Grade 10 Biology Study Notes

Welcome to Cell Biology and Biodiversity

Earth is home to millions of different living things. This strand helps you understand what they are made of, how they are organised, and how scientists study them.

What this strand covers

• Sub-strand 1.1 — Introduction to Biology: What Biology is, its fields of study, careers, and why it matters.
• Sub-strand 1.2 — Specimen Collection and Preservation: How scientists collect and preserve plant and animal samples.
• Sub-strand 1.3 — Cell Structure and Specialisation: Microscopes, cell parts, and how cells are built for specific jobs.
• Sub-strand 1.4 — Chemicals of Life: Carbohydrates, proteins, fats, vitamins, enzymes and water in living things.

This lesson covers

1. Applications of Biology in everyday life
2. Fields of study in Biology and career opportunities
3. Illustrating careers using a career wheel
4. Importance of Biology in everyday life

Applications of Biology in Everyday Life

What is Biology?

Biology is the study of living organisms and how they interact with each other and their environment.

Biology helps us understand all types of living things — from tiny bacteria to large animals and plants. It covers how they grow, reproduce, and keep themselves alive. It also explains what happens inside our bodies, such as how we produce energy and how our immune system fights disease.

Applications of Biology in Everyday Life

Application (a): Food production

Biology helps us make food products and grow crops.

One example is yoghurt. Yoghurt is a thick creamy food made from milk. Tiny living things called microorganisms break down the sugars in milk and change its texture. This process is called microbial fermentation.

Farmers also use Biology to select and breed the best crop varieties so they get the highest yields from their land.

Applications of Biology in Everyday Life

Application (b, c): Healthcare and medicine

Doctors, nurses, laboratory technicians and pharmacists all study Biology to learn how to treat people.

Understanding biological processes is needed for both treatment and medical research. For example, knowing how a virus attacks the body helps a doctor treat the infection and helps a researcher develop a vaccine.

Applications of Biology in Everyday Life

Application (d): Forensic investigations

Biology is used to investigate crimes. Forensic scientists examine hair follicles, fingerprints and blood samples collected at crime scenes to help identify suspects.

A hair follicle is the small pocket in the skin from which a hair grows. Every person's biological material is unique, so it can be matched to a specific individual.

Applications of Biology in Everyday Life

Application (e): Personal care products

Biological materials are used as ingredients in personal care products such as lotion, nail polish remover and perfume.

Application (f): Nutrition

Biology teaches us which nutrients our bodies need and which foods contain them. This helps us prepare complete, balanced meals every day.

Relating the Fields of Study in Biology to Career Opportunities

What are fields of study?

Biology is a wide subject. Scientists divide it into specialised fields, each focused on one group of living things or one aspect of life.

Botany

Botany is the study of plants.

Zoology

Zoology is the study of animals. A zoologist in the community might work as a veterinarian (an animal doctor) or a wildlife officer who protects wild animals.

Taxonomy

Taxonomy is the science of classifying and naming organisms. Scientists place living things into groups based on their similarities and differences, so that the same organism has the same name everywhere in the world.

Relating the Fields of Study in Biology to Career Opportunities

Every field of Biology leads to specific career opportunities. Biology careers are found in hospitals, farms and agricultural stations, research institutions, government agencies and conservation organisations.

Illustrating the Careers Related to Fields of Study in Biology

A career wheel is a circular chart that shows how fields of study in Biology connect to the careers they lead to. The centre is labelled Biology, and each segment of the wheel shows one field with its related careers written inside.

How to make a career wheel

You can make one using locally available materials: manila paper, scissors, a carton box, coloured pencils, marker pens, glue, a ruler and a piece of thread.

1. Write the major fields of Biology on cut pieces of manila paper.
2. List the related careers for each field.
3. Cut the manila paper into equal strips (for example, 30 cm × 10 cm each).
4. Write the careers on each strip using a marker pen.
5. Glue the strips onto a carton box in a circular wheel pattern.
6. Attach a piece of thread and hang it on the class noticeboard.

Factors That Influence Career Choices

When choosing a career, the two most important things to consider are your own ability and your interest.

Ability

Ability means the skills and strengths you already have, or can build through learning. For example, a learner who does well in science subjects should consider science-based careers such as medicine or research.

Interest

Interest means what you are passionate about. A learner who enjoys sports, music or coding should look for careers that match those passions. A person who is genuinely interested in their work tends to stay motivated and enjoy it long-term.

Why both must go together

• If you are interested but lack the skills, you may need extra training — but that is possible.
• If you are skilled but not interested, you may not enjoy the career even if you do well at first.

The best career combines both ability and interest.

