SNC 2D FINAL EXAM REVIEW

UNIT 1: CHEMISTRY - CHEMICAL REACTIONS  

Periodic Table 

- atomic particles, atomic number, mass number (atomic mass) 

Atomic Number=Number of Protons=Number of Electrons and Mass Number=Number of Protons+Number of Neutrons.

Atomic Number: The number of protons in an atom.

Atomic Mass: The total number of protons and neutrons in an atom

Protons: Positively charged particles.

Neutrons: Particles with no charge.

Electrons: Negatively charged particles that orbit the nucleus.

Valence Electrons: Electrons in    the outermost shell.

- families, valence electrons, valence charge  

Alkali Metals (Group 1): 1 valence electrons

Alkaline Earth Metals (Group 2): 2 valence electrons.

Halogens (Group 17): 7 valence electrons.

Noble Gases (Group 18): 8 valence electrons (except He, which has 2).

Group 1: Same as alkali metals.

Atomic diagrams

- Bohr- Rutherford diagrams for atoms and ions 

Bohr diagrams show electrons in energy levels/shells.

- Electron Dot structures  Ionic Compounds 

 the distribution of electrons in the molecule

- naming, writing chemical formulas (zero sum rule or cross -over method ) 

1. Ionic Compounds (Metal + Non-metal):
   
   

   • Metal stays the same name.

   • Non-metal ends in "ide".

   • Cross charges to determine subscripts and simplify.

   • Example: NaCl (Sodium Chloride), MgBr₂ (Magnesium Bromide).

2. Molecular (Covalent) Compounds (Non-metal + Non-metal):
   
   

   • Use prefixes (mono, di, tri, etc.) to indicate the number of atoms.

   • Second element ends in “ide”.

   • Example: N₂O (Dinitrogen monoxide), P₄O₁₀ (Tetraphosphorus decaoxide).

- binary , and polyatomic ions  Molecular (covalent) compounds 

Binary Ions: Ions from two elements (e.g., Na⁺, Cl⁻).

Polyatomic Ions: Ions made of more than one atom (e.g., OH⁻, CO₃²⁻).

Molecular Compounds: Compounds formed by the sharing of electrons between non-metal atoms (e.g., H₂O, CO₂).

- naming, writing chemical formulas (incl. diatomic HOFBrINCl)  

Naming Ionic Compounds

Ionic compounds are typically formed between a metal and a non-metal. The metal becomes a positive ion (cation), and the non-metal becomes a negative ion (anion).

Steps:

1. Name the metal (cation) first. If the metal has more than one possible charge (like transition metals), use Roman numerals to indicate the charge.

2. Name the non-metal (anion) second, changing its ending to "-ide".

Example 1: NaCl

• Na (sodium) is a metal, and Cl (chlorine) is a non-metal.

• Sodium is named first, and chlorine becomes chloride.

• Name: Sodium chloride

Writing Ionic Formulas

To write the formula of an ionic compound, balance the charges of the cation and anion so that the total charge is neutral.

Example 1: Calcium chloride (CaCl₂)

• Ca²⁺ (calcium ion) and Cl⁻ (chloride ion).

• You need two chloride ions to balance the +2 charge from calcium.

• Formula: CaCl₂

Naming Covalent (Molecular) Compounds

Covalent compounds are formed between two non-metals, and the atoms share electrons.

Steps:

1. Name the first non-metal (the one with the lowest group number or highest electronegativity) using its full name.

2. Name the second non-metal, changing its ending to "-ide".

3. Use prefixes (mono-, di-, tri-, etc.) to indicate the number of atoms of each element in the compound.

   • Mono- is often omitted for the first element.

   • Prefixes are used even if there's only one atom of the second element.

Example 1: CO₂

• C (carbon) and O (oxygen) are both non-metals.

• Carbon is named first, and oxygen becomes oxide.

• CO₂ is named carbon dioxide.

Naming and Writing Formulas for Diatomic Molecules (HOFBrINCl)

Some elements naturally exist as molecules of two atoms. These are known as diatomic molecules, and they include:

• H₂ (Hydrogen)

• O₂ (Oxygen)

• F₂ (Fluorine)

• Br₂ (Bromine)

• I₂ (Iodine)

• N₂ (Nitrogen)

• Cl₂ (Chlorine)

Examples of Writing Formulas and Naming Covalent Compounds with Diatomic Elements

Example 1: Nitrogen trichloride (NCl₃)

• Nitrogen (N) is the first element.

• Chlorine (Cl) is the second element.

• The prefix tri- indicates three chlorine atoms.

