INPS School Shakhbout Biology Mid-Term Exam Study Materials 2024-2025 PDF

INPS School Shakhbout – Middle & High Section Science Department (2024-2025) Mid Exam Study Materials Semester 1 Subject : Biology Grade 9 Lessons Standards...

INPS School Shakhbout – Middle & High Section Science Department (2024-2025) Mid Exam Study Materials Semester 1 Subject : Biology Grade 9 Lessons Standards Objectives Lesson 1: Elements and 1. Differentiate between matter, mass, elements, and compounds SCI-HS-PS1-1 compounds. 2. Describe the relative size, location, and electrical charge of protons, neutrons, and electrons in an atom. 3. Describe the atomic number, mass number, and atomic mass and their significance. Lesson 2: Isotopes and 1. Define isotopes radiation SCI-HS-PS1-2 2. Explain the application of radioactive isotopes in biological research and medicine. SCI-HS-LS1-4 3. Define radiation, describe its potential dangers, and explain how it can be beneficially used in medical treatments. Lesson 3: Properties of SCI-HS-PS1-1 1. Distinguish between ionic, covalent, and hydrogen bonds water and explain the formation and characteristics of each type of bond 2. Describe four essential properties of water that support life: cohesion, adhesion, high specific heat, and solvent properties and provide examples of how these properties affect living organisms. Lesson 4: Biological SCI-HS-PS1-6 1. Describe the unique bonding properties of carbon. Macromolecules 2. Compare and contrast dehydration reactions, with hydrolysis reactions. 3. Compare the structures and functions of monosaccharides, disaccharides, and polysaccharides in living organisms. Lesson 1 : Elements and compounds Organisms are composed of matter Matter is anything that takes up space and has mass. Matter is made up of elements An element is a substance that cannot be broken down to other substances by chemical reactions A compound is a substance consisting of two or more elements in a fixed ratio A compound has characteristics (emergent properties) different from those of its elements Trace elements Trace elements are tiny amounts of minerals found in your body, like iron, zinc, and iodine. These elements help with important functions like making red blood cells, supporting your immune system, and regulating hormones. Without enough trace elements, your body can't function properly, leading to health problems. Each element consists of unique atoms An atom is the smallest unit of matter that still retains the properties of an element Subatomic Particles Atoms are composed of subatomic particles Relevant subatomic particles include: – Neutrons (no electrical charge) – Protons (positive charge) – Electrons (negative charge) Neutrons and protons form the atomic nucleus Electrons form a “cloud” of negative charge around the nucleus Neutron mass and proton mass are almost identical. Electrons are so small they are ignored when calculating the total mass of an atom Atomic Number and Atomic Mass Atoms of the various elements differ in their number of subatomic particles An element’s atomic number is the number of protons in its nucleus An element’s mass number is the sum of protons plus neutrons in the nucleus Atomic mass, the atom’s total mass, can be approximated by the mass number Lesson 2 : Isotopes All atoms of an element have the same number of protons but may differ in the number of neutrons Isotopes are two atoms of an element that differ in the number of neutrons Ways of writing isotopes Radioactive Isotopes Some isotopes are stable, meaning they do not change over time. However, others are unstable, or radioactive, and can decay over time, releasing energy in the form in the form of radiation. Radioactive isotopes are often used as diagnostic tools in medicine. Benefits: Radiation can damage or destroy cells. This is beneficial when targeting cancer cells, as it can stop them from spreading. Risks: If radiation also affects healthy cells, it can be harmful, leading to side effects. High exposure to radiation can result in radiation sickness, cause DNA damage, and increase the long-term risk of developing cancer. PET scanners can monitor the growth and metabolism of cancers in the body Ionic, Covalent, and Hydrogen Bonds A chemical bond may be defined as the force of attraction between any two atoms, in a molecule, to form chemical compounds which stabilize the atoms. Covalent Bond: Formed by the sharing of electrons between two non-metals. Polar covalent bonding is a type of chemical bond where a pair of electrons is unequally shared between two atoms. Nonpolar covalent bonds are a type of chemical bond where two atoms share a pair of electrons with each other equally. Ionic Bond: Formed by the transfer of electrons from a metal to a non-metal.  Hydrogen Bond is a relatively weak interaction that occurs when a hydrogen atom, is bonded to a highly electronegative atom such as nitrogen (N), oxygen (O), or fluorine (F). Lesson 3: Properties of Water In the water molecule, the electrons of the polar covalent bonds spend more time near the oxygen than the hydrogen The water molecule is thus polar; the overall charge is unevenly distributed. Therefore the shape of water is V-shaped ( Bent Shape) - + Polarity allows water molecules to form hydrogen bonds with each other. polar ; electrons are not distributed evenly non polar ; the electrons are distributed evenly Five of water’s properties that facilitate an environment for life are 1.High boiling point 2.High heat capacity 3. Universal Solvent 4 High Surface tension 5. Cohesive and adhesive properties. 