Ethiopian New curriculum Grade 9-12


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Forward from: Biology prep
1. Specimen Preparation



2. Fixation (for dead specimens only)

Purpose: Preserves structure & prevents decay.

Method: Chemicals (e.g., formaldehyde, glutaraldehyde).




3. Staining (for both living & dead specimens)

Purpose: Enhances contrast (difference in light intensity between structures for better visibility).

Method: Dyes (e.g., methylene blue, iodine).




4. Mounting on Slide

Living specimens: Directly mounted, stain may be added.

Dead specimens: Fixed, stained, sliced, then mounted.




5. Observation Under Microscope
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Forward from: Biology prep
Light Microscope

├── Optical Components
│ ├── Eyepiece (Ocular Lens) → Magnifies the image (usually 10x)
│ ├── Objective Lenses → Provide different magnifications (4x, 10x, 40x, 100x)
│ ├── Condenser Lens → Focuses light onto the specimen
│ ├── Iris Diaphragm → Controls the amount of light reaching the specimen
│ ├── Light Source → Provides illumination for the specimen

├── Mechanical Components
│ ├── Body Tube → Maintains the correct distance between eyepiece & objective lenses
│ ├── Revolving Nosepiece → Holds and rotates objective lenses
│ ├── Stage → Holds the slide with the specimen
│ ├── Stage Clips → Secure the slide in place
│ ├── Coarse Adjustment Knob → Moves the stage up and down for initial focusing
│ ├── Fine Adjustment Knob → Precisely fine-tunes focus

└── Support Components
├── Arm → Connects the base to the body; used for carrying
├── Base → Provides stability and support for the microscope
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Forward from: Biology prep
Microscope

├── Types of Microscopes
│ ├── Light Microscope
│ │ ├── Uses visible light
│ │ ├── Magnification: Up to 1000x
│ │ ├── Resolution: Lower than electron microscope
│ │
│ ├── Electron Microscope
│ │ ├── Uses electron beams
│ │ ├── Higher resolution and magnification
│ │ ├── Types:
│ │ │ ├── Transmission Electron Microscope (TEM) → 2D image
│ │ │ ├── Scanning Electron Microscope (SEM) → 3D image

├── Magnification vs. Resolution
│ ├── Magnification: Enlarges the image
│ ├── Resolution: Clarity and detail of the image

└── Purpose of Staining Cells
├── Enhances contrast
├── Highlights specific cell structures
├── Common stains: Methylene blue, Iodine, Safranin


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START

Question: "Using the right-hand rule for the motor principle, the right thumb points to?"

Is the rule Fleming’s Left-Hand Rule? → NO (Question specifies *Right-Hand Rule*)

Proceed with Right-Hand Rule analysis:
├─ Method 1: Cross Product (Physics)
│ ├─ Index Finger: Direction of Current (I)
│ ├─ Middle Finger: Direction of Magnetic Field (B)
│ └─ Thumb: Direction of Force (F)

└─ Method 2: Common Teaching Mnemonic
├─ Thumb: Direction of Current (I)
├─ Fingers: Direction of Magnetic Field (B)
└─ Palm: Direction of Force (F)

Question focuses on Thumb Direction:
├─ Cross Product → Thumb = Force (Not the answer)
└─ Common Teaching → Thumb = Current

Conclusion: Most educational resources prioritize the *Common Teaching Method*.

ANSWER: C. In the direction of the current

END






Forward from: Biology prep
1. Short-Sightedness (Myopia):

Problem: Difficulty seeing distant objects clearly.

Causes: Eyeball is too long or the lens is too strong (excessively curved).

Result: Light focuses in front of the retina instead of directly on it.

Correction: Concave lenses (diverging lenses) spread the light rays so they focus correctly on the retina.


2. Long-Sightedness (Hyperopia):

Problem: Difficulty seeing nearby objects clearly.

Causes: Eyeball is too short or the lens is too weak (too flat).

Result: Light focuses behind the retina.

