Chapter 2: Chemical Basis of Life Flashcards
What are the pillars of biology?
I. All life is composed of cells
II. All life is based on Chemistry
III. All life uses DNA as the genetic code
IV. All life evolves by natural selection
V. All life is interconnected in its diverse forms, forming a complex web of relationships and dependencies.
What are the levels of organization in biology?
Atoms, Molecules, Cells, Tissues, Organs, Organism, Population, Community.
What is matter?
Anything that takes up space and contains a mass.
What is the difference between mass and weight?
The mass of an object never changes; weight is how strongly mass is pulled by gravity.
What are the states of matter?
Solid, Liquid, Gas.
What defines an element?
Matter that can’t be broken down into other substances by ordinary physical or chemical processes.
What is an atom?
The smallest unit of matter that retains the properties of an element.
What is the composition of atoms?
Atoms are primarily composed of space, with a nucleus containing protons and neutrons, and an electron cloud.
What is the atomic number?
The number of protons residing in the nucleus, unique to each element.
What is atomic mass?
The total value of protons and neutrons comprising an atom, averaged considering the relative abundance of each isotope.
What is an isotope?
Forms of the same element that vary in their number of neutrons.
What are ionic bonds?
A transfer of electrons between atoms, resulting in charged ions.
What are covalent bonds?
Bonds formed by sharing electrons between atoms.
What are polar molecules?
Molecules with uneven distribution of electrons, resulting in charged regions.
What is hydrogen bonding?
A weak interaction between a covalently bonded atom and a different atom, important for properties of water and DNA.
What is a solution?
A homogeneous mixture of two or more substances, consisting of a solvent and a solute.
What are acids?
Substances that tend to donate Hydrogen ions (H+) when added to water.
What are bases?
Substances that tend to accept Hydrogen ions and increase the concentration of OH- when added to water.
What is the pH scale?
A measure of the concentration of H+ in a solution, ranging from 0-14.
What are buffers?
Solutions that resist changes in pH, containing both a weak acid and a weak base.
What is the typical pH range for biological systems?
Biological systems maintain a pH of 6-8, with blood pH around 7.35-7.45.
