Niveditha

Detailed Explanation of Hydrophobic Molecules

Hydrophobic molecules are substances that do not interact well with water. The term “hydrophobic” literally means “water-fearing”. These molecules do not dissolve in water and tend to separate from it, forming layers or droplets.

1. Why Are They "Water-Fearing"?

To understand hydrophobic molecules, we need to understand a bit about water itself.

Water is a polar molecule, meaning it has a partial positive charge on one end (near the hydrogen atoms) and a partial negative charge on the other (near the oxygen atom). This polarity allows water molecules to form strong hydrogen bonds with each other and with other polar molecules.

Hydrophobic molecules are nonpolar. They do not have positive or negative ends. Because they lack charge, water molecules cannot form hydrogen bonds with them. As a result, water pushes these molecules away, or they group together to minimize contact with water.

The pelvic cavity is the lowest part of the human body’s trunk region. It is a hollow space located beneath the abdominal cavity and surrounded by the bones of the pelvis. It plays a very important role because it holds and protects some of the most vital organs in the body related to urinary, reproductive, and digestive systems.

1. Boundaries of the Pelvic Cavity

The pelvic cavity is like a deep bowl formed by bones, muscles, and ligaments.

• Front and sides: Surrounded by the pelvic bones (ilium, ischium, and pubis).

• Back: Formed by the sacrum and coccyx (the last parts of the vertebral column).

• Top: The imaginary line that separates it from the abdominal cavity (called the pelvic inlet).

Movement in and out of cells is all about how substances like water, gases, nutrients, and waste materials pass through the cell membrane. The cell membrane is like a security gate—it controls what enters and leaves the cell to maintain the right internal conditions. This entire process is called cell transport, and it is essential for the cell’s survival and function.

There are two main types of movement:

1. Passive Transport

This means substances move without the cell using energy. Things move naturally from where there is more of them to where there is less of them. This is called moving down a concentration gradient. There are a few kinds of passive transport:

a) Diffusion

This is the simplest type. It happens when small molecules like oxygen or carbon dioxide pass directly through the membrane from high to low concentration. For example, oxygen from your blood diffuses into your cells…

Introduction

The thoracic cavity is a space inside your chest that protects and holds some of the most important organs in your body. The thoracic cavity is like a big box in your upper body, between your neck and your diaphragm (a strong muscle that helps you breathe). This “box” is surrounded by your ribs, your spine (at the back), and your sternum (breastbone in front).

What’s inside the thoracic cavity?

It holds three main things:

1. Lungs – You have two lungs, one on each side. They help you breathe.

2. Heart – In the middle, slightly to the left. It pumps blood to your whole body.