Life is molecule-driven: Life is three-dimensional, and it begins with molecules. The DNA double helix embodies the central role that three-dimensional structures play in understanding biological processes.
The biological matter comprises small molecules (e.g., water), macromolecules (biopolymers), supramolecular assemblies, or macromolecular complexes, which assemble into subcellular particles and cells, which in their turn form supracellular systems such as tissues and organs. These four types of molecules are often referred to as the molecules of life. The four molecules of life are proteins, carbohydrates, lipids, and nucleic acids. Each of the four groups is vital for every single organism on Earth. Without any of these four molecules, a cell and organism would not be able to live. They provide structure and energy to the cells of all living organisms. In addition, these molecules are necessary for the various functions in cells. Therefore, they are referred to as fundamental molecules of life.
Nucleic acids (DNA and RNA) rich in carbon, hydrogen, oxygen, nitrogen, and phosphorus are only capable of reproduction independently, therefore considered the basis of life. The cell is the smallest structural and functional unit of living organisms, which can exist on its own.
Protein enzymes evolved before DNA genomes. The RNA world contained RNA polymerase ribozymes that can produce single-stranded complementary DNA and then convert it into stable double-stranded DNA genomes.
Proteins are built from a set of only twenty amino acids, each of which has a unique side chain. The side chains of amino acids have different chemistries. The genetic code is the universal language that relates base triplets in DNA to amino acids in proteins. … Subtracting for a necessary stop codon, organisms could code for up to 63 different amino acids. Structure determines function.
An enzyme is a substance that acts as a catalyst in living organisms, regulating the rate at which chemical reactions proceed without itself being altered in the process. … Enzymes catalyze all aspects of cell metabolism. Enzymes catalyze all kinds of chemical reactions that are involved in growth, blood coagulation, healing, diseases, breathing, digestion, reproduction, and many other biological activities. Enzymes work by binding to reactant molecules and holding them in such a way that the chemical bond-breaking and bond-forming processes take place more readily. Reaction coordinate diagram showing the course of a reaction with and without a catalyst. With the catalyst, the activation energy is lower than without.
Cells are made of proteins, which are molecules, and water, which is another molecule, and other things that are all made of molecules. Within the center of the cell is DNA and RNA, both extremely complicated molecules. So we know that the cells of the body are made up of molecules.
Molecules are among the most basic units found inside living organisms. A living organism is a living system, such as a vertebrate, insect, plant, or bacterium. There are many types of molecules, but the most common kinds in biological organisms, like humans, are proteins, carbohydrates, lipids, and nucleic acids.
Proteins are the workhorses of the cell. Proteins are called the workhorses of life as they provide the body with structure and perform a vast array of functions. You can stand, walk, run, skate, swim, and more because of your protein-rich muscles. Proteins are the little machines that make cells work. … Proteins carry messages, break down chemicals, copy DNA, and give cells their structure. Basically, they do everything. Every biological function is performed by proteins.
Life is based on carbon; organic chemistry studies compounds in which carbon is a central element. The properties of carbon make it the backbone of the organic molecules which form living matter. The primary role of RNA is to convert the information stored in DNA into proteins.
There are two types of nucleic acids which are polymers found in all living cells. Deoxyribonucleic Acid (DNA) is found mainly in the cell’s nucleus, while Ribonucleic Acid (RNA) is found primarily in the cell’s cytoplasm. However, it is usually synthesized in the nucleus.
Ionic bonds are the worker bees:
Electrolytes play an important role in the body; they regulate the osmotic pressure in cells and help maintain the function of muscle and nerve cells. These ions enable the flow of electrical signals through the body. Ion channels are specialized proteins in the plasma membrane that provide a passageway through which charged ions can cross the plasma membrane down their electrochemical gradient. Potassium is both an electrolyte and a mineral. It helps keep the water (the amount of fluid inside and outside the body’s cells) and electrolyte balance of the body. Potassium is also important in how nerves and muscles work. Potassium levels often change with sodium levels.
Synaptic vesicles are docked at the presynaptic plasma membrane at regions called active zones. Immediately opposite is a region of the postsynaptic cell containing neurotransmitter receptors; for synapses between two neurons, the postsynaptic region may be found on the dendrites or cell body.
An axon typically develops side branches called axon collaterals, so that one neuron can send information to several others. These collaterals, just like the roots of a tree, split into smaller extensions called terminal branches. Each of these has a synaptic terminal on the tip.
The neuron is the basic working unit of the brain, a specialized cell designed to transmit information to other nerve cells, muscle, or gland cells. Neurons are cells within the nervous system that transmit information to other nerve cells, muscle, or gland cells.
