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Respiration
RESPIRATION
• Involves the release of energy
and gas exchange
• Occurs in all cells of all
organisms
• It is the release of energy from
food (glucose) – “life runs on
sugar”
• Energy is stored as ATP (a high energy
compound) and is released and “restored” in a cycle
ATP
Energy in
Energy out
ADP + P
Cells use a few billion ATP molecules per
minute for cell activities
ATP cycle clip
Two types of respiration
Anaerobic
 Absence of O 2
 Used by some simple
organisms (yeast and
bacteria)
 Occurs in the cytoplasm
 Partial breakdown of
glucose
 Less efficient (less ATP)
Aerobic
 uses O 2
 Used by most organisms
 Occurs in the
mitochondria
 Complete breakdown of
glucose
 More efficient (more ATP
per glucose)
Step 1:
Anaerobic Respiration
(aka fermentation)
Glycolysis: breakdown
Of glucose into pyruvic
acid
Glucose +2 ATP
(6- carbon)
4 ATP ( net gain
2 ATP, the only ATP
released)
2 Pyruvic acid
(3- carbon)
Pyruvic acid (from previous slide)
(3- carbon)
Step 2:
Fermentationpyruvic acid
converted to
another end
product. No more
ATP released.
2 Lactic Acid (no CO2)
- In bacteria, used to make
- cheese, yogurt
- In humans leads to muscle
fatigue when O2 is low
2 ethyl alcohol + 2CO2
-in yeast, bacteria:
used to make beer,
wine and bread
TOTAL ATP= 2
Glycolysis clip
Glucose (6- carbon +2 ATP
4 ATP ( net gain 2 ATP, the only ATP released
2 Pyruvic acid (3- carbon)
2 Lactic Acid (no CO2)
- In bacteria, used to make
- cheese, yogurt
- In humans leads to muscle
fatigue when O2 is low
2 ethyl alcohol + 2CO2
-in yeast, bacteria and
used to make beer, wine
and bread
TOTAL ATP= 2
Glycolysis song
click glucose,
glucose
Aerobic Respiration
• Cristae in mitochondria provide a
large surface area for the series of
reactions that occur during aerobic
respiration
• Step 1: “Anaerobic Phase”- glycolysis
occurs in the cytoplasm
• Step 2: “Aerobic Phase”- occurs in the
mitochondria
• End Products: 6 CO2 + 6 H2O + 36 ATP
Looks like this:
Glucose + 2ATP
(6 Carbon)
4 ATP
(net 2 ATP)
2 Pyruvic Acid (3 carbon)
* O2 *
2 acetyl CoA (a 2 carbon compound combined w
a co-enzyme) + 2CO2 (exhaled)
Krebs
cycle
High energy
Oxidation/
Reduction
4 CO2 + 2ATP
H
Electron
Transport
Chain
low energy
32 ATP
[ e- gives up energy]
H
O2
final H acceptor
6 H 2O
(vapor)
end products: 6 CO2 + 6 H2O + 36 ATP
Krebs Cycle
Each turn of the Krebs cycle produces:
1. CO2
2. ATP
3. Hydrogen- high energy hydrogen atoms are picked up by
coenzymes NAD + FAD and carried to the electron
transport chain
During the e- transport chain (ETC)
• Oxidation occurs when some atoms lose e- (via a gain of H)
• Reduction occurs when some atoms gain e- (via a loss of H)
• Collectively this is called oxidation- reduction
• Low energy H’s combine with free oxygen (the final H
acceptor) to form H2O (vapor)
Summary of Reactions
C6H12O6
(aerobic)
pyruvic acid + O2
CO2+H2O + 36 ATP
C6H12O6
pyruvic acid
lactic acid + 2ATP
(anaerobic } humans and bacteria)
C6H12O6
pyruvic acid
ethyl alcohol + CO2 + 2 ATP
(anaerobic } bacteria and yeast)
“Cowboy respiration’
clip
like our
balloon
demo
Gas Exchange
• The exchange of O2 and CO2 between an
organism and the environment
• the gas exchange surface must be:
– Thin
– Moist
– In contact with O2
– Near a transport system
Adaptations for Gas
Exchange
diffusion occurs across thin,
1.Monera, Protist, and Fungimoist cell membrane
2. Plants- respire 24 hours a day
• gas exchange occurs in: leaves(stomates
and the spongy layer)
• Stems (lenticles)
• roots (root hairs)
3. Land Animals- the trick is to keep the
respiratory surfaces moist!
