Combined Science

Cells

ANIMAL CELL

• Cell Membrane - controls what can enter or leave the cell.

• Cytoplasm - this is where chemical reactions take place

• Nucleus - the control center of the cell.

• Mitochondria - where respiration takes place

• Vacuole - used to transport water salts waste and food particles

  
  

  
  

  PLANT CELL

  
  

  

  
  

DIFFERENCES BETWEEN AN ANIMAL AND A PLANT CELL

Respiratory system

COMPOSITION OF AIR

• Oxygen = 21%

• Carbon dioxide = 0.03%

• Nitrogen = 78%

• Water vapor varies due to humidity

RESPIRATION

Respiration is the process of burning food in the body cells to produce carbon dioxide, water and release energy.

Respiratory gases

• Oxygen

• Carbon dioxide

  • during respiration oxygen is taken in (inhaled when breathing) and carbon dioxide is taken out (exhaled when u breathe out)

Testing for carbon dioxide

You need :

• lime water

• test tube

• Glass straw

The presence of carbon dioxide turns lime water into milky white and the red bicarbonate indicator yellow

Testing for oxygen

Light a wooden splint and the oxygen relights a glowing wooden splint

TRANSPORT SUSTEM

Diffusion

This is the movement of particles of any substance from a region of highly concentrated particles to a region where there is low concentration of particles

Example of diffusion :

• Perfume: The particles of perfume spread out into the air, allowing you to smell it

OSMOSIS

Osmosis: is the movement of water molecules from a region of high concentration to a region of lower concentration through a semi-permeable membrane.

- Water moves through a semi-permeable membrane until the water particles are spread out evenly;

- Osmosis therefore stops when the water particles are in equilibrium.

- E.g. water moves by osmosis from the soil, where there is a high concentration of water into roots, where there is lower concentration of water.

Flower

Blood components

Red blood cells transport oxygen

White bloods cells fight infections and diseases

Platelets help with blood clot

Plasma help transport essential substances

Acid bases and salts

Acids:

- Taste sour

- Turn litmus paper red

- Examples: Lemon juice, vinegar, stomach acid

- Characteristics:

- Release hydrogen ions (H+)

- Corrode materials

Bases:

- Taste bitter

- Turn litmus paper blue

- Examples: Soap, baking soda, toothpaste

- Characteristics:

- Accept hydrogen ions (H+)

- Feel slippery

Salts:

- Formed when acids and bases combine

- Taste salty or bitter

- Examples: Table salt (sodium chloride), sea salt, Epsom salt

- Characteristics:

- Neutralize acids and bases

- Conduct electricity when dissolved in water

Acid-Base Reactions:

- Acids + Bases → Salts + Water

- Example: Hydrochloric acid (HCl) + Sodium hydroxide (NaOH) → Sodium chloride (NaCl) + Water (H2O)

Simple Analogy:

Think of acids, bases, and salts like a seesaw:

- Acids add hydrogen ions (H+), tipping the seesaw one way

- Bases absorb hydrogen ions, tipping the seesaw the other way

- Salts balance the seesaw, neutralizing acids and bases

Key Points:

- Acids release hydrogen ions, bases accept them

- Acids and bases react to form salts and water

- Salts neutralize acids and bases, conduct electricity in water

Common Acid-Base Pairs:

- Hydrochloric acid (HCl) and Sodium hydroxide (NaOH)

- Sulfuric acid (H2SO4) and Calcium hydroxide (Ca(OH)2)

- Acetic acid (CH3COOH) and Baking soda (NaHCO3)

Real-Life Applications:

- Chemistry: Cleaning products, pharmaceuticals

- Biology: Digestion, cellular processes

- Environment: Water treatment, soil pH management

Do you have any specific questions or areas you'd like me to