Chapter 7.1 cellular respiration Flashcards
What is cellular respiration?
- The breakdown of carbohydrates, lipids, and proteins
- release of energy to do work of the cell
- converting chemical potential energy from organic molecules -> chemical potential energy ATP
- a set of catabolic reaction
what is the difference between aerobic and anaerobic?
Aerobic- in the presence of oxygen- makes lots of ATP
Anaerobic- in the absence of oxygen
What are the cellular respiration stages?
- Glycolysis (cytoplasm)
- Pyruvate oxidation (mitochondria)
- citric acid cycle (mitochondria)
- oxidative phosphorylation( mitochondria)
Where do cellular restoration stages occur in prokaryotes if oxygen is present?
- Pyruvate oxidation and the citric acid cycle occur in the cytoplasm.
- oxidative phosphorylation occurs across the plasma membrane
what molecules do and don’t have a lot of potential energy in their chemical bonds?
do- carbohydrates and lipids
don’t- carbon dioxide and water
why does cellular respiration release a lot of energy?
the sum of potential energy in all the chemical bonds of reactants is higher then those of the reactants
how is energy in cellular respiration released?
gradually in a series of chemical reactions
how many molecules are produced from the aerobic respiration of a single molecule of glucose?
32 ATP molecules
how much energy is needed to form one ATP molecule from ADP AND Pi?
at least 7.3 kcal
how much energy is harnessed from a single glucose molecule during cellular respiration?
32 x 7.3= 233.6 kcal of energy for every mole of glucose broken down in the presence of oxygen
how much total energy released by aerobic respiration is harnessed in the form of ATP?
34% (233.6/686) remanding 66% is given off as heat
what are the two ways are ATP produced from glucose
substrate level phosphorylation or electron carriers (oxidative phosphorylation)
what is substrate level phosphorylation and how does it work?
- two coupled phosphorylated organic molecule transfers a phosphate group to ADP to produce ATP (two reactions by one enzyme: hydrolysis of phosphorylated molecule and addition of phosphate group to ADP) hydrolysis reaction releases enough energy for synthesis of ATP. Only small amount of ATP is generated this way (12%)
- Occurs in stage 1 (glycolysis) and 3 (critic acid cycle) cellular respiration.
what are electron carriers and how do they work?
carry electrons and energy from one set of reactions to another. during cellular respiration transport electrons released during catabolism of organic molecules to the electron transport chain, the transferred along series of membrane associated proteins to a final electron acceptor and harnesses energy to produce ATP. oxygen is the final acceptor resulting in the formation of H20 (oxidative phosphorylation) (88% of ATP this way)
how are electron transport chains used?
in respiration to harness energy from fuel molecules such as glucose and photosynthesis.
What are the 4 stages of cellular respiration?
1 glycolysis, 2 pyruvate oxidation- fuel molecules are partially broken down, producing ATP and electron carriers from original glucose
3 citric acid cycle- fuel molecules are fully broken down, producing ATP and electron carriers
4 oxidative phosphorylation- electron carriers donate electrons to the electron transport chain, leading to the synthesis of ATP
what is a oxidation reduction reaction?
a chemical reaction in which electrons are transferred from one atom or molecule to another
(oxidation- loss of electrons)
(reduction- gain of electrons)
what are the two forms of electron carriers?
(NAD+ AND FAD)- oxidized
(NADH AND FADH2) -reduced
what are the chemical formulas for the two types of reduction reactions
NAD+ + 2e- + H+ -> NADH
FAD + 2e- + 2H+ -> FADH2
NAD+ and FAD accept electrons
how can reduced or oxidized molecules be identified?
through the increase in C-H bonds - reduced
through the decrease in C-H bonds- oxidized
What are the chemical formulas for the two types of oxidized reactions?
NADH-> NAD+ + 2e- + H+
FADH2-> FAD + 2e- +2H+
produce NAD+ and FAD which can accept electrons from the breakdown of fuel molecules
What do the reduced and oxidized forms of NADH and FADH2 do?
reduced- can donate electrons
oxidized- allows electrons and energy to be transferred to the electron transport chain
what happens to the electrons during an oxidation reaction for glucose and carbon dioxide?
glucose: c-c and c-h bonds share electrons equally
carbon dioxide: carbon atom has partially lost electrons (oxidation) and oxygen atom is more electronegative so electrons will be found closer to O
what happens to the electrons during a reduction reaction for oxygen and water?
oxygen: electrons are scarred equally
water: oxygen atom has partially gained electrons (reduced) and oxygen is more electronegative so electrons will be found closer to O
why is glucose a good electron donor and oxygen is a good electron acceptor?
glucose: its oxidation to carbon dioxide releases a lot of energy
oxygen: it has a high affinity for electrons
in depth what occurs during the 4 stages of cellular respiration
stage 1: glucose is partially broken down to make pyruvate and energy is transferred to ATP and reduced electron carriers (glycolysis)
stage 2: pyruvate is oxidized to another molecule called acetyl-CoA , producing reduced electron carriers and releasing carbon dioxide.
stage 3: Acetyl-CoA enters the citric acid cycle in a series of chemical reactions. the acetyl group is is oxidized to carbon dioxide and energy is transferred into ATP and reduced electron carriers
stage 4: oxidative phosphorylation, a series of reactions. electron carriers generated in stages 1-3 donate electrons to the electron transport chain and a large amount of ATP is produced.
where do the 4 cellular reparation steps occur in eukaryotes?
glycolysis- cytoplasm
pyruvate oxidation- mitochondria
citric acid cycle- mitochondria
oxidative phosphorylation- mitochondria
