2. Chemical Basis for Life

ANSC 142 Fall 26

Matter

Anything that occupies space and has mass - can be solid, liquid, or gas

Mass

Amount of matter a substance contains

Weight

Force of gravity acting on an object with mass

Volume

How much space an object takes up

Element

Contains only one type of atom

Atom

The smallest unit of matter that retains the properties of a single element

What are the 3 subatomic particles contained in an atom?

1. Neutrons (n0)

2. Protons (p+)

3. Electrons (e-)

Atomic number

number of protons (and electrons) an atom has

Mass number

total number of protons, electrons, and neutrons

*note: the number of protons in an atom always equals the number of electrons

Ions

any particle with a positive or negative charge due to the gain or loss of electrons

Cation

positive-charged atoman

anion

negative-charged atom

Isotopes

different atoms of a single element that has the same amount of protons but different amount of neutrons

Ionic Bond

a bond that is created when one atom transfers an electron to another atom (one atom loses an electron and one atom gains an electron)

Covalent bonds

a bond that is created when one atom shares an electron with another atom (no loss of electrons)

Non-polar covalent bond

an atom in a covalent bond that shares electrons equally

polar covalent bond

an atom in a covalent bond that does not share electrons equally

Hydrogen Bonds

when hydrogen forms a covalent bond with another atom, it will form a bond with other atoms that are covalently bonded to hydrogen so no electrons are transferred from the atoms, therefore this is not a true bond

What two factors influence the chance of bonds?

Concentration and Temperature

Synthetic Reactions (anabolism)

Occurs when two or more atoms combine to form a new and larger molecule (several smaller compounds combine to form a larger compound)

2NH₃ + CO₂ —> CO(NH₂)₂ or A + B —> AB

Decomposition Reaction (catabolism)

Occurs when a chemical is broken down into small components (larger compound breaks down into smaller compounds)

CH₄ —> C + 2H₂ or AB —> A + B

Exchange reaction

combination of decomposition and synthetic reactions - the bond between A &B and between C & D breaks (decomposition) and new bonds are formed between A & D and between B & C (synthesis)

AB + CD —> AD + BC

Properties of Organic Compounds (4)

1. Usually large and complex molecules

2. Always contain carbon

3. Contains C-C or C-H bonds

4. Usually bonded via covalent bonds

Properties of Inorganic Compounds (4)

1. Smaller molecules

2. Lacks carbon (rare)

3. Does not have C-C or C-H bonds

4. Usually bonded via ionic bonds

4 components inorganic compounds contain

1. Water

2. Salts

3. Acids

4. Bases

Solute

Any substance that dissolves within another substance

Solvent

Any liquid that dissolves a solute

Solution

The end product of a solute dissolved in a solvent

Why is water a universal solvent?

It is a polar solvent; it can retain partial positive and negative charge on certain parts of the molecule

Water-Soluble

Ability to readily dissolve in water

Lipid-Soluble

the ability to readily dissolve in the presence of lipids, such as the membrane of tissue cells

Types of Solutions

1. True solutions

2. colloid solutions

3. suspension solutions

What differentiates true and colloidal solutions from suspensions?

Particles in suspensions will settle over time, particles in true and colloidal solutions will not settle over time

Ionization

Dissociate

to separate or split into smaller components

Characteristic of an Acid

Dissociates into one or more Hydrogen ions (H+)

Dissociates into one or more anions (negative ions)

Proton donor or electron acceptor

Characteristics of Base (alkaline)

Dissociates into one or more hydroxide ions (OH-)

Dissociates into one or more cations (positive ions)\

proton acceptor or electron donor

Characteristics of Salts

does not dissociate into hydrogen nor hydroxide ions

dissociates into both cations and anions

What happens to Hyrdochloric Acid when it dissociates?

It splits to hydrogen (H+) and chloride (Cl-) an anion. Since it has an extra proton, it is considered a proton donor. HCl is an acid.

What happens to Sodium Hydroxide (NaOH) when it dissociates?

It splits into hydroxide (OH-) and sodium (Na+), a cation. Since hydroxide has a negative charge, it can accept a proton so NaOH is a base

Acidic PH

pH less than 7

Alkaline pH

pH over 7

Normal body and blood pH

~7.4, neutral

Buffers

substances that maintain a neutral pH level

What is the most important buffer of the body?

Bicarbonate

Monomer of Carbohydrates

Monosaccharides (single)

Disaccharides (2 monosaccharides, loses a molecule of water during this process)

Polysaccharides (formed by combining many monosaccharides)

Function of Carbohydrates

1. provides energy like with glucose

2. able to convert into stored energy

3. provides structural support

Examples of Carbohydrates

sugars, starches, cellulose, glucose, glycogen

Monomer of Lipids

Glycerol and fatty acid chains

Function of Lipids

1. stores energy like carbohydrates

2. can form adipose tissue, which carries its own benefits

Examples of Lipids

Triglycerides (neutral fats), phospholipids, steroids

Triglycerides

neutral fats

saturated fatty acids

have single-bonds between all hydrogen chains

unsaturated fatty acids

have one or more double-bonds between all hydrocarbon chains

Phospholipids

lipid molecules with a hydrophilic head and hydrophobic tail

make up cell membranes, which allowes lipid-soluble substances to easily pass through

this membrane is selective and can control what passes through

Steroids

have a large range of functions including growth, energy, metabolism and usage, homeostasis, etc.

cholesterol

the most common steroid in the body and one of the most important

Monomer of Protein

Amino acids

Function of Proteins

1. structural support

2. regulatory support

3. immunological

4. transportation

   1. catalytic

Examples of Proteins

Collagen, keratin, insulin, antibodies, hemoglobin, enzymes

What are the most essential elements of organic compounds?

