2.1 The Building Blocks of Molecules
3 min read•june 18, 2024
are the building blocks of life, made up of , , and . These tiny particles form , creating molecules essential for biological processes. Understanding atomic structure is key to grasping how living organisms function at the molecular level.
come in various forms, each playing a unique role in biology. From strong in organic molecules to weak in DNA, these connections shape the structure and function of biomolecules, influencing everything from cell membranes to protein folding.
Atomic Structure and Chemical Bonds
Structure of atoms
Top images from around the web for Structure of atoms
The Structure of the Atom | Boundless Chemistry View original
Is this image relevant?
File:Atomic number depiction.jpg - Wikimedia Commons View original
Is this image relevant?
Elements and Atoms: The Building Blocks of Matter · Anatomy and Physiology View original
Is this image relevant?
The Structure of the Atom | Boundless Chemistry View original
Is this image relevant?
File:Atomic number depiction.jpg - Wikimedia Commons View original
Is this image relevant?
1 of 3
Top images from around the web for Structure of atoms
The Structure of the Atom | Boundless Chemistry View original
Is this image relevant?
File:Atomic number depiction.jpg - Wikimedia Commons View original
Is this image relevant?
Elements and Atoms: The Building Blocks of Matter · Anatomy and Physiology View original
Is this image relevant?
The Structure of the Atom | Boundless Chemistry View original
Is this image relevant?
File:Atomic number depiction.jpg - Wikimedia Commons View original
Is this image relevant?
1 of 3
- Atoms are the fundamental building blocks of composed of subatomic particles
- Protons are positively charged particles located in the nucleus
- are neutral particles located in the nucleus
- Electrons are negatively charged particles orbiting the nucleus in shells (energy levels)
- The outermost electrons are called and are crucial for chemical bonding
- indicates the number of protons in an atom and determines the element's identity (carbon has 6 protons)
- represents the sum of protons and neutrons in an atom (carbon-12 has 6 protons and 6 neutrons)
- are atoms of the same element with different numbers of neutrons (carbon-12 and carbon-14)
Formation of chemical bonds
- Chemical bonds are attractive forces between atoms that hold them together, allowing atoms to achieve a stable electronic configuration ()
- Covalent bonds involve the sharing of electrons between atoms
- have equal sharing of electrons (C-C bond in hydrocarbons)
- have unequal sharing of electrons due to differences (O-H bond in water)
- are electrostatic attractions between oppositely charged ions formed when electrons are transferred from one atom to another (Na+ and Cl- in )
- Hydrogen bonds are weak electrostatic attractions between a hydrogen atom and a strongly electronegative atom like oxygen or nitrogen (between water molecules)
Types of bonds in biology
- Covalent bonds are strong and stable bonds commonly found in organic molecules like , , , and , providing structural stability
- Ionic bonds are strong electrostatic attractions found in salts and minerals such as sodium chloride and , important in maintaining proper electrolyte balance in cells and body fluids
- Hydrogen bonds are weaker than covalent and ionic bonds but crucial in maintaining the structure of water and the secondary structure of and nucleic acids, contributing to the specificity of molecular interactions in biological systems like enzyme-substrate binding and DNA base pairing
Molecular Properties
- Electronegativity is the ability of an atom to attract electrons in a chemical bond, influencing bond
- The octet rule states that atoms tend to gain, lose, or share electrons to achieve a stable configuration with eight valence electrons
- refers to the three-dimensional arrangement of atoms in a molecule, affecting its properties
- Polarity in molecules arises from an uneven distribution of charge due to differences in electronegativity and molecular geometry
Molecules in Biological Systems
Types of bonds in biology
- are weak intermolecular attractions between molecules
- are temporary dipoles induced by the movement of electrons, important in the folding and stability of proteins and the interactions between in cell membranes ()
- are covalent bonds formed between the sulfur atoms of two cysteine residues in proteins, contributing to the tertiary structure and stability of proteins (insulin)
- are the tendency of nonpolar molecules to aggregate in aqueous solutions to minimize their contact with water, playing a crucial role in the folding and stability of proteins and the formation of lipid bilayers in cell membranes (membrane proteins)
Key Terms to Review (50)
Anions: Anions are negatively charged ions formed when an atom gains one or more electrons. They play a crucial role in various biological and chemical processes.
