How Understanding Chemistry Helps Concept Building In Biology

Elements, Compounds In Tissue

A list of elements, including carbon, hydrogen, oxygen, along with their presence per mass of living tissue, can be obtained by performing elemental analysis on the plant, animal, or microbial tissue.

Elements Present in Non-Living and Living Matter

The Following are the Representative Inorganic Constituents of Living Tissues:

Composition Of Cells

Given below is the average composition of cells.

The most thrilling aspect of Chemistry involves separating tens of thousands of small and large compounds from living things, figuring out their structures, and, if possible, synthesising them.

Here’s more on each of the components.

Water

When we classify and represent the chemical composition of living tissue, we find that water is by far the most prevalent chemical in living things. Water is closely related to life processes because of the polarity of the water molecule and the hydrogen bonding that results from this. As most of an organism's cellular chemistry and metabolism take place inside the watery contents of the cell's cytoplasm, it is thought that life first evolved in a watery environment. Chemistry can be used to better understand water's characteristics and the role it plays in sustaining life.

For example,

The key to understanding the chemical behaviour of water is its molecular structure, which includes components of the water molecules and the types of bonds that are involved. Two hydrogen atoms joined to an oxygen atom form the structure of a water molecule, which has a bent overall shape. This is because the oxygen atom also carries two pairs of unshared electrons in addition to forming bonds with the hydrogen atoms. Evaluation of the chemical characteristics of water also involves measuring variables like pH and dissolved oxygen:

The O atom hogs electrons and keeps them away from the H atom because it is more electronegative and therefore more electron-hungry than hydrogen. As a result, the hydrogen end of the water molecule is partially positively charged, while the oxygen end is partially negatively charged. Due to its bent shape and polar covalent bonds, water is categorised as a polar molecule.

• In order to determine how acidic or alkaline water is, the pH scale ranges from 0 to 14. The scale used for measurement is a logarithmic one. Most drinking water has a pH between 6.5 and 8.5.

• The quantity of free, non-compound oxygen that is present in water or other liquids is known as dissolved oxygen. Due to its impact on the aquatic life present in a body of water, it is a crucial factor in determining the quality of the water.

Amino acids

Small organic molecules known as amino acids have an alpha (central) carbon atom joined to an amino group, a carboxyl group, a hydrogen atom, and a variable element known as a side chain. The amino, carboxyl, and R functional groups make up the majority of the chemical and physical characteristics of amino acids. There are acidic (like glutamic acid), basic (like lysine), and neutral (like valine) amino acids based on the number of amino and carboxyl groups. Proteins are made of molecules called amino acids. The building blocks of life are amino acids and proteins.

Understanding the molecular structure of amino acids and how they interact to form proteins is made possible by chemistry. It also enables nutritionists to create healthy diets for vegetarians, athletes, and expectant mothers. This helps to explain amino acid deficiency diseases like kwashiorkor, which biologists have characterised.

For instance, Dietitians research nutritional biochemistry. It entails dietary analysis, cell function and metabolism, clinical nutrition, determining and monitoring dietary needs, macronutrients and energy, nutritional genomics, and nutritional psychiatry.

Lipids

Some lipids have phosphorous and a phosphorylated organic compound in them. These are phospholipids. The cell membrane contains them. A prime example is lecithin.

Lipids in some tissues, particularly neural tissues, have more complex structures. It is so because myelin sheath is a highly specialised, lipid-enriched plasma membrane found only in the nervous system that facilitates the conduction of nerve signals throughout the body. Lipids play a significant role in the structure and function of this membrane.

Proteins

The most prevalent protein in the animal kingdom is collagen, and the most prevalent protein in the biosphere as a whole is ribulose bisphosphate carboxylase-oxygenase (RuBisCO). In living things, proteins serve a variety of purposes. Some transport nutrients across cell membranes, others fight off infectious agents, others are hormones, and still others are enzymes. Polypeptides make up proteins. They consist of peptide bonds that connect linear chains of amino acids. Our diets must provide us with certain amino acids that are necessary for our health. Hence, dietary proteins are the source of essential amino acids.

A protein's shape, structure, and physical interactions with other molecules can be determined with the help of chemistry which eventually determines its biological characteristics.X-ray crystallography is the technique most frequently used to examine protein structures. The position of the tens of thousands of atoms within the protein crystal can be predicted using this technique, which involves exposing solid crystals of purified protein to an X-ray beam and analysing the pattern of deflected X rays.

