Chapter 6

Question 1

Cellular respiration definition

Answer 1

A process that releases energy (ATP) from glucose in a series of small steps
- if all the energy were released at once, much of it would be lost as heat and also destroy cells like a bomb

Question 2

Aerobic cellular respiration

Answer 2

-respiration that requires oxygen
-is used by all plants and animals, as well as many microbes
-the energy from glucose is extracted, that energy is put into ATP so cells can use it
-all 3 domains and all eukaryotic kingdoms use it

Question 3

Aerobic cellular respiration equation

Answer 3

Glucose and oxygen into carbon dioxide, water and ATP
C6H12O6 + 6O2&raquo_space; 6CO2 + 6H2O + ATP

Question 4

Krebs cycle

Answer 4

Stage in cellular respiration that completely oxidized the products of glycolysis (oxidize pyruvate)

Question 5

FADH2

Answer 5

Flavin Adenine Dinucleotide- coenzyme that carries electrons in respiration

Question 6

Electron transport chain

Answer 6

Membrane bound molecular complex that shuttles electrons to slowly extract their energy

Question 7

ATP Synthase

Answer 7

Enzyme complex that emits protons through a membrane, triggering the phosphorylation of ADP to ATP

Question 8

3 stages of cellular respiration

Answer 8

1.) glycolysis
transition step
2.) Krebs cycle
3.) electron transport chain

Question 9

Glycolysis

Answer 9

Directly means “splitting of glucose”
-during glycolysis, 1 molecule of glucose is split into two 3-carbon molecules of pyruvate
-these reactions release 2 molecules of ATP
-inside the cytoplasm (outside the mitochondria)

Question 10

Transition step

Answer 10

Comes after glycolysis
-2 molecules of pyruvate are oxidized into 2 molecules of Acetol CoA (a carbon atom is stripped from each and leaves the cell as carbon dioxide)
-this reaction releases 2 molecules of NADH2
-in the mitochondrion (matrix) for eukaryotic cells
-in the cytosol for prokaryotic cells

Question 11

The Krebs cycle

Answer 11

After transition step
-inside the mitochondria (matrix) for eukaryotic cells, the Acetol CoA molecules are disassembled during the the Krebs cycle
-energy from Acetol CoA is transferred to electrons
-these reactions release 2 molecules of NADH2 (and ATP?)
-inside the cytosol for prokaryotic cells

Question 12

The electron transport chain step

Answer 12

After Krebs cycle
-electrons from NADH and FADH are unloaded into the electron transport chain, where the potential energy in the electrons are used to produce more ATP
-they create a proton (H+) gradient
-these electrons require oxygen and release water
-inside the mitochondrion (inner membrane) for eukaryotic cells
-inside the cell membrane for prokaryotic cells
-inside thylakoid membranes of chloroplasts

Question 13

Oxidation of glucose

Answer 13

During glycolysis and the Krebs cycle, electrons are removed from glucose (oxidizing it). NAD+ and FAD+ gain electrons (they are reduced to NADH and FADH2)

Question 14

Reduction of CO2

Answer 14

In the electron transport chain, electrons from NADH and FADH2 are used to reduce (add electrons to) O2, which bonds with hydrogen atoms to form H2O

Question 15

Glycolysis definition

Answer 15

A metabolic pathway occurring in the cytosol of cells (prokaryotic and eukaryotic)
-a 6-carbon molecule splits into two 3-carbon molecules of pyruvate
-Yields 2 ATP and NADH
-doesn’t require oxygen

Question 16

Pyruvate definition

Answer 16

The 3-carbon product of glycolysis

Question 17

NADH definition

Answer 17

Nicotinamide Adenine Dinucleotide
-a coenzyme that carries electrons in glycolysis and cellular respiration

Question 18

2 phospholipid bilayers of the mitochondria

Answer 18

Outer membrane and inner membrane
-many enzymes are embedded in the inner membrane, catalyzing the reactions of the electron transport chain

Question 19

Mitochondrial matrix definition

Answer 19

The fluid enclosed within the inner membrane
-location of the Krebs cycle

Question 20

Intermembrane compartment definition

Answer 20

The space between the mitochondrial membranes (inner and outer)

Question 21

Crista

Answer 21

Plural- Cristae
-fold of the inner mitochondrial membrane along which many reactions of cellular respiration occur

Question 22

5 basic energy investment steps of glycolysis

Answer 22

1.) phosphate is transferred from ATP to glucose
2.) rearrangement
3.) a second phosphate transferred from ATP
4.) a 6-carbon intermediate splits into two 3-carbon intermediates
5.) one of the intermediates is converted into the other type, so there are 2 molecules of PGAL (phosphoglyceraldehyde)

Question 23

5 basic steps of energy harvest in glycolysis

Answer 23

6.) oxidation and phosphorylation
7.) substrate-level phosphorylation yields ATP
8.) rearrangement
9.) removal of H2O
10.) substrate-level phosphorylation yields ATP and 2 molecules of pyruvate per glucose

Question 24

Glycolysis- glucose is activated

Answer 24

-glycolysis requires an input of 2 ATP to activate glucose
-the activated glucose is then converted into two 3-carbon intermediated called PGAL

Question 25

Glycolysis- NADH is produced

Answer 25

-first, each PGAL is oxidized, producing 2 NADH molecules -NADH is an electron carrier molecule (it carries electrons that store energy)

Question 26

Glycolysis- ATP is produced from ADP

Answer 26

PGAL (an enzyme) donates its phosphate group to ADP, producing ATP molecules via substrate-level phosphorylation

Question 27

Glycolysis- a net of 2 ATP are produced

Answer 27

-in total, 4 ATP are produced -2 ATP were used to start the reactions -so, the net yield is 2 ATP

Question 28

Does glycolysis require oxygen?

