⭐ Second Year Science – Full Revision Notes (Based on Your Document)

Breathing

Physical movement of air in and out of the lungs.

Respiration

Chemical reaction in cells releasing energy from glucose and oxygen.

Inhaled air

More oxygen, less carbon dioxide, little water vapour.

Exhaled air

Less oxygen, more carbon dioxide, more water vapour.

Thorax Structure

Includes ribs, intercostal muscles, diaphragm, lungs, trachea, bronchi, bronchioles, alveoli.

Ventilation Mechanism

Breathing in involves diaphragm contraction and rib movement, increasing chest volume.

Gas Exchange

Occurs in alveoli where oxygen diffuses into blood and carbon dioxide diffuses out.

Alveoli Adaptations

Large surface area, thin walls, moist lining, rich blood supply.

Smoking Effects

Tar damages alveoli leading to emphysema; carbon monoxide reduces oxygen transport; nicotine increases heart rate and addiction.

Bronchitis

Inflammation of bronchi.

Emphysema

Alveoli breakdown leading to reduced gas exchange.

Elements

Pure substances made of one type of atom.

Atoms

Smallest particles of elements, containing protons, neutrons, and electrons.

Periodic Table

Organizes elements by atomic number and properties.

Metals vs Non-metals

Metals conduct electricity, are malleable and shiny; non-metals are poor conductors, brittle, and dull.

Electrical Safety

Avoid water, don’t overload sockets, use fuses and circuit breakers.

Conductors vs Insulators

Conductors are metals; insulators include plastic and rubber.

Series Circuit

One loop, current is the same everywhere.

Parallel Circuit

Multiple loops, current splits.

Digestion

Breaking food into small soluble molecules.

Enzymes

Amylase breaks down starch; protease breaks down protein; lipase breaks down fats.

Peristalsis

Muscular contractions pushing food along the digestive tract.

Chemical Change

New substance formed during a reaction.

Compounds

Formed when elements chemically bond.

Mixtures

Not chemically bonded; easy to separate.

Solar System Components

Includes Sun, planets, dwarf planets, moons, asteroids, and comets.

Milky Way

Our galaxy.

Universe

All space, matter, and energy.

Day & Night

Caused by Earth’s rotation.

Seasons

Caused by Earth’s tilt and orbit.

Experimental Errors

Can cause differences between groups.

Digestive System Organs

Includes mouth, esophagus, stomach, small intestine, large intestine, liver, and pancreas.

Function of Small Intestine

Primary site for nutrient absorption in the digestive system.

Role of Liver in Digestion

Produces bile, which helps in the emulsification of fats.

Role of Pancreas in Digestion

Produces digestive enzymes and bicarbonate to neutralize stomach acid.

Food Types

Carbohydrates, proteins, and fats are the three main macronutrients.

Electric Current

Flow of electric charge, measured in amperes.

Voltage

Electric potential difference between two points, measured in volts.

Resistance

Opposition to the flow of electric current, measured in ohms.

Ohm's Law

The relationship between voltage, current, and resistance, described as $V = I \times R$.

Power in Electrical Circuits

Calculated as $P = V \times I$, where P is power in watts.

AC vs DC

Alternating current (AC) changes direction; direct current (DC) flows in one direction.

Short Circuit

An unintended pathway for current that bypasses the intended load, potentially causing damage.

Circuit Components

Includes resistors, capacitors, inductors, and power sources.

Functions of the Respiratory System

To supply the body with oxygen and remove carbon dioxide.

Diaphragm

Muscle that contracts and relaxes to facilitate breathing.

Intercostal Muscles

Muscles between the ribs that assist in breathing movements.

Emphysema Symptoms

Shortness of breath, chronic cough, and reduced exercise tolerance.

Smoke Components

Contains tar, nicotine, carbon monoxide, and various chemicals harmful to health.

Secondhand Smoke

Inhaled smoke from someone else's cigarette. It poses health risks to non-smokers.

Chronic Obstructive Pulmonary Disease (COPD)

A group of lung diseases that block airflow and make it difficult to breathe, including chronic bronchitis and emphysema.

Nicotine Addiction

Physical dependence that develops with regular tobacco use, making it hard to quit.

Health Risks of Smoking

Increases risk of lung cancer, heart disease, stroke, respiratory infections, and many other health conditions.

Smoking Cessation Methods

Include nicotine replacement therapy, medications, counseling, and support groups to help quit smoking.

Role of Diaphragm in Respiration\n\n

The diaphragm contracts and relaxes, playing a crucial role in creating the pressure changes necessary for inhalation and exhalation.

Role of Intercostal Muscles in Respiration\n\n

Intercostal muscles contract to lift the rib cage during inhalation, aiding in lung expansion.

Function of Alveoli\n\n

Alveoli provide a large surface area for gas exchange, allowing oxygen to diffuse into the blood and carbon dioxide to diffuse out.

Function of Lungs in Respiration\n\n

The lungs facilitate the exchange of oxygen and carbon dioxide between the air and the blood.

Formation of Compounds

Compounds are formed when two or more elements chemically bond together, resulting in a new substance with properties different from those of the individual elements.

Physical Changes

Changes that do not alter the chemical composition of a substance, such as changes in state, shape, or size.

Chemical Changes

Changes that result in the formation of new chemical substances, indicated by color change, gas production, or temperature change.

Atoms vs. Elements

Atoms are the basic units of elements, while elements are pure substances made up of only one type of atom.

Biuret Test

Used to test for proteins; if proteins are present, the solution turns from blue to purple.

Emulsion Test

Used to test for lipids; a positive result is indicated by a white emulsion forming when the sample is mixed with ethanol and then water.

Benedict's Test

Used for testing reducing sugars; the solution will turn green, yellow, or brick red depending on the amount of sugar present when heated.

Iodine Test

Used to test for starch; a positive result is indicated by a color change to blue-black when iodine solution is added.

Battery Symbol

Represents a source of electric energy in a circuit.

Resistor Symbol

Indicates a resistor, which opposes the flow of current.

Capacitor Symbol

Denotes a capacitor, which stores electrical energy.

Inductor Symbol

Represents an inductor, which stores energy in a magnetic field.

Switch Symbol

Indicates a switch that can open or close a circuit.

Ground Symbol

Represents a common return path for electric current.

Connection/Join Symbol

Indicates a point where two or more components are connected.

Open Circuit Symbol

Shows a break in the circuit, indicating that electricity cannot flow.

Closed Circuit Symbol

Indicates a complete path for electric current to flow.