Relating the Fields of Study in Biology to Career Opportunities

Anatomy

Anatomy is the study of the structure of living things — their physical parts and how those parts are arranged. For example, an anatomist studies the bones, muscles and organs inside the human body.

Physiology

Physiology studies the normal functions of living things and their parts. Where Anatomy asks what is there?, Physiology asks what does it do? For example, Anatomy identifies the heart; Physiology explains that the heart pumps blood around the body.

Ecology

Ecology is the study of how organisms interact with each other and their environment, including where they live and in what numbers. For example, an ecologist studies why lions are found in grasslands but not in dense forests.

Factors That Should Not Influence Career Choices

Some things should never stop a person from pursuing the career they want. These are: gender, culture, disability, environment and stereotypes.

Gender

No career belongs to only one gender. For example, nursing can be done by both males and females. Restricting careers by gender limits people's potential.

Culture

Culture shapes our values, but it should not limit our career choices. Breaking cultural barriers often leads to a more fulfilling career.

Disability

Disability does not determine what a person can achieve. With the right support, a person with a physical disability can succeed in any career.

Environment

Growing up in a remote area may limit access, but it should not define your career path. People can look for opportunities beyond their immediate surroundings.

Stereotypes

A stereotype is an unfair generalised belief about a group of people. Stereotypes create false limits. You should pursue careers that match your true interest and ability, not what others expect from your group.

Relating the Fields of Study in Biology to Career Opportunities

Genetics

Genetics is the study of heredity — how characteristics such as eye colour, height and blood group are passed from parents to their children. It also studies why variation occurs (why children are not identical to their parents).

Parasitology

Parasitology is the study of parasites, their hosts and the relationship between them. A parasite is a living thing that lives on or inside another organism (the host) and harms it. For example, the malaria parasite lives inside the human body and causes malaria.

Microbiology

Microbiology is the study of microorganisms — living things too small to see with the naked eye. These include bacteria, viruses, fungi and protozoa. A microscope is needed to study them — it uses lenses to make tiny things appear larger.

Importance of Biology in Everyday Life

Biology gives us knowledge and skills that are useful every day and in future careers. Here are the key reasons why Biology matters:

• (a) Career pathways: Biology opens doors to careers in healthcare, agriculture and biotechnology, among many others.
• (b) Research skills: Studying Biology teaches you how to observe, record, analyse and draw conclusions — skills used in any science career.
• (c) Understanding organisms: Biology helps us understand how living things relate to each other and to the environment.
• (d) Classification: Biology helps us organise living things into groups based on their characteristics, bringing order to the vast diversity of life.
• (e) Disease prevention: Biology helps us understand how diseases spread and how the immune system fights them, so we can take steps like washing hands, getting vaccinated and drinking clean water.
• (f) Environmental conservation: Biology helps us understand how human activities such as cutting trees or polluting rivers affect living things, so we can make responsible choices to protect the environment.

Key Points — Sub-strand 1.1: Introduction to Biology

• Biology is the study of living organisms and how they interact with each other and their environment.
• Biology applies to food production (yoghurt, crop breeding), medicine, forensic investigations, personal care products and nutrition.
• The nine main fields: Botany, Zoology, Taxonomy, Anatomy, Physiology, Ecology, Genetics, Parasitology, Microbiology.
• Each field leads to career opportunities in hospitals, farms, research institutions and conservation organisations.
• A career wheel visually links fields to careers and can be made from locally available materials.
• Careers should be chosen based on ability and interest.
• Gender, culture, disability, environment and stereotypes should not influence career choice.
• Biology is important because it opens career paths, builds research skills, helps us understand organisms, enables classification, supports disease prevention and promotes environmental conservation.

Quick Reference — Fields of Study

Introduction to Specimen Collection and Preservation

During biological investigations, scientists collect specimens to study living things up close. A specimen is a sample of an organism or substance used for study.

What this sub-strand covers

1. Apparatus and materials used for collecting, processing and preserving specimens
2. Collecting, processing and preserving specimens using improvised and conventional apparatus
3. Importance of collecting, processing and preserving specimens in Biology

Apparatus and Materials Used for Collecting, Processing and Preserving Specimens

Apparatus for collecting plant specimens and processing

Collecting plant specimens requires different tools from those used for animals. The following apparatus are used:

• Pair of secateurs: a cutting tool with two short blades that cross each other, used to cut plant materials such as twigs and branches.
• Knife: used to cut specimens such as young plants or parts of a plant.
• Trowel: a small hand-held digging tool with a flat pointed blade, used to dig up soil samples or uproot small plants while keeping the roots intact.
• Collecting bag: a bag used to carry soil or plant specimens collected in the field.
• Labels: small tags used to identify specimens and record information such as the plant name, date and location of collection.
• Envelopes: used to hold delicate collected specimens such as butterflies or pressed leaves.
• Tracing paper: placed between layers of specimens during collection or transport to protect delicate specimens from damage.
• Permanent pen: used to write on labels or directly on containers to mark and identify specimens.

