EXAM 3 Flashcards
How do we use cellular respiration in everyday life?
eating, digesting, absorbing nutrient molecules into our bloodstream, and delivering nutrient molecules to the cells
Through cellular respiration, our cells begin to extract some energy. What is important about this?
Our cells need ATP to maintain life, our metabolism is all chemical, a big focus is on breaking down glucose which is the main energy source during activity, and fatty acids and lipids are used during rest
What is gas exchange in cellular respiration?
Diffusion of CO2 and O2 across a cellular membrane barrier; diffusion of CO2 and O2 from air or water to body
What is circulation within cell respiration?
The bulk movement of a fluid throughout an animal body; it transports gas to/from body cells
What is cellular respiration?
Using O2 and producing CO2 to make ATP
What is ventilation in cellular respiration?
The bulk movement of an environmental fluid to the gas exchange surfaces of an animal; moving air or water to gas exchange organ
What is whole body respiration?
The rate of oxygen use and production of CO2 made by a whole animal
What are the stages of cellular respiration in order?
Glycolysis, pyruvate processing, citric acid cycle, electron transport and chemiosmosis
In ATP production, what is substrate level phosphorylation?
The transferring of a phosphate from a fuel source to ATP and it takes place in a glucose oxidation pathway
In ATP production, what is oxidative phosphorylation?
Energy is harnessed through the inner mitochondrial membrane to create ATP from protein complexes called ATP synthase and the electron transport chain
NADH transfers electrons in REDOX reactions
This is the reverse of photosynthesis; glucose is oxidized into CO2 and O2 is reduced into H20; cell respiration liberates the energy that glucose stores in its covalent bonds which will equal the amount of energy photosynthesis needs to make glucose and the cell will use this energy to make ATP; complete respiration of 1 molecule of glucose can provide enough energy to make 38 ATP
Redox: Oxidation
loss of electrons
Redox: Reduction
gaining of electrons
Within cell respiration…
Glucose is being oxidized
Glycolysis
The initial breakdown of glucose, the first set of reactions to occur within cell respiration, this is a series of 10 reactions, creates byproducts pyruvate (a 3 carbon sugar), ATP, NADH (energy carrying molecule that is similar to NADPH, Nicotinamide Adenine Diphosphate), occurs within the cytosol of the cell, does not require oxygen (anaerobic)
Steps of Glycolysis
- Glucose is phosphorylated by ATP to make Glucose 6-PO4 and ADP
- Glucose 6-PO4 is rearranged into an isomer Fructose 6-PO4
- Fructose 6-PO4 is then phosphorylated by ATP to make Fructose 1, 6 Biphosphate
4.Fructose 1,6 Diphosphate then breaks down into two molecules of G3P - Each G3P is then oxidized by NAD+ to make PGA-P and NADH
- Each PGA-P is converted into PGA by losing a PO4 to ADP and making an ATP
- Each PGA is converted into PEP (phosphoenolpyruvate)
- Each PEP donates a phosphate to ADP to make pyruvate and ATP
Summary of Glycolysis
Glucose is broken down into two pyruvates and a total of 4 ATP are made but two are used up meaning there is a net of 2 ATP, NADH (2) is produced and can be used up later in processes, its only about 2% efficient because it only produces 2 ATP from the partial breakdown of glucose
The fate of the pyruvate if oxygen is present
Pyruvate enters the mitochondrion to be broken down by aerobic respiration
The fate of pyruvate if oxygen is not present
Pyruvate remains in the cytosol and is fermented in anaerobic respiration
Aerobic respiration
requires oxygen and can produce very large amounts of ATP
Anaerobic respiration
without oxygen meaning its oxygen dependent, this produces only very small amounts of ATP, some bacteria may survive exclusively on anaerobic respiration
Pyruvate processing
Each pyruvate is processed to release one molecule of CO2 and the remaining two carbons are used to combine and form Acetyl-CoA, occurs in the mitchondrial matrix in eukaryotes, requires oxygen to occur
Steps of Pyruvate Processing
In the presence of O2 in the cytosol, pyruvate will be pumped into the mitochondria (each pyruvate has a potential to produce about 15 ATP), pyruvate is then oxidized by NAD+ and is decarboxylates (loses CO2) to become Acetyl, it then combines with an enzyme called Coenzyme A to become Acetyl-CoA
Products of Pyruvate Processing
Acetyl-CoA, CO2 (waste product), NADH per pyruvate
Fermentation
Occurs only if O2 is not present (anaerobic), pyruvate remains in the cytosol
Fermentation: Lactic Acid Fermentation
occurs in animals, pyruvate is reduced by NADH to form lactate, lactic acid can build up and burn the tissues that creates sores in the muscles (must be removed from the tissues by the bloodstream)
Fermentation: Alcohol Fermentation
occurs in plants and fungi, pyruvate is reduced by NADH and is decarboxylated to form ethanol, this is used in many commercial products, the outcome is 2 ATP and NAD+
Where does the Krebs cycle occur
In the Matrix (the cellular fluid inside the mitochondria)
What are the steps of the Krebs cycle
- Acetyl-CoA combines with a 4-carbon oxaloacetate, to produce a 6-carbon citrate
- Citrate is oxidized by NAD+ and is decarboxylated to become a 5 carbon Ketoglutarate
- Ketoglutarate is oxidized by NAD+ and is dephosphorylated by ADP and is decarboxylated to become Succinate
- Succinate is oxidized by FAD+ to become Fumarate (4-carbon)
- Fumarate is converted to Malate
