Required Practical - Testing for Food Chemicals

Testing for Carbohydrates, Lipids and Proteins

The objective of this experiment is to use qualitative reagents to identify the presence of food chemicals such as sugars, starch and proteins. The tests only tell if a substance is present, not how much.

Test for sugars (Benedict’s test)

Add Benedict’s solution to the food sample.
Heat gently in a water bath for a few minutes.
Observe the colour change.
- A red-brown precipitate forms if reducing sugars (like glucose) are present.
Hazards:
- Benedict’s solution is an irritant.
- Wear safety goggles, avoid contact with skin and eyes.

Test for starch (Iodine test)

Add a few drops of iodine solution to the food sample.
- For example, peel a potato and drop iodine onto it.
Observe the colour change.
- If the food turns to a blue-black colour, there is starch present.
Hazards:
- Iodine is an irritant.
- Wear goggles, avoid contact with skin and eyes.

Test for proteins (Biuret test)

Add 1 cm³ of Biuret solution A to the food sample and mix.
Add 1 cm³ of Biuret solution B, shake or allow layers to form.
Observe the colour change.
- A purple colour or a ring between layers means protein is present.
Hazards:
- Biuret A is corrosive; Biuret B is an irritant.
- Wear goggles and handle carefully.

1Cell Biology

1.1What's in Cells?

1.1.1Types of Cells

1.1.2Properties of Prokaryotes

1.1.3Orders of Magnitude

1.1.4Standard Form

1.1.5Standard Form - Calculations

1.1.6Addition in Standard Form - Calculations

1.1.7Subtraction in Standard Form - Calculations

1.1.8Multiplication in Standard Form - Calculations

1.1.9Division in Standard Form - Calculations

1.1.10Animal Cells

1.1.11Plant Cells

1.1.12Differentiation in Plants & Animals

1.1.13Bacterial Cells

1.1.14Types of Cells HyperLearning

1.1.15Cell Specialisation in Animals

1.1.16Sperm Cells

1.1.17Nerve Cells

1.1.18Muscle Cells

1.1.19Cell Specialisation in Plants - Root Hair Cells

1.1.20Cell Specialisation in Plants - Xylem

1.1.21Cell Specialisation in Plants - Phloem

1.1.22Microscopy

1.1.23Magnification

1.1.24Developments in Microscopy

1.1.25Required Practical - Microscopy

1.1.26Microscopy - Calculations

1.1.27Culturing Microorganisms

1.1.28Contamination

1.1.29Avoiding Contamination

1.1.30Calculating Bacteria

1.1.31Calculating Bacteria - Calculations

1.1.32Required Practical - Bacteria

1.1.33Exam-Style Questions - Cell Structure & Microscopy

1.1.34Diagnostic Misconceptions - Converting

1.1.35Diagnostic Misconceptions - Animal Cells

1.1.36Diagnostic Misconceptions - Mitochondria

1.1.37End of Topic Test - What's in Cells?

