IGCSE Biology Online Course

IGCSE Biology helps learners to understand the biological world in which they live and take an informed interest in science and scientific developments. The syllabus includes the basic principles and concepts that are fundamental to the subject, some current applications of biology, and a strong emphasis on practical skills.

Course Content:

1: Characteristics and classification of living organisms

• Characteristics of living organisms
• Core
  • Describe the characteristics of living organisms
  by defining the terms:
  – movement as an action by an organism
  causing a change of position or place
  – respiration as the chemical reactions in cells
  that break down nutrient molecules and
  release energy
  – sensitivity as the ability to detect and respond
  to changes in the environment
  – growth as a permanent increase in size
  – reproduction as the processes that make
  more of the same kind of organism
  – excretion as removal from organisms of
  toxic materials and substances in excess of
  requirements
  – nutrition as taking in of materials for energy,
  growth and development

Concept and use of a classification system
Core
• State that organisms can be classified into groups by the features that they share
• Define species as a group of organisms that can reproduce to produce fertile offspring
• Define and describe the binomial system of naming species as an internationally agreed system in which the scientific name of an the organism is made up of two parts showing the genus and species

Features of organisms
Core
• List the features in the cells of all living
organisms, limited to cytoplasm, cell membrane
and DNA as genetic material
• List the main features used to place animals and
plants into the appropriate kingdoms
• List the main features used to place organisms
into groups within the animal kingdom, limited
to:
– the main groups of vertebrates: mammals,
birds, reptiles, amphibians, fish
– the main groups of arthropods: myriapods,
insects, arachnids, crustaceans

Dichotomous keys
Core
• Construct and use simple dichotomous keys
based on easily identifiable features

2:Organisation of the organism

Cell structure and organisation
Core
• Describe and compare the structure of a plant
cell with an animal cell, as seen under a light microscope, limited to cell wall, nucleus,
cytoplasm, chloroplasts, vacuoles and location of the cell membrane
• State the functions of the structures seen under the light microscope in the plant cell and in the
animal cell

Levels of organization
Core
• Relate the structure of the following to their
functions:
– ciliated cells – movement of mucus in the
trachea and bronchi
– root hair cells – absorption
– xylem vessels – conduction and support
– palisade mesophyll cells – photosynthesis
– nerve cells – conduction of impulses
– red blood cells – transport of oxygen
– sperm and egg cells – reproduction
• Define tissue as a group of cells with similar structures, working together to perform a shared function
• Define organ as a structure made up of a group of tissues, working together to perform specific functions
• Define organ system as a group of organs with related functions, working together to perform
body functions
• State examples of tissues, organs and organ

• Identify the different levels of organisation
in drawings, diagrams and images of familiar
materia

Size of specimens
Core
• Calculate magnification and size of biological specimens using millimetres as units

3 Movement in and out of cells
Diffusion
Core
• Define diffusion as the net movement of particles from a region of their higher concentration to
a region of their lower concentration down a concentration gradient, as a result of their
random movement
• Describe the importance of diffusion of gases and solutes
• State that substances move into and out of cells by diffusion through the cell membrane

Osmosis
Core
• State that water diffuses through partially permeable membranes by osmosis
• State that water moves in and out of cells by osmosis through the cell membrane
• Investigate and describe the effects on plant tissues of immersing them in solutions of different concentrations
• State that plants are supported by the pressure of water inside the cells pressing outwards on the
cell wall

Active transport
Core
• Define active transport as the movement of particles through a cell membrane from a region of lower concentration to a region of higher concentration using energy from respiration

4 Biological molecules

Core
• List the chemical elements that make up:
– carbohydrates
– fats
– proteins
• State that large molecules are made from smaller molecules, limited to:
– starch and glycogen from glucose
– cellulose from glucose
– proteins from amino acids
– fats and oils from fatty acids and glycerol
• Describe the use of:
– iodine solution to test for starch
– Benedict’s solution to test for reducing sugars
– biuret test for proteins
– ethanol emulsion test for fats and oils
– DCPIP test for vitamin C

State that water is important as a solvent

5 Enzymes

Core

• Define the term catalyst as a substance that ncreases the rate of a chemical reaction and is
• not changed by the reaction
  • Define enzymes as proteins that function as biological catalysts
  • Describe why enzymes are important in all living organisms in terms of reaction speed necessaryto sustain life
  • Describe enzyme action with reference to the complementary shape of an enzyme and
  its substrate and the formation of a product (knowledge of the term active site is not
  required)
  • Investigate and describe the effect of changes in temperature and pH on enzyme activity

