Slides in this set

Slide 1

Preview of page 1

AQA A2 Biology Unit 4
4 Respiration…read more

Slide 2

Preview of page 2

3.4.4 In respiration, glycolysis takes place in the cytoplasm and the remaining steps in the
mitochondria. ATP synthesis is associated with the electron transfer chain in the
membranes of mitochondria.
Aerobic Respiration Aerobic Respiration Conc Anaerobic respiration
glycolysis takes place in the Glycolysis followed by
cytoplasm and involves the acetylcoenzyme A is the production of
oxidation of glucose to effectively a two carbon ethanol or lactate and
pyruvate with a net gain of molecule that combines the regeneration of
ATP and reduced NAD with a four carbon NAD in anaerobic
molecule to produce a six respiration.
pyruvate combines with carbon molecule which
coenzyme A in the link enters the Krebs cycle
reaction to produce
acetylcoenzyme A synthesis of ATP by
oxidative phosphorylation
is associated with the
transfer of electrons
in a series of oxidation- down the electron
reduction reactions the transport chain and
Krebs cycle generates passage of protons across
reduced coenzymes and mitochondrial
ATP by substrate-level membranes.
phosphorylation, and
carbon dioxide is lost…read more

Slide 3

Preview of page 3

· Hydrolysis: Breaking down of large molecules into smaller ones by the addition of water
· Activation Energy: Energy required to bring about a chemical reaction
· Oxidation: Lose of Electrons
· Glycolysis: First part of cellular respiration in which glucose is broken down anaerobically in
the cytoplasm to 2 molecules of pyruvate
· Substrate-Level Phosphorylation: The formation of ATP by the direct transfer of a phosphate
group from a reactive intermediate to ADP
· Aerobic: Connected with the presence of oxygen, aerobic respiration requires oxygen to
release energy from glucose and other foods
· Adenosine Triphosphate: An activated nucleotide found in all living cells that acts as an
energy carrier.
· Redox: Reaction in which oxidation and reduction take place
· Krebs Cycle: Series of aerobic biochemical reactions in the matrix of the mitochondria of
most eukaryotic cells by which energy is obtained through the oxidation of acetylcoenzyme A
produced in the breakdown of glucose
· NAD: (Nicotinamide adenine dinucleotide phosphate) Molecule that carries electrons and
hydrogen ions during aerobic respiration…read more

Slide 4

Preview of page 4

4.1 Respiration Overview
Glucose cannot be used directly by cells as an energy source so they use ATP
· Aerobic Respiration: requires oxygen and produces carbon
dioxide, water and much ATP
There are two different forms of · Anaerobic Respiration ((fermentation): Takes place in the
respiration: absence of oxygen and produces lactate (inn animals) or
ethanol and carbon dioxide in plants, very little ATP is
· Glycolysis: Splitting of the 6 carbon glucose molecule into 2 3-
carbon pyruvate molecules
· Link Reaction: Conversion of the 3-carbon pyruvate into
carbon dioxide and a 2-carbon molecule called
acetylcoenzyme A
Aerobic Respiration steps: · Krebs Cycle: Introduction of acetylcoenzyme A into a cycle of
oxidation-reduction reactions that yield some ATP and a large
number of electrons
· Electron Transport Chain: Use of the electrons produced in
the Krebs Cycle to synthesis ATP with water produced as a by-
product…read more

Slide 5

Preview of page 5

Glycolysis is the initial stage in both aerobic and anaerobic respiration
Occurs in the cytoplasm of all living cells
A hexose sugar is split into 2 molecules of 3-carbon pyruvate
· Activation of Glucose by phosphorylation: Glucose is made more
reactive by adding 2 phosphate molecules, these come from the
hydrolysis of 2 ATP molecules to ADP. This provides energy to
activate the glucose as the activation energy has been lowered
· Splitting of the Phosphorylated glucose: Each glucose molecule is
split into 2 3-carbon molecules known as triose phosphate
It has four stages:
· Oxidation of Triose Phosphate: Hydrogen is removed from each
triose phosphate molecule and transferred to a hydrogen-carrier
molecule (NAD) to form reduced NAD
· Production of ATP: Enzyme controlled reactions convert each
triose phosphate into another 3-carbon molecule called pyruvate,
2 molecules of ATP are regenerated from ADP
· 2 molecules of ATP
Energy Yield: · 2 molecules of reduced NAD
· 2 Molecules pyruvate
As glycolysis occurs in the cytoplasm of cells it doesn't require an organelle or membrane for it to occur
It doesn't require oxygen and without oxygen pyruvate is converted to lactate or ethanol by anaerobic respiration…read more

Slide 6

Preview of page 6

4.2 The Link Reaction
For pyruvate molecules to enter the Krebs cycle they need to by oxidised
Occurs in the mitochondria
Pyruvate produced in the cytoplasm is actively transported into the matrix of mitochondria
· Hydrogen is removed from the pyruvate, the hydrogen is
accepted by NAD to form reduced NAD
Pyruvate undergoes a series of
reactions: · 2-carbon molecule, acetyl group, is formed and then combines
with coenzyme A ((CoA) to produce acetylcoenzyme A
· A carbon dioxide molecule is formed from each pyruvate
Pyruvate + NAD + CoA acetyl CoA + reduced NAD + CO…read more

Slide 7

Preview of page 7
Preview of page 7

Slide 8

Preview of page 8
Preview of page 8

Slide 9

Preview of page 9
Preview of page 9

Slide 10

Preview of page 10
Preview of page 10


No comments have yet been made

Similar Biology resources:

See all Biology resources »