Exam 1 Questions Flashcards by Shaina Johnson

Q

Referring to Huntington’s Disease: What term is the following description describing?

Description: motor, psychiatric, and cognitive

A

Symptoms

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Q

Referring to Huntington’s Disease: What term is the following description describing?

Description: naturally contains CAG repeats

A

HTT protein

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Q

Referring to Huntington’s Disease: What term is the following description describing?

Description: dominant Mendelian

A

Inheritance

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Q

Referring to Huntington’s Disease: What term is the following description describing?

Description: 100% penetrance

A

40 or more polyQ

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Q

Referring to Huntington’s Disease: What term is the following description describing?

Description: control of reflex activity, complex movements

A

Basal ganglia

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Q

Referring to membrane potential and transport across membranes: What term is the following description describing?

Description: electrogenic pump (3 Na+ out, 2 K+ in)

A

Na+/K+ ATPase

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Q

Referring to membrane potential and transport across membranes: What term is the following description describing?

Description: relies on Na+ gradient

A

glucose transport from gut lumen into epithelial cells

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Q

Referring to membrane potential and transport across membranes: What term is the following description describing?

Description: activated by depolarization

A

Voltage-gated Na+ channel

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Q

Referring to membrane potential and transport across membranes: What term is the following description describing?

Description: contributes to negative resting membrane potential

A

K+ leak channel

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Q

Referring to membrane potential and transport across membranes: What term is the following description describing?

Description: transient all-or-none depolarization

A

Action potential

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Q

Fill in the blank: Glycolysis generates ATP under _______________.

A

Anaerobic conditions

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Q

Fill in the blank: The reactions of glycolysis take place in the __________.

A

Cytoplasm

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Q

Fill in the blank: One molecule of glucose has a net production of ___________ and ___________ and finally ______________.

A

2 ATP, 2 NADH + 2 pyruvate, 2 H2O

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Q

After 8 plus hours from your last meal, but before breakfast, glucose in the blood stream is derived largely from what? (Two answers)

A

Glycogen breakdown and gluconeogenesis

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Q

After your first meal of the day, the flux changes and glucose is _________?

A

Used to form glycogen (a form of glucose that is stored)

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Q

After someone eats, do glycolysis rates increase or decrease to break down glucose for energy?

A

Increase

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Q

What changes metabolic flux?

A

Both the level of enzyme activity and the availability of substrates

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Q

In what types of organisms are glycolytic enzymes found?

A

Bacteria, fungi, and vertebrates

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Q

How many reactions are in glycolysis?

A

10

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Q

How many glycolysis reactions have a negative Gibbs Free Energy change and are essentially irreversible?

A

Three

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Q

What enzyme converts glucose to glucose-6-phosphate?

A

Hexokinase or glucokinase

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Q

What are irreversible steps in glycolysis often subjected to?

A

Enzymatic control (to affect flux through the pathway)

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Q

What is stage 1 of glycolysis?

A

The ATP investment stage that costs 2 ATP

Q

What is stage 2 of glycolysis?

A

The ATP harvesting stage that generates 4 ATP to produce a net of 2 ATP

How many ATP(s) does hexokinase consume?

1

What other enzyme reaction (aside from pyruvate kinase) is ATP generated?

Phosphoglycerate kinase

How many pyruvate molecules is produced from one glucose in glycolysis?

Two

Glucokinase has a different enzymatic reaction rate as a function of glucose concentration than does _________?

Hexokinase

Glucokinase requires higher concentrations of glucose to be fully active and is important in which organs for glucose sensing?

Liver and pancreas

Glucokinase is important for affecting what two other processes?

Glycogen production in the liver and insulin secretion from beta cells

Phosphofuctokinase-1 (PFK-1) is a key regulatory step in glycolysis and is affected by the levels of __________, which activates PFK-1 and is an indicator of the need to increase glycolytic flux.

Fructose-2,6-biphosphate

What happens to pyruvate under aerobic conditions?

It is delivered to the citrate cycle for ATP production

What happens to pyruvate under anaerobic conditions? (Example: extreme exercise)

Pyruvate is converted to lactate

What other molecule undergoes oxidation when pyruvate is converted to ethanol or lactase?

NADH

Why does NADH undergo oxidation when pyruvate is converted to ethanol or lactase?

This process provides a critical oxidized coenzyme for glyceraldehyde-3-P dehydrogenase that permits continued functioning of glycolysis and ATP generation

What are the toxic effects of carbon monoxide? (Two important ones)

- Binds to hemoglobin and prevents efficient release of oxygen to peripheral tissues - Binds and inhibits electron transfer in cytochrome c oxidase

What other common toxin affects oxidative phosphorylation and electron transport in the mitochondria?

