Lecture 20 - Glycolysis (Exam 2)

Question 1

During a sprint, are you utilizing oxygen for glycolysis?

Answer 1

No, oxygen is used for longer endurance in the transport chain.

Question 2

Glycolysis involves a sequence of reactions that metabolizes 1 molecules of _______ to 2 molecules of _______ and generates 2 _______.

Answer 2

Glucose
Pyruvate
ATP

Question 3

(AEROBIC/ANAEROBIC) is the process without oxygen and used in glycolysis.

Answer 3

Anaerobic

Question 4

Pyruvate can be completely oxidized under aerobic conditions, which generates much more ______.

Answer 4

ATP

Question 5

Is glycolysis useful for short bursts or long runs? What about the transport chain?

Answer 5

Glycolysis is good for short bursts of energy.

Transport chain is good for longer runs/endurance.

Question 6

After glycolysis is done and we have pyruvate, what are the three fates that can occur to pyruvate?

Answer 6

Fermentation
Lactate
Complete oxidation (mitochondria)

Question 7

_______ is a common and most important fuel.

Answer 7

Glucose

Question 8

In mammals, ________ is the ONLY fuel that the brain uses under conditions of non-starvation.

Answer 8

Glucose

Question 9

In mammals, glucose is the ONLY fuel that ________ can use.

Answer 9

RBCs

Question 10

Pyruvate and lactate can be salvaged an resynthesized to glucose via _________.

Answer 10

Gluconeogenesis

Question 11

What are sources of glucose in the diet?

Answer 11

Disaccharides (especially sucrose and lactose)
Starch
Glycogen

Question 12

The job of the _______ is to make sure all parts of the body gets their favorite type of fuel.

Answer 12

Liver

Question 13

When blood glucose is down (i.e., in times of fasting) _______ is used.

Answer 13

Glycogen

Question 14

Glucose uptake occurs via what type of diffusion?

Answer 14

Facilitated diffusion

Question 15

Glucose uptake occurs via protein transporters called _______.

Answer 15

GLUTs (Glucose Transporters)

Question 16

This type of GLUT is ubiquitous but expressed highly in the brain and RBCs. It has high affinity. (Km 1 mM)

Answer 16

GLUT1

Question 17

This type of GLUT is the main transporter in the liver and pancreas. It has low affinity. (Km 10 mM)

Answer 17

GLUT2

Question 18

This type of GLUT is the main transporter in neurons. It has high affinity. (Km 1 mM)

Answer 18

GLUT3

Question 19

This type of GLUT is present in skeletal muscle, heart, and adipose tissue. It is the only one that is insulin dependent. It’s stored in vesicle right below the plasma membrane. (Km 5 mM)

Answer 19

GLUT4

Question 20

Where does glycolysis occur?

Answer 20

In the cytoplasm of eukaryotic cells

Question 21

Glycolysis is divided into 2 stages, which are…

Answer 21

1) Trapping of glucose and its cleavage into 2 interconvertible 3-carbon molecules
2) Generation of ATP

Question 22

The first stage of glycolysis begins with the phosphorylation of glucose by ________ and ends with the isomerization of _________ ________ to _________ _________.

Answer 22

Hexokinase
Dihydroxyacetone phosphate
Glyceraldehyde 3-phosphate

Question 23

Stage 1 of glycolysis involves 5 steps. The trapping of glucose and preparation phase generates no ATP, but consumes _____ ATP.

Answer 23

2

Question 24

Stage 1 of glycolysis consists of three reactions, which are…

Answer 24

Phosphorylation
Isomerization
2nd Phosphorylation

Question 25

The strategy of stage 1 glycolysis is to trap the glucose in cell and form a compound that can be readily cleaved into...

Answer 25

2 phosphorylated three-carbon units

Question 26

In stage 1 glycolysis, step 1 -- Glucose is phosphorylated to __________ using enzyme _________ (in all tissues) and _________ (in liver). _____ is consumed.

