BIOL 2020 Lecture Notes - Lecture 4: Endoplasmic Reticulum, Metabolic Pathway, Intermembrane Space
Mitochondria
September 18 & 21, 2015
Readings: pg. 86-108 (review), 108-117, 178-210
Metabolism: collection of all biochemical reactions in the cell
• Metabolic pathway
o Catabolic pathway – breaks it down to its component
▪ Provides products to be used
▪ Generates energy that can be used in the cell
o Anabolic pathway – take simple components and build them into larger ones
▪ Synthesis type pathways
▪ Uses energy from catabolic pathways
Product of one enzyme is substrate for another enzyme in the pathway. = flow of products. Pathways
are usually in compartments within a cell to keep the reactions separate.
Functions of Mitochondria:
• Energy metabolism
• Synthesis of amino acids and heme groups
• Calcium transport
• Apoptosis (cell death) regulator
Structure of Mitochondria:
• Division of mitochondria (fission) is associated
with endoplasmic reticulum
• About the size of bacterium
• Outer and inner membrane
• The inner membrane folds inwards to create
cristae
o Have F1 or ATPase synthase particles
• The intermembrane space is within the cristae as
well to increase the area for metabolic processes
• The area inside the mitochondria can be referred
to as the matrix
• The outer mitochondrial membrane has porin which forms a channel that can open and
close to allow the passage of ATP, NAD, pyruvate….etc.
• The inner mitochondrial membrane has a very high protein to lipid ratio
o Multi-subunit, asymmetric proteins
o Membrane has cadriolipin (diphosphatidylgylcerol) lipid that make membrane
impermeable to most molecules so transport mechanism is needed
Oxidation – loss of electrons
Reduction – gain of electrons
• (ydrogen’s can accompany electrons and be accepted or lost
If there is an oxidation reaction, there will also be a reduction reaction. Electrons are associated with
energy to create ATP usually via glucose oxidation. *see pages 108-115
Glycolysis
o Glucose 6C – pyruvate 3C
o Yields 2 ATP and 2 NADH
o Occurs in cytosol
o Can occur in presence or absence of oxygen
o Pathway enzymes are all connected and could be attached to microtubules
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