1. Carbohydrates

2. Lipids

3. Proteins

4. Nucleic Acids

What does excess amino acids form?

Ammonia

Matter

Anything that occupies space and has mass; it can exist in solid, liquid, or gas form.

Mass

The actual amount of matter that a substance contains.

Weight

The force of gravity acting on an object that has mass.

Volume

The measurement of how much space an object occupies.

Major Elements (Human Body)

Elements that compose approximately $96\%$ of total body mass, including carbon ($\text{C}$), hydrogen ($\text{H}$), oxygen ($\text{O}$), and nitrogen ($\text{N}$).

Minor Elements (Human Body)

Elements that compose approximately $3.9\%$ of total body mass, such as sodium ($\text{Na}$), potassium ($\text{K}$), calcium ($\text{Ca}$), chlorine ($\text{Cl}$), and magnesium ($\text{Mg}$).

Trace Elements (Human Body)

Elements that compose approximately $0.1\%$ of total body mass.

Atom

The smallest fundamental unit of matter that retains the properties of a single element, consisting of neutrons ($n^0$), protons ($p^+$), and electrons ($e^-$).

Atomic Number

The total number of protons (which equals the number of electrons) contained within an atom.

Mass Number

The total combined number of protons, electrons, and neutrons contained within an atom.

Ion

Any atomic particle carrying a positive or negative charge as a result of losing or gaining electrons.

Cation

A positively charged atom or ion formed when an atom loses one or more electrons.

Anion

A negatively charged atom or ion formed when an atom gains one or more electrons.

Isotopes

Different atomic forms of a single element that have the same number of protons but different numbers of neutrons.

Radioactive Isotopes

Unstable isotopes that undergo spontaneous decay.

Electron Shell Capacities

The maximum electron limits for the inner to outer atomic shells: Shell 1 ($\text{K}$) holds $2$, Shell 2 ($\text{L}$) holds $8$, Shell 3 ($\text{M}$) holds $18$, Shell 4 ($\text{N}$) holds $32$, Shell 5 ($\text{O}$) holds $50$, and Shell 6 ($\text{P}$) holds $72$.

Ionic Bond

A chemical bond formed when an atom transfers one or more electrons to another atom, creating oppositely charged ions that electrostatically attract each other.

Covalent Bond

A chemical bond formed when two or more atoms share electrons so that there is no net loss or gain of electrons in either atom's valence shell.

Non-polar Covalent Bond

A type of covalent bond where bonding atoms share valence electrons equally.

Polar Covalent Bond

A covalent bond where electrons are shared unequally, giving the more electronegative atom a partial negative charge.

Hydrogen Bond

An intermolecular attraction formed when a hydrogen atom covalently bound to one atom interacts with other covalently bonded atoms; not a true bond because no electrons are transferred or shared.

Surface Tension

A property resulting from hydrogen bonding between the outermost layer of water molecules and underlying molecules, allowing water to pile up.

Capillarity

The physical force that causes water to climb up the sides of a container due to attraction between the positive charges of water molecules and the negative charges of the glass surface.

Synthetic Reaction (Anabolism)

A chemical process wherein two or more smaller atoms or compounds combine to form a new and larger molecule ($\text{A} + \text{B} \rightarrow \text{AB}$), such as the formation of urea from ammonia and carbon dioxide.

Decomposition Reaction (Catabolism)

A chemical process in which a larger compound is broken down into smaller components ($\text{AB} \rightarrow \text{A} + \text{B}$), such as the breakdown of methane ($\text{CH}_4 \rightarrow \text{C} + 2\text{H}_2$).

Exchange Reaction

A reaction combining decomposition and synthesis where existing bonds break and new bonds form by exchanging components ($\text{AB} + \text{CD} \rightarrow \text{AD} + \text{BC}$).

Organic Compounds

Large, complex carbon-containing molecules characterized by $\text{C}-\text{C}$ or $\text{C}-\text{H}$ covalent bonds (e.g., carbohydrates, lipids, proteins, nucleic acids, and ATP).

Inorganic Compounds

Smaller molecules that typically lack carbon, lack $\text{C}-\text{C}$ or $\text{C}-\text{H}$ bonds, and are generally bonded ionically (e.g., water, salts, acids, and bases).

Solute

Any substance that dissolves within another substance.

Solvent

Any liquid medium capable of dissolving a solute.

Solution

The homogeneous end-product resulting from a solute dissolving completely within a solvent.

Suspension

A liquid mixture containing large particles ($> 10^{-5}\,\text{cm}$) that settle out over time.

Acid

A chemical substance that dissociates in water into one or more hydrogen ions ($\text{H}^+$) and anions; acts as a proton donor or electron acceptor.

Base (Alkaline)

A chemical substance that dissociates in water into one or more hydroxide ions ($\text{OH}^-$) and cations; acts as a proton acceptor or electron donor.

Salt

An inorganic compound that dissociates into cations and anions in water without releasing $\text{H}^+$ or $\text{OH}^-$ ions.

Buffer

A substance that maintains a stable physiological pH level by converting strong acids and bases into weak acids and bases (e.g., bicarbonate, $\text{HCO}_3^-$).

Acidosis

A clinical condition resulting from an abnormally low blood pH falling below the normal physiological value of approximately $7.4$, such as a blood pH of $6.4$.