Ch. 6 Cellular Respiration Flashcards
What is the limiting factor in athletic performance?
Aerobic capacity; ability of heart and lungs to deliver oxygen to body cells
How do muscles obtain energy?
From sugar glucose through chemical reactions dependent on oxygen input
Aerobic metabolism
Enough oxygen reaches cells to support energy needs
Aerobic Capacity
Maximum rate that O2 can be taken in and used my muscle cells; most strenuous exercise body can maintain aerobically
Anaerobic Metabolism
When the demand for oxygen exceeds ability for delivery and muscle cells switch to emergency mode; break down glucose inefficiently and produce lactic acid
Plants/Autotrophs
Organisms that make organic matter from inorganic sources like CO2, water and minerals (photosynthesis)
Heterotrophs
Cannot make organic molecules from inorganic ones and must eat the organic materiel to get nutrients
Photosynthesis
Some energy from sunlight is captured in the chloroplast and atoms of carbon dioxide & water are rearranged to produce glucose & oxygen
Cellular Respiration
A process that takes place in the mitochondria of eukaryotic cells where glucose is broken down to carbon dioxide and water and the cell captures some of the released energy to make ATP
What is ATP?
Produced in the mitochondria and is a source of chemical energy that cells use for most of their work
What type of process is cellular respiration?
Exergonic process that transfers energy from bonds in glucose to ATP
How many ATP molecules are produced in cellular respiration?
Up to 32 ATP molecules from each glucose molecule
How much energy does cellular respiration take from glucose?
Only 34% energy originally stored
Kilocalorie
Quantity of heat required to raise the temp of 1 kilogram of water by 1 degree C
Where is the energy necessary for life contained?
In the arrangement of electrons in chemical bonds of organic molecules
What happens when the carbon-hydrogen bonds of glucose are broken?
Electrons are transferred to oxygen (strong tendency to attract electrons) and lose potential energy
Redox Reaction
The movement of electrons from one molecule to another (oxidation, reduction)
How do the atoms of glucose transform during cellular respiration?
Glucose loses hydrogen atoms and becomes oxidized to CO2
How do the atoms of oxygen transform during cellular respiration?
Oxygen gains hydrogen atoms and becomes reduced to H2O
NAD+
Important enzyme in oxidizing glucose that accepts electrons and becomes reduced to NADH
Electron a Transport Chain
Electron carriers that act as a stairway for electrons
What happens to electrons as they are transported down the electron transport chain?
ATP is generated
What is the first stage of cellular respiration and where does it occur?
Glycolysis; occurs in cytoplasm
What happens during glycolysis?
Breaks down glucose into two molecules of a three carbon compound called pyruvate
What is required for the initial split of the glucose molecule?
An investment of 2 ATP molecules per glucose
What happens after the splitting of glucose?
The 3 carbon molecules donate electrons to NAD+ and form NADH
In glycolysis, what happens after NAD+ becomes NADH?
Enzymes transfer phosphate groups from fuel molecules to ADP and form two ATP molecules per molecule of glucose
What remains of the fractured glucose at the end of glycolysis?
2 molecules of pyruvic acid; still holds most energy of glucose and is harvested in second stage
What is necessary for the citric acid cycle to begin?
Each pyruvic acid must lose a carbon as CO2
Acetic Acid
The remaining fuel molecules, each with only two carbon left
What happens after acetic acid is formed?
Electrons are stripped from these molecules and transferred to another molecule of NAD+ to form NADH
What happens after electrons are stripped from acetic acid?
Each acetic acid is attached to a molecule called coenzyme A (CoA) to from acetyl CoA
General function of electron transport chain
collective group of electron “carriers” that function like NAD+ and form ATP as they move down the chain
Where does glycolysis occur?
Cytoplasm
What happens during glycolysis?
Glucose is broken into two 3 carbon molecules of pyruvate
Lactic Acid Fermentation
NADH is oxidized to NAD+ and pyruvate is reduced to lactate
Alcoholic Fermentation
NADH is oxidized to NAD+ and pyruvate is concerted to CO2 and ethanol
