Year 10 Biology IGCSE Revision Booklet

This booklet is a comprehensive guide to everything you need to know before your exams.

In your exam in the summer you will sit a 90 minute paper. In the following pages you
have a list of all the topics you are meant to know for the exam.
Contents of this booklet
1. Syllabus of the IGCSE course covering all points
2. Answering longer questions
3. How to answer an investigation style question
4. How to draw a graph
5. Experimental procedures you need to know

YOU ALSO NEED TO REVISE PRACTICAL SKILLS

LOOK AT APPENDIX A (PAGES 303-307) IN YOUR TEXT
BOOK AND READ!
 1. Syllabus
1 The nature and variety of living organisms
The following sub-topics are covered in this section.
(a) Characteristics of living organisms
(b) Variety of living organisms

(a) Characteristics of living organisms

Students should:

1.1 understand how living organisms share the following characteristics:

• they require nutrition
• they respire
• they excrete their waste
• they respond to their surroundings
• they move
• they control their internal conditions
• they reproduce
• they grow and develop.

(b) Variety of living organisms

Students should:

1.2 describe the common features shown by eukaryotic organisms: plants, animals, fungi and
protoctists
Plants: these are multicellular organisms; their cells contain chloroplasts and are able to carry out
photosynthesis; their cells have cellulose cell walls; they store carbohydrates as starch or sucrose.
Examples include flowering plants, such as a cereal (for example, maize), and a herbaceous
legume (for example, peas or beans).
Animals: these are multicellular organisms; their cells do not contain chloroplasts and are not able
to carry out photosynthesis; they have no cell walls; they usually have nervous co-ordination and
are able to move from one place to another; they often store carbohydrate as glycogen. Examples
include mammals (for example, humans) and insects (for example, housefly and mosquito).
Fungi: these are organisms that are not able to carry out photosynthesis; their body is usually
organised into a mycelium made from thread-like structures called hyphae, which contain many
nuclei; some examples are single-celled; their cells have walls made of chitin; they feed by
extracellular secretion of digestive enzymes onto food material and absorption of the organic
products; this is known as saprotrophic nutrition; they may store carbohydrate as glycogen.
Examples include Mucor, which has the typical fungal hyphal structure, and yeast, which is single-
celled.
Protoctists: these are microscopic single-celled organisms. Some, like Amoeba, that live in pond
water, have features like an animal cell, while others, like Chlorella, have chloroplasts and are
more like plants. A pathogenic example is Plasmodium, responsible for causing malaria.

Students should:

1.3 describe the common features shown by prokaryotic organisms such as bacteria
Bacteria: these are microscopic single-celled organisms; they have a cell wall, cell membrane,
cytoplasm and plasmids; they lack a nucleus but contain a circular chromosome of DNA; some
bacteria can carry out photosynthesis but most feed off other living or dead organisms. Examples
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 include Lactobacillus bulgaricus, a rod-shaped bacterium used in the production of yoghurt from
milk, and Pneumococcus, a spherical bacterium that acts as the pathogen causing pneumonia.
1.4 understand the term pathogen and know that pathogens may include fungi, bacteria, protoctists
or viruses
Viruses: these are not living organisms. They are small particles, smaller than bacteria; they are
parasitic and can reproduce only inside living cells; they infect every type of living organism. They
have a wide variety of shapes and sizes; they have no cellular structure but have a protein coat
and contain one type of nucleic acid, either DNA or RNA. Examples include the tobacco mosaic
virus that causes discolouring of the leaves of tobacco plants by preventing the formation of
chloroplasts, the influenza virus that causes ‘flu’ and the HIV virus that causes AIDS.