Correction: Convex lenses (converging lenses) bend light inward so it focuses correctly onhttps://t.me/ethiobiology2017
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Multiple-Choice Questions on Dynamics

1️⃣ A 5 kg block is acted upon by a 20 N force. What is its acceleration? ⚡🧱
A) 2 m/s²
B) 4 m/s²
C) 5 m/s²
D) 10 m/s²

2️⃣ Which of the following forces is considered a conservative force? 🔄⚖️
A) Friction
B) Normal force
C) Air resistance
D) Gravity

3️⃣ A 10 kg object moving at 4 m/s collides with a stationary 5 kg object. If they stick together, what is their final velocity? 🎯💥
A) 1.33 m/s
B) 2.67 m/s
C) 4 m/s
D) 6 m/s

4️⃣ If a car goes around a circular track at constant speed, what changes? 🚗🔄
A) Velocity
B) Kinetic energy
C) Momentum
D) Mass

5️⃣ A force of 30 N acts on a 3 kg object for 5 seconds. What is its change in velocity? ⚡⏳
A) 10 m/s
B) 20 m/s
C) 30 m/s
D) 50 m/s

6️⃣ A satellite orbits Earth in a circular path. What force keeps it in motion? 🛰️🌍
A) Normal force
B) Gravitational force
C) Magnetic force
D) Air resistance

7️⃣ A 15 N force stretches a spring by 5 cm. What is the spring constant? 🏗️⚖️
A) 3 N/m
B) 75 N/m
C) 300 N/m
D) 500 N/m

8️⃣ A car of mass 1000 kg accelerates from rest to 20 m/s in 5 seconds. What is the force acting on it? 🚗💨
A) 2000 N
B) 4000 N
C) 5000 N
D) 6000 N

9️⃣ Which of the following is NOT an example of rotational motion? 🔄📏
A) A spinning top
B) A wheel rotating
C) A falling ball
D) A satellite orbiting Earth

🔟 A pendulum swings back and forth. Where is kinetic energy at its maximum? ⏳🎢
A) At the highest point
B) At the lowest point
C) Midway between high and low
D) It remains constant

1️⃣1️⃣ A 4 kg object moves at 8 m/s. What is its kinetic energy? 🔋⚡
A) 16 J
B) 32 J
C) 64 J
D) 128 J

1️⃣2️⃣ Which of these statements about momentum is correct? 🚀🛑
A) It is a scalar quantity
B) It is conserved in all collisions
C) It depends only on mass
D) It is measured in Newtons

1️⃣3️⃣ An object in free fall has constant…? 🌍⬇️
A) Velocity
B) Acceleration
C) Momentum
D) Force

1️⃣4️⃣ A 2 kg ball moving at 6 m/s collides with a 4 kg stationary ball. If the 2 kg ball stops, what is the velocity of the 4 kg ball after collision? 🎱💥
A) 1 m/s
B) 2 m/s
C) 3 m/s
D) 4 m/s

1️⃣5️⃣ The force required to maintain an object in uniform circular motion is called? 🔄⚖️
A) Centripetal force
B) Gravitational force
C) Frictional force
D) Magnetic force

1️⃣6️⃣ A roller coaster at the highest point has maximum…? 🎢⬆️
A) Kinetic energy
B) Momentum
C) Potential energy
D) Force

1️⃣7️⃣ A 50 N force is applied at a 30° angle to move a box. What component of force acts in the direction of motion? 📦🔢
A) 25 N
B) 30 N
C) 43.3 N
D) 50 N

1️⃣8️⃣ If an object experiences a net force of zero, it must be…? ⚖️🚫
A) Moving with constant velocity
B) Accelerating
C) At rest
D) Both A and C

1️⃣9️⃣ Which force opposes motion and converts kinetic energy into heat? 🔥⚡
A) Normal force
B) Friction
C) Tension
D) Gravity

2️⃣0️⃣ A 3 kg object moving at 5 m/s hits a wall and stops in 0.2 seconds. What is the force exerted on it? 🚧⚠️
A) 15 N
B) 25 N
C) 50 N
D) 75 N


Answer

1️⃣ C) 5 m/s²
2️⃣ D) Gravity
3️⃣ B) 2.67 m/s
4️⃣ A) Velocity
5️⃣ B) 20 m/s
6️⃣ B) Gravitational force
7️⃣ C) 300 N/m
8️⃣ B) 4000 N
9️⃣ C) A falling ball
🔟 B) At the lowest point
1️⃣1️⃣ D) 128 J
1️⃣2️⃣ B) It is conserved in all collisions
1️⃣3️⃣ B) Acceleration
1️⃣4️⃣ B) 2 m/s
1️⃣5️⃣ A) Centripetal force
1️⃣6️⃣ C) Potential energy
1️⃣7️⃣ C) 43.3 N
1️⃣8️⃣ D) Both A and C
1️⃣9️⃣ B) Friction
2️⃣0️⃣ C) 50 N

