Biology- Cellular Respiration
What happens as the H+ ion passes through this enzyme?
ADP+P is converted to ATP adds the P and energizes it to make ATP
What is the enzyme at the end of the electron transport chain?
ATP Synthase
Why do aerobic organisms, like ourselves, inhale oxygen?
Aerobic organisms inhale oxygen so they can do the electron transport chain with chemiosmosis to generate ATP. Anaerobic organisms can only do glycolysis, so they don't get as much ATP.
Why does cellular respiration happen?
All organisms need energy (ATP) to carry out the characteristics of life. Plants generate glucose during photosynthesis in the chloroplast That glucose goes through a series of reactions and eventually generates ATP in the mitochondria. A healthy cell (when oxygen is present) can generate 36 ATP molecules from a single glucose molecule
Fermentation pathway
Begin with glycolysis in the cytoplasm. Do not break glucose down completely to carbon dioxide and water. (because that only happens in the mitochondria with oxygen) Yield only the 2 ATP from glycolysis. Steps that follow glycolysis serve only to regenerate NAD+. - Pyruvates and NADH are created but there are no other steps to carry the energy to- recycled - NADH goes back into the process, one carbon is cut off -> Ethanol
During the conversion of pyruvate to Acetyl-CoA two additional products are made. What are they and what happens to them?
CO2 is released when we exhale 2 NADH goes to the electron transport chain
What happens if there is no oxygen present?
Cells do glycolysis and then go through the fermentation pathways
How does the food you eat get converted into a usable form of energy for your cells?
Cells use all sorts of molecules for food, including fats/lipids, proteins, nucleic acids, and carbohydrates. The energy stored in each of these molecules varies because of their chemical structures, and therefore their energy-storing bonds, differ. Cells break down food molecules gradually and use the energy stored in the chemical bonds to produce compounds such as ATP that power the activities of the cell.
3 (4 ) steps to making ATP
Glycolysis (takes place in the cytoplasm Input 2 ATP, output 4 ATP, 2 ATP, involves the splitting of glucose into two molecules of pyruvate in the cytoplasm, 2 NADH); Prep Step (2 pyruvate is turned into 2 Acetyl CoA- pyruvate can't get into mitochondria, 2NADH, 2 CO2) Krebs Cycle (takes place in the matrix of the mitochondria, 2 ATP, 6 NADH, 2 FADH2 ) Electron Transport Chain- Chemiosmosis (takes place along the inner membrane of the mitochondria, 32 ATP)
Advantages of glycolysis
Glycolysis produces ATP very fast, which is an advantage when the energy demands of the cell suddenly increase. Glycolysis does not require oxygen, so it can quickly supply energy to cells when oxygen is unavailable.
How is the H+ ion used to establish a concentration gradient?
H+ ions go from the area with a high concentration of H+ ions to the side with the low concentration of H+ ions high concentration on one side and low concentration on the other side
H+ in electron transport chain
Hydrogen ions are delivered by NADH and FADH2. 2. They move across the inner membrane to establish a concentration gradient. 3. The H+ ions travel through ATP synthase (enzyme) and convert ADP to ATP - 32 ATP! H+ slide through ATP synthase (high -> low concentration) and make ATP Chemiosmosis 4. The H+ are accepted by oxygen and form water! This happens across the inner membrane of the mitochondria.
Energy totals in cellular respiration
In the presence of oxygen, the complete breakdown of glucose through cellular respiration results in the production of 36 ATP molecules. This represents about 36 percent of the total energy of glucose. The remaining 64 percent is released as heat. always energy lost
What is the relationship between photosynthesis and cellular respiration?
Photosynthesis removes CO2 and releases oxygen into the atmosphere, and cellular respiration removes oxygen and releases CO2 The energy flows in opposite directions. Photosynthesis "deposits" energy, and cellular respiration "withdraws" energy. The reactants of cellular respiration are the products of photosynthesis and vice versa
When do the pyruvates continue on to the mitochondria?
Pyruvate will only be converted to Acetyl CoA and continue the process if oxygen is present
What happens in the prep step?
Pyruvate→ Carbon Dioxide + Acetyl-CoA the 3-carbon pyruvates lose a carbon and become 2-carbon Acetyl CoA 2 CO2 is released 2 NADH is produced
Aerobic
Requiring air or oxygen for life or survival, used especially to refer to aerobic bacteria.