Each protein's specific function and distinctive 3-dimensional structure are determined by the order of the amino acids. Combinations of three DNA building blocks (nucleotides), which are determined by the order of genes, are used to code for amino acids.

Some Protein and Their Functions

Polysaccharides (Carbohydrates)

Long chains of sugars make up polysaccharides. They are threads containing different monosaccharides as building blocks. One such polymeric polysaccharide is cellulose, which contains only glucose as a monosaccharide. Thus, cellulose is a homopolymer.

Starch is a variant of homopolymer but presents as a storehouse of energy in plant tissues. Glycogen is another variant that exists in animals.

Cellulose makes up the cell walls of plants. Cellulosic paper is made from cotton fibre and plant pulp. In nature, polysaccharides are more complex. Amino-sugars and chemically-altered sugars such as glucosamine, N-acetyl galactosamine, etc., serve as their building blocks. Arthropods, for instance, have a complex polysaccharide called chitin in their exoskeletons.

Nucleic Acids

Nucleic acid is the other type of macromolecule that can be found in any living tissue. These are polynucleotides. All living tissue and cells contain these, along with polysaccharides and polypeptides, as the true macromolecular fraction. A nucleotide is the fundamental component of nucleic acids. Three chemically distinct parts make up a nucleotide. The first is a heterocyclic compound, the second is a monosaccharide, and the third is phosphoric acid or phosphate.

Biophysical and biochemical techniques can be used to experimentally determine the structures of nucleic acids like RNA and DNA. Biophysical techniques, such as X-ray crystallography, NMR, and cryo-EM, use the fundamental physical characteristics of molecules to determine their structure.

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Structure And Reaction

In various contexts, a molecule's structure can mean different things. What we have discovered so far is that all living things, whether they be simple bacterial cells, protozoans, plants, or animals, contain thousands of organic compounds.

These substances or biomolecules exist in specific concentrations, which are expressed in mols/cell, mols/litre, etc. That all these biomolecules have a turnover was one of the greatest discoveries ever made. In other words, they are constantly being transformed into other biomolecules and also produced from other biomolecules.

This forming and breaking occur through chemical reactions that constantly take place in living organisms. Metabolism is the collective term for all of these chemical processes.

Metabolism

The sum of all chemical reactions that take place inside living things' cells is called metabolism. All matter, including living things, is made up of different elements in different combinations. Carbon, hydrogen, nitrogen, oxygen, sulphur, and phosphorus are a few of the elements that are most prevalent in living things. These combine to form the proteins, lipids, carbohydrates, and nucleic acids that make up the building blocks of all living things. To enable the formation of cells, tissues, organ systems, and whole organisms, biologists must comprehend these crucial building blocks and the distinctive structures of the atoms that make up molecules.

A few examples of these metabolic changes include the removal of CO2 from amino acids which turns an amino acid into an amine; the removal of the amino group from a nucleotide base which is known as deamination (a step of protein digestion); and the hydrolysis of a glycosidic bond in a disaccharide. Similar to this, the hydrolysis of starch to produce glucose is an organic chemical reaction.

Some Phenomena Of Biology

Understanding fundamental physics and chemistry is essential to comprehending how biological systems function because all biological processes adhere to the laws of physics and chemistry. For example,

• Food molecules are broken down into smaller molecules through a series of chemical reactions that adhere to the laws of chemistry. For example, proteins are broken down into their 'building block' amino acids.

• The body is made up of atoms, and the process of life depends on the consumption of oxygen, which is transported through the blood to the lungs. Unwanted gases are also released outside, where they are used by plants for photosynthesis.

• The genetic explanation of how physical traits are inherited and a chemical understanding of the molecular structure of DNA came together to produce rapid change in almost all fields of science. In forensics, the Polymerase Chain Reaction is used to produce DNA evidence, and in genetics, where DNA can be used to trace evolutionary changes, new approaches have been born. In medicine, where genetic manipulation has led to new drugs and approaches to healing.

• Neurons - Chemistry has helped us understand how neurons interact through neural transmitters whose molecular shape is essential to their function.

• Since molecules must undergo chemical changes as they are digested, indigestibility is a chemical property.

• When viewed in terms of their molecular composition or characteristics, biomolecules found in "natural foods" are identical to synthetic molecules created in a laboratory.

A molecule's shape affects how it behaves biologically. The formation and function of molecules depend on chemical bonding between atoms. To comprehend biological molecules and processes, we need to understand chemistry. Chemical biology studies how chemistry is applied to biology. Biochemistry studies the chemistry of biomolecules and the regulation of biochemical pathways within and between cells.

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