Respiration Key Terms and Processes Flashcards
Content Revison
What is Cellular Respiration?
A biochemical reaction in which cells convert sugar to CO2 and H2O
Autotrophic Nutrition
The synthesis of organic materials from inorganic sources
Heterotrophic Nutrition
The nutrition in which organisms ingest other organisms to obtain organic material
Energy is used in…
- synthesis of complex structures
- active transport
- locomotion
- bio luminescence
- homeostasis
- production of electricity
- maintenance, repair and division
- activation of chemicals
The Conservation of Energy
Energy cannot be created or destroyed, but can only be converted from one form to another.
Units are joules/kilo joules
Metabolism
All reactions that take place within an organism
Anabolism
Build up of larger, more complex molecules from smaller, more simple ones
Catabolism
The breakdown of larger more complex molecules into smaller, more simpler ones
ATP stands for…
AdenosineTriPhosphate
What does ATP consist of?
ATP is a nucleotide that consists of three main structures: the nitrogenous base, adenine; the sugar, ribose; and a chain of three phosphate groups bound to ribose.
How much energy is released when:
ATP + H2O?
30.6kJmol-1
How much energy released when:
ADP + H2O?
30.6kJmol-1
How much energy released when:
AMP + H2O?
14.2kJmol-1
Why is ATP described as universal energy currency?
- it is hydrolysed energy, which means it is easily and immediately available to the cell in small manageable amounts
- it is continually hydrolysed and resynthesised
- it is found in all living organisms
Describe the Mitochondria
- it is a double membraned organelle
- outer memrane is smooth
- inner membrane is folded into cristae
- matrix is a mixture of gel-like mixture of protein/lipid/DNA/ribosomes/coenzymes
- allows volatile reactions of aerobic respiration to be compartmentalised form the rest of the cell
- contains Kreb’s cycle’s enzymes
- found in all respiring organisms
- 1 micrometer in diameter
- 10 micrometers in length
Describe the inner membrane
- different lipid composition to outer membrane
- impermeable to small ions
- folded
- has electron carriers and ATP synthase enzymes embedded
Describe the matrix
- site of the link reaction
- NAD/FAD
- oxaloacetate
- mitochondrial DNA
- ribosomes
- co enzyme A
Describe NAD
- nicotamine adenine dinucleotide
- reduced when two hydrogens with their electrons are accepted
- present in glycolysis, link reaction and Kreb’s cycle
Describe FAD
- flavin adenine dinucleotide
- transfers one or two electrons or hydrogen atoms
- strong oxidising agent
reduced in the Kreb’s cycle
Describe Co enzyme A
- derived from vitamin B
- used in link reaction to transfer products of glycolysis into the mitochondria
- carries ethanoate groups made by oxidation during the link reaction and Kreb’s cycle
Glycolysis occurs in the…
…cytoplasm of the cell
For each glucose molecule entering the reaction…
- 2 molecules of ATP are used
- 4 molecules of ATP are produced
(net gain : 2 ATPs) - 2 molecules of reduced NAD are produced
- 2 pyruvates are produced
What is substrate level phosphorylation?
Where ATP is formed directly using energy released from the oxidation of the substrate
Describe Glycolysis
- phosphorylation of glucose
- so forming hexose (1,6) bisphosphate
- then splitting into 2 triose phosphates
- for the formation of pyruvate, the formation of reduced NAD
- pyruvate produced from triose phosphate
- total production 4 ATP, net production of 2 ATP
Approximately how much chemical energy does glycolysis release?
Glycolysis releases less than 25% of the chemical energy stored in glucose
Describe the Link Reaction
- pyruvate dehydrogenase removes hydrogen atoms from pyruvate
- these hydrogen atoms are accepted by NAD+ to produce reduced NAD
- pyruvate decarboxylase removes a carboxyl group, CO2 is formed
- CoA accepts acetate to form Acetyl CoA, which carries acetate into the Kreb’s cycle
- pyruvate is oxidised, NAD+ is reduced
- 2 x pyruvate, 2 x NAD+, 2 x CoA, 2 x CO2, 2 x reduced NAD, 2 x Acetyl CoA
The link reaction occurs in…
…the mitochondrial matrix
The Kreb’s cycle takes place in…
…the mitochondrial matrix
Does the Kreb’s cycle require oxygen?
it doesn’t require oxygen, but it cannot take place without it, ∴ it is aerobic
Respiratory substrates such as____ and ____ can enter aerobic respiration at the beginning of the Kreb’s cycle.
- fatty acids (broken down to acetates via CoA)
- amino acids (deaminated/changed to acetate/ pyruvate)
The Kreb’s cycle is the oxidation of ____ to ____
Acetate to CO2
Per acetate :
- 2 x CO2
- 1 x ATP
- 3 x reduced NAD
- 1 x reduced FAD
What is the Kreb’s cycle?
It is a series of chemical reactions used by all aerobic organisms to generate energy through the oxidization of acetate derived from carbohydrates, fats and proteins into carbon dioxide.
The Krebs Cycle serves as what?
A central metabolic pathway for generating building blocks for the cell.
Where does citric acid come from?
When Acetyl-CoA enters the Krebs cycle it combines with a four-carbon acid called oxaloacetic acid. The combination forms the six-carbon acid called citric acid.
The metabolic pathway of the citric acid cycle chemically converts what to what?
Carbohydrates, fats, and proteins into carbon dioxide, and converts water into serviceable energy.
In one concise sentence describe what happens in the Krebs cycle
- the citric acid cycle completed the oxidation of organic molecules generating many reduced NAD/FADH2 molecules
- acetyl group joins with oxaolacetate groups to form citrate which is then transformed (redox reaction) create electron carriers, and a byproduct of ATP
How much ATP is produced per molecule of pyruvate?
One molecule of ATP
How much ATP per molecule of glucose?
2 ATP s per glucose
Products of the Kreb’s cycle? (two turns)
- 6 reduced NAD
- 2 reduced FAD
- 4 CO2
- 2 ATP
What is the first stage of oxidative phosphorylation?
- reduced NAD and FAD are reoxidised when they donate the hydrogen, its then plait into protons and electrons
- electrons are accepted by the electron carriers
- protons go into solution in the matrix
What is the second stage of oxidative phosphorylation?
- electrons are passed along a chaiun of carriers, energy is released and is used to pump protons into the intermembrane space
- an electrochemical gradient starts to build up
- protons diffuse through ion channels associated with ATP synthase
What is stage three of oxidative phosphorylation?
- as protons flow through ATP synthase, the ezyme begins to rotate at the point
- ADP and an inorganic phosphate is joined together
- electrons and protons (hydrogen cations) combine with oxygen to form water
