Homeostasis, metabolism, and bioenergetics 2

Question 1

bioenergetics

Answer 1

study of flow of energy through biological systems

Question 2

ATP

Answer 2

adenosine triphosphate
special carrier for free energy
provides most of the energy for cell functions
made of adenine, ribose, and three linked phosphates
made by adding a phosphate group to an ADP molecule

Question 3

which bonds in ATP are the high energy bonds

Answer 3

two outer most phosphates - they have the most amount of stored energy

Question 4

ATP-PC system

Answer 4

anaerobic pathway that occurs in the cytoplasm
most rapid way of making ATP because it’s only a one enzyme reaction
ADP + phosphocreatine (PC) -> ATP + Creatine

Question 5

explain the anaerobic glycolysis pathway for glucose

Answer 5

1.) glucose molecule enters cell
2.) glucose is phosphorylated to become glucose-6-phosphate by hexokinase
-1 ATP
3.) glucose-6-phosphate is rearranged into fructose-6-phosphate by glucose-6-phosphate isomerase
4.) fructose-6-phosphate is phosphorylated to form fructose-1,6-biphosphate by phosphofructokinase
-1 ATP
5.) fructose-1,6-biphosphate molecule splits into two glyceraldehyde-3-phosphate molecules (G3P)
6.) each G3P molecule is converted to pyruvate

Question 6

two main aerobic pathways

Answer 6

citric acid cycle (Krebs cycle)
electron transport chain

Question 7

cellular respiration

Answer 7

metabolic pathway where organic molecules are oxidized and disassembled in a controlled manner by a series of enzymes

Question 8

what enzyme breaks down ATP

Answer 8

ATPase

Question 9

why don’t we store a lot of ATP

Answer 9

the molecule is large and would make us large
only storing a little causes us to make more as soon as we need it (ex. starting to exercise)

Question 10

which enzyme donates the phosphate group of phosphocreatine to create an ATP molecule

Answer 10

creatine kinase

Question 11

why can we not solely use the ATP-PC system to make ATP

Answer 11

we do not have an unlimited amount of phosphocreatine

Question 12

what is the limiting factor in the anaerobic glycolysis of glucose

Answer 12

phosphfructokinase (enzyme that phosphorylates fructose-6-phophate)

Question 13

what are the products of the anaerobic glycolysis of glucose

Answer 13

4 ATP (net 2)
2 NADH+ + 2H+
2 pyruvate or lactate

Question 14

why must glucose be phosphorylated after entering the cell

Answer 14

phosphorylation prevents it from leaving the cell through the glucose channel
prevents the build up of glucose in the cell and maintains the chemical gradient

Question 15

what does a hexokinase do

Answer 15

adds phosphate group

Question 16

explain the anaerobic glycolysis pathway for glycogen

Answer 16

1.) glycogen already in the cell is converted to glucose-6-phosphate
2.) glucose-6-phosphate is rearranged into fructose-6-phosphate by glucose-6-phosphate isomerase
3.) fructose-6-phosphate is phosphorylated to form fructose-1,6-biphosphate by phosphofructokinase
-1 ATP
4.) fructose-1,6-biphosphate molecule splits into two glyceraldehyde-3-phosphate molecules (G3P)
5.) each G3P molecule is converted to pyruvate

Question 17

what are the products of the anaerobic glycolysis of glycogen

Answer 17

4 ATP (net 3)
2 NADH+ + 2H+
2 pyruvate or lactate

Question 18

where is glycogen stored

Answer 18

in liver and skeletal muscle

Question 19

what happens to pyruvate if there is sufficient oxygen present

Answer 19

the pyruvate will be changed to acetyl CoA where it can start the Krebs cycle

Question 20

what happens to pyruvate if there is not sufficient oxygen present

Answer 20

pyruvate is converted to lactic acid because we don’t want pyruvate building up

Question 21

what is the equation for converting pyruvate to lactic acid

Answer 21

pyruvate + NADH + H+ -> lactic acid + NAD+
then

lactic acid -> lactate + H+

Question 22

what enzyme catalyzes converting pyruvate into lactic acid

Answer 22

lactate dehydrogenase (LDH)

Question 23

explain the preparatory phase of pyruvate of acetyl-CoA

Answer 23

occurs in the mitochondria
pulls off a carbon group and adds a CoA group by pyruvate dehydrogenase complex (PDC) - irreversible
NAD+ is also converting back and forth to NADH + H+ to send electrons to the electron transport chain