Answer 26

Glucose-6-phosphate (G6P) Hexokinase Glucokinase ATP

Question 27

In stage 1 glycolysis, step 2 -- G6P is isomerize to __________ using enzyme ___________.

Answer 27

Fructose-6-phosphate (F6P) | Phosphoglucoisomerase

Question 28

In stage 1 glycolysis, step 3 -- F6P is phosphorylated to ___________ using enzyme ___________ (rate limiting enzyme). ______ is consumed.

Answer 28

Fructose-1,6-bisphosphate Phosphofructokinase ATP

Question 29

In stage 1 glycolysis, step 4 -- F1,6BP is broken down to ___________ and ________ _________ using enzyme _________.

Answer 29

``` Glyceraldehyde-3-phosphate (G3P) Dihydroxyacetone phosphate (DHAP) Aldolase ```

Question 30

In stage 1 glycolysis, step 5 -- DHAP isomerized to G3P using enzyme ________ _______ ________.

Answer 30

Triose phosphate isomerase

Question 31

In the second stage of glycolysis, energy harnessed in G3P is used to form ______.

Answer 31

ATP

Question 32

What is the rate limiting enzyme of glycolysis?

Answer 32

Phosphofructokinase

Question 33

In stage 2 of glycolysis, step 1 -- Oxidative phosphorylation of G3P to form __________ is done by G3P _________. _____ is reduced to ______.

Answer 33

1,3-Bisphosphoglycerate (1,3-BPG) Dehydrogenase NAD+ NADH

Question 34

1,3-BPG has high _______-_______ potential.

Answer 34

Phosphoryl-transfer

Question 35

NADH contains a pair of "high energy" _______. These are sent to the electron transport chain (ETC), play role in oxidative phosphorylation (OXPHOS).

Answer 35

Electrons

Question 36

In stage 2 glycolysis, step 2 -- ________ _______ converts 1,3-BPG to __________. _____ is phosphorylated to _____ to form this, via substrate transfer.

Answer 36

Phosphoglycerate kinase 3-Phosphoglycerate (3-PG) ADP ATP

Question 37

In stage 2 glycolysis, step 3 -- ________ ________ moves phosphate from 3rd position in 3-PG to the 2nd position to form __________.

Answer 37

Phosphoglycerate mutase | 2-Phosphoglycerate (2-PG)

Question 38

In stage 2 glycolysis, step 4 -- Dehydration of 2-PG by ________ forms _________, an enol with high phosphoryl-transfer potential (unstable).

Answer 38

Enolase | Phosphoenolpyruvate (PEP)

Question 39

In stage 2 glycolysis, step 5 -- ________ ________ transfers phosphoryl group from PEP to ______ to form ______. PEP is converted from unstable enol to ________, a stable ketone. This step is irreversible.

Answer 39

Pyruvate kinase ADP ATP Pyruvate

Question 40

What is required for stage 2 glycolysis to operate correctly?

Answer 40

It must go through the steps 2 times

Question 41

Pyruvate can be reduced to lactate, with the regeneration of ______ (low oxygen).

Answer 41

NAD+

Question 42

Pyruvate can be oxidized aerobically via the citric acid cycle after first undergoing an oxidative decarboxylation to form ______ ______.

Answer 42

Acetyl CoA

Question 43

_______ is a disaccharide of glucose and fructose.

Answer 43

Sucrose

Question 44

_______ is a disaccharide of glucose and galactose.

Answer 44

Lactose

Question 45

Fructose and galactose are converted into ________ ________.

Answer 45

Glycolytic intermediates

Question 46

Fructose is quickly turned to ______ in times of high energy.

Answer 46

Fat

Question 47

What is the net generation of ATP in glycolysis?

Answer 47

2 ATP (2 consumed, 4 made)

Question 48

In fructose metabolism, fructose turns to fructose 1-phosphate with the help of _________ and ATP.

Answer 48

Fructokinase

Question 49

In the fructose 1-phosphate step of fructose metabolism, it turns to glyceraldehyde and dihydroxyacetone phosphate with the help of what enzyme?

Answer 49

Fructose 1-phosphate aldolase ***Remember dihydroxyacetone phosphate can be used in glycolysis

Question 50

In fructose metabolism, once glyceraldehyde is reached, the enzyme triose kinase and ATP create...

Answer 50