• Formula: NCl₃

• Name: Nitrogen trichloride

Summary of Key Points:

1. Ionic compounds: Metal + non-metal → named by cation first, anion second.

   • Example: NaCl (Sodium chloride)

2. Covalent compounds: Non-metal + non-metal → named with prefixes for number of atoms.

   • Example: CO₂ (Carbon dioxide)

3. Diatomic molecules: Some elements naturally exist as two atoms. These include H₂, O₂, F₂, Br₂, I₂, N₂, and Cl₂.

   • Example: O₂ (Oxygen)

Physical vs. chemical change  

1. Physical Change

A physical change involves a change in the form or state of matter without altering the chemical composition of the substance. The molecules or atoms stay the same, and no new substances are formed.

Key Characteristics of Physical Changes:

• No new substances are formed.

• The change is often reversible (e.g., melting, freezing, dissolving).

• It can involve changes in state (solid, liquid, gas), shape, or size.

• Examples include:

  • Melting ice into water (solid to liquid).

  • Dissolving sugar in water.

  • Cutting a piece of paper.

Examples of Physical Changes:

• Boiling water: Water turns from liquid to gas but remains H₂O.

• Crushing a can: The can's shape changes, but it is still made of the same metal.

• Freezing water: Water changes from a liquid to a solid, but the chemical structure of H₂O doesn’t change.

2. Chemical Change

A chemical change (or chemical reaction) occurs when a substance undergoes a transformation that results in the formation of a new substance with different properties. During a chemical change, chemical bonds are broken and new bonds are formed.

Key Characteristics of Chemical Changes:

• New substances are produced.

• The change is often irreversible (though some chemical reactions can be reversed under certain conditions).

• Energy changes usually occur (heat, light, sound, or electricity).

• Evidence of a chemical change includes:

  • Color change (e.g., rusting iron turns reddish-brown).

  • Gas production (e.g., bubbles form when baking soda reacts with vinegar).

  • Precipitate formation (e.g., when two clear solutions mix and a solid forms).

  • Energy release or absorption (e.g., burning wood releases heat and light).

Examples of Chemical Changes:

• Burning wood: Combustion results in the formation of new substances like carbon dioxide (CO₂) and water (H₂O).

• Iron rusting: Iron reacts with oxygen in the air to form iron oxide (Fe₂O₃).

• Baking a cake: Chemical reactions between ingredients produce new substances (e.g., carbon dioxide gas makes the cake rise).

• Vinegar and baking soda reaction: Produces carbon dioxide gas (CO₂), water (H₂O), and sodium acetate (CH₃COONa).

- Law of Conservation of Mass 

Law of Conservation of Mass:

• What it says: The total mass of everything before a chemical reaction is the same as the total mass after the reaction.

• In simple words: Matter can’t be created or destroyed—it just changes form.

Example:

Imagine you burn a piece of paper. The paper turns into ash, smoke, and gas. Even though the paper looks different, the total mass of the paper, ash, smoke, and gas is the same before and after burning.

In short: Mass doesn't disappear or appear out of nowhere—it stays the same.

- format of a chemical reaction - balancing (don’t forget HOFBrINCl)  Key Chemical Reaction types 

A chemical reaction shows how reactants (the starting substances) transform into products (the new substances). 

The general format for a chemical reaction is: Reactants→Products

Key Types of Chemical Reactions

Chemical reactions can be classified into several types, and each type follows specific patterns. Here are the main types of chemical reactions:

Synthesis: Two substances combine to make a new compound (A + B → AB).

Decomposition: A compound breaks down into simpler substances (AB → A + B).

Single Displacement: One element replaces another in a compound (A + BC → AC + B).

Double Displacement: Two compounds exchange parts (AB + CD → AD + CB).

Combustion: A substance reacts with oxygen to form CO₂ and H₂O (Fuel + O₂ → CO₂ + H₂O).

- define and identify the different types (incl. combustion)  Acids and Bases - properties, pH and neutralization reactions 

Acids:

• Donate H⁺ ions in water.

• Sour taste, turn litmus paper red, pH < 7.

• Example: HCl (hydrochloric acid).

Bases:

• Donate OH⁻ ions or accept H⁺ ions in water.

• Bitter taste, slippery, turn litmus paper blue, pH > 7.

• Example: NaOH (sodium hydroxide).

pH Scale:

• Measures acidity/alkalinity.

• pH < 7 = acidic, pH = 7 = neutral, pH > 7 = basic.

Neutralization:

• Acid + Base → Salt + Water.

• Example: HCl + NaOH → NaCl + H₂O.

Combustion:

• A reaction with oxygen that produces heat, light, CO₂, and H₂O.

