Chapter 14- Respiration Flashcards
Respiration
The intake of oxygen from the environment, transport of oxygen in the blood and the ultimate oxidation of fuel molecules in the cell.
External respiration
Entrance of air into the lungs and the gas exchange between the alveoli and the blood.
Internal respiration
the exchange of gas between the blood and the cells and the intracellular processes of respiration.
Photosynthesis
Converts the energy of sun into chemical energy of bonds in compounds such as glucose
respiration involves the conversion of:
chemical energy in bonds into the usable energy needed to drive the processes of living cells.
Favored fuel moelcules
Carbohydrates and fats
How is bond energy made available?
When hydrogen is removed from carbohydrates and fats– organic molecules
C-H bond
very energy rich, capable of releasing the largest amount of energy per mole
Energy in CO2
very little. Stable, energy-exhausted end product of respiration
Dehydrogenation
An oxidation reaction
High-energy hydrogen atoms are removed from organic molecules.
Reduction component of the redox reaction:
Acceptance of hydrogen by a hydrogen acceptor (oxygen in the final step)
Energy released by reduction is used to form:
A high-energy phosphate bond in ATP
Electron transport chain
steps of reduction
Two stages of degradative oxidation of glucose
Glycolysis
Cellular respiration
Glycolysis can go into:
- Aerobic respiration
Decarboxylation of pyruvate
Krebs cycle
Electron Transport chain - Anaerobic
Fermentation
Glycolysis
Series of reactions that lead to the oxidative breakdown of glucose into two molecules of pyrubate, production of ATP and the reduction of NAD+ into NADH
all occur in cytoplasm
Steps of glycolysis
Draw out!
Net reaction of glycolysis
Glucose + 2ADP + 2Pi + 2NAD+ ——> 2Pyruvate + 2ATP + 2NADH + 2H2O
In glycolysis one molecules of glucose makes:
2 pyruvates
Two ATP are used but
4 ATPS are generated. Net ATPs= 2
Substrate level phosphorylation
ATP synthesis directly coupled with degradation of glucose without the participation of an intermediate molecule such as NAD+
How many NADH per glucose?
2
(1 per Glyceraldehyde-3-phosphate) hence 2.
In the absence of O2, what must happen for glycolysis to happen?
NAD+ must be regenerated
How is the regeneration of NAD+ accomplished?
By reducing pyruvate to either ethanol or lactic acid
What does fermentation refer to?
All of the reactions involved in production of lactic acid or alcohol
Fermentation produces X ATP per glucose molecule?
Only 2
Alcohol fermentation
Occurs only in yeast and some bacteria. The pyruvate produced in glycolysis is converted to ethanol and NAD+ is regenerated and glycolysis can continue
Lactic acid fermentation occurs in
Occurs in certain fungi and bacteria and in human muscle cells during strenuous activity.
When is pyruvate reduced to lactic acid
When the oxygen supply to muscle cells lags behind the rate of glucose catabolism. NAD+ used in step 5 of glycolysis is regenerated when pyruvate is reduced
What is the most efficient catabolic pathway used by organisms to harvest energy stored in glucose?
Cellular respiration
How many ATPS does cellular respiration yield?
36-38 ATP
Cellular respiration is anaerobic process because?
O2 acts as the final electron acceptor
Where does the metabolic reactions of eukaryotic cells take place?
in the mitochondria
Pyruvate decarboxylation
pyruvate formed during glycolysis is transported from the cytoplasm into the mitochondrial matrix where it is decarboxylated and the acetyl group that remains is transferred to coenzyme A to form acetyl CoA. In the process NAD+ is reduced to NADH.
KREBS cycle begins when
THe two carbon acetyl group from acetyl CoA combines with oxaloacetate, a four carbon molecule to form citrate (6c)
What is the end product of KREBS?
2 CO2 are released anHow many d oxaloacetate is regenerated for use in another turn of the cycle
End products of krebs (2 pyruvates!)
6 NADH
2 FADH2
2 ATP
Net reaction of krebs cycle PER glucose molecule (2 pyruvates)
2 acetyl CoA + 6 NAD+ + 2FAD + 2GDP + 2Pi + 4H2O—-> 4CO2 + 6NADH + 2FADH2+ 2GTP + 4H+ + 2CoA
Electron transport chain is:
a compex carrier mechanism located on the inside of the inner mitochondrial membrane.
What happens during oxidative phosphorylation?
ATP is produced when high-energy potential electrons are transferred from NADH and FADH2 to oxygen by series of carrier molecules.
What happens are electrons are transferred from carrier to carrier?
