BIOL 107 Part E - Enzymes and Photosynthesis (Terms)

Metabolism

The chemical reactions taking place within a cell/organism

First Law of Thermodynamics

Law of thermodynamics stating that the amount of energy in the universe is constant, so energy can only be transferred, not created or destroyed

Entropy

A measure of the disorder in the universe, representative of the unavailability of a system’s energy to do useful work

Second Law of Thermodynamics

Law of thermodynamics stating that the disorder in the universe is increasing, so energy transfers or transformations cause some useful energy to be lost as heat

Free Energy (G)

Amount of a system’s total energy available to do work

Exergonic Reaction

A reaction in which energy is lost as the reaction progresses, thus releasing energy and having a negative change in free energy

Endergonic Reaction

A reaction in which energy is absorbed as the reaction progresses, thus requiring energy and having a positive change in free energy

Sucrase

An integral membrane protein enzyme that facilitates the breakdown of sucrose via hydrolysis into two monosaccharides, glucose and fructose

Activation Energy

Initial input of energy needed to break the bonds and cause a reaction to begin

Alcohol Dehydrogenase (ADH)

A homodimer enzyme found in the cytosol of human liver cells that breaks down ethanol into acetaldehyde

Allergy

When white blood cells in the immune system react to a harmless molecule

Food Intolerance

Lacking the required enzyme needed to digest a molecule

Electron Carriers

Small organic cofactors that work with enzymes, with high and low energy forms that accepts and releases electrons in changing forms

Transpeptidase

An enzyme that synthesizes peptidoglycan in bacteria

Beta Lactamase

A protein encoded by some bacterial plasmids that cuts up penicillin

Antibiotics

Molecules that kill bacteria inside the human body, typically by inhibiting enzymes that are needed for bacterial cells to function

Antiseptics

Molecules that kill bacteria outside the human body, typically by physically damaging the cell wall of bacteria

Photosynthesis

The process by which plants create energy, using (solar energy + water + CO₂ → sugar + O₂)

Light

Radiation with a specific wavelength that travels as photons

Mesophyll

Internal tissue in the middle of leaves that contain chloroplasts and are connected to veins

Stroma Space

Space inside chloroplast filled with dense fluid that is encapsulated by the inner and outer membrane, containing ribosomes, chromosomes, and RNA polymerases

Thylakoid

System contained in the stroma in chloroplasts composed of sacs that are separate from the stroma space, where chlorophyll is found

Chlorophyll

A green pigment (absorbs red and blue) used in photosynthesis that is found in the thylakoid membrane of chloroplasts

Resonance Energy Transfer

A form of energy decay used by chlorophyll in which the excited state goes from molecule to molecule through movement of energy only, not movement of electrons

Electron Transfer

A form of energy decay used by chlorophyll in which the electron in the excited state is moved from one molecule to another

Photosystem (PS)

An molecular machine comprised of integral membrane proteins containing pigment molecules that capture light to excite electrons

Electron Transport Chain (ETC)

Chain structures made of membrane proteins and quinones that transport electrons and allow protons to move across a membrane

Water Splitting Enzymes

Peripheral membrane proteins that perform hydrolysis of water in order to supply electrons

NADP+ Reductase

Peripheral membrane protein enzymes that catalyze the reduction of NADH+ to NADPH through the intake of an electron

ATP Synthase

Enzyme made from peripheral and integral membrane proteins that catalyze the synthesis of ATP from ADP and an inorganic phosphate, powered by a proton gradient

Cyclic Electron Flow

The process that occurs in the thylakoid membrane that uses sunlight to make ATP

Linear Electron Flow

The process that occurs in the thylakoid membrane that uses sunlight to make ATP and NADH

Rubsico

A large polypeptide enzyme that fixes carbon into a useful form (C₅ +CO₂ → C₆)

Calvin Cycle

One part of photosynthesis that transforms 3 carbon dioxide molecules into one G3P sugar molecule

Carbon Fixation

The first phase of the Calvin cycle in which 3 CO2 molecules enter and are fixed into a PGAs to be used for synthesis

3-Phosphoglyceric Acid (PGA)

A low energy 3-carbon molecule formed as the end product of carbon fixation

Synthesis of Sugar

The second phase of the Calvin cycle in which PGA molecules are transformed into G3P sugars powered by ATP hydrolysis

Glyceraldehyde 3-Phosphate (G3P)

A high energy 3-carbon molecule formed as the end product of the Calvin cycle