• Example: CH₄ + O₂ → CO₂ + H₂O + energy

UNIT 2 : PHYSICS - LIGHT AND GEOMETRIC OPTICS  

Electromagnetic spectrum 

The electromagnetic spectrum refers to the entire distribution of electromagnetic radiation according to frequency or wavelength

– relationships between energy and wavelength  Types of Light Emissions (ex. incandescence, laser...) 

Incandescence:

• Description: Light emitted due to the heat of an object. When an object gets hot enough, it starts to emit visible light.

• Example: light bulbs

Fluorescence:

• Description: A material absorbs light (typically ultraviolet) and re-emits it almost instantaneously as visible light.

• Example: Fluorescent lights, highlighter markers.

Phosphorescence:

• Description: Similar to fluorescence, but the re-emission of light occurs over a longer time period.

• Example: Glow-in-the-dark objects or materials.

Chemiluminescence:

• Description: Light produced by a chemical reaction without the involvement of heat.

• Example: Glow sticks, bioluminescence in fireflies.

Bioluminescence:

• Description: A specific type of chemiluminescence occurring in living organisms, where light is produced via biochemical reactions.

• Example: Fireflies, certain types of jellyfish.

Laser (Light Amplification by Stimulated Emission of Radiation):

• Description: Highly coherent, monochromatic light produced through stimulated emission. Lasers emit light in a specific direction and wavelength, with minimal spread.

• Example: Laser pointers, barcode scanners, fiber optic communication.

Images in Mirrors 

- plane, concave, convex 

1. Plane Mirror

• Description: A flat mirror where the reflective surface is smooth and even.

• Image Characteristics:

  • Upright (virtual)

  • Same size as the object

  • Laterally inverted (left and right are swapped)

  • Virtual (appears behind the mirror; cannot be projected onto a screen)

• Example: Bathroom mirrors, dressing mirrors.

2. Concave Mirror

• Description: A mirror that curves inward, like the inside of a spoon.

• Image Characteristics:

  • Real or virtual, depending on the object’s distance from the mirror

  • Inverted or upright depending on the object's position relative to the focal point

  • Magnified (when the object is near the mirror)

  • Reduced size (when the object is farther from the mirror)

• Example: Makeup mirrors (when close), satellite dishes, some telescopes.

• Specific cases:

  • Real image (inverted): If the object is beyond the focal point.

  • Virtual image (upright): If the object is within the focal point.

3. Convex Mirror

• Description: A mirror that curves outward, like the back of a spoon.

• Image Characteristics:

  • Upright (virtual)

  • Reduced size (smaller than the object)

  • Virtual (appears behind the mirror; cannot be projected onto a screen)

• Example: Side mirrors of vehicles, security mirrors in stores.

- Laws of Reflection 

Law 1

The angle of reflection is equal to the angle of incidence .

The reflected ray and the incidence ray are on opposite sides of the normal. 

Law 2

The incident ray, the normal, and the reflected ray lie on the same plane (the surface). 

- draw ray diagrams

In mirrors 

Concave mirror: The reflecting surface is curved inward. Ray diagrams for concave mirrors show how parallel rays converge (meet) at a focal point in front of the mirror.

Convex mirror: The reflecting surface is curved outward. Ray diagrams for convex mirrors show how parallel rays diverge after reflecting, appearing to come from a focal point behind the mirror.

In the diagrams, the important rays to draw are:

• Incident ray: The incoming ray of light.

• Reflected ray (in mirrors) or Refracted ray (in lenses): The ray after it has bounced off or passed through the optical device.

• Principal axis: The straight line passing through the center of the mirror or lens.

• Focal point: The point where light rays converge or appear to converge after interacting with the optical device.

- characteristics of an image (S.A.L.T.) 

• S – Size: Bigger or smaller 

• A – Angle: upright or inverted 

• L – Length: closer or further away from

• T – Type: Virtual or Real image 

- important points from which to draw image (vertex, focus...) 

• Vertex – The turning point of the parabola (where it changes direction).

• Focus – A point inside the parabola that helps determine its shape.

• Directrix – A straight line that is used to define the parabola's curve.

• Axis of Symmetry – A vertical or horizontal line that divides the parabola into two equal halves.

• Focal Length – The distance between the vertex and the focus.

- uses of plane, concave and convex mirrors , explain how they are used in different applications  

1. Plane Mirrors (Flat Mirrors):

• Uses:

  • Home use (bathroom, dressing mirrors) – Provide clear, accurate reflections.

  • Periscopes – Used in submarines to see above water.

  • Security mirrors – Used in stores to watch for shoplifting.

  • Automobiles (side mirrors) – Provide a wide field of view with true image size.

