cell respiration Flashcards
what is the purpose of cellular respiration?
to release energy by oxidizing molecules of glucose to carbon dioxide
what does oxidation mean?
a loss of electrons
what does reduced mean?
a gain of electrons
what % glucose is converted to energy and how much is released?
36% is converted to ATP
64% is given off as heat to help maintain body temperature
what are the electron carriers in cellular respiration?
- NADH
2. FADH2
what are the 5 parts of the mitochondria?
- outer membrane
- inner membrane
- inter-membrane space
- matrix
- cristae
what are the four stages of aerobic cellular respiration?
- glycolysis
- pyruvate oxidation
- Krebs cycle
- electron transport chain
what are the two pathways of cellular respiration?
- aerobic
2. anaerobic
what is aerobic respiration?
a cellular respiration pathway that requires oxygen in order for reactions to occur
where does glycolysis occur?
in the cytoplasm (outside of the mitochondria)
is glycolysis aerobic or anaerobic?
anaerobic
what are the products of glycolysis?
2 Pyruvate, 2 NADH, 2 ATP
what is glycolysis?
the first of 4 steps in aerobic CR, this is the process of a single glucose molecule being broken down into two pyruvate molecules, producing 2 NADH and 2 ATP in the process
what is pyruvate oxidation?
- this is the second step in aerobic CR
- this is the process of pyruvate losing a carbon atom as CO2, the pyruvate then become a 2 carbon molecule bonded with an acetyl group
what are the end products of pyruvate oxidation?
- 2 NADH
- 2 CO2
- 2 acetyl CoA
where does pyruvate oxidation occur?
in the matrix of the mitochondria
is pyruvate oxidation aerobic or anaerobic?
aerobic
where does Krebs cycle occur?
in the matrix of the mitochondria
is Krebs cycle anaerobic or aerobic?
aerobic
what are the end products of Krebs cycle?
- 6 NADH
- 2 FADH2
- 4 CO2
- 2 ATP
what has happened to all 6 carbon atoms by the end of Krebs cycle?
they have all been oxidized and released as CO2
how many ATP are produced by the end of stage 3?
4
how many ATP are produced by the end of stage 4?
36
how many NADH are produced by the end of stage 3?
10
what type of cell contains the highest number of mitochondria?
muscle
what is the first electron acceptor?
NADH
what is the second electron acceptor?
FADH2
what is the final electron acceptor in aerobic respiration?
O2
what stage of CR does not directly produce ATP?
pyruvate oxidation
what us the main role of FADH2?
to accept electrons
when does anaerobic respiration occur?
in the absence of oxygen
what does anaerobic respiration result in?
incomplete oxidation of glucose
how many stages are in anaerobic respiration?
2
what is the first stage of anaerobic respiration?
glycolysis
why doesn’t anaerobic respiration have a functioning electron transport chain?
because there is no oxygen present to grab electrons off ETC at the end
what are the 2 main methods of anaerobically recycling NADH?
- alcohol fermentation
2. lactic acid fermentation
what is fermentation?
a metabolic pathway that includes glycolysis and one or two other reactions in which MADH is oxidized to NAD+ by reducing pyruvate
what is alcohol fermentation?
a carbon dioxide molecule is removed from pyruvate (2) creating a 2 carbon molecule called acetaldehyde (2) , NADH (2) then passes their e- and H+ to acetaldehyde, creating NAD+ (2) and ethanol (2)
what is lactic acid fermentation?
NADH generated during glycolysis transfers its H+ to pyruvate, changing it to lactic acid and regenerating NAD+
what happens when there is an accumulation of lactic acid in the body?
can cause stiffness and fatigue
when does lactic acid fermentation occur?
mainly during times of strenuous exercise, when muscles require more ATP then aerobic respiration can provide
what stage(s) of anaerobic respiration does ATP get produced?
just during glycolysis, so only 2 ATP are produced
