Aadya Isai

1. Definition:- A rapid growth of microscopic algae in water, often resulting in à coloured scum on the surface.

   An algal bloom is a rapid, excessive growth of algae in fresh water or marine environments, often turning the water discoloured (green, red, brown) due to high nutrient levels, especially nitrogen and phosphorus from fertiliser runoff or wastewater.

   
   

   These blooms can be harmless but are often harmful, causing oxygen depletion (hypoxia) that kills fish and other aquatic life.

1) Introduction:

A) Definition:- Pollution is the introduction of harmful substances or energy (like - heat, sound, light) into the natural environment, causing adverse effects on living organisms and ecosystems, making the surrounding impure and unsafe.

B) Causes:- Pollution stems rein hunan activities like burning fossil fuels for energy and transport; industrial emission, vehicle exhaust, agricultural chemicals (pesticides/fertilisers), and improper waste disposal (sewage, plastic, garbage burning).

2) Causes of water pollution:

A. Factories:- Factories cause water pollution by discharging untreated waste water filled with toxic chemicals, heavy metals (like-led, mercury) dyes, oils, and pathogens into rivers, lakes, and groundwater.

B. House hold works:- House holds pollutes water through untreated sewage release, poor drainage systems, and ground water sewage.

Animal population size is shaped by growth factors (like - birth and immigration) and population decline (like - deaths and emigration), all controlled by limiting factors like food supply, water, shelter, predation, diseases, space, as well as environmental conditions (climate, light) and biological interactions (competition, symbiosis) ultimately determining the habitat’s carrying capacity.

How food supply impacts growth: A) Food supply:

Food supply is a primary driver of animal population size; abundant food allows for more births and better survival, leading to population growth, while scarcity cause declines through starvation, reduced reproduction, and increased stress/predation.

B) Predators:

• Predation significantly effects animal population by creating dynamic cycles; more prey leads to move predators, which then reduces the prey to rebound, and restarting the cycle.

1. Definition:

   • Population is the total number of individuals of the same species living in a specific area at a particular time.

   
   

2. Why is population important?

   Population is important because it determines how living organisms survive, interact, and use resources in an area.

   
   

   • Population size helps us understand how many individuals of a species are living in a place and whether their numbers are increasing or decreasing.

   
   

   • It affects the availability of food, water, space, and shelter, since resources are limited.

   
   

1. Which is better? Increase or decrease in population?

   
   

   • Population changes are not automatically better or worse

     • Neither a population increase nor a decrease is inherently “better.”

     • The key factor is whether the population size is balanced with available resources and opportunities.

     
     

   • Benefits of population increase

     • An increase can be positive if there are sufficient jobs, food, housing, education, and healthcare.

     
     

1. Definition: Decomposers are organisms that break down dead organisms and release the nutrients from the dead matter into the environment around them. In simpler words - Decomposers are living things that break down dead plants and animals and return their nutrients to the environment.
   

2. The main types of Decomposers: • Bacteria - tiny organisms that break down dead plants and animals into simpler substances. • Fungi - such as mushrooms and molds, which absorbs nutrients from dead matter. • Detritivores - animals like earthworms, termites, and beetles that eat dead materials and they help to break it into smaller pieces.
   

3. Natural VS Artificial Decomposers: • Natural decomposers are living organisms that break down dead plants, animals, and organic waste into simpler substances. By doing this, they return nutrients to the soil and keep the environment clean. Examples: bacteria and fungi (main decomposers), earthworms and insects (help by breaking waste into smaller pieces). • Artificial methods of decomposition are…

1. The process:

   • The process of decomposing is how nature recycles dead and waste matter back into the ecosystem, allowing materials from once-living organisms to be reused.

     
     

   • Decomposers such as bacteria and fungi act on dead plants, dead animals, and organic waste, beginning the breakdown of this material.

     
     

   • First, they release enzymes onto the dead material, which start the chemical breakdown from the outside.

     
     

   • These enzymes break complex organic substances like proteins, fats, and carbohydrates into much simpler molecules.

     
     

   • Next, decomposers absorb these simpler substances for their own energy and growth, helping them survive and reproduce.

