Exam 2: Ch 8 Flashcards
Organisms can be identified according to …?
The source of carbon they use for metabolism as well as their energy source
Organisms based on carbon source
- autotrophs
- heterotrophs
Organisms based on energy source
- phototrophs
- chemotrophs —> organotrophs &lithotrophs
Autotrophs
“self”, organisms that convert inorganic carbon dioxide into organic carbon compounds
* examples: plants and cyanobacteria
heterotrophs
rely on more complex organic carbon compounds as nutrients (these are provided initially by autotrophs)
* examples: humans, prokaryotes including E.coli
Phototrophs
obtain energy for electron transfer from light
* example: plants
Chemotrophs
obtain energy for electron transfer by breaking chemical bonds
* 2 types of chemotrophs: organotrophs and lithotrophs
* Organotrophs: a type of chemotroph that obtain energy from organic compounds (includes humans, fungi, prokaryotes)
* Lithotrophs: a type of chemotroph that gets its energy from inorganic compounds
Subcategories of chemotrophs:
Chemoautotrophs: chemical energy source and inorganic carbon source
Chemoheterotrophs: chemical energy source and organic carbon source (humans and all animals)
Subcategories of phototrophs
Photoautotrophs: light energy source and inorganic carbon source (plants)
Photoheterotrophs: light energy source and organic carbon source
Metabolism
term used to describe all of the chemical reactions inside a cell, includes chemical reactions that breakdown complex molecules (catabolism) and those that build a complex molecules (anabolism)
Difference between catabolism and anabolism
Catabolism:
large molecules are broken down into smaller ones, thus releasing/making energy
* example: glycolysis
* example of Exergonic reaction
* uses NADH/NAD+ as a common electron carrier
Anabolic
small molecules are assembled into larger ones, thus using energy
* example: photosynthesis and biosynthesis
* example of Endergonic reaction
* fueled by the use of cellular energy
Exergonic
reactions that are spontaneous and release energy
* example: catabolism
* do not require energy beyond activation energy to proceed
Endergonic
reactions that are spontaneous and release energy
* example: catabolism
* do not require energy beyond activation energy to proceed
Enzyme
proteins that serve as catalysts for biochemical reactions inside cells and play an important role in controlling cellular metabolism
* function by lowering the activation energy of a chemical reaction inside the cell
Enzyme structure:
apoenzyme: protein part of an enzyme (lacks necessary cofactor or coenzyme
coenzyme: organic non protein part of an enzyme
cofactor: inorganic non protein part of an enzyme
* help stabilize enzyme conformation and function
holoenzyme: apoenzyme + coenzyme or cofactor = holoenzyme
* it is an enzyme with the necessary cofactor or coenzyme
Competitive inhibition/inhibitor
a molecule similar enough to a substrate that it can compete with the substrate for binding to the ACTIVE site by simply blocking the substrate from binding
* For a competitive inhibitor to be effective, the inhibitor concentration needs to be approximately equal to the substrate concentration
* example: sulfa drugs
Noncompetitive (allosteric) inhibitor
- inhibitor binds to allosteric site of enzyme and causes a change in shape of the enzyme
Respiration is…
Catabolic bc glucose is broken down
Aerobic respiration
- oxygen is required
- glucose is completely broken down to carbon dioxide, water, and lots of ATP
- example: staphylococcus aureus
3 steps of aerobic respiration
- Glycolysis
- Krebs cycle
- Electron transport chain
Glycolysis
- occurs in cytoplasm of prokaryotes in eukaryotes
- produces 8 ATP
Krebs Cycle
- occurs in the cytoplasm of prokaryotes
- occurs in the matrix of the mitochondria for eukaryotes
- produce 24 ATP
- oxygen is the last electron acceptor
Electron transport chain
- occurs in the plasma membrane of the prokaryotes
- occurs in the inner membrane of the mitochondria for eukaryotes
- produces 6 ATP
