LECTURE 2: Chemical Components of the Cell Flashcards
What is matter?
Substance that takes up space and has a mass
What are elements?
Pure substances that cannot naturally break down into smaller substances.
What is an atom?
Smallest unit of matter that has distinct chemical properties.
What are isotopes?
Different forms of the same element with the same number of protons but a different number of neutrons.
What is the octet rule?
The octet rule states that atoms tend to have 8 electrons in their valence shell for stability.
What are chemical reactions?
Chemical reactions involve the “making and breaking of bonds” and occur when electrons of atoms are shared or transferred.
What is the difference between molecules and compounds?
A molecule is a group of bonded atoms, while a compound is a molecule containing more than one type of element.
What are ionic bonds?
Ionic bonds occur between cations and anions when one atom completely donates its electron(s) to another.
What are covalent bonds?
Covalent bonds occur when two nonmetals share electrons.
What are hydrogen bonds?
Hydrogen bonds form between two molecules that have partial charges: one has a hydrogen atom and the other has a high electronegativity atom (N, O, S, F). They are weak but essential for life.
What is the significance of water in biological systems?
Water constitutes “60–70 percent of the human body” and its proSDFGperties are largely due to hydrogen bonds.
What are the key properties of water?
Key properties include high heat capacity, high heat of vaporization, being a good solvent, high cohesion, high adhesion, and unique ice formation.
What is pH?
pH determines the acidity and basicity of a substance based on the concentration of hydrogen ions (H⁺) and hydroxide ions (OH⁻).
What are buffers?
Buffers are substances that can minimize changes in pH by absorbing extra H+ or OH–, helping to maintain stable pH levels.
What are carbohydrates?
Carbohydrates have the general formula (CH₂O)n, with monomers being monosaccharides and functions including energy source and structural support.
What are lipids?
Lipids are mainly nonpolar and insoluble in water, serving functions like long-term energy storage and insulation.
What are proteins?
Proteins consist of amino acids (20 different types) linked by peptide bonds to form polypeptides.
What are nucleic acids?
Nucleic acids are polymers made of nucleotides, which store genetic information and carry instructions to build proteins.
