Bio exam 1

Valence Electrons

Electrons located in the outermost shell of an atom that determine its chemical reactivity.

glycogen role in regulating blood glucose

glycogen stores excess glucose, mainly in the liver and skeletal muscles. When blood glucose levels are high, the liver converts glucose into glycogen for storage. When blood glucose levels drop, the liver breaks down glycogen and releases glucose into the bloodstream, helping maintain normal blood glucose levels.

ester bonds

Covalent bonds between an alcohol and a carboxylic acid. The bonds that form/break during dehydration synthesis/hydrolysis of lipids and nucelic acids.

glucose

enzyme: Amylase + Starch =

glucose + galactose

Enzyme: lactase + lactose =

create cellular energy

principle role for sugar in living things

weak acid vs strong acid

Weak acids partially dissociate in solution, while strong acids fully dissociate into their ions. This distinction affects their pH, reactivity, and buffering capacity.

buffering capacity

the ability of a solution to resist changes in pH upon the addition of an acid or base.

dissociation

The process where a compound or molecule breaks apart into smaller pieces, such as ions, usually when dissolved in water.

carboxyl

functional group most commonly found in lipids

C-H

Bonds between which two elements are most commonly found in lipids

Protons

Positively charged subatomic particles located within the nucleus of an atom.

Atomic Number

The number of protons in an atom's nucleus, which identifies the element.

Electronegativity

An atom's ability to attract shared electrons toward itself.

Ionic Bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions created through the complete transfer of electrons.

Polar Covalent Bond

A covalent bond where electrons are shared unequally between atoms due to a significant difference in electronegativity, creating partial positive ($\delta^+$) and partial negative ($\delta^-$) charges.

Nonpolar Covalent Bond

A covalent bond where electrons are shared equally between atoms because they have similar electronegativities ($\Delta \text{EN} \approx 0\text{ to }0.5$).

Polar Molecule

A molecule with an uneven distribution of electron density, resulting in partial positive ($\delta^+$) and partial negative ($\delta^-$) charges on opposite ends.

Cohesion

The property of water molecules sticking to other water molecules via hydrogen bonding, creating surface tension.

Adhesion

The property of water molecules sticking to other polar or charged surfaces, aiding in capillary action. Prevents backward flow.

High Specific Heat

The property of water that enables it to resist rapid changes in temperature by absorbing or releasing large amounts of heat energy.

Hydrophilic

Describing polar or charged substances that interact favorably with water and readily dissolve in it.

Hydrophobic

Describing nonpolar substances that do not interact favorably with water and do not dissolve in it.

pH Scale

A logarithmic scale ranging from $0$ to $14$ that measures the concentration of hydrogen ions ($\text{H}^+$) in a solution, where values below $7$ are acidic and above $7$ are basic.

Functional Group

A specific group of atoms within a molecule that determines characteristic chemical properties and reactivity.

Hydroxyl Group

A polar functional group consisting of a hydrogen atom bonded to an oxygen atom ($-\text{OH}$), characteristic of alcohols.

Carboxyl Group

An acidic functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group ($-\text{COOH}$).

Amino Group

A basic functional group consisting of a nitrogen atom attached to two hydrogen atoms ($-\text{NH}_2$), which can accept a proton ($\text{H}^+$).

Sulfhydryl Group

A functional group consisting of a sulfur atom bonded to a hydrogen atom ($-\text{SH}$), which can form covalent cross-linking bonds to stabilize protein structure.

Methyl Group

A nonpolar functional group consisting of a carbon atom bonded to three hydrogen atoms ($-\text{CH}_3$).

Phosphate Group

A functional group containing a central phosphorus atom bonded to four oxygen atoms, which contributes negative charge and can react with water to release energy.

Monomer

The single, repeating small molecular unit that serves as the building block of a polymer.

Polymer

A large molecule composed of many repeating monomer subunits covalently bound together.

Dehydration Synthesis

A chemical reaction that joins monomers together into polymers by releasing a water molecule ($\text{H}_2\text{O}$).

Hydrolysis

A chemical reaction that breaks covalent bonds in polymers to yield monomers by adding a water molecule ($\text{H}_2\text{O}$).

Monosaccharide

The single sugar monomer unit of carbohydrates, usually forming a ring structure with a basic empirical formula ratio of $1:2:1$ ($\text{CH}_2\text{O}$).

Glycosidic Bond

The covalent bond that connects monosaccharides together to form disaccharides and polysaccharides.

Starch

An energy-storage polysaccharide stored in plant roots and seeds, composed of glucose monomers linked by digestible $\alpha\text{-1,4}$ glycosidic bonds.

Cellulose

A rigid structural polysaccharide structural in plant cell walls, composed of glucose monomers linked by indigestible $\beta\text{-1,4}$ glycosidic bonds.

Glycogen

A highly branched energy-storage polysaccharide found in animal liver and muscle tissue that plays a vital role in blood glucose regulation.

Chitin

A structural polysaccharide containing nitrogen, found in the exoskeletons of arthropods.