2. Concave Mirrors (Curved Inward):

• Uses:

  • Makeup/shaving mirrors – Magnify the face for close-up details.

  • Headlights/flashlights – Focus light into a beam.

  • Telescopes – Collect and focus light from distant objects.

  • Dental and medical tools – Provide magnified images for better examination.

3. Convex Mirrors (Curved Outward):

• Uses:

  • Security and traffic mirrors – Provide a wider field of view in stores or on roads.

  • Side-view mirrors in vehicles – Show more area but with smaller images.

  • ATMs and self-checkout machines – Help users see their surroundings for security.

Refraction 

- Theory (rules of refraction) 

• Refraction is the bending of light as it passes from one medium to another (e.g., from air to water). The two main rules of refraction are:

First Rule:

• When light travels from a less dense medium (e.g., air) to a denser medium (e.g., water or glass), it bends toward the normal (an imaginary line perpendicular to the surface).

• Example: A straw in water looks bent because light slows down and bends toward the normal.

Second Rule:

• When light travels from a denser medium to a less dense medium, it bends away from the normal.

• Example: When you look from underwater to the air, objects appear shifted due to light bending away.

Key Points to Remember:

Incident ray: The incoming ray of light.

Refracted ray: The bent ray after passing through the medium.

Normal line: An imaginary line at 90° to the surface.

Index of refraction: A measure of how much light slows down in a material (higher index = slower light).

- Index of Refraction calculations 

The formula to calculate the refractive index is:

n=c/n

Where:

• n is the refractive index (no units, it’s a ratio),

• c is the speed of light in a vacuum (approximately 3.0 x 108 m/s) 

• v is the speed of light in the medium (the material through which light is passing).

Refractive Index of Different Materials

Different materials have different refractive indices. For example:

• Air: n≈1.00n (travels most quickly)

• Water: n≈1.33n  (more quickly)

• Glass: n≈1.50n (least quickly)

- Total Internal Reflection

 Definition:

• Total Internal Reflection (TIR) happens when light traveling from a denser medium (e.g., water or glass) to a less dense medium (e.g., air) is completely reflected back into the denser medium instead of refracting (bending) out.

- conditions and examples 

Conditions

• Light must travel from a denser medium to a less dense medium.

• The angle of incidence must be greater than the critical angle.

• The critical angle is the smallest angle at which light is totally reflected instead of refracted.

Examples 

• Optical fibers: Used in internet cables to transmit light signals over long distances.

• Diamonds: Sparkle due to TIR, as light bounces inside before exiting.

• Mirages: Light bends and reflects in hot air layers, creating illusions.

• Periscopes and binoculars: Use TIR to reflect light efficiently within the device.

- phenomena related to refraction and total internal reflection (apparent depth, rainbow formation) 

Apparent Depth (Due to Refraction):

• When you look at objects underwater (like a coin in a pool), they appear closer (shallower) than they really are.

• This happens because light bends away from the normal as it moves from water (denser) to air (less dense), making the object seem higher than its actual position.

• Example: A swimming pool looks shallower than it really is.

Rainbow Formation (Due to Refraction and Total Internal Reflection):

• Rainbows form when sunlight enters raindrops and undergoes refraction, dispersion, and total internal reflection.

Step 1: Light enters a raindrop and refracts (bends), splitting into different colors (dispersion).

Step 2: The light reflects off the inside surface of the drop (TIR).

Step 3: When leaving the drop, it refracts again, and the colors spread out to form a rainbow.

Example: Rainbows appear after rain when sunlight shines through raindrops.

Other Phenomena:

• Mirages: Caused by refraction when light bends due to temperature differences in air, making it look like water is on the road.

• Internal Reflection in Optical Fibers: Light is trapped inside glass fibers and travels long distances without escaping.

UNIT 3 : BIOLOGY - TISSUES, ORGANS AND SYSTEMS  

Cell Theory  

The Cell Theory is a fundamental concept in biology that explains the properties and function of cells. It consists of three main principles:

1. All living things are made up of one or more cells.

2.  The cell is the basic unit of life.

3. All cells come from pre-existing cells.

-Eukaryotes vs. Prokaryotes  

Eukaryotes

Characteristics of Eukaryotic Cells:

• Nucleus: Eukaryotic cells have a true nucleus, which contains the cell’s DNA enclosed in a membrane.

• Organelles: Eukaryotes contain various membrane-bound organelles (like mitochondria, endoplasmic reticulum, Golgi apparatus, etc.) that perform specific functions.

• Cell Size: Eukaryotic cells are typically larger (10–100 micrometers).

• DNA: The DNA is linear and found inside the nucleus.

• Reproduction: Eukaryotic cells reproduce through processes like mitosis (asexual reproduction) and meiosis (sexual reproduction).