Glyceraldehyde 3-phosphate ***Used in glycolysis

Question 51

What are the major regulatory enzymes of glycolysis?

Answer 51

Hexokinase (trapping glucose) Phosphofructokinase (rate-limiting step) Pyruvate kinase (generates ATP)

Question 52

What is the goal of glycolysis in muscle?

Answer 52

To generate ATP during activity

Question 53

What is the goal of glycolysis in liver?

Answer 53

To maintain blood glucose levels | To provide building blocks for other pathways

Question 54

This is a side product of glycolysis that is only present in the liver.

Answer 54

F-2,6-BP

Question 55

In the liver, what does F-2,6-BP activate?

Answer 55

Phosphofructokinase

Question 56

In the liver, phosphofructokinase can be inhibited by what?

Answer 56

Citrate

Question 57

In the liver there is no hexokinase, there is ________. This is not inhibited by glucose 6-phosphate (glucose permanently trapped).

Answer 57

Glucokinase

Question 58

Lactose intolerance is an inability to metabolize lactose. Drinking milk causes disturbances in GI function. It is caused by a deficiency in the enzyme _______ (which breaks down lactose to glucose and galactose).

Answer 58

Lactase

Question 59

Lactose intolerance is an inability to metabolize lactose. Drinking milk causes disturbances in GI function. It is caused by a deficiency in the enzyme _______ (which breaks down lactose to glucose and galactose).

Answer 59

Lactase

Question 60

________, a commonly used sweetener, is a component of sucrose and high fructose corn syrup. Excessive levels of this are linked to fatty liver, insulin sensitivity, obesity, and type 2 diabetes.

Answer 60

Fructose

Question 61

Actions of fructokinase and triose kinase bypass the most important regulatory step in glycolysis, the ____________-catalyzed reaction.

Answer 61

Phosphofructokinase

Question 62

Fructose-derived G3P and DHAP are processed by glycolysis to ________ and ________ in an unregulated fashion.

Answer 62

Pyruvate | Acetyl CoA

Question 63

Excess acetyl CoA converted to fatty acids, which can be transported to adipose tissue to form __________, resulting in obesity. Liver also begins to accumulate fatty acids, resulting in fatty liver.

Answer 63

Triacylglycerols

Question 64

Activity of the fructokinase and triose kinase can deplete the liver of ______ and inorganic phosphate, compromising liver function.

Answer 64

ATP

Question 65

Disruption of galactose metabolism is called...

Answer 65

Galactosemia

Question 66

Classic galactosemia (most common form) is an inherited deficiency in...

Answer 66

Galactose 1-phosphate uridyl transferase

Question 67

In classic galactosemia, afflicted ________ fail to thrive.

Answer 67

Infants

Question 68

The diagnostic criterion of galactosemia is the absence of the ________ in red blood cells. The treatment is to remove _________ (and lactose) from diet.

Answer 68

Transferase | Galactose

Question 69

In galactosemia, although elimination of ________ from diet prevents liver disease and cataract development, majority of patients still suffer from central nervous system malfunction, most commonly a delayed acquisition of language skills.

Answer 69

Galactose

Question 70

Cataract is the clouding of the normally clear lens of the eye. If the transferase is not active in the lens of the eye, the presence of _______ ______ causes the accumulating galactose to be reduced to ________.

Answer 70

Aldose reductase | Galactitol

Question 71

_______ display enhanced rates of glucose uptake and glycolysis.

Answer 71

Tumors

Question 72

Rapidly growing tumor cells metabolize glucose to lactate even in the presence of oxygen, a process called...

Answer 72

Aerobic glycolysis (Warburg effect)

Question 73

Tumors with a high _______ uptake are particularly aggressive, and the cancer is likely to have a poor prognosis.

Answer 73

Glucose