Cyanide

Uncoupling with regard to oxidative phosphorylation refers to mechanisms to ___________. A) Permit H+ movement across the mitochondrial membrane, down its electrochemical gradient, but NOT through the ATP synthase complex B) Move H+ through the ATPase synthase complex without ATP generation

A) Permit H+ movement across the mitochondrial membrane, down its electrochemical gradient, but NOT through the ATP synthase complex

Molecules blocking ATP synthase function, such as oligomycin, produce ____________. A) H+ accumulation in the intermembrane space, but this has no deleterious effect since H+ escapes into the cytoplasm B) H+ accumulation, and eventually cell death

B) H+ accumulation, and eventually cell death

The ATP synthase complex resides in the inner mitochondrial membrane and uses a gradient of ____________. A) Electrons B) H+ ions

B) H+ ions

The ATP synthase complex resides in the inner mitochondrial membrane and uses a gradient of H+ ions to achieve the synthesis of ATP, delivered from the enzyme to the ___________. A) Mitochondrial matrix B) Intermembrane space

A) Mitochondrial matrix

This ATP requires a __________ to insure delivery of the product, ATP, out of the mitochondrion and ultimately into the cytoplasm. A) ATP channel B) ATP-ADP antiporter

ATP-ADP antiporter

Phosphate must be delivered into the matrix and this is achieved by a ______________. A) Phosphate translocase that is a H+ symporter, and uses the H+ gradient to drive phosphate movement B) Phosphate Cl- antiporter

A) Phosphate translocase that is a H+ symporter, and uses the H+ gradient to drive phosphate movement

NADH cannot cross the inner mitochondrial membrane which means electrons must somehow be delivered to the matrix. What two shuttle systems accomplish this?

Malate-aspartate shuttle and glycerol-3-phosphate shuttle

In one of the shuttles used to deliver electrons to the matrix, the electrons from NADH are transferred to what molecule?

Oxaloacetate

In one of the shuttles used to deliver electrons to the matrix, the electrons from NADH are transferred to oxaloacetate, and the product of this reaction _________ is transported across the inner mitochondrial membrane.

Malate

NADH is regenerated by conversion of? A) Malate back to oxaloacetate B) Pyruvate back to lactate

A) Malate back to oxaloacetate

Coenzymes are nonprotein compounds that are required for the activity of certain enzymes. One critical coenzyme central to metabolism is NAD+. In fact it is one of 5 coenzymes required by ___________, the critical enzyme for producing acetyl-CoA. A) Pyruvate dehydrogenase B) Citrate synthase

A) Pyruvate dehydrogenase

Which two American scientists discovered that NAD+ synthesized from niacin (vitamin B3) was critical for health? A) Linus Pauling and Eric Lander B) Joseph Goldberger and Conrad Elvehjem

B) Joseph Goldberger and Conrad Elvehjem

Dietary lack of niacin produces pellagra, characterized by the following symptoms: A) Chorea-like movement B) Skin inflammation, dementia, diarrhea

B) Skin inflammation, dementia, diarrhea

People with pellagra were found in parts of the U.S. where diets lacked vegetables and consisted principally of corn. Interestingly, soaking the corn in ___________, a common practice in Mexico, releases the critical coenzyme from proteins, making it bioavailable. A) Salt water B) Lime

B) Lime

What are the carbon sources for gluconeogenesis?

Amino acids, fatty acids, glycerol, and lactic acid

Which term best fits the following statement: cofactor for pyruvate carboxylase? A) Biotin B) Bicarbonate and ATP C) Oxaloacetate D) Malate transport D) Cori Cycle

A) Biotin

Which term best fits the following statement: reactants for adding carboxy group to biotin? A) Biotin B) Bicarbonate and ATP C) Oxaloacetate D) Malate transport D) Cori Cycle

B) Bicarbonate and ATP

Which term best fits the following statement: mechanism for "moving" NADH equivalents from mitochondrial matrix to cytosol? A) Biotin B) Bicarbonate and ATP C) Oxaloacetate D) Malate transport D) Cori Cycle

D) Malate transport

Which term best fits the following statement: 4 carbon acid converted to 3 carbon, phosphoenolpyruvate with release of CO2? A) Biotin B) Bicarbonate and ATP C) Oxaloacetate D) Malate transport D) Cori Cycle

C) Oxaloacetate

Which term best fits the following statement: A mechanism to convert lactate produced in muscle to glucose in the liver, which is then transported into circulation? A) Biotin B) Bicarbonate and ATP C) Oxaloacetate D) Malate transport D) Cori Cycle

D) Cori Cycle