Chapter 4 - Cellular Metabolism Flashcards
aer-
air
(aerobic respiration)
an-
without
(anaerobic respiration)
ana-
up
(anabolism)
cata-
down
(catabolism)
co-
with
(coenzyme)
de-
undoing
(deanimation)
mut-
change
(mutation)
-strat
spread out
(substrate)
sub-
under
(substrate)
-zym
causing something to ferment
(enzyme)
enzyme
protein that catalyzes a specific biochemical reaction
cellular metabolism
the sum total of chemical reactions in the cell
What are the two types of metabolic reactions and pathways?
anabolic
catabolic
anabolism
(anabolic metabolism)
synthesis of larger molecules from smaller ones
catabolism
(catabolic metabolism)
breakdown of larger molecules
dehydration synthesis
- anabolic process that joins small molecules by enzymatically releasing the equivalent of H₂O
- forms carbohydrates, fats, proteins, and nucleic acids
monosaccharide + monosaccharide ⇄ disaccharide + water
amino acid + amino acid ⇄ dipeptide molecule + water
Are metabolic reactions reversible?
often, but different enzymes often catalyze corresponding anabolic and catabolic reactions
How do enzymes speed metabolic reactions?
lower the amount of activation energy required by straining chemical bonds in substrate
substrate + enzyme ⟶ enzyme-substrate complex ⟶ product + enzyme
substrate
molecule on which an enzyme acts
What is catalase, where is it found, and what is its substrate? Give an example.
- an enzyme
- in the peroxisomes of liver and kidney cells
- hydrogen peroxide, a toxic by-product of certain metabolic reactions
- EXAMPLE: When hydrogen peroxide is poured on a wound, cells release catalase, and the hydrogen peroxide is broken down, releasing oxygen; the foam removes debris.
active site
part of an enzyme that temporarily binds a substrate
What factors affect the rate of enzyme-catalyzed reactions?
- concentration of enzyme or substrate molecules in the cell; higher concentration = faster
- efficiency of the enzyme; some can catalyze only a few reactions per second, some can handle hundreds of thousands
metabolic pathway
series of linked, enzyme-controlled chemical reactions
lipase
enzyme that breaks down fat (lipid)
protease
enzyme that breaks down protein
amylase
enzyme that hydrolyzes polysaccharides (starch, amylum)
amylum
starch, polysaccharide
What digestive enzyme catalyzes the breakdown of the sugar sucrose?
sucrase
What is sucrose, and what is it made of?
- disaccharide
- table sugar
- glucose and fructose
maltase
enzyme that splits maltose
What is maltose, and what is it made of?
- disaccharide produced by the breakdown of starch
- two glucose molecules
lactase
enzyme that splits lactose
What is lactose, and what is it made of?
- disaccharide in milk
- made of glucose and galactose