Examples of Eukaryotes:

• Animals (humans, dogs, fish)

• Plants (trees, flowers, grasses)

• Fungi (mushrooms, yeast)

• Protists (amoebas, paramecium)

Prokaryotes

Characteristics of Prokaryotic Cells:

• No Nucleus: Prokaryotic cells do not have a nucleus. Their DNA is found in a region called the nucleoid but is not enclosed in a membrane.

• No Membrane-Bound Organelles: Prokaryotes lack organelles like mitochondria and the endoplasmic reticulum.

• Cell Size: Prokaryotic cells are usually smaller (0.1–5 micrometers).

• DNA: The DNA is usually a single circular strand.

• Reproduction: Prokaryotic cells reproduce asexually by binary fission (a type of cell division).

Examples of Prokaryotes:

• Bacteria (e.g., Escherichia coli (E. coli), Streptococcus bacteria)

• Archaea (e.g., Halobacterium found in salty environments)

-Levels of Organization in an organism (cell → tissue → organ...)  

Cell → Tissue → Organ → Organ System → Organism

Cell: The smallest unit of life. All living things are made of cells.

• Example: A skin cell, a muscle cell.

Tissue: A group of similar cells that work together to do a job.

• Example: Muscle tissue, skin tissue.

Organ: A part of the body made of different types of tissues working together to do a job.

• Example: Heart, stomach.

Organ System: A group of organs that work together to do a big job in the body.

• Example: The digestive system (mouth, stomach, intestines), the circulatory system (heart, blood vessels).

Organism: A complete living thing made up of all the organ systems working together.

• Example: A human, a dog, a plant.

-Parts of the Cell Cycle including the phases of Mitosis  

The cell cycle is the process by which cells grow, prepare for division, and divide to form new cells. It has two main stages:

1. Interphase (Growth and Preparation)

2. Mitosis and Cytokinesis (Cell Division)

1. Interphase (90% of the cycle)

The cell grows, performs its normal functions, and prepares for division. It consists of three phases:

G1 Phase (Growth 1): The cell grows and produces proteins.

S Phase (Synthesis): DNA is replicated (copied).

G2 Phase (Growth 2): The cell prepares for mitosis by making necessary proteins and organelles.

 2. Mitosis (Division of the Nucleus)

Mitosis ensures that each new cell gets an identical copy of DNA. It has four phases:

1. Prophase:

• Chromosomes become visible (condense).

• The nuclear membrane breaks down.

• Spindle fibers begin to form.

2. Metaphase:

• Chromosomes line up in the middle of the cell.

• Spindle fibers attach to the chromosomes.

3. Anaphase:

• The chromosomes are pulled apart to opposite sides of the cell.

4. Telophase:

• Two new nuclei form around the chromosomes.

• The cell is almost ready to split.

3. Cytokinesis (Division of the Cytoplasm)

• The cell's cytoplasm divides, forming two identical daughter cells.

• In animal cells, the membrane pinches in.

• In plant cells, a cell wall forms.

Importance of the Cell Cycle:

• Growth and repair of tissues.

• Replaces old or damaged cells.

• Ensures genetic information is passed on correctly.

-Animal and Plant Cells 

Animal Cell:

1. Nucleus

• Function: Controls the cell’s activities and contains DNA.

2. Cell Membrane

• Function: Protects the cell and controls what enters and leaves.

3. Cytoplasm

• Function: Gel-like substance where most chemical reactions happen.

4. Mitochondria

• Function: Produces energy for the cell (powerhouse of the cell).

5. Ribosomes

• Function: Make proteins.

6. Endoplasmic Reticulum (ER)

• Function: Transports materials (smooth ER has no ribosomes; rough ER has ribosomes).

7. Golgi Body

• Function: Packages and sorts proteins for transport.

Plant Cell:

1. Nucleus

• Function: Controls the cell’s activities and contains DNA (same as in animal cells).

2. Cell Membrane

• Function: Protects the cell and controls what enters and leaves (same as in animal cells).

3. Cytoplasm

• Function: Gel-like substance where most chemical reactions happen (same as in animal cells).

4. Mitochondria

• Function: Produces energy for the cell (same as in animal cells).

5. Ribosomes

• Function: Make proteins (same as in animal cells).

6. Endoplasmic Reticulum (ER)

• Function: Transports materials (same as in animal cells).

7. Golgi Body

• Function: Packages and sorts proteins for transport (same as in animal cells).

9. Chloroplasts

• Function: Where photosynthesis happens, turning sunlight into food (unique to plant cells).

10. Cell Wall

• Function: Provides structure and support to the cell (unique to plant cells).