Yeasts
Single-celled fungi. Carry out alcoholic fermentation. Saccharomyces cerevisiae - Baker's yeast - Carbon dioxide makes bread dough rise Saccharomyces ellipsoideus - Used to make beer and wine.
Which muscle cells would have more mitochondria, the muscle cells of athletes or the muscle cells of non-athletes? Why?
The muscle cells of athletes would have more mitochondria because athletes need to make more ATP for energy when they exercise
When would your cells switch from aerobic cellular respiration involving the mitochondria to simply lactic acid fermentation?
Your cells would switch from aerobic cellular respiration to lactic acid fermentation when your muscle cells run out of available oxygen while you are exercising when you don't have enough oxygen during physical exertion
ATP
a molecule that carries energy within cells. It is the main energy currency of the cell, and it is an end product of the processes of photophosphorylation (adding a phosphate group to a molecule using energy from light), cellular respiration, and fermentation.
Acetyl Co-A
a molecule that participates in many biochemical reactions in protein, carbohydrate and lipid metabolism. Its main function is to deliver the acetyl group to the citric acid cycle (Krebs cycle) to be oxidized for energy production
Fermentation (Aerobic Respiration)
a process by which energy can be released from food molecules in the absence of oxygen. Fermentation occurs in the cytoplasm of cells.
process that occurs when oxygen is plentiful
aerobic
process that utilizes the electrons stored in NADH and FADH2
aerobic
process which utilizes O2 as a final electron acceptor.
aerobic
results in a net yield of 36 ATP
aerobic
Why do cells need energy in the form of ATP? What happens in an organism if they can no longer convert glucose to ATP?
all organisms need energy to carry out the characteristics of life organisms wouldn't be able to live without it
NAD+
an electron carrier used to temporarily store energy during cellular respiration nicotinamide adenine dinucleotide
ATP Synthase
an enzyme that creates the energy storage molecule adenosine triphosphate (ATP) hydrogen ions slide through it to generate ATP
mitochondria
an organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur. It has a double membrane, the inner layer being folded inward to form layers (cristae).
process known as fermentation
anaerobic
process known as glycolysis with lactic acid fermentation
anaerobic
Where does the prep step occur?
between cytoplasm and mitochondria
process by which glucose is used by the cell
both aerobic and anaerobic
process that requires the use of the some of the ATP in order to get started.
both aerobic and anaerobic
process which produces CO2
both aerobic and anaerobic
obligate anaerobes
can only live in environments without oxygen (poisoned by oxygen)- usually bacteria
facultative anaerobes
can switch between aerobic and anaerobic depending on conditions
Facultative Anaerobes
can switch between aerobic and anaerobic depending on conditions.
Which nutrient cycles are involved in the exchange of materials between the chloroplast and the mitochondria?
carbon cycle
Liver, heart, and kidney
cells produce 34 ATP in ETC step total of 38 ATP NADH can stay NADH in the mitochondria
6 O2 + C6H12O6 →6 CO2 + 6 H2O + ATP Oxygen + Glucose →Carbon dioxide + Water + Energy
cellular respiration
FADH2
created during the Krebs cycle and utilized during the last part of respiration, the electron transport chain.
Where does the electron transport chain and chemiosmosis occur?
cristae membrane of mitochondria
Where does glycolysis occur?
cytoplasm
Why do we experience sore muscles after strenuous exercise?
We experience sore muscles after strenuous exercise because our muscle cells run out of available oxygen and use lactic acid fermentation Lactic acid is a sharp crystal that is painful when it pushes against muscle cells
What is oxygen considered in the electron transport chain?
final electron acceptor
matrix (mitochondria)
fluid-filled center space of the mitochondria the Krebs Cycle happens here
What goes in to glycolysis?
glucose, 2 ATP
What glucose metabolism stage is common to both fermentation and aerobic cellular respiration?
glycolysis
anaerobic respiration pathways
glycolysis (2 molecules of pyruvate) -> lactic acid fermentation or alcoholic fermentation (2 ATP)
What process of cellular respiration happens before the carbon-containing molecules enter the mitochondria?
