Chemical Basis of Life

Chemical evolution

Hydrogen, carbon, nitrogen, and oxygen

They are all composed of a nucleus containing protons and neutrons, surrounded by orbiting electrons.

<p>They are composed of two or more atoms held together by covalent bonds, where electrons are shared between atoms.</p> Signup and view all the answers

<p>A nucleus made up of protons and neutrons surrounded by orbiting electrons.</p> Signup and view all the answers

<p>It consists entirely of a single type of atom and is represented by a unique symbol on the periodic table.</p> Signup and view all the answers

<p>It is the characteristic number of protons in the nucleus of an atom.</p> Signup and view all the answers

<p>It is the sum of the number of protons and neutrons in an atom.</p> Signup and view all the answers

<p>Atoms are weighed in daltons (Da), where each proton and neutron has a mass of one dalton.</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>It is an atom of the same element that has a different number of neutrons, resulting in a different atomic mass.</p> Signup and view all the answers

<p>It is the average of all masses of naturally occurring isotopes of that element, taking into account their relative abundance.</p> Signup and view all the answers

<p>The atomic number of carbon is 6. This indicates that carbon atoms always have 6 protons, making them a distinct element.</p> Signup and view all the answers

<p>They are unstable isotopes that decay over time, emiting radiation such as alpha particles, beta particles, or gamma rays.</p> Signup and view all the answers

<p>It refers to a specific number of atoms, molecules, or other particles, which is equal to 6.022 x 10^23.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>It is the mass of one mole of that molecule.</p> Signup and view all the answers

<p>They are arranged in specific regions called orbitals, which are grouped into levels called electron shells.</p> Signup and view all the answers

<p>It is the outermost electron shell of an atom, and the electrons in this shell are called valence electrons.</p> Signup and view all the answers

<p>By sharing electrons to fill their valence shells, atoms achieve a more stable electron configuration and lower their overall energy.</p> Signup and view all the answers

<p>It is a type of covalent bond in which electrons are shared equally between two atoms of similar electronegativity.</p> Signup and view all the answers

<p>It measures the strength with which an atom attracts electrons towards itself in a chemical bond.</p> Signup and view all the answers

<p>It is a molecule formed by the chemical bonding of two or more atoms of different elements.</p> Signup and view all the answers

<p>It is a type of bond where electrons are completely transferred from one atom to another, creating ions with opposite charges that attract each other.</p> Signup and view all the answers

<p>It is an ion that carries a negative charge, formed when an atom gains one or more electrons.</p> Signup and view all the answers

<p>It represents a range of chemical bonds, from nonpolar covalent bonds (equal sharing of electrons) to ionic bonds (complete transfer of electrons), with polar covalent bonds falling in between.</p> Signup and view all the answers

<p>They can form double and triple covalent bonds.</p> Signup and view all the answers

<p>The shape of a simple molecule is determined by the geometry of its bonds, which influence its interactions with other molecules and its overall properties.</p> Signup and view all the answers

<p>Molecules can be represented in different ways, including molecular formulas, structural formulas, ball-and-stick models, and space-filling models.</p> Signup and view all the answers

<p>Water is essential for life, making up approximately 75% of a cell's volume and playing a crucial role in numerous biological processes.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Water is a polar molecule because the oxygen atom has a partial negative charge due to its higher electronegativity, while the hydrogen atoms have partial positive charges.</p> Signup and view all the answers

<p>It is a weak electrical attraction between a partially positive hydrogen atom in one molecule and a partially negative atom (usually oxygen or nitrogen) in another molecule.</p> Signup and view all the answers

<p>They contribute to water's high cohesiveness, its ability to act as an excellent solvent, and its high heat capacity.</p> Signup and view all the answers

<p>It is a molecule that is attracted to water, typically due to its polar nature or the presence of charged groups.</p> Signup and view all the answers

<p>They allow water to interact with polar molecules, disrupting the bonds holding them together and enabling them to dissolve in water.</p> Signup and view all the answers

<p>Water is cohesive because its molecules are held together by hydrogen bonds, which provide a strong attraction between water molecules.</p> Signup and view all the answers

<p>It is a cohesive force that arises from the attraction between molecules at the surface of a liquid, causing the surface to act like an elastic membrane.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>It provides a layer of insulation on water bodies, preventing them from freezing solid and protecting aquatic life from extreme temperatures.</p> Signup and view all the answers