Saturated Fatty Acid

A fatty acid chain containing only single carbon-carbon bonds, solid at room temperature with a higher melting point. Longer hydrocarbon chains. Packer tighter —> less movement —> less fluidity

Unsaturated Fatty Acid

A fatty acid chain containing one or more double carbon-carbon bonds, liquid at room temperature with a lower melting point. shorter hydrocarbon chains. packed more loosley —> more movement —-> more fluidity

Amphipathic

Describing a molecule that possesses both hydrophilic (polar) and hydrophobic (nonpolar) regions.

Triglyceride

A lipid polymer composed of three fatty acid chains attached to a single glycerol backbone via ester bonds.

Phospholipid

An amphipathic lipid consisting of a hydrophilic phosphate head and two hydrophobic fatty acid tails, forming the bilayer /core structure of cell membranes.

Steroid

A class of lipids characterized by a carbon skeleton composed of four fused hydrocarbon rings.

Amino Acid

The monomer unit of proteins, consisting of a central $\alpha$-carbon bound to an amino group, a carboxyl group, a hydrogen atom, and a variable R group.

Peptide Bond

The covalent bond formed by dehydration synthesis linking the amino group of one amino acid to the carboxyl group of another.

Protein Primary Structure

The unique linear sequence of amino acids in a polypeptide chain. Determines 3D structure.

Secondary Structure

Local structural folding of a polypeptide backbone, such as an $\alpha$-helix or $\beta$-sheet, stabilized by hydrogen bonds.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide chain formed by interactions among side chain R groups.

Quaternary Structure

The protein structure resulting from the combination and interaction of two or more polypeptide subunits.

Denaturation

The loss of a protein's native three-dimensional shape and functional ability caused by factors like extreme temperature or changes in pH.

Hypothesis

A proposed, testable explanation for an observation that makes a prediction that can be tested through an experiment.

monosaccharide

carbohydrate monomer

polysaccharide

carbohydrate polymers

fatty acid

lipid monomer

amino acid

protein monomers

polypeptide (less than 50 amino acids), proteins (more than 50 amino acids)

protein polymers

nucleotides

nucleic acid monomer

DNA, RNA

nucleic acid polymers

Starch

A polysaccharide found in plants for carbohydrate storage. Made up of amylose and amylopectin.

Amylose

A linear polymer of glucose units that forms part of starch, it is soluble in water and contributes to the energy storage in plants.

Amylopectin

A highly branched polysaccharide that, along with amylose, makes up starch. It serves as a major energy storage component in plants.

Amide group

A functional group containing a carbonyl carbon attached to a nitrogen atom. -C(= O)NH-. Properties: Polar, Hydrophilic. Commonly found in proteins

carbon

Life’s chemical backbond. Forms 4 covalent bonds. Bonds with itself, nitrogen, oxygen, hydrogen, and Sulfur.

Sulfhydryl group

-SH. Properties: Polar, forms S-S disulfide bonds. Commonly found in: The amino acid cysteine, proteins

Methyl group

A very stable chemical group made up of one carbon atom bonded to three hydrogen atoms. CH₃. Properties: nonpolar. Commonly found in amino acids, proteins, and nucleic acids.

Carbonyl group

Functional group consisting of a carbon atom double-bonded to an oxygen atom (C=O). Properties: Polar, hydrophilic. Commonly found in carbohydrates and proteins.

ATP

Cell’s battery

carbon, oxygen, hydrogen, nitrogen

four major elements that make up the human body

functions of protein

Regulatory functions (control processes, e.g., hormones), Structural functions (support e.g., collagen), Defense (antibodies), Transport (hemoglobin), Movement (actin and myosin), Enzymes (catalyst for reactions), Metabolism (control biochemical pathways.

Carboxyl group

Polar, negatively charged at the pH of a cell, can donate a proton —> behaves as an acid, hydrophilic. Commonly found in fatty acids, amino acids, protiens.

amino group

Polar, positively charged at the pH of a cell, can accept a proton —> behaves as a base, hydrophilic. Commonly found in amino acids, proteins.

enzymes

Biological catalysts that speed up chemical reactions in cells by lowering activation energy, facilitating metabolic processes.

< 0.4

nonpolar covalent

between 0.4 and 1.8

polar covalent

>1.8

ionic

unsaturated fat

usually liquid at room temp. lower melting point. Packed looser, more movement. Ex: oil

saturated fat

solid at room temperature. High melting point. Packed tighly, less movement.

monounsaturated

unsaturated fatty acid characterized by 1 double bond in carbon chain

polyunsaturated

unsaturated fatty acid characterized by 2 (or more) double bonds in carbon chain

atom structure

cation vs anion

Hydroxyl Group

phosphate group

Monomer vs. Polymer

Dehydration Synthesis vs Hydrolysis

Glucose vs. Fructose

Monosaccharide

Disaccharide

Polysaccharide

Saturated Fatty Acid vs. Unsaturated Fatty Acid

Phospholipid Bilayer

creates a barrier

Cholesterol

Peptide bond

N Terminus

C Termius

Protein Structures

sturtcure determines function