11. Vacuole

• Function: Stores water, nutrients, and waste products. It is much larger in plant cells, helping to maintain cell rigidity.

Key Differences Between Animal and Plant Cells:

• Chloroplasts (for photosynthesis) and cell walls are only found in plant cells.

• Vacuoles are larger in plant cells than in animal cells.

• Animal cells can have multiple small vacuoles and lack a cell wall.

- What enters and exits a typical animal cell? 

What enters the cell:

1. Oxygen (O₂) – Needed for the cell to make energy (goes in from outside the cell).

2. Nutrients (like glucose) – Provide energy and help the cell grow.

3. Water – Keeps the cell hydrated and helps with chemical reactions.

4. Ions (like sodium, potassium) – Help with things like nerve signals and muscle movement.

What exits the cell:

1. Carbon Dioxide (CO₂) – A waste product from making energy, it leaves the cell.

2. Waste Products (like urea) – Other things the cell no longer needs.

3. Excess Water – If there's too much water, it leaves the cell.

4. Hormones – Signals that tell other cells what to do (like insulin).

- embryonic stem cells 

Definition:

Embryonic stem cells are undifferentiated cells found in the early stages of embryonic development. They have the unique ability to develop into any type of cell in the body, which makes them pluripotent (able to form all types of cells except for those needed to support fetal development).

Key Features of Embryonic Stem Cells:

1. Pluripotency:

• These cells can become any of the body's different cell types (e.g., muscle, nerve, skin cells). This makes them valuable for medical research and treatment.

2. Self-Renewal:

• Embryonic stem cells can divide and produce more stem cells, making them useful for therapeutic purposes.

3. Early Development:

• They are found in the blastocyst stage of an embryo, usually about 5 days after fertilization.

- How do cancer cells differ from normal cells?  

• Cancer cells are abnormal cells that grow uncontrollably and can invade surrounding tissues. They differ from normal cells in several key ways:

1. Uncontrolled Growth:

• Normal Cells: Grow, divide, and die in a controlled way. They follow a set pattern and stop dividing when needed.

• Cancer Cells: Do not respond to signals that regulate the cell cycle. They keep dividing uncontrollably, forming a mass of cells called a tumor.

2.  Avoiding Cell Death (Apoptosis):

• Normal Cells: Undergo a natural process of cell death (apoptosis) when they are damaged or no longer needed.

• Cancer Cells: Often avoid apoptosis, allowing damaged cells to survive and continue dividing.

3.  Invasion and Spread:

• Normal Cells: Stay in their designated location in the body and do not invade other tissues.

• Cancer Cells: Can invade surrounding tissues and spread to other parts of the body through a process called metastasis, leading to secondary tumors.

4. Immortality:

• Normal Cells: Have a limited number of divisions before they stop dividing and undergo senescence (aging).

• Cancer Cells: Often have the ability to divide indefinitely, sometimes due to changes in their DNA that protect them from aging.

5. Changes in Appearance:

• Normal Cells: Have a uniform size and shape with a well-defined structure.

• Cancer Cells: May appear irregular in shape and size, with a large nucleus and an abnormal structure.

6. Abnormal Signals for Growth:

• Normal Cells: Respond to signals that tell them when to stop growing and when to repair or die.

• Cancer Cells: May produce their own growth signals or ignore signals to stop growing, leading to continuous growth.

7. Angiogenesis (Blood Vessel Formation):

• Normal Cells: Do not cause the growth of new blood vessels unless needed for repair.

• Cancer Cells: Can stimulate the growth of new blood vessels (angiogenesis) to supply nutrients to the growing tumor.

Conclusion: Cancer cells are different from normal cells because they grow uncontrollably, evade death, and can spread to other parts of the body, making them dangerous. This uncontrolled behavior is due to mutations in the cell's DNA, which disrupt normal cell regulation.

Organ Systems 

- Digestive System

• The digestive system is responsible for breaking down food into nutrients, which the body can absorb and use for energy, growth, and repair. It consists of several organs, each with a specific function.

- parts and their functions, diagram 

1. Mouth:

Function:

• The digestion process begins in the mouth.

• Teeth break down food mechanically (chewing).

• Saliva, produced by salivary glands, contains enzymes (like amylase) that begin breaking down carbohydrates.

2. Esophagus:

Function:

• The esophagus is a muscular tube that moves food from the mouth to the stomach.

• It uses peristalsis, a wave-like muscle contraction, to push food down.

3. Stomach:

Function:

• The stomach is a muscular sac that stores food and uses gastric juices (containing hydrochloric acid and pepsin) to digest proteins.

