Inc 9 Science Finals
---
BIOLOGY 10 – DETAILED NOTES
---
1. Genetics and Inheritance
Genetics is the branch of biology that studies heredity and variation in living organisms. It explains how characteristics are passed from parents to offspring through genes.
A gene is a specific segment of DNA that carries the instructions for the development of a particular trait. Genes are located on chromosomes within the nucleus of a cell. Each gene exists in alternative forms known as alleles, which occupy the same position on homologous chromosomes.
An allele may be dominant or recessive. A dominant allele is expressed in the phenotype even when only one copy is present. A recessive allele is expressed only when two copies are present and no dominant allele is present.
The genotype of an organism refers to the combination of alleles it possesses for a particular trait. The phenotype is the observable physical or biochemical characteristic that results from the genotype and its interaction with the environment.
An organism is homozygous for a trait if it has two identical alleles and heterozygous if it has two different alleles.
---
Mendelian Inheritance
Gregor Mendel conducted experiments on pea plants and established the basic laws of inheritance. He selected traits with clear contrasting forms and performed controlled crosses.
The Law of Segregation states that each organism carries two alleles for a trait, and these alleles separate during the formation of gametes. As a result, each gamete carries only one allele for each trait.
The Law of Independent Assortment states that alleles of different genes are inherited independently of one another, provided the genes are located on different chromosomes or far apart on the same chromosome. This law explains why the inheritance of one trait usually does not affect the inheritance of another.
A Punnett square is a diagram used to predict the possible genotypes and phenotypes of offspring based on parental genotypes.
---
Non-Simple Dominance
Not all traits follow a simple dominant–recessive pattern of inheritance.
In incomplete dominance, neither allele is completely dominant, and the heterozygous individual shows an intermediate phenotype. For example, when a red-flowered plant is crossed with a white-flowered plant, the offspring may produce pink flowers.
In codominance, both alleles in a heterozygous individual are fully expressed. An example of codominance is the AB blood group, where both A and B antigens are present on red blood cells.
Some traits are controlled by multiple alleles, meaning that more than two alleles exist for a gene in the population, even though an individual can carry only two.
---
Mutations and Variation
A mutation is a permanent change in the DNA sequence of a gene or chromosome. Mutations can occur spontaneously or be caused by environmental factors known as mutagens. Mutations are an important source of genetic variation and may be beneficial, harmful, or neutral.
Inherited traits are characteristics passed from parents to offspring through genes. Acquired traits develop as a result of environmental influences or experiences and are not inherited genetically.
---
2. Lamarck and Darwin
Jean-Baptiste Lamarck proposed an early theory of evolution based on the use and disuse of organs. He believed that characteristics acquired during an organism’s lifetime could be passed on to offspring. This theory has been disproven because acquired traits do not cause changes in DNA.
Charles Darwin proposed the theory of natural selection, which explains evolution as a result of inherited variation and environmental pressure. According to Darwin, organisms produce more offspring than can survive. Individuals within a population vary, and those with traits better suited to the environment are more likely to survive and reproduce. Over many generations, these advantageous traits become more common in the population.
---
3. Molecular Biology
Molecular biology studies biological processes at the molecular level, particularly involving DNA and RNA.
A nucleotide is the basic structural unit of nucleic acids. Each nucleotide consists of a phosphate group, a pentose sugar, and a nitrogenous base.
DNA is a double-stranded molecule arranged in a double helix. It has a sugar-phosphate backbone and complementary base pairing, where adenine pairs with thymine and cytosine pairs with guanine. DNA carries the genetic information of an organism.
DNA replication is the process by which DNA makes an identical copy of itself. During replication, the two strands separate, and each strand serves as a template for the formation of a new complementary strand.
---
RNA
RNA is a single-stranded nucleic acid that plays a central role in protein synthesis. RNA contains ribose sugar and uses uracil instead of thymine.
There are three main types of RNA:
* Messenger RNA (mRNA) carries the genetic code from DNA to the ribosome.
* Transfer RNA (tRNA) brings specific amino acids to the ribosome.