     
     
   
   

1. Dead matter:

   • Dead matter refers to organic material from once-living organisms (plants, animals, waste) that is no longer alive and is in the process of breaking down

   
   

   • Simpler words - Dead matter is anything that was once alive—like plants, animals, or waste—that has stopped living and is now slowly being broken down and recycled by nature.

   
   

2. Organic matter:

   • Organic matter (OM) refers to carbon-based compounds from decomposed plants, animals, and microorganisms.

   
   

   • Simpler words - Organic matter is made of carbon-based materials that come from plants, animals, and microorganisms after they die and start to break down.

   
   

Definition

Dopamine is a chemical messenger in the brain known as a neurotransmitter. It helps nerve cells communicate with each other and plays a major role in movement, motivation, pleasure, and learning.

Introduction

Dopamine is essential for normal brain and body function. It influences how we feel pleasure, how motivated we are to act, how we move our muscles, and how we pay attention and learn. Balanced dopamine levels are necessary for both mental and physical health.

Production and Release

Dopamine is produced in specific areas of the brain, mainly the substantia nigra and the ventral tegmental area. Once produced, it is released into the space between nerve cells, where it carries messages by binding to dopamine receptors on nearby neurons.

1. What does“tangled” means?

A tangled cord usually refers to a nuchal cord (wrapped around the baby’s neck) or the cord looping around the baby’s body, arm, or leg. This happens because babies move a lot in the amniotic fluid, and the cord can naturally wrap or twist.

2. Is a tangled cord dangerous?

Most of the time, no.

The umbilical cord is designed to be very strong and flexible, and Wharton’s jelly protects the blood vessels from being squeezed. That means:

• Blood usually continues flowing normally.

Introduction:

During pregnancy, the fetus cannot breathe, eat, or remove waste on its own. Instead, it depends entirely on the placenta. The organ that physically links the fetus to the placenta is the umbilical cord. It forms early in development (around week 5) and grows throughout pregnancy, usually reaching 50–60 cm in length by birth. Because of its protected structure, the cord can bend, twist, and stretch without cutting off blood flow.

Definition:

The umbilical cord is a flexible, tube-like structure that connects a developing fetus to the placenta. It contains blood vessels that transport oxygen, nutrients, and waste between the fetus and the placenta, acting as the fetus’s lifeline during pregnancy.

Structure:

1. Introduction:

   • Definition - Coma is a deep state of unconsciousness in which a person cannot wake up, cannot respond to sound, touch, or pain, and shows very limited brain activity because the brain is not functioning normally.

   • Consciousness VS unconsciousness:

   Consciousness - means a person is awake, aware of themselves, and able to respond to what is happening around them.

   
   

   Unconsciousness - means a person is not aware, cannot respond, and does not have control over their actions or surroundings.

   So, coma is a deep form of unconsciousness where the brain is not working normally and the person cannot be woken up.

   
   

1. Introduction:

   
   

   1. Definition:

   • Food web - A food web is a network of many connected food chains that shows how energy and nutrients move between organisms in an ecosystem.

   
   

   • Energy flow - Energy flow is the movement energy from that sun to producers and then through different organisms as they eat and are eaten.
   

2. Why are they needed?

   
   

   Food web:

   
   

1. Introduction

Tourette syndrome is a neurological condition where a person has tics — movements or sounds they cannot fully control.

Keywords: tics, neurological, childhood

2. Types of Tics

a) Motor Tics

Movements of the body.

1. Introduction of ecology:

   • Ecology is the study of how living things interact with eachother and with their environment.

   
   

   • It looks at how plants, animals, and other organisms depend on air, water, soil and other living things to survive.

   
   

   • A scientist who learns the study of ecology is called an ecologists

2. Ecosystem

   • Definition - An ecosystem is a system where living and non-living things interact.

   
   

Definition - OCD (Obsessive–Compulsive Disorder) is a mental condition where a person gets unwanted, repetitive thoughts (obsessions) and feels the need to do certain actions again and again (compulsions) to reduce anxiety or discomfort, even if they know the actions don’t actually help.

Cause: 1. Brain chemistry

• Imbalance in certain brain chemicals (like serotonin) can affect how the brain controls fear, worry, and habits.

2. Brain structure

• Some areas of the brain that handle decision-making, checking, and danger signals may work differently or be overactive.