(see awesome adaptation sheet)
Respiration in Humans
a)Cellular
Aerobic:
O2+C6H12 O6
cellular
gas exchange
CO2 +H2O + 36 ATP
Anaerobic: (when O2 is not in high
supply)
C6H12 O6
lactic acid + 2ATP
b) Gas exchange: occurs between the
external environment through our
respiratory system.
Functional organization of the
respiratory system
1. Nasal cavity
• warms
• filters (ciliated mucous membranes)
• moistens air
2. Pharynx- “throat”
• area where oral and nasal cavities meet
3. Larynx- “voice box”
• beginning of the trachea,
• mostly cartilage,
• has two pairs of membranes
vocal
cords
4. Epiglottis
• flap of cartilage that covers the larynx
when you swallow
• prevents choking
5. Trachea- “windpipe”
• lined with ciliated mucous membranes
• has cartilage rings to prevent collapse
6. Bronchi- 2 branches of the trachea
• Each branch leads to a lung
• Contain cartilage and ciliated mucous
membranes
7. Bronchioles- smaller branches of bronchi in
each lung (AKA bronchial tubes)
• no cartilage
• contains mucous membranes
• each ends in an alveolus(plural- alveoli)
8. Alveoli- “air sacs”
• Microscopic, 1 cell thick
• Functional unit of resp. system where gas
exchange occurs ( O2
CO2)
• surrounded by capillaries
9. Lung- each bronchus with bronchioles and alveoli is a
lung
»elastic
10. Pleura- membrane surrounding the lung
11. Diaphragm- muscle under the lungs
• Helps to control breathing
Mechanisms for Gas Exchange
Breathing- the movement of air in and out of the
body
a) inhalation- the diaphragm contracts and moves
down
 Chest cavity expands
 Pressure in the cavity decreases
 Air rushes into the lungs
b) exhalation- diaphragm relaxes and moves up
(exhalation cont. )
• Chest cavity gets smaller
• Pressure in cavity increases
• Air is pushed out of lungs
The rate at which you breathe:
-
Mostly involuntary
At 12-25 breaths per minute
Regulated by CO2 concentration in blood
Chemo receptors in vessels send message to medulla in
brain
- High [CO2]-faster rate of breathing
- Low [CO2]- slower
- Medulla affects rate of diaphragm
Gas Exchange
Capillaries surround alveoli
O2 goes into the blood
Carried as oxyhemoglobin (HbO2)
O2 diffuses into cells
Used for aerobic respiration
Products of cellular respiration (CO2 + H2O)
diffuse into blood
* CO2 carried in plasma
once in lungs, CO2 + H2O are released during exhalation
Inside an Alveolus
OO
O222
Inhalation/Exhalation:
Alveolus is 1 cell thick
O2
CO2
O2
CO2
O2
CO2
O2
O2
CO2
O2
CO2
O2
O2
CO2
Capillary blood vessel is 1 cell thick – What is the purpose of that?
3 ways CO2 is carried in your blood
70% as a bicarbonate ion in your plasma
carbonic
CO2 + H2O
anhydrase
carbonic acid
bicarbonate ion
(H2CO3)
(HCO3)
The bicarbonate ions reduce the pH in your blood
and this is detected by the medulla.
20 % as carboxyhemoglobin (HbCO2) on RBCs
10 % floats in your plasma as CO2
High Altitudes
Hypoxia
Initially to compensate- hyperventilate and an
increase in RBC (blood like motor oil)
25% of climbers experience:
AMS- Acute Mountain Sickness
brain swelling, headaches, nausea, weakness
and shortness of breath
 3660 meters: Some people experience
HACE- High Altitude Cerebral Edema
- brain swells severely
- trouble walking; using hands
- may hallucinate
HAPE- High Altitude Pulmonary Edema
- lungs fill with fluid
Mt. Everest Climbers (Summit 8848 m)
- climb slowly
- Use bottled O2
- Be experienced (10-15 years)