Chapter 8 Flashcards
What is the energy currency of animals?
Large amounts of ATP are quickly needed for survival. What are two examples?
Adenosine triphosphate (ATP)
- Crayfish startle response
- Sprint
What are the 2 exercise types and their meaning?
Burst exercise: Very quick, intense exercise that depletes ATP very quickly
Sustained exercise: Steady, sustained exercise in which ATP is replenished for long periods
Each cell must make its own_____?
ATP is not stored. Why?
ATP
Too reactive; could cause reactions to happen that you don’t want.
the ____ at which a cell can work is ____ on the rate at which it can make ATP
ADP + Pi + energy from food —–> ATP
ATP ——> ADP + Pi + ___?
- rate
- dependent
- energy usable by the cell
What are the two major pathways of ATP production?
aerobic and anaerobic
Aerobic metabolism
Every cell has this pathway which uses ___ and ___ energy to produce ____ , _____ , and _____
What are the 4 sets of reactions?
O2 and food energy
H2O, CO2, and ATP
- Glycolysis
- Krebs cycle (citric acid)
- Electron-transport chain
- Oxidative phosphorylation
What are the 6 characteristics of glycolysis?
- Occurs in the cytosol
- Anaerobic (not really because it stops without 02)
- Uses 2 ATP
- Creates 2 ATP (net) and 2 NADH2
- Very inefficient
- 2 pyruvic adics from 1 glucose
What are the 5 characteristics of kreb cycle?
- Occurs in mitochondria
- 2 turns of the wheel for every glucose
- Creates 2 ATP, 8 NADH2 and 2 FADH2.
- 6CO2 is waste
- Neither glycolysis nor the Krebs cycle require O2
- However, without O2, the cells run out of NAD and FAD. This stops the reactions
Electron Transport Chain
Occurs across the _____
Requires ___ major protein complexes
The chain takes ___ from NADH2 and FADH2 and passes them along
Cytochrome oxidase passes the electrons (& H+) to O2, reducing it to H2O
Oxygen is the ____?
Without O2, the cell can’t get rid of the electrons
- inner mitochondrial membrane
- 4
- electrons
- final electron acceptor
Oxidative Phosphorylation
Occurs in _____?
Uses energy from the ____ to make ATP
Which protein omplexes make ATP?
NADH2 can make ____ ATPs, FADH2 makes ___
This makes a total of ___?
____ made 4, so we have a total of 38 ATPs
ATP synthase?
Uncoupling protein or UCP1
- mitochondria
- electron transport chain
- 1, 3, and 4
- 3
- 2
- 34 ATPs
- Substrate level phosphorylation
- Uses the hydrogen gradient to changed ADP to ATP
- Allows hydrogen to go down gradient but just makes heat. brown adiose tissue uses.
4 characteristics of O2 deficiency
- Electron transport stops
* Cytochromes become reduced - Oxidative phosphorylation stops
* The animal loses the ability to generate 34 ATPs! - The cell runs out of NAD and FAD
* Since NAD is required for glycolysis, it stops too. - Produces redox imbalance!
Anaerobic Metabolism
___ can use glycolysis to produce ATP in the absence of O2
How is NAD replenished?
- NADH2 gives up its electrons to ___
- This produces___
- This reaction is carried out by____?
- Lactic acid may be metabolized through the ___ or ___
Vertebrate skeletal muscle
pyruvic acid
lactic acid
lactate dehydrogenase (LDH)
Krebs cycle or gluconeogenesis
What 4 things need to happen for it to be steady-state ATP production?
- ATP produced as fast as it’s used
- Raw materials used no faster than replenished
- Chemical by-products removed as fast as produced
- Changes do not disrupt cell function
Non-Steady-State ATP Production
Aerobic mechanisms not sufficient for satisfying ATP demand so the body has to use other things. What are they?
Continued work will be physiologically impossible. Why?
1.
- Anaerobic glycolysis
- Internal O2 stores may be used (myoglobin)
- Phosphagens may be used
- Increased lactic acid and acidification of tissues
What are the 2 phosphogens?