<p>It is the amount of energy required to raise the temperature of 1 gram of that substance by 1°C.</p> Signup and view all the answers

<p>The strong hydrogen bonds between water molecules require a significant amount of energy to break, leading to a high heat capacity.</p> Signup and view all the answers

<p>They absorb a significant amount of energy to break, making it difficult to raise the temperature of water.</p> Signup and view all the answers

<p>Substances are broken down into new substances, or combine to form new substances, with the breaking and forming of chemical bonds.</p> Signup and view all the answers

<p>They are the starting materials in a chemical reaction.</p> Signup and view all the answers

<p>They are the substances formed as a result of a chemical reaction.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>It is a state in a reversible chemical reaction where the rates of the forward and reverse reactions are equal, resulting in no net change in the concentrations of reactants and products.</p> Signup and view all the answers

<p>Protons (H+) are highly reactive and do not exist independently in solution, so they readily combine with water molecules to form hydronium ions, which is how acidic solutions are represented and measured.</p> Signup and view all the answers

<p>It represents the concentration of a substance in a solution, specifically the number of moles of solute present per liter of solution.</p> Signup and view all the answers

<p>They are substances that donate protons (H+) during chemical reactions, increasing the hydronium ion (H3O+) concentration of a solution.</p> Signup and view all the answers

<p>It is a logarithmic measure of the hydrogen ion concentration in a solution, indicating its acidity or basicity.</p> Signup and view all the answers

<p>They are substances that help to minimize changes in pH by resisting shifts in acidity or basicity, maintaining a relatively stable pH level.</p> Signup and view all the answers

<p>It refers to the ability of an organism to maintain a stable internal environment despite external fluctuations.</p> Signup and view all the answers

<p>It is the kinetic energy of molecules due to their motion.</p> Signup and view all the answers

<p>It states that energy cannot be created or destroyed, only transferred or transformed from one form to another.</p> Signup and view all the answers

<p>It states that the entropy of a closed system always increases over time, meaning that systems tend to move towards a more disordered state.</p> Signup and view all the answers

<p>It is a measure of disorder or randomness in a system.</p> Signup and view all the answers

<p>A chemical reaction is spontaneous if it proceeds on its own without continuous external influence and does not require added energy.</p> Signup and view all the answers

<ol> <li>The products of the reaction have lower potential energy than the reactants, and 2. The products are less ordered than the reactants, meaning there is higher entropy in the products.</li> </ol> Signup and view all the answers

<p>The process of forming increasingly complex carbon-containing molecules from simple molecules, potentially leading to the origin of life.</p> Signup and view all the answers

<p>It demonstrated that complex organic molecules, including amino acids, could be formed from simple molecules like methane, ammonia, hydrogen, and water, under conditions simulating a possible primitive Earth environment.</p> Signup and view all the answers

<ol> <li>Lower potential energy in products: The products of the reaction have less potential energy than the reactants. 2. Higher entropy: The products have a less ordered structure than the reactants.</li> </ol> Signup and view all the answers

<p>A small molecule that can bind to other identical or similar molecules to form a larger molecule, called a polymer, by a process known as polymerization.</p> Signup and view all the answers

<p>The process of joining monomers together, usually through a condensation reaction, to form a polymer.</p> Signup and view all the answers

<p>It is a reaction in which two or more molecules combine to form a larger molecule, with the removal of a small molecule, typically water, as a byproduct.</p> Signup and view all the answers

<p>It is a reaction in which a polymer is broken down into its constituent monomers by the addition of water molecules.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>It is more energetically favorable, meaning that it requires less energy to happen naturally than the reverse reaction of polymerization.</p> Signup and view all the answers

<p>It is believed to have played a crucial role in the origin of life, as the formation of complex molecules from simple monomers is essential for the development of biological systems.</p> Signup and view all the answers

<p>A group of atoms within a molecule that has a characteristic structure and function, often influencing the molecule's chemical reactivity and overall properties.</p> Signup and view all the answers

<p>Carbon is the fundamental building block of life, forming the backbone of all organic molecules, due to its ability to form four covalent bonds with other atoms.</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>They define the chemical behavior of organic molecules, influencing their reactivity, polarity, solubility, and overall properties.</p> Signup and view all the answers

<p>The early Earth's environment, likely rich in simple molecules and subject to significant sources of energy, provided a favorable environment for the emergence and formation of complex organic molecules.</p> Signup and view all the answers