Biological Energy Sources

Question 1

Structure of ATP

Answer 1

Adenine + Ribose = nucloeside (adenosine)
3 phosphate groups + Ribose + Adenine = nucleotide (adenosine triphosphate)
Alpha phosphate is directly attached to ribose
There are alpha, beta, and gamma phosphates

Question 2

Why is the game phosphate highly unstable?

Answer 2

Because of so much negatives

Question 3

ATP Hydrolysis

Answer 3

High energy phosphodiester bond is broken through hydrolysis to make ADP
*this is favorable and spontaneous

Question 4

T or F. ADP Phosphorylation is unfavorable and non spontaneous

Answer 4

True

Question 5

Mechanisms for ATP Formation

Answer 5

Substrate-level phosphorylation

Oxidative phosphorylation

Question 6

When does substrate-level phosphorylation occurs? Explain the mechanism

Answer 6

It occurs during glycolysis and involves the transfer of a phosphate group from a glycolytic intermediate to ADP, forming ATP (also occurs on citric acid cycle- GTP)
*this is always enzyme catalyze and always coupled with a spontaneous and favorable rxn to help it drive forward

Question 7

Oxidative Phosphorylation accounts for the formation for most of ATP. Describe it

Answer 7

ATP synthase is used to form ATP when protons are pumped to the mitochondrial matrix. It uses the energy present in the electrochemical gradient.

Question 8

T or F. Oxidative phosphorylation and substrate level phosphorylation can only occur in the presence of oxygen.

Answer 8

False. Substrate level phosphorylation can occur in the presence or absence of oxygen. For oxidative phosphorylation, oxygen is required. Oxygen is terminal electron acceptor in ETC

Question 9

This is similar to ATP but powers biological rxns involved in signaling cascades and protein synthesis

Answer 9

GTP- produced using substrate-level phosphorylation in the citric acid cycle

Question 10

Other high energy bonds

Answer 10

• Thioester bond in acetyl-CoA

- bonds in the reduced conenzymes: FADH2, NADH

Question 11

What type of bonds do our cells use to store energy for later use and to power non-spontaneous reactions that are necessary for cellular function?

Answer 11

High energy bonds

Question 12

A molecule of ATP contains 3 phosphate groups attached via the alpha phosphate to which hydroxyl group of ribose?

Answer 12

5’

Question 13

Which molecules are involved in carrying electrons from substrates in glycolysis and the citric acid cycle to the ETC?

Answer 13

NADH and FADH2

Question 14

Redox reactions in our cells are used in process that involves?

Answer 14

Energy

Question 15

Redox reactions play a huge role in?

Answer 15

Cellular metabolism

Question 16

OIL RIG

Answer 16

Oxidation- loss of electrons

Reduction- gain of electrons

Question 17

Reduction

Answer 17

• gain of electrons
  -fewer bonds to oxygen
  -more bonds to hydrogen
  Ex. Aldehyde to alcohol

Question 18

Oxidation

Answer 18

• lose electrons
• more bonds to oxygen
  -less bonds to hydrogen
  Ex. Alcohol to aldehyde

Question 19

Alkene is more reduced or oxidized than alkane ?

Answer 19

Oxidized

Question 20

What molecules play major roles in redox reactions in the cellular metabolism?

Answer 20

NADH and FADH2

Question 21

NADH

Answer 21

• when NAD+ gains a hydrogen it becomes more reduced and in the process, it oxidized a molecule which lose a hydrogen
• oxidation of NADH is spontaneous as well.

Question 22

FADH2

Answer 22

• when FAD+ gain 2 e- (2 hydrogens) it becomes reduced to FADH2 and it was also an oxidizing agent for a the other molecule involved in this process
• can be partially oxidized by losing only one 1 electron (FADH) or fully oxidized by losing 2 electrons (FADH2)

Question 23

NADH and FADH2 are used in which pathways

Answer 23

Glycolysis, citric acid cycle, and beta-oxidation

Question 24

The pumps use the energy gain from electron transfers to drive what against their concentration gradient?

Answer 24

Hydrogen ions, or protons

Question 25

The proton gradient powers oxidative phosphorylation via what?

Answer 25

ATP synthase

Question 26

What is the final acceptor in the ETC?

Answer 26

Diatomic oxygen molecule that is reduced to water

Question 27

Measure how energetically favorable reduction is

Answer 27

Reduction potential | The more positive the reduction potential is, the more a substance likes to be reduced

Question 28

Place the following in order of most to least oxidized: ethane, ethane, methane, and ethene

Answer 28

Ethane, ethene, ethane, methane

Question 29

If. A redox reaction required a biological reducing agent carrying two electrons, which of the following could serve as this reducing agent?

Answer 29

NADH and FADH2

Question 30

Oxygen is the final acceptor in the ETC, which means it reduction potential must be __________ than the complex immediately before it and it oxidation potential must __________ than the complex immediately before it

Answer 30

Higher; Lower

Question 31

What is the cell’s predominant source of fuel

Answer 31

Glucose- can be easily stored as glycogen and its catabolism liberates large amounts of ATP via aerobic respiration

Question 32

Can glucose simply cross the membrane

Answer 32

No. There are special transmembrane glucose transporters

Question 33

4 most important glucose transporters

Answer 33

GLUT 1-4

Question 34

How does the body make a smart choice about how to use glucose?

Answer 34

The presence of diverse glucose transporters and their differential expression across cell types

Question 35

Type of glucose transporter. Location | Nearly all tissue, especially fetal tissues, erythrocytes, and cancer cells

Answer 35

GLUT 1

Question 36

Type of glucose transporter. Function - Baseline cellular glucose uptake - expression increases when glucose is low

Answer 36

GLUT 1

Question 37

Type of glucose transporter. Location | Liver, kidney, pancreatic beta cells

Answer 37

GLUT 2

Question 38

type of glucose transporter. Function - bidirectional transport for glycolysis/ glycogenesis and - glucose sensor

Answer 38

GLUT 2

Question 39

Type of glucose transporter: Location | - neurons, placenta

Answer 39

GLUT 3

Question 40

Type of glucose transporter. Function - high glucose affinity - transports glucose into cell even when extracellular concentrations are low

Answer 40

GLUT 3

Question 41

Type of glucose transport. Location | Skeletal and cardiac muscle, adipose tissue

Answer 41

GLUT 4

Question 42

Type of glucose transporter. Function - glucose storage as glycogen or triglycerides - unregulated by glucose and insulin - insulin sensitive

Answer 42

GLUT 4- regulated by hormone insulin and primarily expressed after meals when blood glucose levels are high

Question 43

Type 2 Diabetes. Which glucose transporter becomes insensitive to insulin and stops being expressed with normal insulin levels?

Answer 43

GLUT 4

Question 44

T or F. A cancer cell from a particular tissue is likely to express more glucose transporters than a healthy cell from the same tissue.

Answer 44

True. Cancer cells are cells in which the regulation of growth and division have been significantly altered. Because cancerous cells grow more quickly and I divided more frequently, their energy demands are higher,