body systems part 2 quiz 1 Flashcards
What are reactions in living organisms regulated by?
ptotein catalysts called enzymes
What do enzymes control?
cells chemical reactions (metabolism)
-control speed of reaction
What are catalysts?
enzymes that regulate the speed of a reaction without being themselves altered
Why are not many catalysts required?
because they can be used over and over again
What do catalysts do in relation to activation energy?
lowers it without adding heat
what is activation energy?
amount of energy required to start a reaction
what can enzymes be used for?
breaking down substances (catabolism) or build substances (anabolism)
What is a substrate?
the molecule on which enzyme works
what is the active site?
the area where the substrate and enzyme join
what do some enzymes require the help from?
coenzymes (vitamins) and cofactors (minerals) to help them bind to substrates
What affects enzyme reaction?
- temperature due to each enzyme workung best at specific temperatures
- PH, each enzyme works best at specific PH
What happens to enzymes in changes of temperature?
they denature or coagulate
What happens to the concentration of substrate when there are no enzymes?
faster reaction
What happens to the concentration of substrate when there are enzymes?
faster reaction but at a certian point the rate levels fall off due to the limit in the speed of the enzyme can work
What are competitive inhibitors?
molecules that have similar shapes to substrate so they compete with the substarye for active sites on the enzymes
ex, carbon monoxide, cyanide
What are 2 inhibitors?
1.Malathion
2.Pencillin
What is malathion?
insecticide inverersibly binds to important nervous system enzyme
What is penicillin?
bacteria need to make cell walls, no cell walls means they cant reproduce
what is precursor activity?
-The activation of the last enzyme in a metabolic pathway by the initial substrate combining with the regulatory site.
-This initial meeting creates a better fit for the molecules, speeding up production of final products. “On Switch”
what is feeback inhibition?
-The final product in an enzyme pathway turns off the whole pathway.
– Regulates amount of product, too much of anything isn’t good.
-“Off Switch”
what are both feedback and precursor activity termed?
allosteric activity
what is allosteric activity?
change in enzyme shape causd by the binding of a molecule
what is the benedict reagent test?
determines concentration of reducing sugars.
-when added to colourless solution, after heating solution goes from blue to green/yellow ( trace amounts), orange/red (moderate amounts), dark red (a lot)
what is the iodine test?
detetcs presence of starch
-iodine solution turns blue/purple when starch is present
what is the Biuret test?
presence of proteins
-solution turns violet/purpe when protein is present
what is the sudan IV dye test?
presence of lipids
-forms an orange colour (does not dissolve, top layer will show)
what is the brown paper test?
presence of fats
-when a substance with lipids is placed on the brown bag, bag turns translucent.