Collecting, Processing and Preserving Specimens for Biological Studies Using Improvised and Conventional Apparatus

Improvising a sweep net

A sweep net can be made from locally available materials. An improvised sweep net works the same way as a conventional one — you swing it through the air or vegetation to catch flying insects.

Materials needed

• Thin metal wire
• A plastic or wooden rod
• A piece of old mosquito net
• A pair of scissors
• Masking tape
• A needle and yarn

How to make a sweep net

1. Use the metal wire to create a loop of about 30 cm in diameter.
2. Cut the mosquito net into a rectangular piece of about 100 cm by 45 cm.
3. Fold the net and attach one side to the loop, leaving one side open.
4. Sew the sides and the bottom of the net together to form a net bag. Safety tip: handle the needle carefully to avoid pricking yourself.
5. Secure the loop tightly to the wooden or plastic rod.
6. Wrap the net around the loop and secure it tightly.

Collecting, Processing and Preserving Specimens for Biological Studies Using Improvised and Conventional Apparatus

Improvising a pooter

A pooter is used to suck up small insects from surfaces such as tree bark or rocks. An improvised pooter works by creating suction — when you suck through one tube, the insect is drawn into the container through the other tube. A piece of mesh over the inner tube stops insects from being inhaled.

Materials needed

• A small plastic container with a lid
• Two flexible rubber or plastic tubes (one about 20 cm long, one about 30 cm long)
• A large nail and wooden hammer
• Plasticine or glue
• A piece of old mosquito net and a string

How to make a pooter

1. Use the nail and hammer to make two holes in the lid, about 5 cm apart, each the same diameter as the rubber tubes.
2. Tie a small piece of mosquito net to the end of the shorter tube using a string.
3. Insert both tubes through the holes so that the tube with the net is closer to the top of the container (the net sits inside). The shorter tube faces downward toward the insect; the longer tube goes to your mouth.
4. Seal the gaps between the lid and the tubes with plasticine or glue to make the container airtight.
5. Bend the tubes in opposite directions — one curves toward the specimen, the other curves toward your mouth.

Apparatus and Materials Used for Collecting, Processing and Preserving Specimens

Apparatus for collecting animal specimens

Different apparatus are used to collect different types of animals. Each tool is designed for a specific animal or situation.

• Pair of forceps: used to pick small stinging animals and plants without touching them directly.
• Sweep net: used to capture flying insects during field studies. It is swung through the air or through vegetation to catch insects.
• Fish net: used to trap small aquatic (water) animals.
• Pooter: used to suck small animals such as insects from the bark of trees or rock surfaces. When you suck through one tube, the insect is drawn into the container through the other tube.
• Pitfall trap: a container buried in the ground with its opening level with the soil surface. Small crawling animals fall into it and cannot climb out.
• Light trap: used to collect flying insects at night. The insects are attracted to a light source and are caught.
• Tullgren funnel: used to remove small animals such as insects from soil samples. A heat or light source above drives animals downward through a funnel into a collection bottle below.
• Hand lens: used to magnify small objects when observing them in the field. A hand lens is a small convex lens held in a frame — you hold it close to your eye and bring the object toward it until it appears clear and larger.
• Petri dish: a shallow flat-bottomed dish with a loose-fitting lid, used to hold small specimens such as insects, or to grow microorganisms.
• Hand gloves: worn to protect the hands when handling stinging insects or plant materials.

Collecting, Processing and Preserving Specimens for Biological Studies Using Improvised and Conventional Apparatus

Collecting plant specimens

Plant specimens are collected from the field using appropriate tools. Collected specimens are used for study, identification and making herbariums.

How to collect plant specimens

1. Put on hand gloves for protection.
2. Use a digger to uproot a small herbaceous plant carefully. Shake off the soil while keeping the root system intact.
3. Use a pair of secateurs to cut a twig from a shrub or tree.
4. Place the specimens in a collecting bag.
5. Label each specimen using its local name, the date and the location where it was collected.
6. Carry the collected plants to the laboratory.
7. Wash your hands with soap and clean water after collecting specimens.

Environmental tip: Collect only the number of plants needed. Do not over-collect, as this damages the environment.

Road safety tip: Observe road safety rules when collecting specimens near roads.

Collecting, Processing and Preserving Specimens for Biological Studies Using Improvised and Conventional Apparatus

Processing plant specimens — making a herbarium

A herbarium is a collection of preserved dry plant specimens with relevant information attached. Herbariums are used in schools, museums and botanical gardens for study and reference.