1.2Cell Division

1.2.1Chromosomes

1.2.2The Cell Cycle

1.2.3Mitosis

1.2.4Stem Cells

1.2.5Use of Stem Cells

1.2.6Disadvantages of Stem Cells

1.2.7Exam-Style Questions - Mitosis & Cell Cycle

1.2.8Diagnostic Misconceptions - Mitosis

1.3Transport in Cells

1.3.1Diffusion

1.3.2Factors Affecting Diffusion

1.3.3Surface Area : Volume

1.3.4Surface Area : Volume - Calculations

1.3.5Exchange Surfaces

1.3.6Examples of Exchange Surfaces

1.3.7Osmosis

1.3.8Osmosis 2

1.3.9Required Practical - Osmosis in Plant Tissue

1.3.10Active Transport

1.3.11Transport in Cells

1.3.12Grade 9 - Cell Transport

1.3.13Diagnostic Misconceptions - Water Moving

1.3.14Diagnostic Misconceptions - Active Transport

1.3.15End of Topic Test - Cell Division & Transport

2Organisation

2.1Principles of Organisation

2.1.1Cells & Tissues

2.1.2Organs

2.1.3Organ Systems

2.1.4Organisms

2.2Enzymes

2.3Circulatory System

2.3.1Types of Blood Vessels

2.3.2Blood Vessels - Arteries

2.3.3Blood Vessels - Capillaries

2.3.4Blood Vessels - Veins

2.3.5The Heart - Structure

2.3.6The Heart - Function

2.3.7Important Blood Vessels

2.3.8Double Circulatory System

2.3.9Gas Exchange

2.3.10Gas Exchange - Calculations

2.3.11Alveoli

2.3.12Blood Components

2.3.13Platelets

2.3.14Red Blood Cells

2.3.15White Blood Cells

2.3.16End of Topic Test - Circulatory System

2.4Non-Communicable Diseases

2.4.1Health Issues

2.4.2Disease Interactions

2.4.3Sampling

2.4.4Sampling - Calculations

2.4.5Risk Factors

2.4.6Examples of Risk Factors

2.4.7Risk Factor Graphs

2.4.8Coronary Heart Disease

2.4.9Heart Valve Disease

2.4.10Heart Failure

2.4.11Treating Heart Disease

2.4.12Comparing Treatments of Heart Disease

2.4.13Cancer

2.4.14Cancer Risk Factors

2.4.15End of Topic Test - Non-Communicable Diseases

2.4.16Exam-Style Questions - Coronary Heart Disease

2.5Plant Tissues, Organs & Systems

2.5.1Plant Organs

2.5.2Leaves

2.5.3Transpiration

2.5.4Rate of Transpiration

2.5.5Measuring Transpiration

2.5.6Translocation

2.5.7Transpiration Tissues - Xylem Cells

2.5.8Transpiration Tissues - Root Hair Cells

2.5.9Stomata

2.5.10States of Stomata

2.5.11Premium Knowledge - Transpiration

2.5.12End of Topic Test - Plants

2.5.13Exam-Style Questions - Plant Tissues

2.5.14Diagnostic Misconceptions - Plant Food

2.5.15Diagnostic Misconceptions - Plants & Water

2.5.16Diagnostic Misconceptions - Plants Don't Breathe

3Infection & Response

3.1Communicable Disease

3.2Monoclonal Antibodies

3.2.1Monoclonal Antibodies

3.2.2Producing Monoclonal Antibodies

3.2.3Uses of Monoclonal Antibodies

3.2.4Grade 9 - Monoclonal Antibodies

3.3Plant Diseases

3.3.1Ion Deficiencies in Plants

3.3.2Plant Defences

3.3.3Signs of Plant Disease

3.3.4Identifying Disease

3.3.5Other Plant Diseases

3.3.6End of Topic Test - Antibodies & Plant Disease

4Bioenergetics

5Homeostasis & Response

5.1Homeostasis

5.1.1Homeostasis

5.1.2Regulating Internal Conditions

5.1.3Homeostasis & Negative Feedback

5.1.4The Body's Negative Feedback Loop

5.1.5Exam-Style Questions - Exercise & Homeostasis

5.2The Human Nervous System

5.3Hormonal Coordination in Humans

5.3.1Endocrine Glands

5.3.2The Endocrine System

5.3.3Thyroxine

5.3.4Adrenaline

5.3.5Blood Glucose

5.3.6Detecting Glucose

5.3.7Diabetes

5.3.8Type 1 Diabetes

5.3.9Type 2 Diabetes

5.3.10Water Balance

5.3.11Kidneys

5.3.12Urea

5.3.13Urine Production

5.3.14Urine

5.3.15Dialysis

5.3.16Dialysis - Pros & Cons

5.3.17Transplants

5.3.18Transplants - Pros & Cons

5.3.19Puberty

5.3.20Menstruation

5.3.21Menstrual Hormones

5.3.22Menstrual Cycle

5.3.23Contraception - 'Natural Methods'

