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88 Cards in this Set
- Front
- Back
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Define cellular respiration |
The process by which energy from food molecules is transferred into ATP |
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What is the "respiratory substrate" |
The term given to the substance broken down during cellular respiration. |
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What is the main respiratory substrate used by cells in cellular respiration |
Glucose |
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What affects the volume of oxygen used, and the volume of CO2 produced, in cellular respiration? |
The level of activity of the organism The type of food being respired External factors, such as temperature |
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What is aerobic respiration? |
A form of cellular respiration that takes place in the presence of oxygen. |
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What is the word equation for aerobic respiration? |
Glucose + Oxygen > Carbon dioxide + Water |
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What is the symbol equation for aerobic respiration? |
C6H12O6 + 6O2 > 6CO2 + 6H2O (+ATP) |
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What does aerobic respiration provide? |
Readily transferable energy for all cellular reactions |
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What happens when energy from respiration is needed? |
The third phosphate bond in ATP can be broken by hydrolysis, catalysed by the enzyme ATPase. |
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What is the result of hydrolysing ATP? |
Adenosine diphosphate (ADP) & a free inorganic phosphate group (Pi) |
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How much energy is released for every mole of ATP hydrolysed? |
30.5kJ |
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What is the energy produced by hydrolysing ATP used for? |
Some is transferred to the environment, warming it up. The rest is available for any energy-requiring biological activity. |
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The breakdown of ATP into ADP and Pi is....? |
Reversible |
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What is phosphorylation? |
The addition of phosphate to an organic compound. i.e adding a phosphate to ADP to get ATP |
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state two features of the phosphorylation of ADP to ATP |
-Catalysed by ATPase -Requires 30.5kJ of energy |
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ATP cannot be stored in the body in large amounts. What happens instead? |
The raw materials to make ATP are almost always available so the compound is made as and when it is needed. |
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Mind map the picture diagram for ATP to ADP |
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What is the FIRST STAGE OF AEROBIC RESPIRATION |
Glycolysis |
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DOES GLYCOLYSIS REQUIRE OXYGEN |
NO. |
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WHAT IS PRODUCED DURING GLYCOLYSIS |
A LITTLE ATP |
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What happens during glycolysis |
The splitting of the respiratory substrate begins & molecules are prepared to enter the second stage of process |
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What is the second phase/ set of reactions during aerobic respiration |
The Krebs Cycle. |
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Does the Krebs cycle need oxygen to occur? |
Yes. |
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Does the Krebs cycle need oxygen to occur? |
Yes. |
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What is the role of the link reaction in aerobic respiration |
To move products of GLYCOLYSIS into the Krebs Cycle & the electron transport chain. |
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What controls the reactions in aerobic respiration |
Enzymes |
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Why are many different enzymes involved in aerobic respiration |
Because each one is specific to a particular reaction |
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What controls the rate of reaction in aerobic respiration |
The inhibition of the various enzymes. Usually inhibits by other chemicals in the reaction chain |
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Where does glycolysis take place |
It is not associated with any particular organelle |
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Where are the enzymes that control glycolysis found |
In the cytoplasm |
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Where does the link reaction take place |
The Mitochondria |
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Where does the Krebs cycle take place |
The Mitochondria |
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Where does the electron transport chain take place |
The Mitochondria |
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Describe the structure of a mitochondria |
-has a double membrane -inner membrane formed in folds -folds are called cristae -the matrix contains the enzymes of the krebs cycle -cristae carry the stalked particles associated with ATP synthesis |
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How is most ATP produced. |
During cellular respiration, through a series of oxidation and reduction reactions in the electron transport chain |
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What is oxidation |
-removal of substances -removal of substances-addition of oxygen or removal of hydrogen -removal of substances-addition of oxygen or removal of hydrogen -removal of substances-addition of oxygen or removal of hydrogen -removal of substances-addition of oxygen or removal of hydrogen -addition of oxygen or removal of hydrogen |
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what is reduction |
Addition of electrons to a substance (Brought about by addition of hydrogen / removal of oxygen) |
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What happens to hydrogen during cellular respiration |
Hydrogen is removed from compounds & picked up by a hydrogen acceptor. This means the hydrogen acceptor has gained a hydrogen so it is REDUCED. The hydrogen is then passed to the next hydrogen acceptor & along the electron transport chain. A series of linked redox reactions takes place. Each redox reactions releases a small amount of energy. This is used to drive the synthesis of a molecule of ATP. |
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What is the most common hydrogen acceptor |
NAD |
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What is NAD |
