Chapter Nine Flashcards
Energy enters biological systems as ________ and eventually leaves as _____
sunlight, heat
Matter is ________ with biological systems
recycled
Photosynthesis uses ________ to convert _____ and ______ _______ into more complex molecules
sunlight, water and carbon dioxide
Cellular respiration uses _______ molecules and _____ to create ATP
organic, oxygen
ATP is used for ________ ____
cellular work
Fermentation and cellular respiration are _______ (exergonic and spontaneous)
catabolic
What is the equation for cellular respiration?
C6H12O6 + 6O2 –> 6CO2 + 6H2O + Energy (ATP + heat)
Aerobic respiration ______ directly do work; intermediate ATP is used for work
doesn’t
What is a redox reaction?
an oxidation-reduction reaction
What is oxidation?
loss of electrons from one substance
What is reduction?
addition of electrons to another substance
Energy from a fuel ______ be harnessed efficiently if it is all released at once
cannot
Energy breaks down in a _________ manner to avoid explosion
step-wise
What happens in the electron tranport chain?
NADH passes its gained electron to the top of the chain that ends in oxygen –> there is a controlled fall of electrons to harness freed energy –> regenerates ATP
What are the 3 main stages of cellular respiration?
- glycolysis
- pyrucate oxidation and citric acid cycle
- oxidative phosphorylation: electron transport and chemiosmosis
What is the result of a redox reaction?
oxidative phosphorylation
What is substrate-level phosphorylation?
when an enzyme transfers a phosphate group to ADP
What is glycolysis?
glucose (sugar) broken into 2-3 carbon molecules; sugar splitting
Glycolysis takes place ______ of mitochondria (cytosol); rest of respiration _______ mitochondria
outside, inside
What is the product of glycolysis?
2 pyruvate, 2 ATP, 2 NADH
In pyruvate oxidation, energy is changed to a __ ______ intermediate form before entering the _____ ______
2 carbon, Krebs cycle
How many carbon dioxide molecules and NADH are released per pyruvate in pyruvate oxidation?
one
What does the citric acid (Krebs cycle) do?
convert each carbon on the 2-carbon intermediate into carbon dioxide
How many ATP are produced per pyruvate in the Krebs cycle?
one ATP
How many NADH and FADH2 are produced per pyruvate in the Krebs cycle?
3 NADH and 2 FADH2
Each glucose gets ____ full cycles
2; one for each pyruvate
What happens in the electron transport chain for oxidative phosphorylation?
electron carrier (NADH and FADH2) pass electrons down a chain (lower energy at each level) eventually ending at oxygen
What happens with the released energy in the electron transport chain?
released energy pumps hydrogen ions across inner mitochondrial membrane
What is chemiosmosis?
an energy coupling mechanism
What happens in chemiosmosis?
- hydrogen ions moce down concentratin gradient back across membrane via ATP synathse
- catalyzes phosphorylation of ADP to ATP (attaches a phosphate group to ADP)
What is the net ATP of glycolysis?
2 ATP
What is the net ATP of the citric acid cycle?
2 ATP
What is the net ATP of oxidative phosphorylation?
26-28 ATP
What is the (total) net ATP of cellular respiration?
30-32 ATP
What is the net energy of cellular respiration?
about 34% of total energy harvested from glucose oxidation
- would have been less if it occured all at once (rest lost as heat)
What is anaerobic respiration?
the generation of ATP without oxygen
__________ is sometimes considered a simple term of anaerobic respiration
Fermentation
True anaerobic respiration uses a _________ molecule as the final electron acceptor in the electron transport chain
non-oxygen
- commonly a sulfate ion
What is fermentation?
glycolysis and some way to regenerate NAD+
What is the net ATP for each glucose molecule in fermentation?
2 ATP
What are 2 common types of fermentation?
- Alcohol: produces carbon dioxide
-
Lactic acid: does not produce carbon dioxide
- quick means of energy production when oxygen levels are low
Glycolysis accepts a range of __________
carbohydrates
__________ and __________ are broken into glucose and other simple sugars
disaccharides and polysaccharides
________ are mainly used as a source of amino acids but can be used as a fuel
proteins
Proteins are broken down into _____ _____, then convertedd to intermediates of ________ and the ________ cycle
amino acids, glycolysis, citric acid
____ are broken down into glycerol and fatty acids
fats
_______ is convervet to a glycolysis intermediate
glycerol
_____ _____ are broken into 2-carbon sections that enter the citric acid cycle
fatty acids
