2 Respiration

Question 1

define respiration

Answer 1

breakdown of larger molecules to simpler molecules like CO2 and H2O; liberates energy

Question 2

pros and cons to respiration

Answer 2

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

Question 3

respiration should be kept at a _____ level to keep the rate of metabolic activities low

Answer 3

minimal

Question 4

what are the 2 types of respiration and which one is desirable?

Answer 4

aerobic and anaerobic. aerobic is desirable.

Question 5

how much heat does respiration release in kcal?

Answer 5

673 kcal

Question 6

in what units can respiration rate be exrpessed?

Answer 6

Gas:

• mg or mL of O2 consumed/kg/h
• mg or mL of CO2 consumed/kg/h

Heat:
- kcal or kJ/ton/day

Question 7

true or false: glycolysis requires oxygen

Answer 7

false

Question 8

how many ATPs does glycolysis produce?

Answer 8

8

Question 9

name substrates for respiration

Answer 9

- glucose/organic acids
precursors:
- polysaccharides
- fats and oils
- proteins

Question 10

how many ATPs does the TCA cycle yield?

Answer 10

38

Question 11

how many ATPs does the pentose phosphate pathway yield?

Answer 11

30

Question 12

describe the pentose phosphate pathway

Answer 12

• glucose comes in, a pentose leaves
• pentoses can be used for nucleotide synthesis
• one carbon released through each cycle

Question 13

what is the first step of anaerobic respiration?

Answer 13

glycolysis

Question 14

what are the possible products of anaerobic respiration?

Answer 14

• acetaldehyde + CO2
• ethyl alcohol
• lactic acid

Question 15

what’s needed for the production acetaldehyde + CO2?

Answer 15

pyruvate, decarboxylase

Question 16

what’s needed for the production of ethyl alcohol?

Answer 16

acetaldehyde and alcohol dehydrogenase

Question 17

whats needed for the production of lactic acid?

Answer 17

pyruvate and lactic decarboxylase

Question 18

what environmental factors influence produce respiration?

Answer 18

• temp
• O2
• CO2
• ethylene
• growth regulators
• other stresses

Question 19

what produce related factors influence respiration?

Answer 19

• commodity
• variety
• maturity
• nature of substrates
• climacteric behavior

Question 20

as a general trend, (larger/smaller) organisms tend to live longer because they breathe (more/less)

Answer 20

larger

Question 21

what do we use to determine a produce’s temperature sensitivity

Answer 21

Q10

Question 22

what makes a fruit/veggie exhibit climacteric respiration?

Answer 22

ripening with ethylene.

Question 23

what do we use to identify the nature of the respiring substrate?

Answer 23

Respiratory Quotient (RQ)

Question 24

On a a respiration rate vs oxygen concentration graph, what is the bottom of the dip of the curve called?

Answer 24

Extinction point (EP)

Question 25

what is the EP?

Answer 25

minimum oxygen level needed to maintain aerobic respiration in storage

Question 26

name some growth regulators and what they do

Answer 26

• Alar: delays/accelarates
  ripening; improves color
• GA: higher yield/greater disease resistance
• NAA: prevention of abscission, fruit thinning
• MH: sprouting inhibition

Question 27

what are considered “other” stresses?

Answer 27

• chilling injury
• freezing injury
• physical and mechanical damages

Question 28

measures to take to control respiratory activity:

Answer 28

• 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

Question 29

give examples of instruments you can use to measure respiration rate (3)

Answer 29

• O2 or CO2 sensor (electronic sensor)
• Manometer (pressure sensor)
• Chemical measurement with regulated air flow and NaOH