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Forward from: Biology prep
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Forward from: Biology prep
Heart

┌───────────────┴───────────────┐
│ │
Right Side Left Side
│ │
│ │
Right Atrium Left Atrium
│ │
(Receives deoxygenated) (Receives oxygenated)
│ │
▼ ▼
Tricuspid Valve Bicuspid (Mitral) Valve
│ │
▼ ▼
Right Ventricle Left Ventricle
│ │
(Pumps to lungs) (Pumps to body)
│ │
Pulmonary Valve Aortic Valve
│ │
▼ ▼
Pulmonary Artery Aorta
(Carries blood to lungs) (Carries blood to body)
│ │
▼ ▼
Pulmonary Veins Arteries/Capillaries
(Bring oxygenated blood) (Distribute oxygen)


Superior & Inferior Vena Cava
(Return deoxygenated blood)

Join there's more
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Forward from: Biology prep
1. The Human Diet

🔽
Food → Provides Energy, Raw Materials, Disease Resistance
🔽
Nutrients
➝ Macronutrients (Large Amounts) → Carbohydrates | Proteins | Fats
➝ Micronutrients (Small Amounts) → Vitamins | Minerals
➝ Water & Fiber


---

2. Macronutrients

🔽
Carbohydrates → Energy Source
➝ Types: Simple (Glucose), Double (Sucrose), Complex (Starch, Glycogen)
➝ Sources: Bread, Rice, Potatoes, Teff
➝ Key Tests:

Iodine Test → Blue-Black (Starch)

Benedict’s Test → Orange-Red (Simple Sugars)


🔽
Proteins → Growth & Tissue Repair
➝ Structure: Amino Acids → Peptide Bonds → Proteins
➝ Sources: Meat, Fish, Dairy, Legumes
➝ Deficiency:

Marasmus → Severe Deficiency

Kwashiorkor → Protein Deficiency with Normal Calories
➝ Key Test: Biuret Test → Purple Color (Protein Present)


🔽
Fats & Oils (Lipids) → Energy Storage & Hormones
➝ Types: Saturated (Butter) | Unsaturated (Olive Oil)
➝ Health Risks: High Saturated Fats → Cholesterol → Heart Disease
➝ Key Tests:

Grease Spot Test → Translucent Mark (Lipids)

Ethanol Test → Cloudy White Layer (Lipids)



---

3. Micronutrients

🔽
Minerals
➝ Calcium (Bones & Teeth) → Deficiency: Rickets
➝ Iron (Hemoglobin Production) → Deficiency: Anemia
➝ Sodium (Nerve Function & Fluid Balance) → Excess: High Blood Pressure
➝ Sources: Dairy, Leafy Greens, Red Meat, Salt

🔽
Vitamins
➝ Vitamin A (Vision & Immunity) → Deficiency: Night Blindness (Carrots, Fish Liver Oil)
➝ Vitamin B1 (Metabolism) → Deficiency: Beri-Beri (Cereals, Yeast)
➝ Vitamin C (Tissue Formation) → Deficiency: Scurvy (Citrus Fruits)
➝ Vitamin D (Calcium Absorption) → Deficiency: Rickets (Sunlight, Fish Liver Oil)
➝ Key Test: DCPIP Test → Colorless (Vitamin C Present)


---

4. Water & Fiber

🔽
Water
➝ Functions: Solvent, Transport, Temperature Regulation, Waste Removal
➝ Deficiency Effects: Dehydration → Organ Failure

🔽
Fiber
➝ Function: Aids Digestion & Prevents Constipation
➝ Sources: Vegetables, Whole Grains, Fruits


---

5. Balanced Diet & Malnutrition

🔽
Balanced Diet → Correct Proportions of Nutrients
➝ Energy Needs Depend On: Age | Gender | Activity Level | Pregnancy

🔽
Malnutrition
➝ Undernutrition → Stunted Growth, Weak Immunity
➝ Overnutrition (Obesity) → Risk of Heart Disease & Diabetes
➝ Key Data: BMI Calculation