* Ribosomal RNA (rRNA) forms the structural and functional components of ribosomes.
---
Protein Synthesis
Protein synthesis is the process by which cells build proteins using genetic information.
Transcription is the process by which a complementary mRNA molecule is formed from a DNA template. This process occurs in the nucleus and is catalyzed by the enzyme RNA polymerase.
Translation is the process by which the sequence of bases in mRNA is used to assemble amino acids into a polypeptide chain. Translation occurs at ribosomes, where tRNA molecules deliver amino acids in the correct order.
The genetic code is a triplet code in which each group of three nucleotides, called a codon, specifies one amino acid. The genetic code is universal and ensures accurate protein formation.
---
4. Evolution
Evolution is the gradual change in the genetic composition of a population over many generations.
Relative frequency refers to the proportion of a particular allele compared to all alleles of that gene in a population.
Variation refers to differences in traits among individuals of the same species. Variation arises from mutations and genetic recombination.
Fitness is the ability of an organism to survive and reproduce successfully in its environment.
A niche describes the role of an organism within its ecosystem, including how it obtains resources, interacts with other organisms, and survives environmental conditions.
Natural selection occurs when individuals with favorable inherited traits are more likely to survive and reproduce. Over time, this leads to an increase in the frequency of advantageous alleles.
Adaptations are inherited traits that improve an organism’s chances of survival and reproduction.
Speciation is the formation of new species due to reproductive isolation and accumulated genetic differences.
---
Got it. Here’s the same full set of Chemistry 10 notes in plain text, full sentences, no bold or special formatting:
---
CHEMISTRY 10 – DETAILED NOTES
1. Law of Conservation of Mass
The law of conservation of mass states that mass cannot be created or destroyed in a chemical reaction. The total mass of the reactants before a reaction is equal to the total mass of the products after the reaction. This is why chemical equations must always be balanced, with the same number of each type of atom on both sides.
2. Atomic Structure
Atoms are the smallest units of matter that retain the properties of an element. Each atom consists of three subatomic particles: protons, which are positively charged and found in the nucleus; neutrons, which are neutral and also in the nucleus; and electrons, which are negatively charged and move around the nucleus in energy levels or shells.
The atomic number is the number of protons in an atom, while the mass number is the sum of protons and neutrons. Atoms of the same element with different numbers of neutrons are called isotopes. Electrons are arranged in energy levels, and the number of valence electrons determines how an element reacts chemically.
3. Periods and Groups / Periodic Table Trends
The periodic table arranges elements by increasing atomic number. Periods are horizontal rows, and all elements in a period have the same number of electron shells. Groups are vertical columns, and elements in the same group have the same number of valence electrons and similar chemical properties.
Trends across a period include decreasing atomic radius, increasing ionization energy, decreasing reactivity of metals, and increasing reactivity of non-metals. Trends down a group include increasing atomic radius, increasing reactivity of metals, and decreasing reactivity of non-metals. These trends occur due to changes in nuclear charge and electron shielding.
4. Chemical Bonding
Chemical bonding is the force that holds atoms together in compounds. Ionic bonds form when electrons are transferred from a metal to a non-metal. The metal becomes a positively charged cation, and the non-metal becomes a negatively charged anion. The resulting opposite charges attract each other. Covalent bonds form when two non-metal atoms share electrons, which allows both atoms to complete their outer shells. The octet rule states that atoms gain, lose, or share electrons to achieve eight electrons in their outer shell.
5. Chemical Reactions
A chemical reaction is a process in which reactants are converted into products. Reactants are the starting substances, and products are the substances formed.
Types of chemical reactions include combination reactions, in which two or more substances combine to form one product; decomposition reactions, in which a compound breaks down into two or more simpler substances; displacement reactions, in which a more reactive element replaces a less reactive one in a compound; and double displacement reactions, in which ions are exchanged between two compounds.
6. Predicting and Balancing Chemical Equations
Chemical equations must obey the law of conservation of mass, so the number of atoms of each element is equal on both sides. Predicting products involves identifying the type of reaction and the reactivity of the elements involved. Balancing equations ensures that mass is conserved.