Atomic number: The atomic number is the number of protons found in the nucleus of an atom, and it uniquely identifies an element. This number determines the chemical properties of an element and its place in the periodic table, as elements are arranged according to their atomic numbers. The atomic number also indicates the number of electrons in a neutral atom, influencing how atoms interact and bond with one another.
Atoms: Atoms are the basic units of matter and the fundamental building blocks of all substances. Each atom consists of a nucleus containing protons and neutrons, surrounded by electrons in orbitals. Atoms combine to form molecules, which are essential for the structure and function of all living organisms.
Calcium phosphate: Calcium phosphate is a family of minerals containing calcium and phosphate, commonly found in various forms such as hydroxyapatite, which is a major component of bone and teeth. This compound plays a critical role in biological systems, particularly in the formation and maintenance of skeletal structures.
Carbohydrates: Carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen atoms. They are a primary source of energy for living organisms and are found in foods like bread, pasta, and fruits.
Carbohydrates: Carbohydrates are organic compounds made up of carbon, hydrogen, and oxygen, typically in a ratio of 1:2:1. They serve as a primary energy source for living organisms and are also important for structural components in cells. Carbohydrates are classified into three main categories: sugars, starches, and fibers, each playing distinct roles in biological processes, metabolism, and digestion.
Cations: Cations are positively charged ions that occur when an atom loses one or more electrons. They are essential in various biological processes, including nerve impulse transmission and muscle contraction.
Chemical bonds: Chemical bonds are the attractive forces that hold atoms together to form molecules and compounds. These bonds are essential for the structure and function of all biological molecules.
Chemical Bonds: Chemical bonds are the forces that hold atoms together in a molecule, allowing for the formation of compounds. These bonds are crucial because they determine the structure and properties of molecules, influencing everything from reactivity to stability. Understanding chemical bonds is essential for grasping how atoms interact and how complex biological molecules, like proteins and nucleic acids, are formed.
Covalent bond: A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These bonds form when atoms attain stability by having full outer electron shells.
Covalent Bonds: Covalent bonds are a type of chemical bond that involves the sharing of electron pairs between atoms. This bonding occurs when two atoms come together, allowing each atom to achieve a full outer electron shell, which is essential for stability. Covalent bonds can form between identical atoms or different atoms, playing a crucial role in the creation of molecules and compounds essential for life.
Dispersion forces: Dispersion forces, also known as London dispersion forces, are weak intermolecular attractions that arise from temporary fluctuations in electron density within molecules. These forces are present in all molecules, regardless of whether they are polar or nonpolar, and play a crucial role in determining the physical properties of substances, such as boiling and melting points.
Disulfide Bonds: Disulfide bonds are covalent linkages formed between the sulfur atoms of two cysteine residues in proteins, playing a critical role in stabilizing protein structure. These bonds help maintain the three-dimensional shape of proteins by connecting different parts of the molecule, which is essential for proper protein function. The formation and breakage of disulfide bonds can also be influenced by the cellular environment, adding another layer of regulation to protein structure and activity.
Electron: An electron is a subatomic particle with a negative electric charge. It orbits the nucleus of an atom in various energy levels or shells.
Electron transfer: Electron transfer is the movement of electrons from one molecule or atom to another. It plays a critical role in various biochemical processes, including cellular respiration and photosynthesis.
Electronegativity: Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. This property is crucial for understanding how atoms interact and bond with each other, influencing molecular formation and reactivity. The differences in electronegativity between atoms can lead to the creation of polar covalent bonds and contribute to the overall properties of molecules.
Electrons: Electrons are subatomic particles with a negative charge that orbit the nucleus of an atom. They play a crucial role in chemical bonding and electricity, as their movement and interactions with other atoms determine how molecules are formed and how they behave in reactions.
Elements: Elements are pure substances consisting of only one type of atom. They cannot be broken down into simpler substances by chemical means.