BMI = \frac{\text{Weight (kg)}}{\text{Height (m)}^2}

Above 30 → Obese



---

6. Laboratory Tests for Nutrients

🔽
| Nutrient | Test Used | Positive Result | |-----------|----------------|----------------| | Starch | Iodine Test | Blue-Black | | Reducing Sugars | Benedict’s Test | Orange-Red (After Heating) | | Proteins | Biuret Test | Purple/Mauve | | Lipids | Ethanol Test | Cloudy White Layer | | Vitamin C | DCPIP Test | Colorless |


---

7. Evaluating Local Diets

🔽
Example Ethiopian Balanced Diet
✅ Breakfast → Bread, Chickpeas, Tea/Milk
✅ Lunch → Kei Wot, Injera, Orange/Banana
✅ Dinner → Shiro Wot, Injera, Green Pepper

🔽
Challenges & Solutions
❌ Food Shortages → Malnutrition ✅ Increase Protein Intake
❌ High Processed Food Consumption → Obesity ✅ More Fruits & Vegetables
❌ Saturated Fats → Heart Disease ✅ Reduce Processed/Fried Foods


---

Final Summary

✅ Macronutrients (Carbs, Proteins, Fats) → Provide Energy & Growth
✅ Micronutrients (Vitamins, Minerals) → Support Metabolism & Immunity
✅ Water & Fiber → Essential for Digestion & Cellular Function
✅ Balanced Diet → Prevents Malnutrition (Undernutrition & Overnutrition)
✅ Nutrient Tests → Identify Key Food Components for a Healthy Diet

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START


1. Importance of Breathing
│ ➔ Supplies O₂, removes CO₂.
│ ➔ Humans rely on active breathing (not diffusion).


2. Structure of the Respiratory System

├─ Nasal Passages: Filter, warm, moisten air.
├─ Trachea: C-shaped cartilage, cilia, mucus.
├─ Larynx: Voice production.
├─ Bronchi/Bronchioles: Branch into lungs.
└─ Alveoli: Gas exchange site (large surface area + capillaries).


3. Breathing Mechanism

├─ Inhalation
│ ├─ Diaphragm contracts (flattens).
│ ├─ Ribs rise (external intercostals contract).
│ └─ Thoracic volume ↑ → air enters.

└─ Exhalation
├─ Diaphragm relaxes (domes up).
├─ Ribs drop (gravity/internal intercostals).
└─ Thoracic volume ↓ → air exits.


4. Gas Exchange in Alveoli

├─ Requirements: Moist surfaces, short diffusion distance, rich blood supply.
├─ Process:
│ ├─ O₂ diffuses into blood.
│ └─ CO₂ diffuses out of blood.
└─ Air Composition:
├─ Inhaled: 21% O₂, 0.04% CO₂.
└─ Exhaled: 16% O₂, 4% CO₂.


5. Factors Affecting Breathing Rate

├─ Exercise → ↑ O₂ demand.
├─ Anxiety → "Fight or flight" response.
├─ Drugs: Stimulants ↑ rate; depressants ↓ rate.
├─ Altitude → Low O₂ → ↑ breathing.
├─ Weight → Restricted diaphragm movement.
└─ Smoking → Damages lungs (see below).


6. Effects of Smoking

├─ Chemicals:
│ ├─ Nicotine (addictive).
│ ├─ CO (reduces O₂ transport).
│ └─ Tar (carcinogen; paralyzes cilia).
├─ Diseases:
│ ├─ Bronchitis, COPD, lung cancer (90% smoking-linked).
│ └─ Heart disease.
└─ Economic Impact: Healthcare costs, lost income.


7. Breathing Hygiene & Artificial Respiration

├─ Hygiene:
│ ├─ Cover mouth when coughing/sneezing.
│ ├─ Oral hygiene.
│ └─ Avoid smoking/shisha.
└─ Artificial Respiration:
├─ Clear airway.
├─ Tilt head, pinch nostrils.
└─ 12 breaths/minute.


Key Definitions

├─ Tidal Volume: ~500 mL at rest.
├─ Vital Capacity: Max air volume.
└─ Diaphragm: Muscle controlling breathing.