7. Reaction Rates
The rate of a chemical reaction is how quickly reactants are converted into products. Factors affecting reaction rate include temperature, with higher temperatures increasing the rate; concentration, with higher concentrations increasing the rate; surface area, with greater surface area of solids increasing the rate; and catalysts, which speed up reactions without being consumed. Increasing collision frequency and energy leads to faster reactions.
8. Acids, Bases, and Salts
Acids produce hydrogen ions (H+) in aqueous solution. They taste sour and turn blue litmus red. Bases produce hydroxide ions (OH-) in aqueous solution. They taste bitter and turn red litmus blue. Salts are formed when acids react with bases in a neutralization reaction, producing water and a salt. The pH scale measures the acidity or basicity of a solution from 0 (very acidic) to 14 (very basic).
9. Naming Ionic and Multivalent Compounds
Ionic compounds are named by stating the cation first followed by the anion. Multivalent metals can have more than one charge. The charge is indicated using Roman numerals. For example, Fe2+ is iron(II) and Fe3+ is iron(III). Polyatomic ions are groups of atoms with an overall charge. Common examples include SO4 2- (sulfate), NO3- (nitrate), CO3 2- (carbonate), OH- (hydroxide), and NH4+ (ammonium). The name of the polyatomic ion remains unchanged in the compound.
10. Organic Chemistry: Types of Compounds
Organic chemistry studies carbon-containing compounds. Common types include hydrocarbons, which contain only carbon and hydrogen, such as methane and ethane; alcohols, which contain a hydroxyl group (–OH), such as ethanol; and organic acids, which contain a carboxyl group (–COOH), such as ethanoic acid.
11. Alkanes: Naming and Drawing
Alkanes are saturated hydrocarbons with only single bonds between carbon atoms. Alkanes are relatively unreactive and burn easily in oxygen to produce carbon dioxide, water, and energy.
Alkanes are named based on the number of carbon atoms in the longest continuous chain. One carbon is methane, two carbons is ethane, three carbons is propane, four carbons is butane, and five carbons is pentane.
To draw an alkane, first draw the carbon atoms in a straight chain, connect the carbon atoms with single bonds, and then add hydrogen atoms so that each carbon has four bonds.
Alkanes are mainly used as fuels, such as methane in natural gas and propane in gas cylinders.
Acids are named by using their ending. Anything ending in -ide, add the prefix hydro- and change the suffix to -ic to form the name of the corresponding acid. For example, chlorine becomes hydrochloric acid, while sulfur becomes hydrosulfuric acid when using this naming convention. Anything ending in -ate, remove any prefix like hydro-, then change the suffix to -ic acid. For instance, sulfate transforms to sulfuric acid, while phosphate becomes phosphoric acid. Conversely, for compounds ending in -ite, the suffix is changed to -ous acid; this means that nitrate would become nitrous acid, while sulfite would convert to sulfurous acid.
In summary, the transformation follows these key rules:
For -ide compounds, use 'hydro-' and change to -ic acid.
For -ate compounds, drop prefixes and change to -ic acid.
For -ite compounds, simply change the suffix to -ous acid.
---
---
ASTRONOMY 10 – COMPLETE NOTES
1. The Universe
The universe is all of space, time, matter, and energy. The observable universe is the portion we can detect with telescopes, while the total universe may be much larger. According to the Big Bang theory, the universe began about 13.8 billion years ago from a hot, dense state and has been expanding ever since. Evidence includes the cosmic microwave background radiation, a faint glow left over from the early universe. Observations show that galaxies are moving away from each other, which supports the expansion of the universe.
The Earth is about 4.6 billion years old.
2. The Solar System
The solar system consists of the Sun and all objects gravitationally bound to it, including planets, dwarf planets, moons, asteroids, and comets. The planets in order from the Sun are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. The inner planets (Mercury, Venus, Earth, Mars) are terrestrial planets with rocky surfaces, while the outer planets (Jupiter, Saturn, Uranus, Neptune) are gas giants made mostly of gas and ice.
