Download Respiration and Mitochondria Summary

Definition:
A series of chemical reactions in the cytoplasm and mitochondria of cells, where
chemical energy (glucose) from food is transferred to ATP.
ATP is a chemical that carries the energy to power every reaction and process that goes
on in all living things. It is then recharged from food molecules by cellular respiration.
ATP can store chemical energy until it is needed by the cell.
Aerobic Respiration:
C6H12O6 + 6 02
glucose
Requires oxygen to work; has four distinct stages (see later).
--- 6 CO2 + 6 H2O + 36 ATP + heat
+ oxygen --- carbon dioxide + water + energy + heat
Anaerobic Respiration: Does not require oxygen. Only a small amount of ATP is
produced. Occurs in complex animals, some bacteria and fungi (eg. yeast).
-
Alcohol Fermentation: In plants and micro-organisms.
eg. Yeast
(a fungi) uses fermentation and produces alcohol and CO2, used by humans
for making beer, wine and bread.
-
Lactic Acid Fermentation: In animals and some bacteria.
eg. In
human muscle cells this occurs when not enough oxygen is available during
rapid exercise. It results in a build-up of lactic acid which causes muscle
fatigue and soreness.
http://micro.magnet.fsu.edu/cells/mitochondria/mitochondria.html
http://academic.brooklyn.cuny.edu/biology/bio4fv/page/mito.htm
STRUCTURE: Mitochondria are oval-shaped organelles with two plasma membranes, an
outer membrane and a highly folded inner membrane that gives a larger surface area
for chemical reactions. The intermembrane space is the space between the outer and
inner membranes.
The folding of the inner membrane divides the mitochondrion into different areas to
provide a larger surface area and produces membrane compartments (cristae) that hold
different materials. The inner membrane allows only certain molecules to pass through
it and is much more selective than the outer membrane.
The matrix is the gel-like fluid substance within the inner membrane. The cristae
protrude into the matrix. Many enzymes are also found in the mitochondria – some are
dissolved in the fluid matrix, while some form part of the inner membrane.
FUNCTION: The main chemical reactions occurring inside the mitochondria are the
last stages of aerobic respiration. Respiration is the breakdown of chemicals from food
to convert the energy they contain into ATP. Materials for this reaction are
transported from the cytoplasm into the mitochondria which allows the cell to control
these reactions. The ATP produced in respiration is transported out of the
mitochondria to where it is needed and used by the cell.
NUMBER OF MITOCHONDRIA IN CELLS: The density of mitochondria in a cell
reflects the cell’s energy requirements. Cenerally they are clustered where the action
is. Cells such as muscle, kidney and liver cells have hundreds of mitochondria because
they have a high energy demand so must produce large amounts of ATP. Muscle cells
work hard contracting so need lots of energy. Kidney and liver cells carry out a number
of different reactions needing ATP. Sperm cells also have lots of mitochondria as they
require large amounts of ATP energy to swim to the ovum (egg).
STAGE
LOCATION
SUMMARY
PRODUCTS
Glycolysis
“splitting sugar”
Cytoplasm
Begins the breakdown of glucose.
Requires ATP & ADP. No oxygen
required. Can be anaerobic.
Pyruvate,
2ATP, H,
NADH2
Formation of Acetyl
Co-enzyme A
Mitochondrial
matrix
Pyruvate is combined with an enzyme
(Co-enzyme A) to form Acetyl CoA.
CO2, H, Acetyl
Co-enzyme A
Krebs Cycle or
Citric Acid Cycle
Mitochondrial
matrix
A series of reactions in which Acetyl
Co-enzyme A is modified.
Requires H20 & ADP.
No oxygen required.
CO2, 2ATP, H,
NADH2
Electron Transport
Chain
Cristae of
mitochondria
A chain of chemical reactions where
Hydrogens (electrons) from previous
stages are passed along to release
energy used to produce a large amount
of ATP.
Oxygen is required.
Requires H, O2, ADP
32 ATP, H2O
Diagram showing the stages of Aerobic Respiration
http://canada.canacad.ac.jp/BiologyIBHL1/3104