A coenzyme, one of the small molecules that assist in enzyme catalysed reactions. |
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What happens when NAD accepts hydrogen atoms from a metabolic pathway |
It becomes reduced NAD. So, NADH. |
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What is the oxidised form of NAD? |
NAD^+ |
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What is FAD |
A hydrogen carrier and coenzyme that accepts hydrogen from reduced NAD & forms reduced FAD. (FADH2) Each time, a molecule of ATP Is formed in the process. |
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state a few ways of investigating the site of ATP synthesis at a cellular level |
-break open cells & centrifuge contents to obtain a fraction containing just Mitochondria. supply with glucose & oxygen. should produce ATP. -use electron microscope high resolution to see the inner membrane of mitochondria which is covered in stalked particles, which provide a greater surface area -stalked particles & bits of membrane associated with them can be separated from mitochondria. demonstrates ATP synthesis will not happen without it. so, stalked particles are vital for forming ATP. |
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Summarise what happens during glycolysis |
6C glucose is split by a series of ten reactions into two molecules of the 3-Carbon (3C) pyruvate compound. |
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What type of respiration is pyruvate from GLYCOLYSIS used in |
Both aerobic and anaerobic |
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What does glycolysis mean? |
'sugar splitting' |
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Where does the glucose for glycolysis come from? |
Either directly from the blood, or may be produced by breakdown of glycogen stores in muscle&liver cells. |
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What is step one in glycolysis |
ATP is used to provide energy to phosphorylate the 6C glucose.; two phosphate groups are added. This makes the sugar more reactive so it is unable to pass through the cell membrane, so it becomes trapped within the cell. |
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What is step two in glycolysis |
The phosphorylated sugar is split into two molecules of a 3 carbon sugar. This is GP (glycerate 3 phosphate.) GP is then converted by several steps into a molecule of pyruvic acid, which is found in solution as pyruvate ions. During these reactions, a small amount of ATP is produced. |
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How are the two 3C sugars converted into pyruvate. |
-2 hydrogen atoms removed from the 3C sugars. NAD (hydrogen acceptor) takes up the hydrogen. reduced NAD passes through the outer mitochondrial membrane into the electron transport chain. -A small amount of ATP is made directly from the energy transfer when the 3C is converted into pyruvate: The phosphorylation at the beginning is reversed when the final compound is converted to pyruvate. The released phosphate group from this converts the ADP into ATP. |
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What happens if there is plenty of oxygen, and if there is not, by the end of glycolysis |
If there is plenty of oxygen, the pyruvate will enter the mitochondria & be used in the aerobic reactions of the Krebs cycle. If oxygen levels are low, the pyruvate remains in the cytoplasm and is converted into either ethanol or lactate. Only a little ATP will be produced. This is anaerobic respiration. |
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state the four features of aerobic respiration |
-in mitochondria -complete oxidation -waste products; H2O, CO2 -net energy: 31 ATP |
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state the four features of anaerobic respiration |
-in cytoplasm -incomplete oxidation -waste products: lactic acid, ethanol, co2 -net energy: 2 ATP |
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What happens if the muscles do not get enough oxygen to supply their needs |
Products of glycolysis cannot go on to the Krebs cycle (the aerobic stage of cellular respiration). The muscles will anaerobically respire. |
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In mammals, what happens during anaerobic respiration? |
The pyruvate from GLYCOLYSIS is converted to lactic acid. |
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What is lactic acid |
A 3C compound that dissociates to form lactate and hydrogen ions. |
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What happens as a result of anaerobic respiration & why |
Only two ATP molecules are produced per glucose molecule respired. This is because some of the reduced NAD is used to reduce pyruvate to lactate, rather than to enter the electron transport chain. |
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Where does the lactate go during anaerobic respiration |
Moves out of cells into the blood. |
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Word equation for anaerobic respiration |
Glucose > Lactic acid |
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Symbol equation for anaerobic respiration |
C6H12O6 > 2C3H6O3 |
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Why does lactate in the blood prevent mammalian muscle contraction? |
Lactate and hydrogen in the blood lower the PH of the blood. This affects the CNS. This reduces nervous stimulation, which eventually stops muscle contraction. This is a protective adaptation to give the muscles time to recover and return to aerobic respiration. This allows the pH of blood to be raised again. |
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How do you remove lactate from the body? |
Lactate must be oxidised back to pyruvate to enter the Krebs cycle to be respired aerobically, producing carbon dioxide, water & ATP. It takes oxygen to oxidise the accumulated lactate. So, you must breathe deeply. |
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Anaerobic respiration in plant cells, symbol and word equation |
Glucose> ethanol + carbon dioxide + ATP
c6h12o6 > 2c2h5OH + 2CO2 + ATP |
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what happens to the pyruvate produced as the end product of the GLYCOLYSIS reaction when there is plenty of oxygen available. |
It is fed through into the mitochondria where it enters the krebs cycle via the link reaction |
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what is the Krebs cycle |
A series of biochemical steps that lead to the complete oxidation of glucose resulting in the production of carbon dioxide, water & relatively large amounts of ATP. |
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Where is the ATP produced |