5.3.24Contraception - Sterilisation

5.3.25Contraception - Condoms

5.3.26Contraception - The Pill

5.3.27Contraception - Diaphragm & IUDs

5.3.28Contraception - Other Options

5.3.29Hormones for Infertility

5.3.30In Vitro Fertilisation

5.3.31Fertility Treatments - Pros & Cons

5.3.32End of Topic Test - Homeostasis & Hormones

5.3.33Grade 9 - Hormonal Coordination

5.3.34Exam-Style Questions - Hormones & Contraception

5.4Plant Hormones

5.4.1Plant Hormones

5.4.2Types of Tropisms

5.4.3Auxins & Tropisms

5.4.4Effect of Light on Seedlings

5.4.5Required Practical - Light or Gravity on Seedlings

5.4.6Uses of Plant Hormones

5.4.7End of Topic Test - Hormones

6Inheritance, Variation & Evolution

6.1Reproduction

6.2Variation & Evolution

6.2.1Variation

6.2.2Evolution & Speciation

6.2.3Natural Selection

6.2.4Selective Breeding

6.2.5Selective Breeding 2

6.2.6Uses of Selective Breeding

6.2.7Dangers of Selective Breeding

6.2.8Genetic Engineering

6.2.9Genetic Engineering 2

6.2.10Uses of Genetic Modification

6.2.11Advantages of Genetic Modification

6.2.12Disadvantages of Genetic Modification

6.2.13Cloning

6.2.14Cloning Plants

6.2.15Cloning Animals

6.2.16Adult Cell Cloning

6.2.17End of Topic Test - Variation & Evolution

6.2.18Exam-Style Questions - Selective Breeding

6.3Genetics & Evolution

6.3.1Natural Selection

6.3.2Controversy Around Natural Selection

6.3.3Darwin's Theory of Evolution

6.3.4Inheritance Theory

6.3.5Speciation

6.3.6Alfred Russel Wallace

6.3.7Evidence for Evolution

6.3.8Fossils

6.3.9Resistant Bacteria

6.3.10Genetics

6.3.11Extinctions

6.3.12Grade 9 - Evolution

6.3.13Diagnostic Misconceptions - Natural Selection

6.4Classification

6.4.1Classification of Living Organisms

6.4.2Traditional System

6.4.3Classification of Living Organisms: Updated System

6.4.4Evolutionary Trees

6.4.5End of Topic Test - Genetics & Classification

7Ecology

7.1Adaptations & Interdependence

7.1.1Communities: Ecosystems

7.1.2Communities: Resources

7.1.3Species Interdependence

7.1.4Stable Communities

7.2Organisation of Ecosystems

7.2.1Population Dynamics

7.2.2Predator-Prey Graphs

7.2.3Impact of Environmental Change

7.2.4Causes of Environmental Change

7.2.5Assessing Ecosystems

7.2.6Organism Abundance

7.2.7Required Practical - Population Size

7.2.8Assessing Ecosystems - Calculations

7.2.9The Carbon Cycle

7.2.10The Water Cycle

7.2.11The Cycling of Materials

7.2.12Decay

7.2.13Anaerobic Decay

7.2.14Biogas Generators

7.2.15Required Practical - Decay

7.2.16End of Topic Test - Organisation of Ecosystems

7.2.17Grade 9 - Ecosystems

7.2.18Exam-Style Questions - Decomposition

7.3Biodiversity

7.3.1Humans & Biodiversity

7.3.2Waste Management

7.3.3Human Activities

7.3.4Land Use

7.3.5Deforestation

7.3.6Carbon Dioxide

7.3.7The Greenhouse Effect

7.3.8Global Warming

7.3.9Maintaining Biodiversity

7.3.10End of Topic Test - Adaptations & Biodiversity

7.4Trophic Levels

7.4.1Trophic Levels

7.4.2Trophic Levels: Food Chains

7.4.3Trophic Levels: Decomposers

7.4.4Pyramids of Biomass

7.4.5Transfer Efficiency

7.4.6Reasons for Energy Wastage

7.4.7Transfer Efficiency - Calculations

7.4.8Premium Knowledge - Trophic Levels & Food Chains

7.4.9Exam-Style Questions - Food Chains

7.4.10Diagnostic Misconceptions - Arrows

7.5Food Production

7.5.1Food Security

7.5.2Food Production: Biotechnology

7.5.3Declining Fish Stock

7.5.4Sustainable Fishing

7.5.5Farming

7.5.6Food Production - Calculations

7.5.7End of Topic Test - Food & Trophic Levels

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