Acids are substances with hydrogen ions (H), while bases (alkaline) have many hydroxide (OH) ions. Ph Scale: Acids: -Vinegar (acetic) -Citrus fruits (citric) - carbonated drinks (carbonic) - Batteries (sulphuric) Bases: - baking soda (sodium bicarbonate) - Drain cleaner (sodium hydroxide) - Washing powder - toothpaste Strong vs weak acids: - Strong: fully dissociate into ions - Weak: partially dissociate into ions Concentrated acids: High proportion of acid in solution Dilute acids: Lower proportion of acid Strong bases: sodium hydroxide, potassium hydroxide Alkalis: subset of bases soluble in water (bases that dissolve in water Non- alkaline bases= insoluble bases (coper oxide) An indicator is a substance that changes color depending on the pH of the solution it is in Acids have hydrogen (H+) ions Bases have hydroxide (OH-) ions When an acid reacts with a base, they undergo a neutralization reaction Neutralization Formula: Acid + Base -> water + salt Acid + carbonate -> water + salt + CO2 Acid + metals -> water + hydrogen Strong acids: Hydrochloric acid: HCl Sulfuric acid: H2SO4 Nitric Acid: HNO3 When red cabbage is boiled it can be used as indicator, but doesn’t tell you the exact pH Titration:  Titration is the slow addition of one solution of a known concentration (called a titrant) to a known volume of another solution of unknown concentration until the reaction reaches neutralization, which is often indicated by a color change. A quantitative analysis to determine the concentration of an unknown solution by adding a solution of known concentration in a drop at a time. The actual reaction that takes place during neutralization is between a hydrogen ion from acid and hydroxide ion from base that combine to form water. The solution of known concentration is the titrate The solution whose concentration is to be determined is the analyte. The equivalence point is obtained when the titrate completely neutralizes the analyte