• It churns food to mix it with digestive enzymes, turning it into a thick liquid called chyme.

4. Small Intestine:

Function:

• The majority of digestion and nutrient absorption occurs in the small intestine.

• It has three parts: the duodenum (where most digestion occurs), the jejunum, and the ileum.

• Enzymes from the pancreas and bile from the liver help break down food. Nutrients are absorbed through the walls of the small intestine into the bloodstream.

5. Liver:

Function:

• The liver produces bile, which is stored in the gallbladder and helps break down fats.

• It also processes nutrients absorbed from the small intestine and detoxifies harmful substances.

6. Gallbladder:

Function:

• The gallbladder stores and concentrates bile produced by the liver, releasing it into the small intestine to aid in fat digestion.

7. Pancreas:

Function:

• The pancreas produces digestive enzymes that help break down proteins, fats, and carbohydrates in the small intestine.

• It also produces insulin, a hormone that helps regulate blood sugar levels.

8. Large Intestine (Colon):

Function:

• The large intestine absorbs water and salts from the remaining indigestible food matter, turning it into solid waste (feces).

• It also houses beneficial bacteria that help break down certain materials and produce vitamins.

9.  Rectum and Anus:

Function:

• The rectum stores feces until they are eliminated through the anus.

• The anus controls the release of waste material from the body.

Summary:

Mouth: Begins digestion (mechanical and chemical).

Esophagus: Moves food to the stomach.

Stomach: Breaks down food using acid and enzymes.

Small Intestine: Digests and absorbs nutrients.

Liver: Produces bile and processes nutrients.

Gallbladder: Stores bile.

Pancreas: Produces enzymes for digestion and insulin for blood sugar control.

Large Intestine: Absorbs water, forms feces.

Rectum and Anus: Stores and eliminates waste.

- Respiratory System

• The respiratory system is responsible for bringing oxygen into the body and removing carbon dioxide. It involves a series of organs that work together to allow breathing and gas exchange.

- parts and their functions, diagram 

1. Nasal Cavity (Nose):

Function:

• Air enters the body through the nose, where it is filtered, moistened, and warmed.

• Tiny hairs called cilia and mucus trap dust, bacteria, and other particles.

2. Pharynx (Throat):

Function:

• The pharynx is a passageway that connects the nasal cavity to the larynx and esophagus.

• It directs air into the larynx and food into the esophagus.

3.  Larynx (Voice Box):

Function:

• The larynx contains the vocal cords, which vibrate to produce sound.

• It also helps protect the trachea by preventing food or liquids from entering the airway.

4. Trachea (Windpipe):

Function:

• The trachea is a tube that connects the larynx to the bronchi.

• It is lined with cilia and mucus that help trap and move particles out of the respiratory system.

5. Bronchi:

Function:

• The trachea divides into two bronchi, one leading to each lung.

• The bronchi carry air into the lungs and continue to divide into smaller tubes called bronchioles.

6. Bronchioles:

Function:

• The bronchioles are small branches of the bronchi that carry air into the alveoli.

• They regulate airflow by constricting or dilating.

7. Alveoli:

Function:

• The alveoli are tiny air sacs at the end of the bronchioles where gas exchange occurs.

• Oxygen from the air passes through the walls of the alveoli into the blood, while carbon dioxide from the blood passes into the alveoli to be exhaled.

8.  Lungs:

Function:

• The lungs are the primary organs of respiration, located in the chest cavity.

• They contain the bronchi, bronchioles, and alveoli, where the exchange of oxygen and carbon dioxide occurs.

9.  Diaphragm:

Function:

• The diaphragm is a muscle located below the lungs.

• It contracts and relaxes to control the movement of air in and out of the lungs(breathing).

Breathing Process:

1. Inhalation (Inspiration):

• The diaphragm contracts and moves downward, while the rib muscles expand the chest cavity, creating a vacuum that draws air into the lungs. 

• Oxygen-rich air fills the alveoli, and oxygen is transferred into the blood.

Exhalation (Expiration):

• The diaphragm relaxes and moves upward, and the rib muscles contract, reducing the chest cavity's size.

• Air, now rich in carbon dioxide, is pushed out of the lungs through the trachea, bronchi, and out through the nose or mouth.

Gas Exchange:

• In the alveoli, oxygen from the air diffuses into the bloodstream, and carbon dioxide from the blood diffuses into the alveoli to be exhaled. This exchange occurs across the thin walls of the alveoli, which are surrounded by capillaries (tiny blood vessels).

Summary of Respiratory System Function:

Nose/Mouth: Filters and moistens air.

Trachea/Bronchi: Carry air to the lungs.

Lungs/Alveoli: Exchange gases (oxygen in, carbon dioxide out).

