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IGCSE Biology
,Unit 1: Human Biology
There are millions of different plants and animals in the world. To make it easier to identify them, we place them into different
groups. These groups contain organisms whose characteristics are similar. The process of classifying organism is called
taxonomy. Classification itself means identifying and grouping organisms.
Living organisms are placed into groups, called kingdoms.
There are five kingdoms:
Plants Multicellular (Their bodies are made up of many cells)
Cells contain chloroplasts which carry out photosynthesis (carbon dioxide + water -> glucose + oxygen)
Green
Contains a stem, roots, leaves and the flower
Cells contain (in addition to nucleus, cell membrane and cytoplasm) cell wall, vacuole and chloroplasts
Animals Multicellular
Movement involves coordination by the nervous system
Gains energy by feeding on other animals/plants
Cells lack cell walls so they can change shape
Fungi Some such as mushrooms and Mucor are Multicellular. Others such as yeasts are unicellular (made of
single cells).
Cannot carry out photosynthesis
Body is usually organized into a mycelium made from thread-like structures called hyphae.
They have cell walls made of chitin
Feed on nutrients from the dead – or they decompose by producing extracellular enzymes that digest
the dead material outside of the organsim
Produces spores for reproduction
Protoctists Unicellular
Examples include amoeba, chlorella and plasmodium (which is responsible for malaria)
Prokaryotes Unicelluluar
Eukaryotes
Examples include bacteria
Bacteria
Unicellular – have a cell wall, cell membrane, cytoplasm and
plasmids
Lacks nucleus but contains DNA
Some can photosynthesis but most feed off other living or dead
organisms
Examples include Lactobacillus bulgaricus
Viruses are parasitic, smaller than
bacteria, have no cellular structure but
have a protein coat and one type of
nucleic acid, either DNA or RNA. They can only reproduce inside living cells and infect every
type of living organism. Examples include the influenza virus, and HIV. Fungi, bacteria,
protoctists or viruses can be pathogens – agents that cause disease.
Defining ‘Living’
Movement
Respiration
,Senses
Growth
Reproduction
Excretion
Nutrition
*Note: Viruses are NOT living things. They do not feed, respire, excrete, move, grow or respond to their surroundings. They only
reproduce – but they do it parasitically by entering a host cell and taking over the host’s genetic machinery to make more virus
cells.
Understanding Genus’s and Species
A genus is the second last classification group. Kingdoms such as animals are divided into smaller groups such as mammals. That
can then be divided into even smaller groups such as… dolphins! And then even smaller, such as pink-nose dolphin! Get the
idea? Unfortunately we’re talking about Latin names here.
Key point here: No different species can reproduce with each other.
An example would be Homosapien. ‘Homo’ is the genus, because there are lots of other ‘Homos’ out there such as Homo
neanderthelansis. ‘Sapien’ is the species name.
Other Groups Lower Down Kingdoms
Anyways these are the groups from the biggest down to the smallest – or from the very first level of classification down to the
last.
- kingdom
- phylum
- class
- order
- family
- genus
- species
Kate Perry Cooks Only For Good Singers
Nutrition
Carbohydrate molecules are made up of small sub-units called sugars. Sugars are made from
carbon, hydrogen and oxygen atoms arranged in a ring/hexagon-shaped molecule. Examples
include glucose C6H12O6. Groups of sugar molecules can link together to make larger
molecules and long chain polymers called polysaccharides. Carbs provide the main source of
energy for respiration in living organisms.
Fats are made up of glycerol linked to fatty acids. Like
carbohydrates, fats are also a source of energy. Examples of
fatty acids include oleac acid, stearic acid and palmitic acid.
, Proteins are made up of long chains of amino acids linked together. Proteins are important for growth and repair. Examples
include glycine, alanine, valine and cysteine.
Water makes up the bulk of the cytoplasm. It takes part in the many chemical reactions happening inside the cytoplasm. Salts
of potassium, sodium, calcium and many others play an important role in these reactions.
Carbohydrates Provides quick energy. 60% of our diet should comprise 'carbs'. They make Pasta, cereals and potatoes
up 5% of our body mass.