Hydrogen bond: A hydrogen bond is a weak interaction between a hydrogen atom bonded to an electronegative atom and another electronegative atom. It plays a crucial role in the structure and properties of water and biological molecules.
Hydrogen bonds: Hydrogen bonds are weak attractions that occur between a hydrogen atom covalently bonded to an electronegative atom, such as oxygen or nitrogen, and another electronegative atom. These bonds play a critical role in shaping the properties of water, the structure of biological molecules, and the formation of DNA's double helix, influencing how these molecules interact and function in living organisms.
Hydrophobic interactions: Hydrophobic interactions are the tendency of nonpolar substances to aggregate in aqueous solutions to minimize their exposure to water. This phenomenon plays a critical role in the formation and stability of biological macromolecules, such as proteins and membranes, where nonpolar regions cluster together away from water, leading to unique structural configurations and functionalities.
Ion: An ion is an atom or molecule that has gained or lost one or more electrons, giving it a net positive or negative charge. Ions are crucial in various biological processes and chemical reactions.
Ionic bond: An ionic bond is a type of chemical bond formed through the electrical force between oppositely charged ions. It typically occurs when one atom donates one or more electrons to another atom, resulting in a stable electron configuration for both.
Ionic bonds: Ionic bonds are a type of chemical bond formed through the electrostatic attraction between positively and negatively charged ions. This occurs when atoms transfer electrons, resulting in one atom becoming positively charged (cation) and the other negatively charged (anion). Ionic bonds play a crucial role in the formation of various biological molecules, as they help stabilize structures and interactions in cellular processes.
Isotopes: Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons, resulting in different atomic masses. This variation in neutron count leads to some isotopes being stable while others are radioactive, which means they decay over time. Understanding isotopes is crucial in studying the building blocks of molecules, as they influence chemical reactions, molecular structure, and can be used in various applications like dating materials or tracing biological processes.
Lipids: Lipids are a diverse group of hydrophobic molecules that include fats, oils, and steroids. They are essential for storing energy, forming cell membranes, and acting as signaling molecules.
Lipids: Lipids are a diverse group of organic molecules that are hydrophobic or amphiphilic, meaning they do not mix well with water. They play crucial roles in biological systems, including energy storage, structural components of cell membranes, and signaling molecules. Their unique properties allow them to form various structures like triglycerides, phospholipids, and steroids, which are essential for life.
Mass number: The mass number is the total count of protons and neutrons in an atom's nucleus, providing a crucial understanding of an element's atomic structure. This number helps distinguish between isotopes of an element, as different isotopes have the same number of protons but varying numbers of neutrons. Understanding mass number is essential for grasping how atoms interact and bond to form molecules, which are the building blocks of matter.
Matter: Matter is anything that has mass and takes up space. It is composed of atoms, which are the basic units of chemical elements.
Molecular geometry: Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule. This shape is crucial because it influences the physical and chemical properties of the substance, including reactivity, polarity, phase of matter, color, magnetism, and biological activity. Understanding molecular geometry helps in predicting how molecules interact with each other, which is essential for grasping the building blocks of larger biological systems.
Neutrons: Neutrons are subatomic particles found in the nucleus of an atom that have no electric charge. They contribute to the atomic mass and play a crucial role in the stability of the nucleus.
Neutrons: Neutrons are subatomic particles found in the nucleus of an atom, characterized by their lack of electric charge. They play a critical role in stabilizing the nucleus by offsetting the repulsive forces between positively charged protons, contributing to the overall mass of an atom. Neutrons, along with protons, make up the atomic mass and are fundamental to the structure and stability of atoms, which are the building blocks of molecules.
Nonpolar covalent bonds: Nonpolar covalent bonds are chemical bonds where two atoms share a pair of electrons equally. This occurs because the atoms have similar electronegativities.
Nonpolar covalent bonds: Nonpolar covalent bonds are a type of chemical bond where two atoms share a pair of electrons equally, resulting in no charge separation across the molecule. This type of bond typically forms between atoms with similar electronegativities, meaning they have an equal ability to attract electrons. As a result, nonpolar covalent molecules are often hydrophobic and do not dissolve well in water, connecting closely to the concept of molecular interactions and properties.