Stalked particles on the inner mitochondrial membrane in presence of oxygen |
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what happens during the link reaction |
the pyruvate crosses into the mitochondria through the mitochondrial membrane from the cytoplasm. an atom of carbon is removed from pyruvate (decarboxylation) resulting in the formation of a carbon dioxide molecule & a 2 carbon compound. The compound joins with coenzymeA to form 2C acetyl coenzyme A. (Acetyl coA). At the same time, the pyruvate is oxidised, losing hydrogens to NAD (dehydrogenation) which results in reduced NAD (NADH). This reduced NAD is used later in the electron transport chain to produce ATP. The energy contained in the acetyl coA is released in the Krebs cycle. Enzymes known as decarboxylases remove carbon dioxide and enzymes known as dehydrogenases remove hydrogen |
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What is the word equation for the link reaction |
pyruvate (3c) + coA + NaD > acetyl coA + Co2 + reduced NAD. |
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summarise the krebs cycle |
>2C acetyl coA combines with a 4C compound to form the 6C compound citric acid. at this point, it has entered the krebs cycle. >The 6C citric acid now goes through a cyclical series of reactions during which the compound is broken down in a number of stages to give the original 4C compound. Two further molecules of carbon dioxide are removed in the process & are give. Off as a waste product. >The 4C compound then combines with more 2C acetyl coA & the cycle begins again. |
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How many molecules of reduced NAD&FAD & ATP are produced for each molecule of pyruvate that enters the krebs cycle |
Three molecules of reduced NAD One molecule of reduced FAD one ATP |
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Why does the Krebs turn twice |
each 3C passes through. The 6C splits into two 3C in the beginning
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What occurs in the final stage of respiration |
Oxidative phosphorylation |
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What is an electron transport chain |
A series of electron carrying compounds along which electrons are transferred in a series of redox reactions, driving the production of ATP |
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What is an electron transport chain |
A series of electron carrying compounds along which electrons are transferred in a series of redox reactions, driving the production of ATP |
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What is oxidative phosphorylation |
The oxygen dependent process in the electron transport chain where ADP is phosphorylated. |
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What is chemiosmosis |
The process that links the electron passed down the electron transport chain & the production of ATP, by the movement of hydrogen ions through the membrane along electrochemical, concentration & Ph gradients. |
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What are the 4 main election carriers |
>coenzymes NAD and FAD >cytochromes >cytochromes oxidase >oxygen |
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Explain coenzymes NAD and FAD as electron carriers |
Both act as hydrogen acceptors for hydrogen released in the Krebs cycle. One molecule of ATP is produced when FAD is reduced & accepts hydrogen from the reduced NAD, which becomes oxidised is in the process. |
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Explain cytochromes as electron carriers |
Protein pigments with iron group rather like haemoglobin. Involved in electron transport and are reduced by electrons from reduced FAD & reduced NAD, which is oxidised again. A molecule of ATP is produced at this stage. |
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Explain cytochrome oxidase as electron carriers? |
An enzyme that received the electrons from the cytochromes and is reduced as the cytochromes are oxidised. A molecule of ATP is also produced at this stage. |
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Explain oxygen as a electron carrier |
It is the final hydrogen acceptor in the chain. When oxygen is reduced, water is formed and the chain is at the end. |
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When each molecule of hydrogen passes along the electron transport chain from reduced NAD, how many molecules of ATP are made |
3 |
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When hydrogen enters chain from reduced FAD, how many molecules of ATP are made |
Two |
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Where does the electron transport chain/ATP production occur |
What Inner membrane of the mitochondria, which is folded up to form cristae, which are covered with stalked particles |
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What is the chemiosmotic theory |
The theory that explains what happens to hydrogen ions (protons) that are left behind when they electrons are passed along the electron transport chain, and how the movement of the hydrogen ions is coupled to the actual production of ATP |
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Explain the proposal of the chemiosmotic theoru |
Mitchell proposed that hydrogen ions are actively transported into the space between inner and outer membranes using the energy provided as the electrons pass along the electron transport chain. the active transport hydrogen ions across the inner membrane results and a different hydrogen ion concentration on either side of the inner membrane. remembering space as a higher concentration of hydrogen ions and the matrix of the mitochondria so there is a concentration gradient across the membrane. as a result of the different hydrogen ion concentrations across the membrane there's also a ph gradient and because positive hydrogen ions are concentrated in the membranes based that is also an electrochemical gradient. these factors which are the concentration gradient the pH gradient and the electrochemical gradient all mean that there is a tendency for hydrogen ions to move back into the matrix. the only way that this can be done is to a special process which are found on the stalked particles in mitochondria and have an ATPase enzyme associated with them. ASDA hydrogen ions move along with a electrical concentration on pH gradients as their energy is used to drive the synthesis of ATP. |
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Why was the chemiosmotic immediately not accepted immediately in the 1960s? |
Because the widely held model for ATP formation in the cell was that a high-energy phosphate group was directly transferred to ADP from another intermediate like the process of glycolysis. However nobody could find this intermediate compound. |