Fats Provides slow energy. 25% of our diet should be fat. They make up 10% of Oils, dairy products, nuts and
our body mass. fish
Protein Builds and repairs muscle. We only need 15% of our diet to be protein. Meat, pulses and fish
Makes up 18% of the mass in our body.
Fibre Can't be digested. Fills you up and keeps you 'regular' Fresh fruit, vegetables and
wholegrain cereals
Minerals Calcium – Making teeth and bones Found in diary products, fish,
Phosphorus – making teeth and bones; part of many chemicals such as bread, vegetables, red meat
DNA e.g.
Magnesium – Making bones, found inside cells
Iron – Part of haemoglobin in red blood cells, helps carry oxygen
Water Maintains fluid levels The tap
Vitamin Use Effect of Deficiency Where you get it
A Making a chemical in the retina; also Night blindness, damaged cornea Fish liver oils, liver, butter,
protects the surface of the eye margarine, carrots
B1 Helps with cell respiration Beri-Beri Yeast extract, cereals
B2 Helps with cell respiration Poor growth, dry skin Green vegetables, eggs, fish
B3 Helps with cell respiration Pellagra (dry red skin, poor growth, Liver, meat, fish
and digestive disorders)
C Sticks together cells lining surfaces such Scurvy Fresh fruit and vegetables
as the mouth
D Helps bones absorb calcium and Rickets, poor teeth Fish liver oils; also made in
phosphate skin in sunlight
Food Tests
Test for Starch
Dilute iodine solution reacts with starch, forming a very dark blue colour. This test will work on a solid sample of food, such as
potato, or a suspension of starch on water.
Test for Glucose
Glucose is called a reducing sugar. This is because the test for glucose
involves chemically reducing an alkaline solution of copper sulphate to
copper(I) oxide.
The test for glucose is called the Benedict’s test. Simply add a few drops
of Benedict’s solution, which contains alkaline copper sulphate, to some
glucose. Add enough to turn the mixture blue. Then heat the mixture in
a boiling water bath. The clear blue solution will gradually change
colour, forming a cloudy orange or brick red precipitate of copper(I)
oxide. All ‘single’ sugars such as fructose are reducing sugars, as well as
some ‘double’ sugars, such as the milk sugar.
IGCSE Biology
,Unit 1: Human Biology
There are millions of different plants and animals in the world. To make it easier to identify them, we place them into different
groups. These groups contain organisms whose characteristics are similar. The process of classifying organism is called
taxonomy. Classification itself means identifying and grouping organisms.
Living organisms are placed into groups, called kingdoms.
There are five kingdoms:
Plants Multicellular (Their bodies are made up of many cells)
Cells contain chloroplasts which carry out photosynthesis (carbon dioxide + water -> glucose + oxygen)
Green
Contains a stem, roots, leaves and the flower
Cells contain (in addition to nucleus, cell membrane and cytoplasm) cell wall, vacuole and chloroplasts
Animals Multicellular
Movement involves coordination by the nervous system
Gains energy by feeding on other animals/plants
Cells lack cell walls so they can change shape
Fungi Some such as mushrooms and Mucor are Multicellular. Others such as yeasts are unicellular (made of
single cells).
Cannot carry out photosynthesis
Body is usually organized into a mycelium made from thread-like structures called hyphae.
They have cell walls made of chitin
Feed on nutrients from the dead – or they decompose by producing extracellular enzymes that digest
the dead material outside of the organsim
Produces spores for reproduction
Protoctists Unicellular
Examples include amoeba, chlorella and plasmodium (which is responsible for malaria)
Prokaryotes Unicelluluar
Eukaryotes
Examples include bacteria
Bacteria
Unicellular – have a cell wall, cell membrane, cytoplasm and
plasmids
Lacks nucleus but contains DNA
Some can photosynthesis but most feed off other living or dead
organisms
Examples include Lactobacillus bulgaricus
Viruses are parasitic, smaller than
bacteria, have no cellular structure but
have a protein coat and one type of
nucleic acid, either DNA or RNA. They can only reproduce inside living cells and infect every
type of living organism. Examples include the influenza virus, and HIV. Fungi, bacteria,
protoctists or viruses can be pathogens – agents that cause disease.