Free energy is released, which is used to form ATP
Cytochromes
How most of the molecules of the ETC
electron carriers that resemble hemoglobin in the structure of their active site
Cytochromes contain:
A central iron atom which is capable of undergoing a reversible redox reaction
Redox reaction of ETC:
Electrons that are transferred from one carrier to the next, each carrier is reduced as it accepts an electron and oxidized as it passes it on to the next carrier.
Final acceptor
O2
What else does O2 pick up ?
A pair of H ions from the surrounding medium, forming water
Citric acid cycle forms:
18 ATP (oxidative) 4 ATP (oxidative) 2 ATP (substrate) total =36 ATP
Carbohydrates are hydrolyzed into:
monosaccharides, most of which are converted into glucose or glycolytic intermediates
Where are how are fat molecules stored?
Stored in adipose tissue as triglycerides
How are triglycerides hydrolyzed?
By lipase to fatty acids and glycerol
True or false: glycerol can be converted to PGAL
TRUE
How is glycerol converted into PGAL?
A fatty acid is activated in cytoplasm (need 2 ATP)
Fatty acid is transported into the mitochondrion and taken through a series of beta oxidation cycles that convertit into two-carbon fragments
which are then converted into acetyl COA
which enter krebs cycle
Which each round of B-oxidation of a saturated fatty acid, what is generated?
1 NADH and 1 FADH2
Transamination reaction
Proteins lose an amino group to form an alpha-leto acid
When does the body degrade proteins?
When there is not enough carbs or fat available
The carbon atoms of most amino acids are converted into:
acetyl CoA, pyruvate, or one of the intermediates of the citric acid cycle.
Oxidative deamination
Removes ammonia molecule directily from the amino acid.
Ammonia
toxic substance in vertebrates
Respiration in Cnidaria (Protozoa and Hydra)
Every cell is in contact with the external environment (water_ and resp. gases can be exchanged between the cell and the environment by simple diffusion through the cell membrane
Respiration in annelids
Mucus secreted by cells on the external surface of the earthworm’s body provides a moist surface for gaseous exchange by diffusion. The circulatory system brings O2 to the cells and waste products such as CO2 back to skin for excretion.
Anthropod respiration (grasshopper)
consists of a series of respiratory tubules called trachae whose branches reach almost every cell
Tubes open to the surface in openings called spiracles
no carrier of oxygen is needed in this respiratory system.
Air enters human lungs through:
Most, pharynx (throat), larynx, trachea, bronchi, bronchioles, and the alveoli.
Alveoli
Where gas exchange between the lungs and circulatory system occurs across– has very thin walls.
air-filled sacs at the terminals of the airway branches
What is the primary functions of the respiratory system in humans?
Provide the necessary energy for growth, maintenance of homeostasis, defense mechanisms, repair and reproduction of cells in the body.
Also provides a large area for gas exchange as well as moves oxygenated air over this area to protect it
Inhalation
The diaphragm contracts and flattens and the external intercostal muscles contract, pushing the rib cage and chest wall up and out. Causes the thoracic cavity to increase in volume- reduces pressure and causes lungs to expand and fill with air.
What innervates the diaphragm?
The phrenic nerve
Exhalation
Passive process. Lungs and chest wall are highly elastic and tend to recoil after inhalation.
Diaphragm and external intercostal muscles relax, and the chest wall pushes inward. The consequent decrease in the thoracic cavity volume causes the air pressure to increase. Lungs deflate and air is forced out the alveoli.
Ventilation is regulated by
Neurons in the medulla.
Rhythmic discharges of neurons stimulates:
The intercostal muscles or the diaphragm to contract.
What happens when the partial pressure of CO2 rises?
The medulla stimulates an increase in the rate of ventilation
What is the primary goal of ventilation?
To maintain proper concentrations of oxygen, carbon dioxide, and hydrogen ions in tissues
What are primary stimulus for respiration?
Excessive co2 and hydrogen ions
Do oxygen blood levels have a significant effect on the respiratory center?
NO
What are oxygen blood levels monitored by?
The peripheral chemoreceptors, which indirectly stimulate respiratory center
Pulmonary capillaries
A dense network of minute blood vessels that surrounds the alveoli.
Gas exchange occurs by diffusion across these capillary walls and those of the alveoli
Gas moves from region of:
higher partial pressure to regions of lower partial pressure
Oxygen diffuses from the alveolar air into the :
blood
Carbon dioxide diffuses from the blood into the:
lungs to be exhaled
Photosynthesis only occurs during:
the day
Photosynthesis produce ____ and gives of _____
glucose, oxygen
Respiration requires ______ to degrade _____
oxygen. glucose
Where to the gases diffuse into air space in plants through?
The stomatas of the leaf or the lenticels (openings) of woody stems.
What kind of plants use anaerobic respiration?
takes place in simple plants when molecular oxygen is lacking in a manner similar to that of animals.
