Enzymes Flashcards

Flashcards to review key concepts about enzymes from lecture notes.

Enzymes are _ that act as bio catalysts.

Globular proteins that speed up reaction rates by lowering activation energy without being consumed in the process.

__ or endozymes, such as DNA and RNA polymerase, function within the cells.

Intracellular enzymes that remain and function within the cells, occurring in the cytoplasm or cell organelles.

__ or exozymes are enzymes released outside the cell.

Extracellular enzymes released outside the cell, such as digestive enzymes like amylase released into the alimentary canal.

enzymes are formed of amino acids only; enzymes have non-protein substances associated.

Simple enzymes are formed of amino acids only; conjugated enzymes (holoenzymes) have non-protein substances associated with a protein moiety.

Apoenzyme

Protein component of a conjugated enzyme.

Prosthetic group

Non-protein substances like cofactors (inorganic ions) and coenzymes (organic ions) that attach to apoenzymes.

The _ is the area on the enzyme where the substrate attaches.

The active site is the location on an enzyme where the substrate binds.

Enzymes are typically __ and possess active sites.

All enzymes are proteins (except ribozymes and ribonucleizymes); they have active sites, are specific, and have high efficiency.

Enzymes lower the _, but don't change the initial or final energy amounts.

Enzymes lower the activation energy of a reaction, but do not alter the initial energy of substrate or final energy of the product.

Transition State

The point where the substrate begins to form product.

Enzymatic reactions begin with __ binding to the enzyme's active site.

Enzymatic reactions occur by binding of the substrate with the active site of the enzyme, forming an enzyme-substrate (ES) complex.

Active Site

The area on the enzyme where the substrate attaches.

Lock-and-Key Model

The active site has a rigid shape, and only substrates with a matching shape can fit.

Induced-Fit Model

The active site is flexible, and the shapes of the enzyme, active site, and substrate adjust to maximize the fit.

Enzyme activity increases with __ until saturation is reached.

Enzyme activity increases with substrate concentration until the enzyme is saturated, reaching a steady state.

Enzymes are most active at their _.

Enzymes are most active at their optimum pH.

The optimum temperature for most human enzymes is __.

Human enzymes typically have an optimum temperature around 37 degrees Celsius.

Enzymes _ at high temperatures and have low activity at low temperatures.

At high temperatures, enzymes denature changing the shape of the active site; at low temperatures, enzyme activity is low due to a lack of energy.

Optimum Temperature

The temperature at which an enzymatic reaction occurs fastest.