Definition - Adaptation is the process by which animals develop physical or behavioral traits that improve their ability to survive and reproduce in their specific environment.

Why? 1. To get food

If the environment changes or food becomes harder to find, animals with features that help them get food survive better.

Example: A giraffe’s long neck helps it reach leaves high up.

2. To stay safe from predators

Animals develop features that help them hide, run, or defend themselves.

1. Definition - Adaption in plants is the process of developing special features that allow them to survive and thrive on a particular environment or habitat.

2. Why? - Plants need to adapt so they can survive on the place they live. Every environment has challenges, and adaptation help plants handle those challenges.

3. How? - plants adopt in these ways:

   • By changing their structures (structural adaptation)

   • By changing how they look inside (physiological adaptation)

   • By changing how they behave (behavioural adaptation)

   
   

Treatment

There is no cure, but treatment slows symptoms and improves quality of life.

Medicines

• Cholinesterase inhibitors (donepezil, rivastigmine, galantamine)– Help with memory, thinking, and behaviour in early to moderate stages.

• Memantine– Helps in moderate to severe stages by improving daily function and reducing confusion.

• Newer drugs aim to reduce amyloid protein buildup, but they work only for some patients.

1. Definition - Alzheimer’s disease is a long-term brain disorder that slowly damages memory, thinking, and behaviour.

   
   

2. Changes in a person’s life with Alzheimer’s

   • They forget recent events and repeat things.

   • Daily tasks like cooking or dressing become harder.

   • They get confused about time, places, and people.

   • Mood and behaviour change (easily upset, worried, or angry).

Cell Cycle — How Cells Prepare to Divide

The cell cycle is the full series of steps a cell goes through before dividing.

Key phases:

1. Interphase

   • This is where the cell spends most of its life.

   • It has three sub-phases:

     
     

What Is Cell Division?

• Cell division is the process by which a parent cell splits into two (or more) daughter cells.

• In eukaryotes (cells with a nucleus), this usually happens as part of the cell cycle: a cycle of growth, DNA replication, and division.

• There are two main types of cell division in eukaryotes: mitosis and meiosis.

Why Cell Division Is Important

• Growth: your body need more cells to grow.

Fruit (definition):In botany, a fruit is the mature, ripened ovary of a flowering plant, usually containing seeds. It forms after fertilization and helps protect and disperse the seeds.

Simple explanation:

A fruit is the part of a plant that develops from the flower and holds the seeds. Examples: apples, oranges, tomatoes, and berries.

Key points:

• Comes from the flower of the plant

• Contains seeds (botanical definition)

Parasitic plants:

These are plants that cannot make all their own food, so they attach to another plant and take water, nutrients, or sometimes even sugars from it. The plant they take from is called the host.

How they work:

They use a special structure called a haustorium to connect to the host’s tissues and absorb what they need.

Types:

ADHD stands for Attention Deficit Hyperactivity Disorder. It’s a neurodevelopmental condition that affects how a person focuses, controls impulses, and manages energy. People with ADHD may experience:

• Inattention: Trouble focusing, getting easily distracted, forgetting things, or having difficulty organizing tasks.

• Hyperactivity: Feeling restless, needing to move constantly, or talking excessively.

• Impulsivity: Acting without thinking, interrupting others, or struggling to wait for their turn.

ADHD isn’t caused by laziness—it’s linked to differences in brain development and function, particularly in areas that manage attention and self-control. It can show up in children and continue into adulthood, though the symptoms may change over time.

ADHD Overview

Fertilisation in plants occurs when the sperm cell from the pollen fuses with the egg cell in the ovule.

Here’s what happens:

• After pollen lands on the stigma, it forms a pollen tube that extends down through the style.

• The male cell inside the pollen travels through this tube.

• In the ovary, the tube reaches an ovule.

• The male cell then fuses with the egg cell inside the ovule.

Gangrene is a dangerous condition where part of the body’s tissue dies because it either loses its blood supply or becomes severely infected. When blood flow is blocked, the tissue cannot get oxygen or nutrients, so it slowly breaks down and dies. This causes dry gangrene, where the skin becomes dark, dry, and shriveled. When bacteria enter a wound and spread quickly, it leads to wet or gas gangrene, which damages tissue much faster and can produce swelling, fluid, and sometimes gas inside the skin.