Question 24

what enzyme catalyzes the conversion of pyruvate to acetyl-CoA

Answer 24

pyruvate dehydrogenase complex (PDC)
multi-enzyme complex

Question 25

what 5 things can be converted to acetyl-CoA

Answer 25

pyruvate, amino acids, fatty acids, glycerol, and ketone bodies

Question 26

explain the citric acid cycle (Krebs cycle)

Answer 26

occurs in the mitochondria 1.) acetyl group is transferred to oxaloacetate to form citrate 2.) citrate is eventually converted back into oxaloacetate 3.) oxalocetate is converted back to citrate to continue the cycle as long as there is sufficient intermediates

Question 27

what enzyme transfers an acetyl group to oxaloacetate to form citrate

Answer 27

citrate synthesis

Question 28

what is the reaction for the transfer of an acetyl group to oxaloacetate

Answer 28

acetyl-CoA + oxaloacetate -> citrate + CoA

Question 29

what is the rate limiting enzyme of the citric acid cycle

Answer 29

isocitrate dehydrogenase

Question 30

what are the products for one turn of the Krebs cycle

Answer 30

1 ATP 3 NADH + H+ 1 FADH2 2 CO2 *double the quantities for one glucose molecule

Question 31

explain the electron transport chain

Answer 31

occurs in the mitochondria 1.) NADH + H+ and FADH2 are brought to the electron transport chain from previous processes and release high energy electrons 2.) NAD+ and FAD are recycled to go get more 3.) pairs of high energy electrons move across the ETC to create energy 4.) this energy created fuels the cytochrome pumps 5.) pumps pump H+ from mitochondrial matrix to the mitochondrial intermembrane space, thus creating an electrochemical gradient 6.) H+ move down the concentration gradient through the protein ATP synthase 7.) ATP synthase transfers the kinetic energy into ATP from ADP and phosphate 8.) 1 ATP for every 3 H+ 9.) high energy electron pairs that come to the end of the ETC combines with H+ and oxygen to form water

Question 32

what is the equation for the high energy electrons to become water

Answer 32

2H+ + 1/2O2 + 2e- -> H2O

Question 33

what enzyme catalyzes the creation of water from high energy electrons

Answer 33

cytochrome oxidase

Question 34

what is the rate limiting enzyme of the electron transport chain

Answer 34

cytochrome oxidase - if we don't have enough of this enzyme, we cannot do the conversion of electrons to H2O which stops the electron transport chain

Question 35

what is oxygen's role in the electron transport chain

Answer 35

final acceptor of electrons

Question 36

how much ATP is made from each NADH + H+ and FADH2 molecule that goes through the electron transport chain

Answer 36

NADH + H+ = 2.5 FADH2 = 1.5

Question 37

what is the grand total of net ATP from one glucose molecule (explain how you got to the number)

Answer 37

32 ATP

Question 38

what is the grand total of net ATP from one glycogen molecule (explain how you got to the number)

Answer 38

33 ATP (one more ATP molecule from glycolysis)

Question 39

explain how fatty acids are used for energy

Answer 39

go through beta oxidation to yield ATP occurs in the mitochondria

Question 40

what are the products of each round of beta oxidation

Answer 40

1 acetyl-CoA (except for last round which yields 2) 1 NADH + H+ 1 FADH2

Question 41

what is the equation to determine the number of rounds of beta oxidation a fatty acid will go through

Answer 41

of carbons / 2 -1 ex. 14 carbon fatty acid will go through 6 rounds

Question 42

what is the equation to determine the number of acetyl-CoA molecules you will get out of a fatty acid

Answer 42

of carbons / 2 ex. 14 carbon fatty acid will make 7 acetyl-CoA molecules

Question 43

why are amino acids (proteins) not usually a major source of energy

Answer 43

we need proteins for so many other things that we only use them as fuel when absolutely necessary ex. long starvation

Question 44

what is the amino acid structure

Answer 44

amino group, carboxyl group, alpha carbon with attached H, and R group (variant)

Question 45

what are the 3 ways to use proteins as an energy source

Answer 45

1.) convert them to glucose via gluconeogenesis 2.) convert them to acetyl-CoA 3.) convert them to citric acid cycle intermediates

Question 46

what is ATP cycling

Answer 46

formation and breakdown of ATP ATP is formed when energy is released (exergonic reactions) ATP is oxidized to aid in exergonic reactions