Biology Notes for IGCSE 2014 & 2024

(0654) Coordinated Science  Subheadings and key concepts covered B9.1. Nervous control in humans: CNS and PNS, types of neurons, the Ref...

All organisms are able to sense changes in their environment, called stimuli , and respond to them. The part of the body that senses the...

Auxins are plant growth substances , produced by the shoot and root tips of growing plants. - Auxins in the shoot → stimulate ce...

Tropism   are responses by part of a plant   toward   of   away   from a   stimulus   coming from one direction. The movement is alwa...

Knee jerk is an involuntary reflex.  Two types of action controlled by the human nervous system are: voluntary and involuntary act...

  Farmer sometimes use   hormones   to make their animals   grow faster , or to produce more of a particular product . One hormone use...

Credit:biologie.uni-hamburg.de Hormone is a chemical substance, secreted by endocrine gland, carried by the blood , which alters the...

The amount of focusing needed by the lens depends on the distance of the object being viewed – light from near objects requires a m...

You need to be able to label parts of the eye on diagrams. 

Effectors are muscles or glands which respond when they receive impulses from motor neurones. Examples of effectors are the biceps and ...

A reflex action is an automatic response to a stimulus.  A reflex arc describes the pathway of an electrical impulse in response...

The human nervous system is made up of two parts:  Central nervous system (CNS) - brain and spinal cord : role of coordination Peri...