It becomes life-threatening because the infection does not stay in one place. As bacteria spread deeper, they can reach the muscles and even the bone, causing a serious bone infection called osteomyelitis. If the bacteria enter the bloodstream, they can cause sepsis, where blood pressure drops, organs start failing, and the body can no longer fight the infection. The toxins released by the bacteria also…

Transpiration Pull

• Happens in the whole plant, mainly from leaves upward.

• When water evaporates from tiny pores (stomata) in the leaves, it creates a pulling force.

• This pull drags the entire column of water upward from the roots to the leaves.

• Works through xylem tubes.

• It’s like water forming a long straw, and the evaporation at the top pulls everything up.

Pollination is the transfer of pollen from an anther of a plant to the stigma of a plant, later enabling fertilisation and the production of seeds. Pollinating agents can be animals such as insects, for example bees, beetles or butterflies; birds, and bats; water; wind; and even plants themselves. Pollinating animals travel from plant to plant carrying pollen on their bodies in a vital interaction that allows the transfer of genetic material critical to the reproductive system of most flowering plants.

• Some flowers are specially shaped or coloured to make pollination easier.

• After successful pollination, the flower usually begins changes that lead to fertilisation, which later forms seeds and sometimes fruits.

• Not all plants need the same method; some

depend on their flower structure, timing, or

scent to improve pollination.

The parts of a flower:

Plants use water in photosynthesis, the process that makes their food. Inside the leaves, sunlight gives energy to split water into hydrogen and oxygen. The hydrogen combines with carbon dioxide from the air to form glucose—the plant’s food. The oxygen is released into the air. So, without water, plants cannot make energy or grow.

Water also transports minerals and nutrients. The roots absorb water from the soil, and the minerals in the soil dissolve in it. This mixture travels through tiny tubes called xylem all the way up to the leaves. The movement happens because water naturally moves from areas of more water (in the soil) to areas of less water (inside the plant).

Another vital job of water is to keep the plant firm and upright. Each cell in a plant holds water that presses against its walls. This pressure, called turgor pressure, keeps stems and leaves stiff. If…

Farmers and gardeners often add fertilisers to the soil where their crops are growing. The fertilizers provide mineral salts, which make the plants grow larger and healthier. Although fertilisers are expensive, the cost to farmers is outweighed by the extra money they can get for their crop.

What are fertilisers?

Fertilizers are any material of natural or synthetic origin that’s is applied to soil or to plant tissues to supply plant nutrients.

Or in other words - A chemical or natural substance added to soul or land to increase its fertility.

What are the benefits of fertilizers?

It supplies key nutrients to plants, such as nitrogen - N, phosphorus- P, and potassium - P (These may lag in the natural soil).

Definition

Photosynthesis is the process by which green plants, algae, and some bacteria use light energy from the Sun to make food (glucose) from carbon dioxide and water.

It takes place mainly in the leaves of plants and is essential for all life on Earth because it provides food and oxygen.

Where Photosynthesis takes place and why?

Photosynthesis happens inside special structures in plant cells called chloroplasts.

Each chloroplast contains a green pigment called chlorophyll, which absorbs sunlight.

1. Light absorption:

   The green pigment chlorophyll, found in tiny cell parts called chloroplasts, absorbs sunlight. This happens mostly in the leaves.

   
   

2. Exciting electrons:

   The light energy makes electrons in chlorophyll get excited — meaning they gain energy and start moving faster.

   
   

3. Energy transfer through reactions:

   These energized electrons travel through a set of chemical steps called the electron transport chain. As they move, their energy is used to make two special energy-carrying molecules — ATP (adenosine triphosphate) and NADPH.

   
   

Inheritance is the process by which traits or characteristics are passed by parents to offspring’s through their genes.

In simpler words - Inheritance means getting features from your parents.

Examples:- You might inherit your mother’s eye colour or your father height.

This happens because those traits are carried in the DNA for generations and now passed down to you.

What all can inherited?

1. Biological traits - blood group, health conditions, body type, diseases, etc….

Teaching dakshu and ishaan about heart

Flash card - about diffusion.

Biology - diffusion

Definition (with example), my way of definition(with example), main factors effect ign diffusion - concentration difference (with example), temperature (with example).

Enzymes - definition and examples - continuing tommorow