cellular respiration
if oxygen is available, organisms can obtain energy from food by this process
aerobic
pathways of cellular respiration that require oxygen ("in air")
anaerobic
pathways of cellular respiration that do not require oxygen ("without air")
glycolysis
the first set of reactions in cellular respiration
NAD+
one of the reactions of glycolysis removes 4 electrons, now in a high-energy state, and passes them to this electron carrier (nicotinamide adenine dinucleotide)
Krebs cycle
the second stage of cellular respiration
matrix
the innermost compartment of the mitochondrion and the site of the Krebs cycle reactions
Fermentation
When oxygen is not present, glycolysis is followed by a pathway that makes it possible to continue to produce ATP without oxygen, and the combined process of this pathway is called this
What happens during Glycolysis?
Glucose breaks down into two molecules of pyruvate
What combines with Acetyl Coa to form Citric Acid?
a 4-carbon molecule or pyruvic acid
What are the 3 stages of Cellular Respiration and where do they occur?
Glycolysis, the Krebs cycle, and the Electron Transport Chain. Glycolysis occurs in the cytosol, the Krebs cycle occurs in the matrix of the mitochondria, and the Electron Transport Chain occurs in the inner mitochondrial membrane of the mitochondria
What compound is used to extract energy from during the Kreb's cycle?
pyruvic acid produced in glycolysis is broken down into carbon dioxide in a series of energy-extracting reactions
Does Glycolysis require energy and why?
Glycolysis does require energy to break apart from glucose to form pyruvic acid
What is the function of NAD+?
NAD+ accepts a pair of high-energy electrons and become NADH
What is the goal of Cellular Respiration as compared to Photosynthesis?
The goal is to make ATP
What are the products of each stage of Cellular Respiration?
Glycolysis produces 4 ATP, 2 Pyruvic Acid, and 2 NADH. The Krebs cycle produces 2 ATP, 6 NADH, 2 FADH2, and 4 CO2. The Electron Transport Chain produces 32 ATP and H2O
How many ATP are made at each step of Cellular Respiration?
Glycolysis produces 4 ATP, the Krebs cycle produces 2 ATP, and the Electron Transport Chain produces 32 ATP
Which of the following is the correct sequence of events in cellular respiration?
glycolysis ? Krebs cycle ? electron transport chain
Which of these is a product of cellular respiration?
water
Which process does NOT release energy from glucose?
photosynthesis
Unlike photosynthesis, cellular respiration occurs in
all eukaryotic cells
The starting molecule for glycolysis is
glucose
Which of the following is NOT a product of glycolysis?
glucose
The Krebs cycle does NOT occur if
oxygen is not present
The Krebs cycle produces
carbon dioxide
In eukaryotes, electron transport occurs in the
inner mitochondrial membrane
Which of the following is NOT a stage of cellular respiration?
fermentation
Cellular respiration is called an aerobic process because it requires
oxygen
Photosynthesis is to chloroplasts as cellular respiration is to
mitochondria
The products of photosynthesis are the
reactants of cellular respiration
Glycolysis provides a cell with a net gain of
2 ATP molecules
Glycolysis requires
ATP
The Krebs cycle starts with
pyruvic acid and yields carbon dioxide
Which of the following pass high-energy electrons to the electron transport chain?
NADH and FADH2
Cellular respiration uses 1 molecule of glucose to produce approximately
36 ATP molecules
Lactic acid fermentation occurs in
muscle cells
During fermentation,
NAD+ is regenerated, allowing glycolysis to continue
Breathing heavily after running a race is your body's way of
repaying an oxygen debt
The energy needed to win a 1-minute footrace is produced mostly by
lactic acid fermentation
Photosynthesis occurs only in plants, algae, and some bacteria. In contrast, _________ occurs in all eukaryotic cells.
cellular respiration
Glycolysis rearranges a 6-carbon glucose molecule into 3-carbon molecules of __________
pyruvic acid
When ___________ pass through ATP synthase, ATP molecules are produced from ADP molecules
H+ ions
Glycolysis alone nets only ____ molecules of ATP from each glucose molecule
2
The body gets rid of lactic acid in a chemical pathway that requires __________
oxygen
Why does lactic acid fermentation "kick in" during a sprint race?
to get the ATP it needs to help out the body and help breathe
Alcoholic Fermentation
carried out by yeast; produces alcohol; produces carbon dioxide
Lactic acid Fermentation
carried out in muscle cells; produces lactic acid
Alcoholic Fermentation and Lactic acid Fermentation
begin with pyruvic acid; convert NADH to NAD+; do not require oxygen; occur in the cytoplasm; release energy
Alcoholic fermentation is used to make which product?
bread
What kind of taste do lactic acid bacteria give foods?
sour
What are some milk products made from lactic acid fermentation?
sour cream, yogurt, and cheese
What is one main different between fermentation and aerobic respiration?
Fermentation is anaerobic, so it takes place without oxygen. Aerobic respiration takes place with oxygen.
At what time does the runner's body switch from energy supplied by lactic acid to energy supplied by cellular respiration?
90 seconds
What process gives a runner more energy?
cellular respiration
You are in a race that lasts 25 minutes. Where will your body get the energy it needs?
breakdown of fats
Compare the ATP production of a sprinter and that of a long-distance runner.
A sprinter's muscle cells produce most of their ATP by lactic acid fermentation, which can last about 90 seconds. For the long-distance runner, cellular respiration is the only way to supply enough ATP. Cellular respiration releases energy more slowly and
aerobic step in cellular respiration
Krebs cycle
an energy molecule with three phosphate groups
ATP
anaerobic step of cellular respiration in which glucose is split
glycolysis
Alcoholic fermentation produces both ethyl alcohol and _________
carbon dioxide
Which process releases energy from food in the presence of oxygen?
cellular respiration
Why do most organisms undergo the process of cellular respiration?
The process of cellular respiration takes place in stages. During cellular respiration, cells trap bits of chemical energy and use them to make ATP.
How do cells release energy from food in the presence of oxygen?
Glycolysis does not require oxygen but the Krebs cycle and electron transport chain do require oxygen. Oxygen serves as the final electron acceptor of the electron transport chain, during which the majority of ATP is produced.
How do cells release energy from food without oxygen?
When oxygen is not present, glycolysis is followed by a pathway that continues the production of ATP. This pathway plus glycolysis is called fermentation. Fermentation releases energy from food molecules by producing ATP.
The calorie used on food labels is equal to
1000 calories
Calorie is also referred to as a
kilocalorie
Cells use the energy stored in chemical bonds of foods to produce compounds that directly power the cell's activities such as
ATP
The equation that summarizes cellular respiration using chemical formulas is
6O2 + C6H12O6 -> 6CO2 + 6H2O + Energy
If cellular respiration took place in just one step, most of the ________ would be lost in the form of light and ________
energy, heat
Cellular respiration begins with a pathway called _________, which takes place in the ________ of the cell.
glycolysis, cytoplasm
At the end of glycolysis about _____ percent of the chemical energy is locked in the bonds of the ________ molecule
90, pyruvic acid
Cellular respiration continues in the _______ of the cell with the _______ and electron transport chain
mitochondria, Krebs cycle
The pathways of cellular respiration that require oxygen are said to be _______. Pathways that do not require oxygen are said to be _________
aerobic, anaerobic
The energy flow in photosynthesis and cellular respiration occurs in the ______ direction
opposite
Photosynthesis ______ energy in Earth's "savings account" for living organisms
deposits
Cellular respiration removes _______ from the air
oxygen