- Malate is oxidized by NAD+ to become Oxaloacetate
What is the goal of oxidative phosphorylation
Use the NADH (and FADH2) from glucose oxidation to make ATP
Oxidative Phosphorylation: Electron Transport Chain
creates a H+ gradient by pumping H+ to one side of the inner membrane
Oxidative Phosphorylation: Chemiosmosis Coupling
Harness the movement of H+ ions back across the membrane to produce ATP
Electron Transport Chain
a series of membrane proteins within the Crista that transfer electrons; each NADH and FADH is oxidized (the electrons travel through the ETC, H+ ions build up on the inner space (lumen) of the Crista, the pH becomes more acidic), chemiosmosis occurs as H+ move through an H+ channel in an ATP synthase molecule also embedded within the Crista, this generates power and is used to make ATP, each NADH supplies enough energy to make 3 ATP, and each FADH supplies enough energy to make 2 ATP
Where do the electrons in the electron transport chain come from
NADH and FADH; energy is transferred with the electrons
What are the steps of the electron transport chain
- At each step, the electrons fall to a lower energy state, releasing a little bit of energy
- At the end of the chain, the lower-energy electrons are handed off to O2 which then combines with free H+ ions to form water
- The energy is then used to power proton pumps, which pack hydrogen ions from the mitochondrial matrix into the inter membrane space
- The protons rush back into the mitochondrial matrix with great kinetic energy which can be used to build ATP
Anaerobic Bacterial Respiration
Fermentation
Aerobic Bacterial Respiration
Similar to mitochondria but uses the cell membrane, pump H+ to the outside of the cell, some bacteria (gram neg) have an inner and outer membrane, pump H+ to inner membrane space
Eukaryotes
mitochondria
Prokaryotes
Pump H+ out of the cell
Both eukaryotes and prokaryotes
Glycolysis, Electron Transport Chain, double membrane, protein gradient
Dalton’s law
the pressure exerted by a mixture of gases in a fixed volume is equal to the sum of the pressures that would be exerted by each gas alone in the same volume
1. Total pressure of gas mixture = sum of all components
2. Partial pressure = pressure contribution of one gas, percentage of total
Partial Pressure
Measure of thermodynamic activity of the gas’s molecules
1. Pressure measured in mmHg, kPa, atm
Standard Pressure = 760 mmHg, 101kPa
2. Oxygen is 21% , CO2 is 0.03%, and Nitrogen is 78% of the atmosphere
3. The standard pressure of oxygen is 20 kPa
Fick’s 2nd Law of Diffusion
Square distance from gas exchange affects the diffusion time
time it takes for diffusion = distance squared/ 2x diffusion coefficient
Diffusion
Small or inactive animals can rely on diffusion alone, it is effective for animals that are small (<1mm), higher concentration to lower concentration, random movement of particles within a fluid, effective for fast transport of molecules for distance of <1 mm
Bulk Flow and Diffusion
Relied on by larger/more active animals, bulk flow to gas exchange surfaces, diffusion at gas exchange surfaces, bulk flow to cells (not likely to lose any content), diffusion into cells (relies on the difference in pressure), higher hydrostatic pressure to lower hydrostatic pressure, directed movement of a mixture fluids carrying dissolved particles, effective for fast, long distance transport
More bulk flow leads to
small diameter vessel, longer pathway, greater pressure gradient
Less bulk flow leads to
Larger diameter vessel, shorter pathway, smaller pressure gradient
What are the variables in gas exchange
Respiratory medium (air or water), epithelium, blood
What does epithelium mean and how does it relate to gas exchange
it is a layer between the air and the blood, the thinner the better, on cold days breathing in the cold air for a long time can damage the epithelium
What is the gas exchange surface
A very large surface area is needed (if you spread out the tissue, it would be about the size of a tennis court), thing walls are also needed (diffusion distance plays a role which allows gas exchange)
Aquatic
Thing gill structures
Terrestrial
Respiratory structures inside the body, ventilation needed, respiratory surfaces are internal so they are less likely to become damaged
Requirements to Breathe
large surface area, thin walls between respiration medium and blood, ventilation where the movement of RM to surface for gas exchange, nearby blood that can pick up the oxygen from the lungs and drop off CO2
What can make it hard to breathe
Emphysema (the walls between alveoli break down which makes the interior surface of the lungs more smooth, less surface area), pneumonia (fluid accumulating in the lungs, increasing the distance between the RM and the lung capillaries for diffusion), chest wound (equalizes pressure gradient between lung and atmosphere where there should be a gradient), pulmonary embolism (a blood clot blocks an artery which takes blood into the lungs)
What are the differences in respiration
Respiratory medium, ventilation method, respiratory surface, countercurrent/crosscurrent flow
Respiratory medium
Water vs. Air; water contains less partial pressure of O2 than air; there is O2 in water but it varies depending on what type of water it is in
Ventilation method
When air is intentionally provided to a space and stale air is removed, how the respiratory medium gets to the respiratory surface
Respiratory surface
part of the animal where gas is exchanged with the environment; gills, lungs, etc.