END


### 8. Key Definitions
- Tidal Volume: Air inhaled/exhaled at rest (~500 mL).
- Vital Capacity: Maximum air volume lungs can hold.
- Alveoli: Microscopic air sacs for gas exchange.
- Diaphragm: Dome-shaped muscle below lungs.

---

Summary: The respiratory system ensures O₂ supply and CO₂ removal via specialized structures (e.g., alveoli) and coordinated muscle movements. Factors like exercise, smoking, and environment impact breathing efficiency, necessitating hygiene practices to maintain health.


### The Respiratory System
By the end of this section, you should be able to:
- Explain the importance of breathing.
- Describe the structure and function of the respiratory system.
- Understand gas exchange, factors affecting breathing, and the effects of smoking.
- Demonstrate knowledge of breathing hygiene and artificial respiration.

---

### 1. Importance of Breathing
- Purpose: Supplies oxygen (O₂) to cells and removes carbon dioxide (CO₂), a waste product of cellular respiration.
- Diffusion limitation: Humans cannot rely on simple diffusion (unlike single-celled organisms) due to large body size and high cell count.

---

### 2. Structure of the Human Respiratory System
#### Key Components:
- Nasal passages:
- Filter dust/pollen via hairs and mucus.
- Warm and moisten inhaled air.
- Trachea:
- Lined with cilia and mucus to trap particles.
- Supported by C-shaped cartilage rings (prevents collapse during swallowing).
- Larynx (voice box): Produces sound via vocal cords.
- Bronchi & Bronchioles: Branching tubes leading to alveoli.
- Alveoli:
- Tiny air sacs with a large surface area (~500 million; equivalent to a tennis court).
- Site of gas exchange; surrounded by capillaries.
- Diaphragm & Intercostal muscles: Control breathing movements.

---

### 3. Mechanism of Breathing
#### Inhalation:
- Process:
- Diaphragm contracts (flattens).
- External intercostal muscles contract, lifting ribs upward/outward.
- Thoracic volume ↑ → pressure ↓ → air rushes in.
#### Exhalation:
- Process:
- Diaphragm relaxes (domes upward).
- Ribs drop due to gravity/internal intercostal muscle contraction.
- Thoracic volume ↓ → pressure ↑ → air forced out.
- Ventilation: Movement of air in/out of lungs.

---

### 4. Gas Exchange in Alveoli
- Key Requirements:
- Large surface area, moist surfaces, short diffusion distance (0.001 mm), rich blood supply.
- Process:
- O₂ diffuses from alveoli into blood (high to low concentration).
- CO₂ diffuses from blood into alveoli.
- Composition of Air:

| Gas | Inhaled Air | Exhaled Air |
|--------------|-------------|-------------|
| Oxygen | 21% | 16% |
| CO₂ | 0.04% | 4% |
| Nitrogen | ~80% | ~80% |

---

### 5. Factors Affecting Breathing Rate
1. Exercise: ↑ O₂ demand → ↑ breathing rate/depth.
2. Anxiety: Triggers "fight or flight" response → rapid breathing.
3. Drugs:
- Stimulants (e.g., cocaine) ↑ breathing rate.
- Depressants (e.g., opioids) ↓ breathing rate.
4. Altitude: Low O₂ at high elevations → ↑ breathing rate (compensatory mechanism).
5. Weight: Obesity restricts diaphragm movement → breathlessness.
6. Smoking: Damages lungs → chronic diseases (see below).

---

### 6. Effects of Smoking
- Chemicals in Smoke:
- Nicotine: Addictive.
- Carbon Monoxide (CO): Binds to hemoglobin, reducing O₂ transport.
- Tar: Carcinogen; paralyzes cilia, leading to infections.
- Diseases:
- Bronchitis: Inflammation of bronchi.
- COPD (Chronic Obstructive Pulmonary Disease): Alveoli destruction → ↓ surface area.
- Lung cancer: 90% linked to smoking.
- Economic Impact: Loss of income (illness/death), increased healthcare costs.

---

### 7. Breathing Hygiene
- Practices:
- Cover mouth/nose when coughing/sneezing.
- Maintain oral hygiene (prevents bad breath/infection).
- Avoid smoking/shisha.
- Artificial Respiration (Mouth-to-Mouth):
1. Check airway for obstructions.
2. Tilt head back, lift chin.
3. Pinch nostrils, seal mouth, and blow air into lungs (12 breaths/minute).

---









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