The solar system also contains the Kuiper Belt, a region beyond Neptune containing icy bodies, and the Oort Cloud, a distant spherical shell of icy objects that is the source of long-period comets.
3. Small Bodies of the Solar System
Asteroids are rocky bodies that orbit the Sun, mostly in the asteroid belt between Mars and Jupiter. Comets are icy bodies that develop bright tails when they approach the Sun due to sublimation, the process where solids turn directly into gas. Meteors are streaks of light produced when small space debris enters Earth’s atmosphere and burns up. If debris survives and reaches the ground, it is called a meteorite.
4. The Sun
The Sun produces energy through nuclear fusion, which converts hydrogen into helium in its core. This energy is released as light and heat, which drives climate, weather, and energy cycles on Earth.
5. Stars
Stars form from clouds of gas and dust called nebulae. Gravity causes the gas and dust to collapse, forming a protostar. When the core becomes hot enough, nuclear fusion begins, and a star enters the main sequence, where it spends most of its life.
The life cycle of a star depends on its mass. Low-mass stars become red giants and then white dwarfs. High-mass stars become supergiants and may explode as supernovae, leaving behind neutron stars or black holes. The Hertzsprung-Russell diagram shows the relationship between a star’s luminosity and surface temperature.
6. Galaxies
A galaxy is a large system of stars, gas, and dust bound together by gravity. Galaxies are classified as spiral, elliptical, or irregular. Our galaxy, the Milky Way, is a spiral galaxy containing the Sun, the solar system, and billions of other stars. Galaxies form clusters, which can form superclusters.
7. Observation and Tools
Astronomers use telescopes to observe distant objects. Optical telescopes collect visible light, radio telescopes detect radio waves, and space-based telescopes avoid atmospheric interference. Spectroscopy allows scientists to analyze light from stars and galaxies to determine their composition, temperature, and motion.
Distances in space are measured using methods such as:
* Parallax, which measures the apparent shift of a nearby star against distant background stars as Earth orbits the Sun. The angle of shift can be used to calculate the star’s distance.
* Triangulation, which uses geometry to determine distances by measuring angles and a baseline, such as the distance between two points on Earth.
* Light years, the distance light travels in one year, and astronomical units, the average distance between Earth and the Sun.
8. Earth-Moon-Sun System
The Moon orbits the Earth, and the Earth orbits the Sun. The phases of the Moon are caused by the changing positions of the Sun, Earth, and Moon. New Moon occurs when the Moon is between Earth and the Sun, and Full Moon occurs when Earth is between the Moon and the Sun. The Moon waxes from New Moon to Full Moon and wanes from Full Moon to New Moon.
Formation of the Moon: The giant impact hypothesis suggests a Mars-sized object collided with the early Earth, and the debris from the collision coalesced to form the Moon.
Eclipses occur when the Sun, Moon, and Earth align. A solar eclipse happens when the Moon passes between Earth and the Sun, casting a shadow on Earth. A lunar eclipse happens when Earth passes between the Sun and the Moon, casting a shadow on the Moon. Shadows have two parts: the umbra, where the Sun is completely blocked, and the penumbra, where the Sun is partially blocked. Solar eclipses can be total, partial, or annular.
Tides are caused by the gravitational pull of the Moon and Sun on Earth’s oceans. High tides occur on the side of Earth facing the Moon and on the opposite side. Seasons are caused by Earth’s axial tilt of about 23.5 degrees, which changes the angle of sunlight and the length of days.
9. Basic Definitions and Units
A light year is the distance light travels in one year, approximately 9.46 trillion kilometers. An astronomical unit (AU) is the average distance between Earth and the Sun, about 150 million kilometers. Light from distant galaxies is redshifted if the galaxies are moving away and blueshifted if they are moving closer. These shifts help measure the motion and expansion of the universe.