glycolysis and prep step
Why is the electron transport chain also called electron transport phosphorylation?
the electron transport chain is also called electron transport phosphorylation because when H+ goes through the ATP Synthase, a phosphate is added to ADP+P to make ATP adding a phosphate= phosphorylate
H+
the nucleus of a hydrogen atom separated from its accompanying electron. hydrogen ion
Concentration Gradient
the process of particles moving through a solution or gas from an area with a higher number of particles to an area with a lower number of particles.
cellular respiration
the process that releases energy from food in the presence of oxygen
The two pyruvate molecules from glycolysis cannot enter the mitochondria in their original forms. Describe the changes that happen to pyruvate in the cytoplasm before the Acetyl-CoA enters the Krebs cycle in the matrix of the mitochondria.
the pyruvate releases one of its carbons and the new 2-carbon molecule is Acetyl-CoA this releases CO2 when we exhale
What is the purpose of the sugar in the above recipe?
the yeast uses it for a source of fuel to make ATP
anaerobic
used to describe an organism, a cell, a process or a mechanism that can function without air
What goes in to the electron transport chain/chemiosmosis?
10 NADH, 2 FADH2, 6 O2
What comes out of glycolysis?
2 ATP, 2 NADH, 2 pyruvate
What comes out of the Krebs Cycle?
2 ATP, 6 NADH, 2 FADH2, 4 CO2
What goes in to the Krebs Cycle?
2 Acetyl-CoA
What comes out of the prep step?
2 Acetyl-CoA, 2 CO2, 2 NADH
There are two types of fermentation processes. Alcoholic fermentation is performed by yeast. What are the two end products of alcoholic fermentation?
2 CO2 and ethyl alcohol/ethanol
ATP involved in glycolysis
2 invested, 4 produced net= 2 ATP
What goes in to the prep step?
2 pyruvate
What comes out of the electron transport chain/chemiosmosis?
32 ATP, 6 H2O
What gas is a waste product of the Krebs Cycle? How does this gas contribute to the continuation of the carbon cycle?
4 CO2 are released in the Krebs cycle We release the CO2 from the Krebs Cycle when we exhale, and the CO2 is used in photosynthesis. Photosynthesis releases oxygen, which is used in the Krebs Cycle
There are two electron carriers involved in the Krebs Cycle. What are they and where are they taking their high-energy electrons?
6 NADH and 2 FADH2 They take their high-energy electrons to the electron transport chain
What are the products of the Krebs Cycle and where do they go after being generated by the Krebs Cycle?
6 NADH and 2 FADH2 go to the electron transport chain 2 ATP 4 CO2 goes to the lungs to be exhaled
Anaerobic Pathways- Making ATP Without Oxygen
Do not use oxygen. Produce much less ATP than Aerobic pathways - Anaerobic = 2 ATP. (Aerobic = net total of 36/38 ATP) - Main type is Fermentation. - Obligate anaerobes- can only live in environments without oxygen (poisoned by oxygen)- usually bacteria - Facultative anaerobes - can switch between aerobic and anaerobic depending on conditions.
importance of oxygen in the ETC
Electron transport phosphorylation requires the presence of oxygen. Oxygen withdraws spent electrons from the electron transport chain, then combines with H+ to form water.
How do organisms generate energy when oxygen is not available?
Fermentation is a process by which energy can be released from food molecules in the absence of oxygen. Fermentation occurs in the cytoplasm of cells
glucose's energy in glycolysis
Most of glucose's energy (90%) remains locked in the chemical bonds of pyruvic acid (pyruvates)at the end of glycolysis.
The major production of ATP during aerobic metabolism occurs when electrons from _____and _____ are transferred to ____ (the final electron acceptor).
NADH, FADH2, oxygen
Does glycolysis require oxygen?
No, it is anaerobic
Which type of bacteria do you think arose first through evolution? Obligate anaerobes (must have NO oxygen to survive) or Facultative anaerobes (prefers to thrive in no oxygen, but can tolerate oxygen)? Why?
Obligate anaerobes arose first through evolution because there used to be no oxygen in the atmosphere, and obligate anaerobes need no oxygen to survive.