2 Structure and functions in living organisms

The following sub-topics are covered in this section.
(a) Level of organisation
(b) Cell structure
(c) Biological molecules
(d) Movement of substances into and out of cells
(e) Nutrition
(f) Respiration
(g) Gas exchange
(h) Transport
(j) Co-ordination and response

(a) Level of organisation

Students should:

2.1 describe the levels of organisation in organisms: organelles, cells, tissues, organs and systems

(b) Cell structure

Students should:

2.2 describe cell structures, including the nucleus, cytoplasm, cell membrane, cell wall, mitochondria,
chloroplasts, ribosomes and vacuole
2.3 describe the functions of the nucleus, cytoplasm, cell membrane, cell wall, mitochondria,
chloroplasts, ribosomes and vacuole
2.4 know the similarities and differences in the structure of plant and animal cells
2.5B explain the importance of cell differentiation in the development of specialised cells
2.6B understand the advantages and disadvantages of using stem cells in medicine

(c) Biological molecules

Students should:

2.7 identify the chemical elements present in carbohydrates, proteins and lipids (fats and oils)
2.8 describe the structure of carbohydrates, proteins and lipids as large molecules made up from
smaller basic units: starch and glycogen from simple sugars, protein from amino acids, and lipid
from fatty acids and glycerol
2.9 practical: investigate food samples for the presence of glucose, starch, protein and fat
2.10 understand the role of enzymes as biological catalysts in metabolic reactions
2.11 understand how temperature changes can affect enzyme function, including changes to the shape
of active site

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2.12 practical: investigate how enzyme activity can be affected by changes in temperature
2.13 understand how enzyme function can be affected by changes in pH altering the active site
2.14B practical: investigate how enzyme activity can be affected by changes in pH

(d) Movement of substances into and out of cells

Students should:

2.15 understand the processes of diffusion, osmosis and active transport by which substances move
into and out of cells
2.16 understand how factors affect the rate of movement of substances into and out of cells, including
the effects of surface area to volume ratio, distance, temperature and concentration gradient
2.17 practical: investigate diffusion and osmosis using living and non-living systems

(e) Nutrition
Students should:

Flowering plants
2.18 understand the process of photosynthesis and its importance in the conversion of light energy to
chemical energy
2.19 know the word equation and the balanced chemical symbol equation for photosynthesis
2.20 understand how varying carbon dioxide concentration, light intensity and temperature affect the
rate of photosynthesis
2.21 describe the structure of the leaf and explain how it is adapted for photosynthesis
2.22 understand that plants require mineral ions for growth, and that magnesium ions are needed for
chlorophyll and nitrate ions are needed for amino acids
2.23 practical: investigate photosynthesis, showing the evolution of oxygen from a water plant, the
production of starch and the requirements of light, carbon dioxide and chlorophyll

Humans
2.24 understand that a balanced diet should include appropriate proportions of carbohydrate, protein,
lipid, vitamins, minerals, water and dietary fibre
2.25 identify the sources and describe the functions of carbohydrate, protein, lipid (fats and oils),
vitamins A, C and D, the mineral ions calcium and iron, water and dietary fibre as components of
the diet
2.26 understand how energy requirements vary with activity levels, age and pregnancy
2.27 describe the structure and function of the human alimentary canal, including the mouth,
oesophagus, stomach, small intestine (duodenum and ileum), large intestine (colon and rectum)
and pancreas
2.28 understand how food is moved through the gut by peristalsis
2.29 understand the role of digestive enzymes, including the digestion of starch to glucose by amylase
and maltase, the digestion of proteins to amino acids by proteases and the digestion of lipids to
fatty acids and glycerol by lipases
2.30 understand that bile is produced by the liver and stored in the gall bladder
2.31 understand the role of bile in neutralising stomach acid and emulsifying lipids
2.32 understand how the small intestine is adapted for absorption, including the structure of a villus
2.33B practical: investigate the energy content in a food sample

(f) Respiration
Students should:

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2.34 understand how the process of respiration produces ATP in living organisms
2.35 know that ATP provides energy for cells
2.36 describe the differences between aerobic and anaerobic respiration
2.37 know the word equation and the balanced chemical symbol equation for aerobic respiration in
living organisms
2.38 know the word equation for anaerobic respiration in plants and in animals
2.39 practical: investigate the evolution of carbon dioxide and heat from respiring seeds or other
suitable living organisms

(g) Gas exchange

Students should:

Humans
2.46 describe the structure of the thorax, including the ribs, intercostal muscles, diaphragm, trachea,
bronchi, bronchioles, alveoli and pleural membranes
2.47 understand the role of the intercostal muscles and the diaphragm in ventilation
2.48 explain how alveoli are adapted for gas exchange by diffusion between air in the lungs and blood
in capillaries
2.49 understand the biological consequences of smoking in relation to the lungs and the circulatory
system, including coronary heart disease
2.50 practical: investigate breathing in humans, including the release of carbon dioxide and the effect
of exercise

(h) Transport
Students should:

2.51 understand why simple, unicellular organisms can rely on diffusion for movement of substances in
and out of the cell
2.52 understand the need for a transport system in multicellular organisms

Flowering plants
2.53 describe the role of phloem in transporting sucrose and amino acids between the leaves and
other parts of the plant
2.54 describe the role of xylem in transporting water and mineral ions from the roots to other parts of
the plant
2.55B understand how water is absorbed by root hair cells
2.56B understand that transpiration is the evaporation of water from the surface of a plant
2.57B understand how the rate of transpiration is affected by changes in humidity, wind speed,
temperature and light intensity
2.58B practical: investigate the role of environmental factors in determining the rate of transpiration
from a leafy shoot

Humans
2.59 describe the composition of the blood: red blood cells, white blood cells, platelets and plasma
2.60 understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones
and heat energy
2.61 understand how adaptations of red blood cells make them suitable for the transport of oxygen,
including shape, the absence of a nucleus and the presence of haemoglobin
2.62 understand how the immune system responds to disease using white blood cells, illustrated by
phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen

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2.63B understand how vaccination results in the manufacture of memory cells, which enable future
antibody production to the pathogen to occur sooner, faster and in greater quantity
2.64B understand how platelets are involved in blood clotting, which prevents blood loss and the
entry of micro-organisms
2.65 describe the structure of the heart and how it functions
2.66 explain how the heart rate changes during exercise and under the influence of adrenaline
2.67 understand how factors may increase the risk of developing coronary heart disease
2.68 understand how the structure of arteries, veins and capillaries relate to their function
2.69 understand the general structure of the circulation system, including the blood vessels to and
from the heart and lungs, liver and kidneys

(j) Co-ordination and response

Students should:

2.80 understand how organisms are able to respond to changes in their environment
2.81 understand that homeostasis is the maintenance of a constant internal environment, and that
body water content and body temperature are both examples of homeostasis
2.82 understand that a co-ordinated response requires a stimulus, a receptor and an effector

Flowering plants
2.83 understand that plants respond to stimuli
2.84 describe the geotropic and phototropic responses of roots and stems
2.85 understand the role of auxin in the phototropic response of stems

Humans
2.86 describe how nervous and hormonal communication control responses and understand the
differences between the two systems
2.87 understand that the central nervous system consists of the brain and spinal cord and is linked to
sense organs by nerves
2.88 understand that stimulation of receptors in the sense organs sends electrical impulse along
nerves into and out of the central nervous system, resulting in rapid responses
2.89 understand the role of neurotransmitters at synapses
2.90 describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a
finger from a hot object
2.91 describe the structure and function of the eye as a receptor
2.92 understand the function of the eye in focusing on near and distant objects, and in responding to
changes in light intensity
2.93 describe the role of the skin in temperature regulation, with reference to sweating,
vasoconstriction and vasodilation
2.94 understand the sources, roles and effects of the following hormones: adrenaline, insulin,
testosterone, progesterone and oestrogen
2.95B understand the sources, roles and effects of the following hormones: ADH, FSH and LH

4 Ecology and the environment

The following sub-topics are covered in this section.
(a) The organism in the environment
(b) Feeding relationships

(a) The organism in the environment

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Students should:

4.1 understand the terms population, community, habitat and ecosystem

4.2 practical: investigate the population size of an organism in two different areas using quadrats
4.3B understand the term biodiversity
4.4B practical: investigate the distribution of organisms in their habitats and measure biodiversity
using quadrats
4.5 understand how abiotic and biotic factors affect the population size and distribution of organisms

(b) Feeding relationships

Students should:

4.6 understand the names given to different trophic levels, including producers, primary, secondary
and tertiary consumers and decomposers
4.7 understand the concepts of food chains, food webs, pyramids of number, pyramids of biomass
and pyramids of energy transfer
4.8 understand the transfer of substances and energy along a food chain
4.9 understand why only about 10% of energy is transferred from one trophic level to the next

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 2. Answering longer questions
• Look how many marks are available. If it is six marks you need at least six separate
points, ideally seven in case one of yours isn’t correct.
• Read the question twice and underline the key words
• Look at the command word at the beginning. Is it describe, explain, or state? Think
before writing!
• Use specific technical biology words (see the glossary from page 309 in your text
book)

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 3. How to answer an investigation style question
These questions can occur on either of the two papers you sit and form part of your examination
alternative to coursework.