---
---
RADIATION 10 – COMPLETE NOTES
1. Types of Radiation
Radiation refers to the emission of energy in the form of particles or electromagnetic waves. There are three main types of radiation relevant to this course:
* Alpha (α) radiation consists of two protons and two neutrons, which is the same as a helium nucleus. Alpha particles are positively charged and have a relatively large mass. Because of their size, they have low penetration ability and can be stopped by a sheet of paper or even the outer layer of human skin. Alpha radiation is commonly used in smoke detectors and some medical treatments.
* Beta (β) radiation consists of high-speed electrons (β−) or positrons (β+) emitted from the nucleus during radioactive decay. Beta particles are lighter than alpha particles and carry a single negative or positive charge. They have medium penetration ability and can pass through paper but are usually stopped by a few millimeters of aluminum. Beta radiation is used in medical treatments, such as targeting cancer cells, and in monitoring thickness in industrial processes.
* Gamma (γ) radiation is a form of electromagnetic radiation, similar to X-rays but with higher energy. Gamma rays have no mass and no charge and have high penetration ability, requiring dense materials such as lead or thick concrete to block them. Gamma radiation is widely used in medical imaging, cancer radiotherapy, and sterilization of medical equipment.
---
2. Radioactive Decay
Radioactive decay is the process by which unstable atomic nuclei lose energy by emitting radiation. During decay, a nucleus can emit alpha, beta, or gamma radiation to reach a more stable state.
* Half-life is the time it takes for half of the radioactive nuclei in a sample to decay. Different isotopes have different half-lives, ranging from fractions of a second to billions of years.
* Decay equations represent how a radioactive nucleus changes during decay. For example:
* Alpha decay: Uranium-238 → Thorium-234 + α
* Beta decay: Carbon-14 → Nitrogen-14 + β− + antineutrino
* Gamma decay: Often follows alpha or beta decay to release excess energy as a gamma photon.
The type of decay depends on the nature of the unstable nucleus. Alpha decay reduces the mass number by 4 and atomic number by 2. Beta decay changes a neutron to a proton (or vice versa), changing the atomic number but not the mass number. Gamma decay only releases energy and does not change the atomic or mass number.
---
3. Calculating Parent Elements from Decay Products
When a radioactive element decays, you can calculate the original parent element from the daughter element using the type of decay:
* Alpha decay (α): The parent loses 2 protons and 4 total nucleons.
Reverse calculation: *add 2 to atomic number, add 4 to mass number**.
* Beta-minus decay (β−): A neutron turns into a proton, increasing atomic number by 1.
Reverse calculation: *subtract 1 from atomic number, mass number stays the same**.
* Beta-plus decay (β+) / positron emission: A proton turns into a neutron, decreasing atomic number by 1.
Reverse calculation: *add 1 to atomic number, mass number stays the same**.
Examples:
* Alpha decay: Thorium-234 (Z=90) is produced. Parent element = Uranium-238 (Z=92).
* Beta-minus decay: Carbon-14 (Z=6) is produced. Parent element = Boron-14 (Z=5).
* Beta-plus decay: Oxygen-15 (Z=8) is produced. Parent element = Fluorine-15 (Z=9).
---
4. Applications of Radiation
Radiation has many practical applications:
* Medical uses:
* Radiotherapy uses targeted radiation to kill cancer cells.
* Diagnostic imaging uses gamma rays or X-rays to create images of bones and internal organs.
* Archaeological dating:
* Carbon-14 dating is used to determine the age of organic materials, such as fossils, by measuring the remaining amount of Carbon-14 isotope.
* Nuclear power generation:
Nuclear reactors use the energy released from *fission** to heat water, producing steam that drives turbines to generate electricity.
---
5. Nuclear Reactions
* Fission is the splitting of a heavy atomic nucleus into two smaller nuclei, along with the release of energy and additional neutrons. The released neutrons can trigger a chain reaction, which is used in nuclear power plants and nuclear weapons.
* Fusion is the combining of two light atomic nuclei to form a heavier nucleus, releasing a large amount of energy. Fusion is the process that powers the Sun and other stars, where hydrogen nuclei fuse to form helium. Fusion releases more energy per reaction than fission and produces less radioactive waste.
---