science study notes y10

genetics

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Key People

• Gregor Mendel: inheritance of traits in pea plants guy

• Charles Darwin: theory of evolution by natural selection —> genetic variation.

Key Processes

Facts to Memorise

• DNA structure: Double helix composed of sugar, phosphate, and four nitrogenous bases (A, T, C, G).

• Number of chromosomes in humans: 46 (23 pairs).

• Stages of mitosis: Prophase, Metaphase, Anaphase, Telophase.

• Stages of meiosis: Meiosis I and Meiosis II.

• Mendel's laws: Law of Segregation and Law of Independent Assortment.

• DNA replication involves enzymes such as helicase, DNA polymerase, and ligase.

• The process of fertilization occurs in the oviduct fallopian tube

• The placenta serves as the interface for nutrient and waste exchange between mother and fetus.

Comparing mitosis and meiosos

Punnett squares

To solve problems involving Punnett squares:

1. Identify the genotypes of the parents.

2. Determine the possible gametes each parent can produce.

3. Set up the Punnett square with one parent's gametes on the top and the other parent's on the side.

4. Fill in the squares by combining the alleles from each parent.

5. Calculate the ratios of genotypes and phenotypes from the completed Punnett square.

   Remember to use capital letters for dominant traits and lowercase for recessive traits.

   Double-check your allele combinations to avoid mistakes.

physics

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Key Laws/Theories

Key Equations

Key Units

• Distance: Metres (m)

• Speed: Metres per second (m/s)

• Acceleration: Metres per second squared (m/s²)

• Force: Newtons (N)

• Mass: Kilograms (kg)

Key Graphs

• Distance vs. Time Graph: Shows how distance changes over time; the slope indicates speed.

• Velocity vs. Time Graph: Shows how velocity changes over time; the slope indicates acceleration.

Facts to Memorise

• SI Units: Distance (m), Mass (kg), Time (s), Speed (m/s)

• Acceleration due to gravity (g) = 9.81 m/s²

• Newton's Laws of Motion:

  • First Law: An object at rest stays at rest, and an object in motion stays in motion unless acted upon by a net force.

  • Second Law: F = ma (Force = mass x acceleration)

  • Third Law: For every action, there is an equal and opposite reaction.

Reference Information

• Average Speed Formula: Average Speed = Total Distance / Total Time

• Acceleration Formula: Acceleration = (Final Velocity - Initial Velocity) / Time

• Distance vs. Time Graph: Slope represents speed; steeper slope indicates higher speed.

evolution 

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Key People

• Charles Darwin: first guy who thought of evolution through natural selection

• Alfred Wallace: he thought of the same thing as charles but later and separatly

Fundamental Theories

Key Evidence for Evolution

Key Concepts in Natural Selection

Facts to Memorise

• Theory of Evolution by Natural Selection

• Key figures: Charles Darwin and Alfred Wallace

• Key terms: evolution, natural selection, mutation, speciation, extinction

• Fossil record as evidence of past life

• Types of evolution: convergent, divergent, adaptive radiation, co-evolution

• Punctuated equilibrium vs. gradualism

  • Punctuated Equilibrium views evolution as marked by rapid shifts interspersed with stasis, while Gradualism emphasizes continuous, incremental change over time.

Reference Information

• The geological timescale and its eras

• The process of fossilization

• The principles of superposition and radiometric dating

• Key examples of natural selection: peppered moths, antibiotic resistance in bacteria

Problem-Solving Steps

To analyze a case study of natural selection:

1. Identify the population and its variations.

2. Determine the environmental pressures affecting the population.

3. Explain how certain traits provide a selective advantage.

4. Describe the process of reproduction and how traits are passed on.

5. Discuss the long-term changes in the population over generations.

Cause and Effect

chemistry reactions 

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Key Reactions

Fundamental Theories

• Law of Conservation of Mass: States that mass is neither created nor destroyed in a chemical reaction.

• Atomic Theory: Proposes that all matter is composed of atoms, which are indivisible and indestructible particles.

Facts to Memorise

pH scale: Acidic (0-6), Neutral (7), Basic (8-14)

the facts that aren’t so important

• Common polyatomic ions:

  • Nitrate (NO3-)

  • Hydroxide (OH-)

  • Sulfate (SO4²-)

  • Carbonate (CO3²-)

  • Phosphate (PO4³-)

  • Ammonium (NH4+)

• Common acids and their formulas:

  • Hydrochloric acid (HCl)

  • Sulfuric acid (H2SO4)

  • Nitric acid (HNO3)

• Common bases: Sodium hydroxide (NaOH), Calcium hydroxide (Ca(OH)2)

• The reactivity series of metals (from most to least reactive): Potassium, Sodium, Calcium, Magnesium, Aluminum, Zinc, Iron, Tin, Lead, Copper, Silver, Gold.

• Common indicators: Litmus paper, Phenolphthalein, Universal indicator.

• Common reactions: Combustion, Decomposition, Displacement, Neutralization, Precipitation.

chemistry breaking and making bonds

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Fundamental Theories

• Kinetic Theory of Matter: A theory that explains the behavior of matter in terms of particles in motion, which helps to understand how temperature and concentration affect reaction rates.

• Collision Theory: A theory that states that for a reaction to occur, reactant particles must collide with sufficient energy and proper orientation.

Key Processes

Facts to Memorize

• Activation energy is the minimum energy required for a reaction to occur.

• Exothermic reactions release energy (∆H = -ve) while endothermic reactions absorb energy (∆H = +ve).

• Common examples of exothermic reactions: combustion of fuels, respiration, and heat packs.

• Common examples of endothermic reactions: photosynthesis, ice packs, and decomposition of metal carbonates.