Chapter 7.1 cellular respiration

Question 1

What is cellular respiration?

Answer 1

• The breakdown of carbohydrates, lipids, and proteins
• release of energy to do work of the cell
• converting chemical potential energy from organic molecules -> chemical potential energy ATP
• a set of catabolic reaction

Question 2

what is the difference between aerobic and anaerobic?

Answer 2

Aerobic- in the presence of oxygen- makes lots of ATP

Anaerobic- in the absence of oxygen

Question 3

What are the cellular respiration stages?

Answer 3

1. Glycolysis (cytoplasm)
2. Pyruvate oxidation (mitochondria)
3. citric acid cycle (mitochondria)
4. oxidative phosphorylation( mitochondria)

Question 4

Where do cellular restoration stages occur in prokaryotes if oxygen is present?

Answer 4

• Pyruvate oxidation and the citric acid cycle occur in the cytoplasm.
• oxidative phosphorylation occurs across the plasma membrane

Question 5

what molecules do and don’t have a lot of potential energy in their chemical bonds?

Answer 5

do- carbohydrates and lipids

don’t- carbon dioxide and water

Question 6

why does cellular respiration release a lot of energy?

Answer 6

the sum of potential energy in all the chemical bonds of reactants is higher then those of the reactants

Question 7

how is energy in cellular respiration released?

Answer 7

gradually in a series of chemical reactions

Question 8

how many molecules are produced from the aerobic respiration of a single molecule of glucose?

Answer 8

32 ATP molecules

Question 9

how much energy is needed to form one ATP molecule from ADP AND Pi?

Answer 9

at least 7.3 kcal

Question 10

how much energy is harnessed from a single glucose molecule during cellular respiration?

Answer 10

32 x 7.3= 233.6 kcal of energy for every mole of glucose broken down in the presence of oxygen

Question 11

how much total energy released by aerobic respiration is harnessed in the form of ATP?

Answer 11

34% (233.6/686) remanding 66% is given off as heat

Question 12

what are the two ways are ATP produced from glucose

Answer 12

substrate level phosphorylation or electron carriers (oxidative phosphorylation)

Question 13

what is substrate level phosphorylation and how does it work?

Answer 13

• two coupled phosphorylated organic molecule transfers a phosphate group to ADP to produce ATP (two reactions by one enzyme: hydrolysis of phosphorylated molecule and addition of phosphate group to ADP) hydrolysis reaction releases enough energy for synthesis of ATP. Only small amount of ATP is generated this way (12%)
• Occurs in stage 1 (glycolysis) and 3 (critic acid cycle) cellular respiration.

Question 14

what are electron carriers and how do they work?

Answer 14

carry electrons and energy from one set of reactions to another. during cellular respiration transport electrons released during catabolism of organic molecules to the electron transport chain, the transferred along series of membrane associated proteins to a final electron acceptor and harnesses energy to produce ATP. oxygen is the final acceptor resulting in the formation of H20 (oxidative phosphorylation) (88% of ATP this way)

Question 15

how are electron transport chains used?

Answer 15

in respiration to harness energy from fuel molecules such as glucose and photosynthesis.

Question 16

What are the 4 stages of cellular respiration?

Answer 16

1 glycolysis, 2 pyruvate oxidation- fuel molecules are partially broken down, producing ATP and electron carriers from original glucose
3 citric acid cycle- fuel molecules are fully broken down, producing ATP and electron carriers
4 oxidative phosphorylation- electron carriers donate electrons to the electron transport chain, leading to the synthesis of ATP

Question 17

what is a oxidation reduction reaction?

Answer 17

a chemical reaction in which electrons are transferred from one atom or molecule to another
(oxidation- loss of electrons)
(reduction- gain of electrons)

Question 18

what are the two forms of electron carriers?

Answer 18

(NAD+ AND FAD)- oxidized

(NADH AND FADH2) -reduced

Question 19

what are the chemical formulas for the two types of reduction reactions

Answer 19

NAD+ + 2e- + H+ -> NADH
FAD + 2e- + 2H+ -> FADH2

NAD+ and FAD accept electrons

Question 20

how can reduced or oxidized molecules be identified?

Answer 20

through the increase in C-H bonds - reduced

through the decrease in C-H bonds- oxidized

Question 21

What are the chemical formulas for the two types of oxidized reactions?

Answer 21

NADH-> NAD+ + 2e- + H+
FADH2-> FAD + 2e- +2H+

produce NAD+ and FAD which can accept electrons from the breakdown of fuel molecules

Question 22

What do the reduced and oxidized forms of NADH and FADH2 do?

Answer 22

reduced- can donate electrons

oxidized- allows electrons and energy to be transferred to the electron transport chain

Question 23

what happens to the electrons during an oxidation reaction for glucose and carbon dioxide?

Answer 23

glucose: c-c and c-h bonds share electrons equally
carbon dioxide: carbon atom has partially lost electrons (oxidation) and oxygen atom is more electronegative so electrons will be found closer to O

Question 24

what happens to the electrons during a reduction reaction for oxygen and water?

Answer 24

oxygen: electrons are scarred equally
water: oxygen atom has partially gained electrons (reduced) and oxygen is more electronegative so electrons will be found closer to O

Question 25

why is glucose a good electron donor and oxygen is a good electron acceptor?

Answer 25

glucose: its oxidation to carbon dioxide releases a lot of energy
oxygen: it has a high affinity for electrons

Question 26

in depth what occurs during the 4 stages of cellular respiration

Answer 26

stage 1: glucose is partially broken down to make pyruvate and energy is transferred to ATP and reduced electron carriers (glycolysis)
stage 2: pyruvate is oxidized to another molecule called acetyl-CoA , producing reduced electron carriers and releasing carbon dioxide.
stage 3: Acetyl-CoA enters the citric acid cycle in a series of chemical reactions. the acetyl group is is oxidized to carbon dioxide and energy is transferred into ATP and reduced electron carriers
stage 4: oxidative phosphorylation, a series of reactions. electron carriers generated in stages 1-3 donate electrons to the electron transport chain and a large amount of ATP is produced.

Question 27

where do the 4 cellular reparation steps occur in eukaryotes?

Answer 27

glycolysis- cytoplasm
pyruvate oxidation- mitochondria
citric acid cycle- mitochondria
oxidative phosphorylation- mitochondria