1.Water: The Solvent of Life A solution is a liquid that is a completely homogeneous mixture of substances The solvent is the dissolving agent of a solution The solute is the substance that is dissolved An aqueous solution is one in which water is the solvent Water is a versatile solvent. This means that water dissolve other polar molecules as well as charged molecules. This is due to the water polarity because of the H- bonds. Water is called as universal solvent because of the ability of water to dissolve more substances than any other liquids  Water cant dissolve non -Polar substances. For example oil doesn’t dissolve in water because oil is non polar ( Un charged molecules ) and water is polar. Dissolving happens when the attractions between the water molecules and the sodium and chloride ions overcome the attractions of the ions to each other. This causes the ions to separate from one another and become thoroughly mixed into the water. 2.Water boiling point Water has high boiling point (100 °C )compared with other liquids such as oil or Ethanol ( Alcohol). This is because water requires more energy to break its hydrogen bonds before it can then begin to boil. waters boiling point is 100c and it requires more energy to break its hydrogen bonds before it begins to boil 3.Water surface tension surface tension is a measure of how difficult it is to stretch or break the surface of a liquid. Water has high surface tension because of the hydrogen bonds pull the molecules together into the smallest possible area. This is the reason why some insects can walk and stand on the surface of water water has high surface tension because of the hydrogen bonds pull eachother into the smallest possible area 4. Water heat capacity Heat Capacity is : is the amount of heat required to raise the temperature of an object by 1 0C Specific heat of a substance is the amount of energy required to raise the temperature of 1 gram of the substance by 1oC. Both of them are defined as the amount of energy required to raise the temperature but, in specific heat, the capacity is calculated per unit mass of a substance. Water has a higher specific heat capacity because of the strength of the hydrogen bonds. It requires a significant of energy to separate these bonds. This explains why sand heats up more than water, even though both receive the same amount of sunlight.  5. Water cohesive and adhesive properties Cohesion : is an attraction between similar molecules ( water with water ) Adhesion : is an attraction between different substances, for example, between water and plant cell walls Hydrogen bonds present between water molecules is responsible for water's cohesive nature. The importance of the cohesive and adhesive properties in facilitate an environment for life : For plants, adhesion allows for the water to stick to the organic tissues of plants. Cohesion keeps molecules of the same substance together. For plants, cohesion keeps the water molecules together. Lesson 4: Biological Macromolecules Almost all biological molecules contain the element carbon. For this reason, all life is considered carbon- based. Organic compounds are compounds that contain carbon atom. a carbon atom can form four covalent bonds with other atoms. Carbon atoms can bond with each other, forming a variety of organic compounds. These organic compounds can take the form of straight chains, branched chains, and rings.  Carbon is a component of almost all biological molecules. Macromolecules are large molecules formed by joining smaller organic molecules together. Macromolecules are also called polymers. Polymers are molecules made from repeating units of identical or nearly identical compounds called monomers. Monomers are atoms or small molecules that bond together to form more complex structures such as polymers. Macromolecules are organized into four major categories: o Carbohydrates o Lipids o Proteins o Nucleic acids Macromolecules Monomer Basic Chemical Example Function formula Carbohydrates Monosaccharides CHO Sugar , starch , stores energy (Sugar) cellulose provides structural support Nucleic acids Nucleotides CHONP DNA , RNA stores and communicates genetic information Proteins Amino acids CHON Protein transports substances hormones , speeds reactions enzyme provides structural support provides hormones Lipids Fatty acids and CHO Oil , butter stores energy glycerol provides steroids waterproofs coatings The Synthesis and Breakdown of Polymers (Dehydration synthesis and hydrolysis reaction ) Dehydration synthesis is a chemical reaction that forms polymers from monomers by removing water. Hydrolysis is the reverse of dehydration synthesis. In hydrolysis, water is added to a polymer splitting it up into monomers.  Carbohydrates serve as fuel and building material Carbohydrates include sugars and polymers of sugars The simplest carbohydrates are monosaccharides, or simple sugars Carbohydrate macromolecules are polysaccharides, polymers composed of many sugar building blocks Types of Monomer Brief Example Where to Find Carbohydrates or Description Polymer Monomer Short chains of Glucose Vegetables ,fruits honey and Monosaccharide carbohydrates Fructose dairy products simple sugar galactose Polymer Two Sucrose Sucrose : Table sugar and Disaccharide monosaccharides Maltose syrup linked together. Lactose Maltose : grains and starchy vegetables complex sugar Lactose : the milk of all mammals Polysaccharide Polymer Long chains of Starch -Starch is and found in plants. carbohydrates Glycogen -Glycogen is found in animals. Cellulose -Cellulose found in the cell walls of plants and their organs such as fruits, leaves, and vegetables.