Answer 28

No, it doesn't require oxygen -glycolysis can occur in anaerobic conditions

Question 29

Glycolysis reactants and products

Answer 29

Requires: 1 glucose, 2 NAD+, and 2 ADP Yields: 2 pyruvate, 2 electron carrying NADH molecules, and 2 ATP

Question 30

Acetol CoA

Answer 30

Acetyl Coenzyme A- molecule that enters the Krebs cycle -product of partial oxidation of pyruvate

Question 31

How many times does the Krebs cycle turn for 1 glucose?

Answer 31

The Krebs cycle turns twice for each glucose -1 glucose=2 pyruvate

Question 32

What is the net output for the Krebs cycle?

Answer 32

-2 ATP -6 NADH -2 FADH -(4 CO2 is released)

Question 33

Chemiosmotic Phosphorylation definition

Answer 33

Reactions that produce ATP using ATP synthase and the potential energy of a proton gradient

Question 34

What is ATP synthase?

Answer 34

It is an enzyme that uses the potential energy in a proton gradient (H+) to produce ATP

Question 35

6 steps of the Krebs cycle

Answer 35

-Acetol CoA combines with a 4-carbon molecule called oxaloacetate, yielding a 6-carbon citrate -citrate is rearranged and oxidized, converting it into several intermediates (for each turn of the cycle, these reactions give off 2 molecules of carbon dioxide) -as citrate is converted, each turn of the cycle produces 1 ATP via substrate-level phosphorylation -as citrate is converted, each turn of the cycle transfers electrons to different electron carrier molecules, yielding 3 NADH and 1 FADH2

Question 36

Krebs cycle, what is citrate converted into

Answer 36

Citrate is converted into isocitrate, a-ketoglutarate, succinyl CoA, succinate, fumarate, and oxaloacetate -CIKSSFMO

Question 37

How many ATP does the electron transport chain yield?

Answer 37

34 ATP

Question 38

What happens at the end of the electron transport chain?

Answer 38

Electrons are donated to an oxygen atom, which combines with hydrogen atoms to form water (oxygen is the final electron acceptor. Without it, the chain shuts down)

Question 39

Aerobic cellular respiration math on how to get the yield of ATP

Answer 39

-glycolysis produce 2 ATP and 2 NADH -NADH transferred to mitochondrion (2 ATP lost) -transition step produce 2 NADH -Krebs cycle produce 2 ATP, 6 NADH, and 2 FADH2 -electron transport chain produce 34 ATP (theoretical yield), cashed in 10 NADH (30/34 ATP), cashed in 2 NADH (4/34 ATP) -36 ATP produced per glucose molecule (theoretical yield) -30 actual yield because of loss of energy

Question 40

What other food molecules enter the energy extracting pathways and how?

Answer 40

-polysaccharides like glycogen and starch are digested to glucose which enter at glycolysis -proteins are digested as amino acids, which enter as pyruvate, acetol CoA, or Krebs cycle intermediates -fats are digested to glycerol and fatty acids. Glycerol is converted to pyruvate and fatty acids are broken down to Acetyl CoA molecules (both of which enter the Krebs cycle)

Question 41

Anaerobic Respiration definition

Answer 41

-includes the Krebs cycle and the electron transport chain -ETC uses electron acceptor molecules other than oxygen (like CO2, NO3- nitrate, and SO4^2- sulfate) -many prokaryotes like bacteria and archaea use it -Produce less ATP than aerobic respiration

Question 42

Fermentation definition

Answer 42

-no Krebs cycle or electron transport chain -simply allows glycolysis to continue producing small amounts of ATP -alcohol, lactic acid, and other byproducts -yields only 2 ATP

Question 43

How does fermentation regenerate itself?

Answer 43

-electrons from NADH are transferred to pyruvate, this regenerates NAD+ for glycolysis to continue

Question 44

Alcoholic fermentation definition

Answer 44

-microbes carry out alcoholic fermentation -NADH reduces pyruvate from glycolysis to ethanol and CO2 and then its recreated

Question 45

Lactic acid fermentation definition

Answer 45

-bacteria and muscle cells both carry out lactic acid fermentation -NADH reduces pyruvate to lactic acid and NAD+ and then recreated

Question 46

Compare photosynthesis and respiration

Answer 46

Photosynthesis: -food- produced -energy- stored as glucose and other sugars -light- required -H2O- consumed -CO2- consumed -O2- released Respiration: -food- consumed -energy- released from glucose and other food molecules -light- not required -H2O- released -CO2- released -O2- consumed