6: Plant Nutrition

Photosynthesis
Core
• Define photosynthesis as the process by which plants manufacture carbohydrates from raw materials using energy from light
• State the word equation for photosynthesis: carbon dioxide + water → glucose + oxygen, in
the presence of light and chlorophyll
• Investigate the necessity for chlorophyll, light and carbon dioxide for photosynthesis, using
appropriate controls
• Investigate and describe the effects of varying light intensity, carbon dioxide concentration and
temperature on the rate of photosynthesis, e.g. in submerged aquatic plants

Leaf structure
Core
• Identify chloroplasts, cuticle, guard cells and stomata, upper and lower epidermis, palisademesophyll, spongy mesophyll, vascular bundles, xylem and phloem in leaves of a dicotyledonous plant

 Mineral requirements
Core
• Describe the importance of:
– nitrate ions for making amino acids
– magnesium ions for making chlorophyll

7 Human nutrition
 Diet
Core
• State what is meant by the term balanced diet for humans
• Explain how age, gender and activity affect the dietary needs of humans including during pregnancy and whilst breast-feeding
• Describe the effects of malnutrition in relation to starvation, constipation, coronary heart disease,
obesity and scurvy
• List the principal sources of, and describe the
dietary importance of:
– carbohydrates
– fats
– proteins
– vitamins, limited to C and D
– mineral salts, limited to calcium and iron
– fibre (roughage)
– water

Alimentary canal

Core
• Define ingestion as the taking of substances, e.g.
food and drink, into the body through the mouth
• Define mechanical digestion as the breakdown of
food into smaller pieces without chemical change
to the food molecules
• Define chemical digestion as the breakdown of
large, insoluble molecules into small, soluble
molecules
• Define absorption as the movement of small
food molecules and ions through the wall of the
intestine into the blood
• Define assimilation as the movement of digested
food molecules into the cells of the body where
they are used, becoming part of the cells
• Define egestion as the passing out of food that
has not been digested or absorbed, as faeces,
through the anus
• Describe diarrhoea as the loss of watery faeces
• Outline the treatment of diarrhoea using oral rehydration therapy
• Describe cholera as a disease caused by a bacterium
• Identify the main regions of the alimentary canal and associated organs, limited to mouth, salivary
glands, oesophagus, stomach, small intestine (duodenum and ileum), pancreas, liver, gall bladder and large intestine (colon, rectum, anus)
• Describe the functions of the regions of the alimentary canal listed above, in relation to ingestion, digestion, absorption, assimilation indigestion of food

Mechanical digestion
Core
• Identify the types of human teeth (incisors,
canines, premolars and molars)
• Describe the structure of human teeth, limited to
enamel, dentine, pulp, nerves and cement, as well
as the gums
• Describe the functions of the types of human teeth
in mechanical digestion of food
• State the causes of dental decay in terms of a coating of bacteria and food on teeth, the bacteria respiring sugars in the food, producing acid which dissolves the enamel and dentine
• Describe the proper care of teeth in terms of diet and regular brushing

7.4 Chemical digestion
Core
• State the significance of chemical digestion in the alimentary canal in producing small, soluble molecules that can be absorbed
• State the functions of enzymes as follows:
– amylase breaks down starch to simpler
sugars
– protease breaks down protein to amino acids
– lipase breaks down fats to fatty acids and
glycerol
• State where, in the alimentary canal, amylase, protease and lipase are secreted
• State the functions of the hydrochloric acid in gastric juice, limited to killing bacteria in food and giving an acid pH for enzymes

Absorption
Core
• Identify the small intestine as the region for the absorption of digested food
• State that water is absorbed in both the small intestine and the colon, but that most absorption
of water happens in the small intestine

8:Transport in plants
Core
• State the functions of xylem and phloem
• Identify the position of xylem and phloem as seen in sections of roots, stems and leaves, limited to non-woody dicotyledonous plants

 Water uptake
Core
• Identify root hair cells, as seen under the light microscope, and state their functions
• State the pathway taken by water through root, stem and leaf as root hair cells, root cortex cells,xylem and mesophyll cells
• Investigate, using a suitable stain, the pathway of water through the above-ground parts of a plant

Transpiration
Core
• State that water is transported from the roots to leaves through the xylem vessels
• Define transpiration as loss of water vapour from plant leaves by evaporation of water at the surfaces of the mesophyll cells followed by  diffusion of water vapour through the stomata
• Investigate and describe the effects of variation of temperature and humidity on transpiration
rate

