5.7 Respiration Flashcards by Daa Gyamfi

What is Respiration?

Respiration is a chemical reaction which occurs in all living cells, releasing energy from glucose

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Why do organisms need to Respire?

Provides energy for 
•DNA replication & cell division
• Active transport 
• Movement
• Metabolic reactions e.g. to form peptide bonds in protein synthesis.

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What is Atp and its role?

Adenosine(adenine + ribose) Triphosphate that functions as an immediate energy source for reaction by hydrolysing and losing a phosphate group

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What is the chain reactions involved to Completely hydrolyse 1 ATP?

30.5kJ 30.5kJ 13.8kJ
↑ ↑ ↑
ATP + H2O → ADP + H2O → AMP
↓ ↓ ↓
Phosphate Phosphate Phosphate

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How is ATP formed?

ATP synthase catalyses the formation of ATP from ADP and the Inorganic Phosphate

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What are some features of atp that make it suited to its job?

relatively stable in solutions
despite this is readily hydrolysed by enzymes
Universal as appears in all living cells
easily transported whilst in solution

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Name the 4 main stages in aerobic respiration and where they occur?

Glycolysis: cytoplasm.
Link reaction: mitochondrial matrix.
Krebs cycle: mitochondrial matrix.
Oxidative phosphorylation via electron transfer chain: membrane of cristae.
* 2,3,4 only happen with air(aerobic conditions)

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What is Glycolysis?

the first step in Respiration that turns glucose into 2 pyruvates

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Outline the steps of glycolysis?

Phosphorylation of glucose to Hexose bisphosphate
Hexose Bisphosphate split into Triose phosphate
Triose phosphate oxidized to Pyruvate using NAD
* PRODUCTS per glucose: 2NADH & 2ATP per glucose

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What is NAD?

a coenzyme that helps catalyses redox reactions by carrying protons or electrons

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How are NAD different from NADP?

NAD for respiration

NADP for photosynthesis

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What happens after pyruvate is formed?

with Oxygen present

enters mitochondrial matrix through active transport to enter link reaction

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What happens after pyruvate is formed?

Anaerobic respiration

converted in cytoplasm to lactate(animals) or ethanol(yeast), NADH reoxidsed to continue glycolysis and

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What happens during the Link reaction?

pyruvate is decarboxylated and dehydrogenated
pyruvate + NAD + CoA →
Acetyl CoA + reduced NAD + CO2

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Steps of Link reaction?

1.Pyruvate oxidized to acetate + CO2
NAD reduced during process
2.Acetate combines with coenzyme A (CoA) to form Acetylcoenzyme A

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What is the Krebs Cycle?

happen in the mitochondrial matrix where many enzyme catalysed reactions occur to makes products like the H+, NADH &FADH2 used for oxidative phosphorylation

What are the products of the Krebs cycle?

Per 1 Acetyl-CoA

• 1ATP by substrate-level phosphorylation
• 2 CO2 from decarboxylation
• FADH2 & 3(NADH & H+)
 (used in oxidative phosphorylation)
* 1 Coenzyme a

Steps of Krebs cycle?

acetyl Coenzyme A from link reaction releases acetyl group
Acetyl group + OXALOACETATE → Citrate(6C compound)
6C compound oxidised to form a 5C compound & CO2, H reduces NAD
5C oxidised forms 4C compound & CO2, H reduces NAD , ATP formed
4C compounds, via dehydrogenation reduces FAD and NAD
4C regenerates Oxaloacetate

What is the Electron Transfer Chain (ETC)?

Series of carrier proteins embedded in membrane of the cristae of mitochondria.

What happens in the Electron Transfer Chain (ETC)?

Electrons released from reduced NAD & FAD undergo successive redox reactions.
The energy released is coupled to maintaining proton gradient or released as heat.
Oxygen acts as final electron acceptor

What is Oxidative Phosphorylation?

Formation of ATP using energy from the electron transfer chain, in the presence of oxygen (aerobic)

What are the final steps of Aerobic respiration?

Oxidative Phosphorylation

NADH &FADH2 reoxidise and release the H+ ions(protons)
Some energy released from the ETC is used to actively transport H+ ions (protons) from mitochondrial matrix into intermembrane space.
H+ ions move down concentration gradient back into mitochondrial matrix via channel protein ATP synthase.
ATP synthase catalyses ADP + Pi → ATP

What is Chemiosmosis, how is it relevant to ATP production?

The flow of protons down their concentration gradient across a membrane. When occurs through the protein channels associated with ATP synthase, they cause a conformational change that allows ADP and P to combine

Name the stages in respiration that produce ATP by substrate-level Phosphorylation.

glycolysis

* Krebs cycle (aerobic/ requires oxygen)

What happens during Anaerobic respiration in animals?

only glycolysis continues, much less ATP produced reduced NAD + pyruvate →lactate + NAD (for further glycolysis)

What happens during Anaerobic respiration yeast and some plant cells?

Only glycolysis continues, much less ATP produced | Pyruvate is decarboxylated to form ethanal. Ethanal dehydrodgenated to ethanol oxidising NADH

What are the benefits of being able to respire Anaerobically?

* ATP production for vital metabolic processes continues despite lack of oxygen * Production of ethanol/ lactate converts reduced NAD back into NAD so glycolysis can continue = maximum yield of ATP in the conditions

What is Respiratory quotient ?

CO2 produced/ O2 used Can be used to determine: • Respiratory substrate being used • type of respirato goin on(anaerobic values are larger)

Name molecules that can be used as alternative Respiratory substrates

* (amino acids from) proteins * (glycerol and fatty acids from) lipids * disaccharides converted to monosaccharides changed to glucose

Why do different Respiratory substrates have different relative energy values?

Depends on the number of hydrogens in the structure which are oxidised to water e.g. more hydrogens in a fatty acids than carbohydrate.

What a Respirometer?

apparatus used to measure the rate of respiration by measuring the rate of exchange between oxygen and carbon dioxide

Suggest how a student could investigate the effect of a named variable on the rate of respiration of a single celled organism

1. Use respirometer (pressure changes in boiling tube cause a drop of coloured liquid to move 2. Use a dye as the terminal electron acceptor for the ETC

What is the purpose of Sodium Hydroxide solution (Soda lime) in a Respirometer?

Absorbs CO2 so that there is a net decrease in pressure as O2 is consumed

How could a student calculate the rate of Respiration using a Respirometer?

(Volume of O2 produced or CO2 consumed/ time) x mass of sample. Volume = distance moved by coloured drop x (0.5 x capillary tube diameter)2 x π

Describe the structure of a Mitochondrion

surrounded by double membrane.(inner, outer, inter) folded inner membrane forms cristae: site of electron transport chain. fluid matrix: contains mitochondrial DNA, respiratory enzymes, lipids, proteins, ribosomes

What are the RQ values for | Carbohydrates,lipids & Amino acids

* Carbohydrates = 1 * Amino acids = 0.8 * Lipids = 0.7

what are the steps of glycolysis

1. Glucose Phosporlyated by 2 Atp 2. Hexose Biphospate split into 2 Triose phosphate 3.Triose phosphate oxidised to Pyruvate 3* oxidation of 1 TP reduces 1NAD & forms 2 ATP

what could be the rection eqautionS for glycolysis

Glucose + 2 ATP → Hexose biphosphate + 2ADP Hexose biphosphate → 2 Triose phosphate (TP) 2 TP+ 4(ADP+i) 2NAD → Pyruvate + 4ATP + 2NADH