Insect Respiration
since insects don’t breathe through their mouths they have holes in the surface of their body in their exoskeleton, this works well for insects because they don’t have to bring oxygen in very far, they are cold blooded and need less oxygen because it does less cell respiration,
Tracheoles
smaller sections of tubules that are specific to parts of the insects body; these are connected to the tracheae
Air sacs
these are contained within the lungs of insects that aid by lowering the specific gravity
Spiracles
the holes within the exoskeleton that allows air into the body; these can be opened or closed (if its cold outside, they will close to prevent water loss; if they are active, they can open them to help with ventilation)
Tracheae
the passageways that are connected to the spiracles that allow air to move through the body; this is not connected to the throat of the insects; they are not ventilated; site of gas exchange
Fish Gills
Pass water over gills to exchange gas
Lamelle in fish gills
a thin structure that contains blood vessels
Sharks: Ram Ventilation
Open mouth, allow water to flow over gills, must be moving forward
Bony Fish: Operculum
Bony covering over the gills, allows fish to increase pressure inside their mouth then open operculum (little holes) so water will be pushed across the gills
Countercurrent exchange
Diffusion of O2 from water into the blood, blood is going to be gaining O2 as it moves to the head of the fish and water is going to be losing O2 as it moves toward the tail of the fish
Concurrent Flow
Less efficient because hey are moving in the same direction, there will be no more exchange at 50%
Breathing water
Lower risk of dehydration across thin respiratory surface, higher buoyancy of tissue requires less support of exchange surfaces
Breathing air
Higher solubility of oxygen (by 1000x), lower density so its easier to pump across exchange surface, faster diffusion of gasses, osmotic differences can increase loss of water
Swim Bladder
Some fish may breathe air on occasion as a floatation device that helps them stay neutrally buoyant, gulp air from the surface, and occasionally use the blood vessels on the surface to take O2 from the blood
lungfish/early tetrapods use swim bladder for gas exchange
Amphibians: Positive Pressure Ventilation
Gulp air in by positive pressure that increases the pressure within their mouths and then uses muscles to push the air into their lungs
Reptiles: Adaptations for Dryness
No gas exchange through their skin because it is so thick it prevents water loss, their lungs are more intricate and they have larger surface area, their ribs expand (increase volume=decrease pressure) then air will flow to a space of high to low pressure and goes into the lungs from the air, negative pressure so air is sucked in
Inhaling
Diaphragm contracts and increases in volume, the rib muscles are relaxing creating more space by expanding, the pressure inside the lungs decreases
Exhaling
the diaphragm relaxes, rib muscles contact, the pressure inside the lungs increases
Alveoli
Air sacs are the location of gas exchange (O2 into the blood and CO2 into the air) and covered in surfactant which is a liquid that helps break things apart within the lungs, increased surface area of the lungs
Dead space in tidal breathing
Volume in passageways between outside air and alveoli
ex: if tidal volume = 500 mL and dead space = 150 mL how much air actually gets to the alveoli? (500-150=350)
Bird Respiration
No gas exchange occurs here, air sac bellows form pumping air across lungs, lungs, air is pushed across the lungs and picks up O2 containing lots of blood vessels in crosscurrent arrangement, one-way breathing with a countercurrent exchange system
Bird Ventilation: Inspiration & Expiration
Inspiration 1: air is pulled into rear air sacs as the chest expands
Expiration 1: Air pushed out of rear air sacs and over lungs
Inspiration 2: Air pulled from the lungs and into the front air sacs
Expiration 2: Air pushed out of front air sacs and out of the body
The main structures of the blood
Plasma (serum), red blood cells (erythrocytes), white blood cells (leukocytes and platelets)
Plasma (serum)
main structure of blood; a yellowish serum that consists of water (the main component), proteins (involved in the osmotic balance), solutes (nutrients like glucose and salts that need transported)
Red Blood Cells (RBC, erythrocytes)
main structure of blood; the most dense; consist of hemoglobin, carbonic anhydrase; they lack a nucleus so the red bone marrow in the body continues to produce these; they lack a mitochondria so they cannot produce proteins
if you are dehydrated you might have more RBCs because there is less plasma
Hemoglobin in RBC
In RBCs; iron containing respiratory pigment of vertebra RBC’s and consists of globin