2 Respiration Flashcards
define respiration
breakdown of larger molecules to simpler molecules like CO2 and H2O; liberates energy
pros and cons to respiration
pros:
- source of energy
- source of intermediate products
- maintenance of tissue vigor
cons:
- loss of food value
- hastening of senescence
- loss of sell-able weight
- quality loss
respiration should be kept at a _____ level to keep the rate of metabolic activities low
minimal
what are the 2 types of respiration and which one is desirable?
aerobic and anaerobic. aerobic is desirable.
how much heat does respiration release in kcal?
673 kcal
in what units can respiration rate be exrpessed?
Gas:
- mg or mL of O2 consumed/kg/h
- mg or mL of CO2 consumed/kg/h
Heat:
- kcal or kJ/ton/day
true or false: glycolysis requires oxygen
false
how many ATPs does glycolysis produce?
8
name substrates for respiration
- glucose/organic acids precursors: - polysaccharides - fats and oils - proteins
how many ATPs does the TCA cycle yield?
38
how many ATPs does the pentose phosphate pathway yield?
30
describe the pentose phosphate pathway
- glucose comes in, a pentose leaves
- pentoses can be used for nucleotide synthesis
- one carbon released through each cycle
what is the first step of anaerobic respiration?
glycolysis
what are the possible products of anaerobic respiration?
- acetaldehyde + CO2
- ethyl alcohol
- lactic acid
what’s needed for the production acetaldehyde + CO2?
pyruvate, decarboxylase
what’s needed for the production of ethyl alcohol?
acetaldehyde and alcohol dehydrogenase
whats needed for the production of lactic acid?
pyruvate and lactic decarboxylase
what environmental factors influence produce respiration?
- temp
- O2
- CO2
- ethylene
- growth regulators
- other stresses
what produce related factors influence respiration?
- commodity
- variety
- maturity
- nature of substrates
- climacteric behavior
as a general trend, (larger/smaller) organisms tend to live longer because they breathe (more/less)
larger
what do we use to determine a produce’s temperature sensitivity
Q10
what makes a fruit/veggie exhibit climacteric respiration?
ripening with ethylene.
what do we use to identify the nature of the respiring substrate?
Respiratory Quotient (RQ)
On a a respiration rate vs oxygen concentration graph, what is the bottom of the dip of the curve called?
Extinction point (EP)
what is the EP?
minimum oxygen level needed to maintain aerobic respiration in storage
name some growth regulators and what they do
- Alar: delays/accelarates
ripening; improves color - GA: higher yield/greater disease resistance
- NAA: prevention of abscission, fruit thinning
- MH: sprouting inhibition
what are considered “other” stresses?
- chilling injury
- freezing injury
- physical and mechanical damages
measures to take to control respiratory activity:
- harvest at cool times and when plants are properly mature
- cool and store as fast as possible
- maintain lowest permissible temperature
- maintain the cold storage properly
- regulate O2 and CO2 levels, ethylene
- waxing/coating
- gentle handling
give examples of instruments you can use to measure respiration rate (3)
- O2 or CO2 sensor (electronic sensor)
- Manometer (pressure sensor)
- Chemical measurement with regulated air flow and NaOH
