What Are Proteins and Lipids? Chp-01 Biomolecules

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Your body uses proteins to build and repair cells, and to make hormones, enzymes, hemoglobin and antibodies. These protein molecules come in all shapes and sizes, each with a specific job to do.

Each protein chain has a certain shape, determined by the chemical properties of its amino acids. These chains are linked together by peptide bonds, which connect the carbonyl C of one amino acid to the amino N of another.


Proteins are large molecules made of amino acids that are used in a wide range of functions within cells. They catalyze metabolic reactions, transport molecules, and respond to stimuli.

They also help cells grow and survive by carrying in essential nutrients or by taking out wastes. Throughout the body, thousands of proteins are working together to carry out these tasks.

Each protein is made up of one or more long chains of amino acid residues that are linked together through covalent peptide bonds. Their unique amino acid sequences dictate their structure and activity.


Lipids are a group of molecules made up of fatty acids and alcohols. They are nonpolar and hydrophobic in nature, and can be used in biochemistry for a variety of functions.

Fatty acids are classified as unsaturated or saturated depending on whether the carbon atoms have single bonds or double bonds. Unsaturated fatty acids are usually made of palmitic acid or oleic acid, while saturated fatty acids are usually made of stearic acid.

The lipids that make up the membranes of cells are called phospholipids. They have a glycerol backbone to which two fatty acid chains and a phosphate group are attached.

These fatty acids can be combined to create a range of different types of lipids. These include triglycerides (made of a glycerol backbone and three fatty acids), oils, waxes, and steroids.


Membranes are the protective layers that surround many cell organelles, including the nucleus and mitochondria. They also act as the interface between intracellular and extracellular spaces, where they play an important role in communication and interactions among cells.

The membrane’s lipid bilayer structure allows it to be selectively permeable, which means that only substances that meet certain criteria can pass through unaided. This is especially true for molecules such as oxygen and carbon dioxide gases, alcohol, and water-soluble materials like glucose.

Biological membranes are used to control the movement of ions and molecules within and between cells. This is achieved through permeability barriers that facilitate the passage of selected substances through channels and pores formed by membrane proteins.

Membrane proteins are a dynamic and integral part of the cell membrane and account for at least half of the mass of most membranes. These proteins are involved in signaling, transportation, and other processes in the cell.


Biochemistry is the study of how chemical processes occur in living organisms. It is a laboratory-based science that brings together knowledge from chemistry, physics and many branches of biology.

Biochemists study a wide range of molecules, including proteins, nucleic acids, lipids, hormones, and vitamins. They work to determine their structure and use these molecules to solve problems related to human health, agriculture, genetics, and the environment.

In addition to examining how specific molecules interact with each other, biochemists also explore the relationship between cellular function and metabolism. Metabolism is the series of chemical reactions that a living organism uses to extract energy from food and store it for later use.

Biochemistry studies the chemistry and physical properties of biomolecules, such as carbohydrates, proteins, lipids, nucleic acids, enzymes, and vitamins. This helps scientists understand how the body functions, how diseases develop and spread, and how to prevent them.

What Are Proteins and Lipids? Chp-01 Biomolecules

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