Diaphragm/Rib Muscles: Control breathing by moving air in and out of the lungs.

The respiratory system works together with the circulatory system to deliver oxygen to the cells of the body and remove waste gases, supporting cellular functions and overall health.

- Circulatory System 

Parts of the Circulatory System:

1. Heart:

   • Function: The heart is the pump that keeps blood moving through the body. It pumps blood to the lungs for oxygenation and to the rest of the body to deliver oxygen and nutrients.

   • Structure: The heart has four chambers – two atria (upper chambers) and two ventricles (lower chambers).

2. Blood Vessels:

   • Arteries:

     • Function: Carry oxygen-rich blood away from the heart to the body's tissues.

     • Example: Aorta is the largest artery, which delivers blood from the heart to the body.

   • Veins:

     • Function: Carry deoxygenated blood back to the heart.

     • Example: Vena Cava is the large vein bringing deoxygenated blood from the body to the heart.

   • Capillaries:

     • Function: Tiny blood vessels where gas exchange (oxygen and carbon dioxide) and nutrient exchange occur between blood and cells.

     • They connect arteries to veins.

3. Blood:

   • Red Blood Cells (RBCs):

     • Function: Carry oxygen from the lungs to the body and return carbon dioxide back to the lungs.

     • Structure: They contain hemoglobin, which binds to oxygen.

   • White Blood Cells (WBCs):

     • Function: Part of the immune system, they protect the body from infections and diseases.

   • Platelets:

     • Function: Help the blood to clot, preventing excessive bleeding when you get injured.

   • Plasma:

     • Function: The liquid part of blood that transports water, nutrients, waste, and hormones throughout the body.

Functions of the Circulatory System:

1. Transport: The circulatory system transports oxygen, nutrients, and hormones to cells and removes waste products like carbon dioxide.

2. Temperature Regulation: Blood helps maintain body temperature by distributing heat throughout the body.

3. Protection: White blood cells protect the body from infection, and platelets help in clotting to prevent excessive bleeding.

4. Hormone Transport: The circulatory system helps transport hormones from the glands to target organs.

How Blood Flows Through the Circulatory System:

1. From the Heart to the Lungs:
   The right side of the heart pumps deoxygenated blood to the lungs via the pulmonary artery. In the lungs, the blood picks up oxygen and releases carbon dioxide.

2. From the Lungs to the Heart:
   The oxygenated blood returns to the left side of the heart through the pulmonary veins.

3. From the Heart to the Body:
   The left side of the heart pumps oxygenated blood into the aorta, which carries it through arteries to all parts of the body.

4. From the Body to the Heart:
   After delivering oxygen and nutrients, the veins carry deoxygenated blood back to the heart, entering through the vena cava.

Key Points:

• The heart is the pump, blood vessels (arteries, veins, and capillaries) are the transportation system, and blood carries oxygen, nutrients, waste, and immune cells.

• The circulatory system helps to maintain body temperature, protect against infections, and ensure all body cells get the nutrients and oxygen they need.

- interrelationship between the systems

1. Respiratory System & Circulatory System:

How they work together:

The respiratory system brings oxygen into the body when you breathe in and removes carbon dioxide (a waste product). The circulatory system carries the oxygen from the lungs to all the cells in the body and carries carbon dioxide back to the lungs to be exhaled.

Example: When you breathe in, oxygen moves from your lungs into the blood (circulatory system). The blood then carries the oxygen to your heart, which pumps it to your body’s cells.

2. Digestive System & Circulatory System:

How they work together:

The digestive system breaks down food into nutrients (like glucose). These nutrients are absorbed into the blood by the circulatory system, which then transports them to your cells for energy and growth.

Example: After you eat, your digestive system breaks down food into smaller molecules. These nutrients are absorbed into the blood, and the circulatory system delivers them to your body.

3. Respiratory System & Digestive System:

How they work together:

The respiratory system provides the oxygen your cells need to turn the food (from the digestive system) into energy.

Example: When you eat food, your body uses oxygen from the respiratory system to help break down the nutrients from food (like glucose) and turn them into energy.

How These Systems Work Together:

Step 1: The digestive system breaks down food into nutrients (like glucose).

Step 2: The circulatory system absorbs these nutrients and carries them to the cells.

Step 3: The respiratory system provides oxygen to the cells, which they need to turn the nutrients (like glucose) into energy.

Step 4: The circulatory system removes carbon dioxide (waste from energy production) and sends it to the lungs to be exhaled.

In short:

The digestive system gives your body nutrients.

The respiratory system gives your body oxygen.

The circulatory system delivers both oxygen and nutrients to your cells and removes waste.