Module 1 notes.2

Atom

The basic unit of matter, made up of protons, neutrons, and electrons.

Element

Matter containing only one type of atom.

Atomic Number

The number of protons in an atom, which defines the element.

Mass Number

The total number of protons and neutrons in an atom.

Isotopes

Atoms of the same element with different mass numbers.

Electron Shells

Electrons are arranged in shells, with the smallest shell holding 2 electrons and most other shells holding up to 8.

Molecules

Compounds formed when atoms share electrons, created through covalent bonds.

Covalent Bond

A bond formed when atoms share electrons in pairs.

Why Atoms Bond

Atoms share electrons to fill their outer shells and become more stable.

Important Biological Molecules

Living things contain molecules such as carbohydrates, lipids, proteins, and nucleic acids.

Polarity (of Water)

The main important feature of water, affecting its properties.

Hydrogen Bonds

Weak bonds formed between hydrogen and an atom with a lone electron pair.

Water Mixtures

Water can form solutions, suspensions, and colloids.

Solubility

A molecule's ability to dissolve in water depends on polarity, charge, and number of polar groups.

Ion

An atom or molecule with an overall positive or negative charge.

Oxidation

The loss of electrons, making the atom or molecule more positive.

Reduction

The gain of electrons, making the atom or molecule more negative.

Memory Trick: OIL RIG

Oxidation Is Loss; Reduction Is Gain.

Ionic Bonding

When ions combine through ionic bonding.

Solubility of Ionic Compounds

Some ionic compounds dissolve easily in water, while others are poorly soluble.

Chemical Reactions

Rearrangements of atoms that form new chemical combinations.

Reactants

What you start with in a chemical reaction.

Products

What you make in a chemical reaction.

Example of a Chemical Reaction

Hydrogen + Oxygen → Water (2H₂ + O₂ → 2H₂O).

pH

A measure of the acidity or basicity of a solution based on hydronium ion concentration.

Acidic Solution

Characterized by H₃O⁺ > OH⁻ and a pH below 7.

Basic Solution

Characterized by H₃O⁺ < OH⁻ and a pH above 7.

Neutral Solution

Characterized by H₃O⁺ = OH⁻ and a pH of 7.

Neutralization

When acids and bases can neutralize each other.

Energy

The capacity to do work and produce heat.

Kinetic Energy

Energy of movement.

Potential Energy

Stored energy.

Chemical Energy

A common form of potential energy in cells.

Exergonic Reaction

A reaction that gives off energy as heat.

Endergonic Reaction

A reaction that requires energy to run.

Metabolism

The sum of all exergonic and endergonic reactions occurring in a cell.

Catabolism

Breaks down/disassembles molecules, generally exergonic.

Anabolism

Builds/assembles molecules, requiring parts and energy, generally endergonic.

Reaction Coupling

A catabolic reaction can power an endergonic reaction.

Carbohydrates

A major class of biological molecules used for energy, made of monosaccharides.

Monosaccharides

Single sugars usually containing a 3–6 carbon chain or ring.

Disaccharides

Two monosaccharides joined together (e.g. sucrose = glucose + fructose).

Polysaccharides

Long chains of monosaccharides, used for storage (e.g. glycogen in animals).

Lipids

Hydrophobic molecules that serve as storage, structural components, and hormones.

Fatty Acids

Can be saturated, unsaturated, or polyunsaturated.

Proteins

Large molecules made of one or more polypeptide chains that perform various functions.

Polypeptide

A chain of amino acids.

Nucleic Acids

Biological molecules like DNA and RNA that carry genetic information.

Nucleotide

Made of a phosphate group, pentose sugar, and nitrogenous base.

ATP

Adenosine triphosphate, the primary energy carrier in cells.

Cellular Contents

Cells contain cytosol, organelles, and cytoplasmic inclusions.

Plasma Membrane

Isolates the cell, allowing for selective permeability and sensitivity to the external environment.

Fluid Mosaic Model

Describes the plasma membrane's composition and fluidity.

Cell Junctions

Structures connecting cells together and facilitating communication.

Passive Transport

Movement of substances across a cell membrane without energy.

Diffusion

Movement from high concentration to low concentration.

Osmosis

The movement of water across a membrane.

Facilitated Diffusion

Movement across a membrane using proteins, without energy.

Active Transport

Energy-requiring movement of substances against their concentration gradient.

Bulk Transport

Transport mechanisms including phagocytosis, pinocytosis, and exocytosis.

Major Organelles

Include mitochondria, ribosomes, endoplasmic reticulum, and Golgi apparatus.

Nucleus

Contains the nuclear envelope, nucleolus, and chromatin.

Cytoskeleton

Protein framework providing shape and support to cells.

Cell Movement Structures

Include pseudopodia, cilia, flagella, and microvilli.

Cell Division

Includes DNA replication and the phases of mitosis.

Meiosis

Produces haploid gametes through two divisions.

Protein Production

Involves transcription of RNA and translation into proteins.

Glycolysis

Breaks monosaccharides down into pyruvate, occurring in the cytosol.

Fermentation

An anaerobic process using pyruvate for electron regeneration.

BIG PICTURE STUDY MAP

Chemistry: Atoms → Elements → Molecules → Ions → Chemical Reactions → pH → Energy.

Biomolecules Overview

Comprises Carbohydrates + Lipids + Proteins + Nucleic Acids + High-Energy Molecules.

Cell Biology Overview

Cell Contents → Plasma Membrane → Cell Junctions → Diffusion/Osmosis → Facilitated Diffusion → Active Transport → Bulk Transport.

Atoms

Made of protons, neutrons, and electrons.

Element

Matter containing only one type of atom.

Atomic Number

The number of protons in an atom.

Mass Number

Mass number = protons + neutrons.

Isotopes

Atoms of the same element with different mass numbers.

Molecules

Compounds formed when atoms share electrons.

Covalent Bond

Formed from shared pairs of electrons.

Polarity of Water

The main important feature of water.

Hydrogen Bonds

Form between hydrogen and an atom with an unshared electron pair.

Ion

An atom or molecule with an overall charge.

Oxidation

Loss of electrons, makes the atom more positive.

Reduction

Gain of electrons, makes the atom more negative.

Ionic Bonding

Occurs when ions combine.

Chemical Reaction

Rearrangements of atoms that form new chemical combinations.

Reactants

What you start with in a chemical reaction.

Products

What you make in a chemical reaction.

Acidic Solutions

H₃O⁺ > OH⁻, pH below 7.

Basic Solutions

H₃O⁺ < OH⁻, pH above 7.

Kinetic Energy

Energy of movement.

Potential Energy

Stored energy.

Exergonic Reactions

Give off energy as heat.

Endergonic Reactions

Require energy to run.

Catabolism

Breaks down molecules and is generally exergonic.

Anabolism

Builds molecules and is generally endergonic.

Monomers

Smaller building blocks of polymers.

Polymers

Larger molecules made from monomers.

Dehydration Synthesis

Builds molecules through the loss of water.

Hydrolysis

Breaks molecules apart by splitting water.