How to make a herbarium

1. Dry the specimen: Place the plant between two layers of newspaper. Spread it out flat so all parts are visible.
2. Press the specimen: Place the newspaper layers between two pieces of plywood (about 40 cm × 30 cm). Put a heavy object such as a large book on top to flatten it.
3. Leave for a few days until the specimen is completely dry.
4. Mount the specimen: Use glue or cellotape to fix the dried plant onto a piece of cardboard. Spread the leaves and flowers out properly.
5. Attach a label at the lower right side of the specimen. The label must include: the name of the plant, date of collection and its locality (where it was collected).
6. Cover the mounted specimen with a transparent material to protect it.

Collecting, Processing and Preserving Specimens for Biological Studies Using Improvised and Conventional Apparatus

Collecting animal specimens

Animal specimens are collected using appropriate apparatus, depending on the type of animal. Protective equipment must be worn at all times to stay safe.

How to collect animal specimens

1. Wear protective clothing including hand gloves.
2. Walk around the school environment with your teacher's guidance.
3. Use the appropriate apparatus to collect different small animals such as termites, ants, butterflies, grasshoppers, cockroaches, earthworms, millipedes, lizards, toads and frogs.
4. Place each type of animal in its own appropriate container — for example, specimen bottles for insects, envelopes for butterflies.
5. Label each container with the name of the animal.
6. Wash your hands thoroughly with soap and water after the activity.

Matching animals to collection apparatus

Collecting, Processing and Preserving Specimens for Biological Studies Using Improvised and Conventional Apparatus

Processing and preserving insects and arthropods

After collection, insect and arthropod specimens must be processed and preserved so they can be kept for long-term study. An arthropod is an animal with a hard outer shell, jointed legs and a segmented body — insects, millipedes and spiders are all arthropods.

How to process and preserve insects and arthropods

1. Wear protective clothing.
2. Sort the animals by observable features: number of legs, presence or absence of wings, and presence or absence of compound eyes.
3. Immobilise and kill the animals using appropriate chemicals such as ethanol.
4. Dry the specimens using a desiccator or by sun-drying.
5. Pin each specimen onto a soft board using pins, with wings spread out where appropriate.
6. Attach a label at the lower right side recording the name, date and location of collection.
7. Cover the mounted specimens with a transparent material.
8. Wash your hands with soap and water after the activity.

Collecting, Processing and Preserving Specimens for Biological Studies Using Improvised and Conventional Apparatus

Preservation methods and storage

Preservation is a procedure that keeps collected specimens intact so they can be used for future study. After collection, specimens are first cleaned with water to remove dirt before preservation begins.

Methods of preservation

• Drying (desiccation): moisture is removed from the specimen. This is the most common method for plant specimens and small animals. Drying stops microorganisms from causing decay. At home, people use the same idea when they dry fish, vegetables or meat in the sun.
• Freezing: specimens are stored at very low temperatures to stop them from breaking down. This method is suitable for soft-bodied animals that would be damaged by drying.
• Chemical preservation (fixation): specimens are treated with chemicals such as ethanol. Ethanol immobilises small animals, stabilises their structure and prevents decay. Always wear gloves and a face mask when handling preservation chemicals.
• Embedding: the specimen is fixed firmly inside a solid medium such as paraffin wax. This supports and protects the specimen's structure for detailed examination.
• Pinning: insects are pinned onto a soft board and displayed in an insect box.

Storage

After preservation, specimens must be stored correctly:

• Dry specimens are stored in jars or bottles in a controlled environment.
• Specimens preserved in liquid must be fully covered by the liquid with the lid closed tightly.

Labelling and documentation

Every preserved specimen must have a label recording: the local and scientific name, date collected, preservation method, habitat and location of collection. Labels can be printed, hand-written, tagged, barcoded or colour-coded.

Collecting, Processing and Preserving Specimens for Biological Studies Using Improvised and Conventional Apparatus

Processing and preserving vertebrates

A vertebrate is an animal with a backbone, such as a rat, frog or lizard. Preserving vertebrates requires additional steps compared to insects.

How to preserve a vertebrate specimen

1. Wear protective clothing.
2. Sort the vertebrates into groups of the same kind.
3. Immobilise and kill using appropriate chemicals. Safety tip: avoid inhaling the chemicals.
4. Use a scalpel to dissect the animal and remove internal organs.
5. Use cotton wool to soak up excess blood.
6. Dry the specimen in a desiccator or by sun-drying.
7. Pin the specimen on a soft board as illustrated.
8. Attach a label recording the name, date and location of collection.