Biology 101 Lecture Notes Review

Flashcards covering the fundamentals of biology, including the scientific method, basic chemistry, biomolecules, and enzyme kinetics based on lecture notes.

Biology

The study of living things.

Metabolism

The set of all chemical reactions occurring within an organism, including processes like digestion, respiration, assimilation of food, and excretion.

Sensitivity

The ability of an organism to sense and respond to the environment, such as plants growing toward light.

Reproduction

The production of new individuals of the same type.

Evolution

The selective adaptation of organisms to environmental conditions over time.

Death and Decay

The process where metabolic processes stop and microorganisms digest the organism.

Growth

An increase in size.

Healing

The repair of minor wounds or damaged tissue.

Homeostasis

The maintenance of constant internal conditions in an organism, such as the regulation of temperature and $pH$.

Hypothetico-deductive approach

The approach used by the scientific method.

Observation

The first step of the scientific method.

Hypothesis

A testable explanation for an observation.

Null hypothesis

A statement predicting no relationship or effect between variables.

Scientific theory

An extensively tested hypothesis that is supported by evidence.

Scientific law

A description of a consistent natural phenomenon.

Big Bang Theory

The theory explaining the origin of the universe, which is estimated to be approximately $10-17$ billion years old.

Early Earth Atmosphere

A reducing environment without oxygen, composed of nitrogen, ammonia, water vapor, carbon dioxide, methane, and hydrogen.

Atom

The basic unit of matter composed of protons, neutrons, and electrons.

Proton

A subatomic particle with a positive ($+$) charge and a mass of about $1.007\,\text{amu}$.

Electron

A subatomic particle with a negative ($-$) charge and a mass of about $0.0005\,\text{amu}$, located in shells around the nucleus.

Neutron

A subatomic particle with a neutral ($0$) charge and a mass of about $1.008\,\text{amu}$.

Atomic Number

The number of protons in the nucleus, which determines the identity of an element.

Atomic Mass

The sum of protons and neutrons in an atom, measured in atomic mass units ($\text{amu}$).

Element

A substance made of atoms with the same atomic number that cannot be broken down chemically into simpler substances.

Valence Shell

The outermost electron shell of an atom.

Octet Rule

The principle that an atom is chemically stable when its valence shell is full, usually requiring $8$ electrons ($2$ for the first shell).

Molecule

Two or more atoms sharing electrons via chemical bonds.

Compound

A substance containing atoms from two or more different elements.

Ion

An atom or molecule that has gained or lost electrons, resulting in an electrical charge.

Cation

A positively charged ion, such as $Na^+$ or $K^+$.

Anion

A negatively charged ion, such as $Cl^-$ or $PO_4^{3-}$.

Ionic Bond

A bond formed by the attraction between ions with opposite charges.

Covalent Bond

A chemical bond where atoms share one or more pairs of electrons.

Polar Covalent Bond

A bond where electrons are shared unevenly between atoms due to differences in electronegativity.

Electronegativity

The ability of an atom to attract electrons toward itself.

Water ($H_2O$)

A polar molecule with a bond angle of $104.5$ degrees, where oxygen carries a partial negative charge and hydrogens carry partial positive charges.

Hydrophilic

Water-loving; describing substances that are able to interact with or dissolve in water.

Hydrophobic

Water-fearing; describing nonpolar molecules that do not interact well with or dissolve in water.

Stanley Miller's Experiment

An investigation showing that organic molecules, including amino acids, could form from inorganic molecules under early Earth conditions.

Primordial Soup

The accumulation of organic molecules in the environment of early Earth.

Condensation Reaction

Also known as dehydration synthesis; a reaction that joins molecules together by removing water.

Hydrolysis

A reaction that breaks chemical bonds by adding water.

Carbohydrate

Biological molecules made of carbon, hydrogen, and oxygen that provide energy storage and production.

Monosaccharide

A single sugar molecule, such as glucose, which serves as the building block of carbohydrates.

Disaccharide

Two monosaccharides joined together, such as maltose.

Polysaccharide

A carbohydrate made of many sugar molecules linked together, such as starch.

Lipid

Hydrophobic molecules made of fatty acids and glycerol; includes fats and oils.

Saturated Fatty Acid

A fatty acid with no carbon-carbon double bonds, forming straight chains typically found in animal fats.

Unsaturated Fatty Acid

A fatty acid containing one or more double bonds in the carbon chain.

Cis Fat

An unsaturated fat where the double bond causes a bend in the carbon chain.

Trans Fat

An unsaturated fat with a straighter structure than cis fats due to its linear atomic arrangement.

Amino Acids

The building blocks of proteins, consisting of an amino group, an acid group, and a unique side chain ($R$ group).

Essential Amino Acids

Amino acids that animals cannot synthesize and must obtain from their diet, including lysine, leucine, and tryptophan.

Primary Protein Structure

The specific sequence of amino acids in a polypeptide chain.

Secondary Protein Structure

Folding patterns like the alpha helix and beta pleated sheet formed by hydrogen bonding in the amino acid backbone.

Tertiary Protein Structure

The three-dimensional shape of a single folded polypeptide chain determined by side-chain interactions.

Quaternary Protein Structure

The structure formed when two or more folded polypeptide chains combine.

Disulfide Bridge

A bond between sulfur-containing amino acids that stabilizes protein folding.

Denaturation

The unfolding or loss of a protein's normal shape due to high temperature or $pH$ changes, resulting in loss of function.

Enzyme

A protein that acts as a catalyst to speed up chemical reactions by $100$ million to $10$ billion times by lowering activation energy.

Active Site

The specific region on an enzyme where the substrate binds.

Substrate

The specific molecule upon which an enzyme acts.

Activation Energy

The minimum energy required to start a chemical reaction.

Exothermic Reaction

A chemical reaction that releases energy, often as heat.

Coupled Reaction

Two linked reactions where the energy released from one powers the other.

Oxidation

The loss of electrons during a chemical reaction, resulting in a decrease in potential energy.

Reduction

The gain of electrons during a chemical reaction, resulting in an increase in potential energy.

$NAD^+$/$NADH$

An electron carrier molecule that transfers energy during metabolic reactions by switching between oxidized ($NAD^+$) and reduced ($NADH$) states.

Kinase

An enzyme that adds phosphate groups to molecules.

Protease

An enzyme that breaks down proteins.

Competitive Inhibition

When an inhibitor competes with the substrate for the enzyme's active site, preventing the substrate from binding.

Noncompetitive Inhibition

When an inhibitor binds to a site other than the active site, changing the enzyme's shape and reducing its function.

Feedback Inhibition

A regulatory mechanism where the final product of a metabolic pathway inhibits an earlier step to prevent overproduction.