Nucleic acids: Nucleic acids are large biomolecules essential for all forms of life, primarily responsible for storing and transmitting genetic information. The two main types of nucleic acids are DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), which serve different functions in the biological processes of organisms. They play a critical role in coding, decoding, regulation, and expression of genes, linking them to the building blocks of life and the structure and function of biological molecules.
Octet rule: The octet rule is a chemical principle that states that atoms tend to bond in such a way that they have eight electrons in their valence shell, achieving a stable electronic configuration similar to that of noble gases. This rule helps explain the formation of chemical bonds and the reactivity of different elements as they strive to fulfill their electron needs, promoting stability in molecules.
Periodic table of elements: The periodic table of elements is a tabular arrangement of chemical elements organized by atomic number, electron configuration, and recurring chemical properties. Elements are presented in order of increasing atomic number in rows called periods and columns called groups or families.
Phospholipid bilayer: The phospholipid bilayer is a fundamental structure of cell membranes, consisting of two layers of phospholipids with hydrophilic (water-attracting) heads facing outward and hydrophobic (water-repelling) tails facing inward. This arrangement creates a semi-permeable membrane that separates the interior of the cell from the external environment, playing a crucial role in maintaining cellular integrity and function.
Polar covalent bond: A polar covalent bond is a type of chemical bond where electrons are shared unequally between atoms due to differences in electronegativity. This results in a molecule with a partial positive charge on one end and a partial negative charge on the other.
Polar covalent bonds: Polar covalent bonds are a type of chemical bond where two atoms share electrons unequally due to a difference in their electronegativities. This unequal sharing creates a dipole moment, leading to partial positive and negative charges within the molecule. Polar covalent bonds play a crucial role in the formation and properties of many biological molecules, influencing everything from molecular structure to interactions between different substances.
Polarity: Polarity refers to the distribution of electrical charge across a molecule, leading to regions of partial positive and partial negative charges. This characteristic influences how molecules interact with each other, affecting properties like solubility, boiling point, and the behavior of biological systems. Understanding polarity is essential for grasping the building blocks of molecules and the unique properties of water.
Proteins: Proteins are large, complex molecules made up of amino acids and play many critical roles in the body. They are essential for building tissues, enzymes, and hormones.
Proteins: Proteins are large, complex molecules made up of chains of amino acids, essential for the structure, function, and regulation of the body’s tissues and organs. They play crucial roles in nearly all biological processes, including catalyzing biochemical reactions, transporting molecules, and providing structural support to cells. Understanding proteins is fundamental as they connect molecular building blocks, biological functions, and nutritional aspects critical for human health.
Proton: A proton is a subatomic particle found in the nucleus of an atom that carries a positive electric charge. It determines the element's atomic number and contributes to the mass of the atom.
Protons: Protons are positively charged subatomic particles found in the nucleus of an atom. They play a critical role in determining the atomic number of an element, which defines the element's identity, and they also influence the chemical behavior of atoms by contributing to the overall charge balance with electrons.
Radioactive isotopes: Radioactive isotopes are atoms of an element that have unstable nuclei and emit radiation as they decay to a stable form. These isotopes can be used in various scientific applications, including medical imaging and dating of archaeological finds.
Sodium Chloride: Sodium chloride, commonly known as table salt, is an ionic compound composed of sodium (Na+) and chloride (Cl-) ions. It plays a crucial role in biological systems, influencing various physiological functions such as fluid balance, nerve transmission, and muscle contraction.
Valence electrons: Valence electrons are the outermost electrons of an atom that are involved in forming chemical bonds. They play a crucial role in determining how atoms interact with each other and form molecules. The number of valence electrons an atom has influences its reactivity, the types of bonds it can form, and its overall chemical properties.
Van der Waals forces: Van der Waals forces are weak intermolecular forces that occur between molecules due to transient shifts in electron density. These forces are critical in understanding the interactions between molecules and play a significant role in the stability and structure of various biological macromolecules.
Van der Waals interactions: Weak attractions between molecules or parts of molecules due to temporary partial charges. These interactions are critical in biological systems for maintaining structure and function.