Each question is normally out of 6 marks and has 7 marking points available.

These are the same 7 types of marking point EVERY TIME. That means if you learn how to answer these
questions you can guarantee yourself a high mark on this type of question.

 Compare – This marking point refers to talking about the variable you are going to change (your
independent variable) and how you will vary it

 Organism – This marking point is for discussing how you will stop the organism being
investigated affecting the results e.g. same species / size / age / sex

 Replication – This marking point is for saying you intend to carry out repeats (to increase the
reliability of your experiment)

 Measure – This covers two marking points:

o The first is for saying what you will measure during the investigation (the dependent
variable)
o The second is for stating the time you will leave between readings

 Same –This also covers two marking points and they are each for stating a variable you will keep
the same (a control variable). These should be different to your Organism variable from above
e.g. temperature / light intensity

Example question from June 2009

“Design an investigation you could carry out to find out if the distance seeds are sown apart affects the
growth of the young plants they produce”

 Compare: Seeds should be sown at different distances apart

 Organism: The same species/age of plant should be used
 Replication: Repeats should be carried out
 Measure 1: To determine growth measure the mass/length/height of the plant. . .
 Measure 2: . . .After a period of X days
 Same 1: Ensure the same levels of light intensity/pH/water/nutrients/minerals etc. . .
 Same 2: . . .and light intensity/pH/water/nutrients/minerals etc.

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 4. How to draw a graph
These questions can occur on either of the two papers you sit and form part of your examination
alternative to coursework.

Each question is normally out of 5 marks and has 5 marking points available (out of six possible choices).

They have the same 6 types of marking point EVERY TIME. That means if you learn how to answer
these questions you can guarantee yourself a high mark on this type of question.

 Scale – must be linear and take up over half the graph grid provided in each direction

 Line – FOR LINE GRAPHS ONLY; line of best fit should be present and correct, in most cases
this will be joining each point with a straight line using a ruler

 Axes – must be drawn on and labelled the correct way around (independent variable on the X axis,
dependent variable on the Y axis)

 Points – must all be plotted correctly

 Units – must be present on the axis label where appropriate

 Key – mostly for bar charts and line graphs with multiple lines, must be present if required and
must clearly indicate which points belong to which category

5. Experimental procedures you need to know (and where to find

them in your textbook)
 2.9 practical: investigate food samples for the presence of glucose, starch, protein and fat (page 58)
 2.12 practical: investigate how enzyme activity can be affected by changes in temperature (pages 9-10)
 2.14B practical: investigate how enzyme activity can be affected by changes in pH (page 11)
 2.17 practical: investigate diffusion and osmosis using living and non-living systems (page 17)
 2.23 practical: investigate photosynthesis, showing the evolution of oxygen from a water plant,
the production of starch and the requirements of light, carbon dioxide and chlorophyll (pages
136, 137 and 143-144)
 2.33B practical: investigate the energy content in a food sample (pages 60-61)
 2.39 practical: investigate the evolution of carbon dioxide and heat from respiring seeds or other
suitable living organisms (pages 14 and 5)
 2.50 practical: investigate breathing in humans, including the release of carbon dioxide and the
effect of exercise (pages 44 and 44-45)
 2.58B practical: investigate the role of environmental factors in determining the rate of
transpiration from a leafy shoot (page 163)
 4.2 practical: investigate the population size of an organism in two different areas using quadrats
(pages 189-190)
 4.4B practical: investigate the distribution of organisms in their habitats and measure
biodiversity using quadrats (pages 191-192)
 5.6 practical: investigate the role of anaerobic respiration by yeast in different conditions (pages
283-284)