Compounds with a higher free energy than ATP
Creatine phosphate
Arginine phosphate - only in invertebrate but they can use both.
pros and cons
Fatigue
Multiple causes of fatigue
- Lactic acid accumulation can cause paralysis
- Acidification was thought to be a cause
- Hyperthermia
- Sustained exercise (best studied)
- May be lack of glycogen (in muscles)
- Lack of glucose resupply
- Hyperthermia may be a factor
- Cellular-molecular mechanisms now thought to be most important explanations
- Accumulation of Ca2+ in the wrong place is another explanation
Muscle Fiber Types
- Tonic fibers
- Slow-twitch (Type I) fibers
- Fast-twitch/oxidative (Type IIa) fibers
- Fast-twitch/glycolytic (Type IIb) fibers
- contract very slowly and do not product twitches; found in postural muscles of lower vertebrates and mammalian muscle spindles (interfusal fibers)
- contract and fatigue slowly (red meat)
- contract quickly and fatigue relatively slowly (not as slowly as Type I fibers)
- contract and fatigue rapidly (white meat)
Exercise: Transitions
It takes a bit of time for aerobic mechanisms to meet the demand for ATP
Oxygen ___does not ____as fast as exercise
____mechanisms and _____must be used!
What did this leads to _____ and what did it used to be called?
- delivery
- increase
- Anaerobic
- phosphagens
- oxygen debt
- Exercise-postexercise oxygen consumption (EPOC)
Transitions vary depending on the extent of exercise
How ATP is made troughout the duration of exercise.
Response to Impaired O2 Intake
Hypoxia?
Anoxia?
Why would an animal experience these?
What is metabolic depression?
- Low oxygen levels available
- No oxygen levels available
- high elevation and diving
- A reduction in an animals (or tissues) ATP requirements below those normally needed for rest
Response to Impaired O2 Intake
During anoxia animals must use ____
- Vertebrates produce ____, which they don’t ____
- Most invertebrates ____ produce lactic acid
- They use different pathways, producing several by-products that are often excreted (ethanol)
Anaerobic pathways are very disadvantageous. Why?
_______ aids animals since it reduces the demand for ATP
anaerobic pathways
lactic acid
excrete
don’t
Don’t make alot of ATP and causes buildup of byproducts.
Metabolic depression
Hypoxia
- Animals may show ____ or ____of ATP synthesis (O2 consumption)
- Span of regulation has evolved for the environment in which the animals live
conformity or regulation
The Challenge of Diving
- The brains of most vertebrates require ___ paths
- The dive time of most mammals and birds is limited by ___?
- If the dive time is extreme, they must use ___
- Oxygen is delivered to brain; other organs use anaerobic metabolism
- Crocodiles, sea turtles, lizards, most freshwater/terrestrial turtles
- If the dive time is extreme, they must use ___
aerobic
O2 stores
anaerobic strategies
The Challenge of Diving
- Some freshwater and terrestrial turtles can survive complete anoxia of their entire body for extended periods
- _____ of the brain is key
- Turtles become ____
- Huge amounts of lactic acid present
- ____and ____serve asbuffers
- _____ of the brain is key
- Metabolic depression
- comatose
- Shell and bones
Water-Breathing Anaerobes
- O2-free aquatic environments are more common than those in terrestrial environments
- Some animals can survive as anaerobes
- Some examples?
- Ribbed mussels can be buried in __and survive for __ days in a __ environment
- Some ___ can survive and reproduce in O2-free environments for __ months
- Rare in aquatic vertebrates
- ___can survive without oxygen for up to __ days at ___C
- clams, mussels, bivalve molluscs
- mud
- 5
- N2
- annelids
- 7
- Goldfish
- 6
- 10
Invertebrate Anaerobiosis
- Most common products?
- Reactions in addition to Kreb’s cycle
- Some produce ATP
- Although there is an energy cost, most excrete end products to reduce ___ and prevent self-limitation due to redox imbalance
- 2 Advantages over animal anaerobic glycolysis?
- Acetic acid, succinic acid, propionic acid, alanine
- acidification
- Pathways may also use amino acids
- Pathways can send carbon chains to be used for biosynthesis
Vertebrate Anaerobiosis
- Goldfish and crucian carp can survive for long periods without oxygen while remaining conscious
- Swimming muscles contain alcohol dehydrogenase
- Produces ethanol
- Allows excretion of carbon chains through the gills
- Produces ethanol
- These fish exhibit much less metabolic depression
- Crucian carp can also store glycoge in then brain