Defining ‘Living’
Movement
Respiration
,Senses
Growth
Reproduction
Excretion
Nutrition
*Note: Viruses are NOT living things. They do not feed, respire, excrete, move, grow or respond to their surroundings. They only
reproduce – but they do it parasitically by entering a host cell and taking over the host’s genetic machinery to make more virus
cells.
Understanding Genus’s and Species
A genus is the second last classification group. Kingdoms such as animals are divided into smaller groups such as mammals. That
can then be divided into even smaller groups such as… dolphins! And then even smaller, such as pink-nose dolphin! Get the
idea? Unfortunately we’re talking about Latin names here.
Key point here: No different species can reproduce with each other.
An example would be Homosapien. ‘Homo’ is the genus, because there are lots of other ‘Homos’ out there such as Homo
neanderthelansis. ‘Sapien’ is the species name.
Other Groups Lower Down Kingdoms
Anyways these are the groups from the biggest down to the smallest – or from the very first level of classification down to the
last.
- kingdom
- phylum
- class
- order
- family
- genus
- species
Kate Perry Cooks Only For Good Singers
Nutrition
Carbohydrate molecules are made up of small sub-units called sugars. Sugars are made from
carbon, hydrogen and oxygen atoms arranged in a ring/hexagon-shaped molecule. Examples
include glucose C6H12O6. Groups of sugar molecules can link together to make larger
molecules and long chain polymers called polysaccharides. Carbs provide the main source of
energy for respiration in living organisms.
Fats are made up of glycerol linked to fatty acids. Like
carbohydrates, fats are also a source of energy. Examples of
fatty acids include oleac acid, stearic acid and palmitic acid.
, Proteins are made up of long chains of amino acids linked together. Proteins are important for growth and repair. Examples
include glycine, alanine, valine and cysteine.
Water makes up the bulk of the cytoplasm. It takes part in the many chemical reactions happening inside the cytoplasm. Salts
of potassium, sodium, calcium and many others play an important role in these reactions.
Carbohydrates Provides quick energy. 60% of our diet should comprise 'carbs'. They make Pasta, cereals and potatoes
up 5% of our body mass.
Fats Provides slow energy. 25% of our diet should be fat. They make up 10% of Oils, dairy products, nuts and
our body mass. fish
Protein Builds and repairs muscle. We only need 15% of our diet to be protein. Meat, pulses and fish
Makes up 18% of the mass in our body.
Fibre Can't be digested. Fills you up and keeps you 'regular' Fresh fruit, vegetables and
wholegrain cereals
Minerals Calcium – Making teeth and bones Found in diary products, fish,
Phosphorus – making teeth and bones; part of many chemicals such as bread, vegetables, red meat
DNA e.g.
Magnesium – Making bones, found inside cells
Iron – Part of haemoglobin in red blood cells, helps carry oxygen
Water Maintains fluid levels The tap
Vitamin Use Effect of Deficiency Where you get it
A Making a chemical in the retina; also Night blindness, damaged cornea Fish liver oils, liver, butter,
protects the surface of the eye margarine, carrots
B1 Helps with cell respiration Beri-Beri Yeast extract, cereals
B2 Helps with cell respiration Poor growth, dry skin Green vegetables, eggs, fish
B3 Helps with cell respiration Pellagra (dry red skin, poor growth, Liver, meat, fish
and digestive disorders)
C Sticks together cells lining surfaces such Scurvy Fresh fruit and vegetables
as the mouth
D Helps bones absorb calcium and Rickets, poor teeth Fish liver oils; also made in
phosphate skin in sunlight
Food Tests
Test for Starch
Dilute iodine solution reacts with starch, forming a very dark blue colour. This test will work on a solid sample of food, such as
potato, or a suspension of starch on water.
Test for Glucose
Glucose is called a reducing sugar. This is because the test for glucose
involves chemically reducing an alkaline solution of copper sulphate to
copper(I) oxide.
The test for glucose is called the Benedict’s test. Simply add a few drops
of Benedict’s solution, which contains alkaline copper sulphate, to some
glucose. Add enough to turn the mixture blue. Then heat the mixture in
a boiling water bath. The clear blue solution will gradually change
colour, forming a cloudy orange or brick red precipitate of copper(I)
oxide. All ‘single’ sugars such as fructose are reducing sugars, as well as
some ‘double’ sugars, such as the milk sugar.