Transport in animals

Core
• Describe the circulatory system as a system of blood vessels with a pump and valves to ensure
one-way flow of blood

Heart
Core
• Name and identify the structures of the mammalian heart, limited to the muscular wall,
the septum, the left and right ventricles and atria, one-way valves and coronary arteries
• State that blood is pumped away from the heart into arteries and returns to the heart in veins
• State that the activity of the heart may be monitored by ECG, pulse rate and listening to sounds of valves closing
• Investigate and state the effect of physical activity on the pulse rate
• Describe coronary heart disease in terms of the blockage of coronary arteries and state the possible risk factors as diet, stress, smoking, genetic predisposition, age and gender

Blood and lymphatic vessels
Core
• Describe the structure and functions of arteries,
veins and capillaries
• Name the main blood vessels to and from the:
– heart, limited to vena cava, aorta, pulmonary
artery and pulmonary vein
– lungs, limited to the pulmonary artery and
pulmonary vein
– kidney, limited to the renal artery and renal vein

9 Blood
Core
• List the components of blood as red blood cells, white blood cells, platelets and plasma
• Identify red and white blood cells, as seen under the light microscope, on prepared slides and in
diagrams and photomicrographs
• State the functions of the following components
of blood:
– red blood cells in transporting oxygen,
including the role of haemoglobin
– white blood cells in phagocytosis and
antibody production
– platelets in clotting (details are not required)
– plasma in the transport of blood cells, ions, soluble nutrients, hormones and carbon dioxide

10:Diseases and immunity
Core
• Define pathogen as a disease-causing organism
• Define transmissible disease as a disease in which the pathogen can be passed from one host to
another
• State that the pathogen for a transmissible disease may be transmitted either through direct
contact, e.g. through blood or other body fluids, or indirectly, e.g. from contaminated surfaces or food, from animals, or from the air
• State that the body has defences:
– mechanical barriers, limited to skin and hairs
in the nose
– chemical barriers, limited to mucus and
stomach acid
– cells, limited to phagocytosis and antibody
production by white blood cells
– which can be enhanced by vaccination

Diseases and immunity continued
Core
• Explain the importance of hygienic food preparation, good personal hygiene, waste disposal and sewage treatment in controlling the spread of disease

11 Gas exchange in humans

Core
• List the features of gas exchange surfaces in humans, limited to large surface area, thin surface, good blood supply and good ventilation with air
• Name and identify the lungs, diaphragm, ribs,
intercostal muscles, larynx, trachea, bronchi,
bronchioles, alveoli and associated capillaries
• State the differences in composition between inspired and expired air, limited to oxygen,carbon dioxide and water vapour
• Use limewater as a test for carbon dioxide to investigate the differences in composition between inspired and expired air
• Investigate and describe the effects of physical activity on rate and depth of breathing

12Respiration
Core
• State the uses of energy in the body of humans:
muscle contraction, protein synthesis, cell
division, active transport, growth, the passage
of nerve impulses and the maintenance of a
constant body temperature
• State that respiration involves the action of
enzymes in cells

Aerobic respiration
Core
• Define aerobic respiration as the chemical
reactions in cells that use oxygen to break down
nutrient molecules to release energy
• State the word equation for aerobic respiration as
glucose + oxygen → carbon dioxide + water
• Investigate the uptake of oxygen by respiring organisms, such as arthropods and germinating
seeds

Anaerobic respiration
Core
• Define anaerobic respiration as the chemical
reactions in cells that break down nutrient
molecules to release energy without using
oxygen
• State the word equations for anaerobic
respiration in muscles during vigorous exercise (glucose → lactic acid) and in
the microorganism yeast (glucose → alcohol + carbon dioxide)
• State that anaerobic respiration releases much less energy per glucose molecule than aerobic respiration

13:Excretion in humans

Core
• State that urea is formed in the liver from excess
amino acids
• State that carbon dioxide is excreted through the
lungs
• State that the kidneys excrete urea and excess water and salts
• Explain that the volume and concentration of urine produced is affected by water intake, temperature and exercise
• Identify on drawings, diagrams and images, the ureters, bladder and urethra

Details of the assessment

All candidates take three papers.
Candidates who have studied the Core subject content, or who are expected to achieve a grade D or below, should
be entered for Paper 1, Paper 3 and either Paper 5 or Paper 6. These candidates will be eligible for grades C to G.
Candidates who have studied the Extended subject content (Core and Supplement), and who are expected to
achieve a grade C or above, should be entered for Paper 2, Paper 4 and either Paper 5 or Paper 6. These candidates
will be eligible for grades A* to G.