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*Textbooks we use for CAPS different grades and subjects*

*Lifesciences*

Grade 10-12 we use understanding life sciences

*Physical science*

Grade 10 Siyavula
Grade 11 Siyavula.
Grade 12 mind the gap

*Mathematics*

Grade 10 Classroom mathematics
Grade 11 classroom mathematics
Grade 12 mind action series

Comment with the one you use if it's different from this one

BREATHING ESSAY

Describe the mechanism of the breathing process and explain how the correct level of
respiratory gases are restored soon after running a 100 m sprint,

Mechanism of breathing process
• Inhalation (Inspiration)
• Diaphragm contracts and becomes less convex
• Abdominal muscles relax
• External intercostals muscle contract
• internal intercostal muscle relaxes
• Ribs are raised upwards and outwards
• Thoracic cavity enlarges in volume
• and pressure in lungs decreases
• Air flows through the air passages into lungs
• Lungs expand

Exhalation (Expiration)
• Diaphragm relaxes and return to its convex dome-shaped position
• External intercostals muscles relax
• and internal intercostals contract
• Ribs and sternum move inwards and downwards
• Volume of thoracic cavity decreases
• Pressure inside thoracic cavity increases
• Pressure on lungs increases and
• air rich in carbon dioxide is forced out of lungs
• through the air passages into atmosphere
Homeostatic control of carbon dioxide and oxygen

When the carbon dioxide concentration in the blood increases

• it is detected by the sensory cells (pH receptors) in the walls of the aorta near the heart
and brain
• and at the base of the carotid arteries and
• afferent sensory impulses are transmitted
• to the respiratory control centre in the medulla oblongata
• and the cardio-vascular centre
• from where efferent impulses are transmitted to the diaphragm
• and external inter-costal muscles
• which contract more actively to increase the rate and depth of breathing
• as a result, more oxygen is inhaled And
• more carbon dioxide is exhaled
• the cardiac muscles contract faster (heart beat rate increases)
• and the carbon dioxide containing blood is pumped faster to lungs
• and oxygen containing blood faster to the tissue cells
• the peripheral arterioles contract
• so that the blood flows faster through the tissues
• when the carbon dioxide concentration decreases the process slows down.

Newton’s first law of motion

States that an object continues in a state of rest or in a state of constant velocity, unless compelled to change that state by a net force.

nertia: Inertia is the natural tendency of an object to remain at rest or in motion at a constant speed along a straight line.

Mass (kg): Mass of a body is a quantitative measure of inertia

Newton’s second law of motion:
When a net external force F acts on an object the object will accelerate. The acceleration is directly proportional to the net force and inversely proportional to the mass of the object. The direction of the acceleration is the same as the direction of the net force. F=ma

Newton’s third law of motion:
Whenever one body exerts a force on a second body, the second body exerts an oppositely directed force of equal magnitude on the first body.

Newton’s law of universal gravitation:
Any two objects exert a force on each other, which is directly proportional to the product of their masses and indirectly proportional to the square of the distance between them.

Weight: Weight of an object is the gravitational force that the earth (or the planet it is on) exerts on the object. The direction of the weight is DOWN! W=mg

The normal force: The normal force is the perpendicular component of the force that the supporting surface exerts on the object being supported.

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LIFE SCIENCES ESSAYS GRADE 10-12 The document provides a clear structure on how to write the essays. This document has been created from information available from the internet and it is not meant for any business purposes (FREE SUPPLY) but to help South African Life sciences

GRADE 12

S C O P E - June Exam – 2020

1 DNA, RNA and Protein Synthesis
2 Meiosis
3 Diversity of Reproductive Strategies
4 Human Reproduction
5 Genetics and Inheritance
6 Human Nervous System
7 Receptors – Eye and Ear

One Paper Only

2 ½ hours: 150 Marks: 4 Questions

(Everything studied from January to June)

STRUCTURE OF EXAM
Section A – Objective Questions [50 marks]
Section B - Short Questions: 40 + 40 [80 marks]
Section C – Unstructured Mini Essay [20 marks]

ESSAY COULD BE ON ANYTHING – SO LEARN EVERYTHING.

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