Lactic Acid fermentation (choice 2 after 1st step)
Once your muscle cells run out of available oxygen during heavy exercise or long-term exercise lasting more than 90 seconds, they still have to make ATP This happens in the cytoplasm. Lactic Acid is a very sharp crystal that creates an "OUCH" when pressed against the muscle cells (aka sore muscles!!).
Lactic Acid Fermentation
Once your muscle cells run out of available oxygen during heavy exercise or long-term exercise lasting more than 90 seconds, they still have to make ATP (in the cytoplasm)
What is the final destination of the H+ and high energy electrons carried by NADH generated during glycolysis?
The H+ and high energy electrons carried by NADH go to the electron transport chain with chemiosmosis
Label on the mitochondria where the Krebs Cycle takes place and also label where the electron transport chain takes place.
The Krebs Cycle takes place in the matrix (fluid inside the mitochondria) the electron transport chain along the cristae membrane of the mitochondria
How does the electron transport chain use high-energy electrons from glycolysis and the Krebs cycle?
The electron transport chain uses the high-energy electrons from glycolysis and the Krebs cycle to convert ADP into ATP. ATP Synthase- make ATP NADH and FADH2- energy carriers (electrons and hydrogen)
Why are the Krebs cycle and the electron transport chain considered the aerobic portions of cellular respiration?
They are aerobic because the electron transport chain needs oxygen happen in the mitochondria
summary of electron transport chain
This happens across the mitochondrial inner membrane (cristae membrane). NADH and FADH2 deliver their electrons. The H+ ions (from NADH and FADH2) form a concentration gradient across the membrane. movement from area with high concentration -> low concentration (diffusion) The H+ ions move through ATP synthase and create 32 ATP. ATP Synthase (enzyme) only works when H+ ions
Alcoholic fermentation (choice 1 after 1st step)
This process is done by yeast to make bread and beer The CO2 that is generated makes the bubbles. When baking bread, the alcohol burns off
Alcoholic Fermentation
This process is done by yeast to make bread and beer. The CO2 that is generated makes the bubbles. When baking bread, the alcohol burns off.
How many ATP are produced?
glycolysis- 2 Krebs cycle- 2 Electron transport chain with chemiosmosis- 32
What are the final products?
glycolysis- 2 NADH, 2 pyruvate Krebs cycle- 4 CO2, 6 NADH, 2 FADH2 Electron transport chain with chemiosmosis- water
What are the starting materials?
glycolysis- glucose Krebs cycle- 2 Acetyl CoA Electron transport chain with chemiosmosis- 6 O2, 2 NADH, 2 NADH, 6 NADH, 2 FADH2
Inside or outside the mitochondria?
glycolysis- outside (cytoplasm) krebs cycle- inside (matrix) electron transport chain with chemiosmosis- inside (cristae membrane)
inner membrane (mitochondria)
has many folds called cristae the electron transport chain happens here ATP synthase
parts of the mitochondria
inner membrane, outer membrane, cristae, matrix
glycolysis
involves the splitting of glucose into two molecules of pyruvate in the cytoplasm
Why is glycolysis considered an anaerobic process?
it does not require oxygen it happens outside of the mitochondria
Where does the Krebs cycle occur?
matrix of mitochondria
process that makes ATP in the presence of carbon monoxide
neither aerobic or anaerobic
NADH
nicotinamide adenine dinucleotide chemical that occurs naturally in the body and plays a role in the chemical process that generates energy (cell respiration)
Electron Transport Chain
occurs across the inner membrane. O2 goes in and H2O and 32 ATP are generated
Pyruvic acid (pyruvate)
organic acid which occurs as an intermediate in many metabolic processes, especially glycolysis.
What is the final electron acceptor for the H+ ion and the high-energy electrons and what substance will they form? (This is why we breathe!)
oxygen is the final electron acceptor for the H+ ion and the high energy electrons the oxygen, H+, and electrons for water
What are some of the organisms that perform photosynthesis?
plants, algae, and some bacteria
What are some of the organisms that perform cellular respiration?
plants, animals, fungi, protists, and most bacteria
FADH
redox cofactor that is created during the Krebs cycle and utilized during the last part of respiration, the electron transport chain
Why does the cell have to release the chemical energy in food molecules gradually?
so energy isn't lost as heat and light
Krebs Cycle (Citric Acid Cycle)
takes place in the matrix and generates 2 ATP and CO2