BSC 300 Lecture 9: 2-8-18

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plumtermite154

18 Apr 2018

School

University of Alabama

Department

Biological Sciences

Course

BSC 300

Professor

jenny

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Document Summary

Important concepts to remember about the first step of harvesting energy from glucose: Steps 1, 3, and 10-- essentially irreversible (large - g values) under ordinary cell conditions: energy investment to get reactions going, hydrolysis of atp in 2 of first 3 reactions. First step activates glucose with addition of phosphate. Inorganic phosphate attached to form 1,3-biphosphoglycerate: high-energy anhydride bond, greater energy of hydrolysis than in phosphoanhydride bond of atp, catalyzed by phosphoglycerate kinase. In presence of oxygen tca cycle in mitochondrion. Fermentation restores nad+ from nadh: under aerobic conditions, glycolysis depletes the supply of nad+ by reducing it to nadh. In fermentation, nadh is oxidized to nad+ by reducing pyruvate. In muscle and tumor cells pyruvate is reduced to lactate. In yeast and other microbes, pyruvate is reduces and converted to ethanol: fermentation is inefficient with only about 8% of the energy of glucose captured as atp. Inner and outer mitochondrial membranes enclose the intermembrane space.

Related Questions

Q1:

Enzymes are essential for the conversion of organic molecules in biochemical pathways. Which of the following statements is incorrect?

Enzymes reduce the activation energy of chemical reactions.

Enzymes are catalysts and appear unchanged at the end of the reaction.

Enzymes change the equilibrium of a reaction.

Enzymes form a complex with the substrate.

Enzymes facilitate both the conversion of substrates into products and of products into substrates.

Q2:

NADH and NADPH are important energy carriers in biochemical pathways. Which of the following statements about these compounds is incorrect?

NADP+ is reduced by two electrons (involving 2 protons) from photosystem I to form NADPH + H+.

NADH is produced both during glycolysis and in the TCA cycle.

NADH feeds electrons into the respiratory chain of mitcohondria, which are ultimately used to form water.

In the absence of oxygen NADH produced during glycolysis is reoxidised by formation of lactate from pyruvate or by formation of ethanol from acetaldehyde (fermentation).

The majority of NADH produced during oxidation of glucose (in the presence of oxygen) is generated during glycolysis.

Q3:

The respiratory chain converts the reducing power of NADH into the production of ATP. Which of the following statements is incorrect?

Electrons are passed through the respiratory chain in a way to optimise the production of heat.

The complexes of the respiratory chain use the energy of redox reactions to pump protons across the inner mitochondrial membrane.

The ATP synthase uses the protonmotive force to synthesize ATP.

The principle of energy conversion by respiratory chain and ATP synthase is called âchemiosmosisâ.

The electrons from NADH are passed along the respiratory chain in a number of redox reactions mostly involving complexes

raspberrytortoise897

Fill in the blank in the following table:

metabolic cycle	location pro/ eukaryote	components	substrates	products	pathway purpose
embden- meyerhof- parnas (glycolysis)	cytoplasm/ cytoplasm	10 enzymes
pentose phosphate pathway	cytoplasm/ cytoplasm	dozen enzyme	1 Glucose (6 carbon), 1 NADP, 1ATP	1 Ribose-P (5 carbon) + 1CO2, 1NADPH, or sugars, 1 ADP	Nucleotide synthesis, NADPH for anabolism
PDH reaction	cytoplasm/ mitochondria matrix
TCA/ Krebs/ citric acid cycle					generation of high energy electron carriers, provide metabolic precursors
Electron transport chain + ATP synthase (aerobic respiration)
Electron transport chain + ATP synthase (anaerobic respiration)			1Nitrate or sulfate or CO2, 1NADH + ____ ADP Or 1FADH2+ ____ ADP	N2, or NO2 or H2S or CH4 1NAD + ____ ATP Or 1FADH2+ ____ ATP	Generate proton motive forces abd use to generate ATP regenerate NAD+
Fermentation	cytoplasm/ cytoplasm	1 or more enzymes (vary by organism)	1 pyruvate, 1 NADH	1 alcohol or acid (maybe 1 CO2) NAD+	Regenerate NAD+

Which of the following is common to both aerobic and anaerobicmicrobes?

	Fermentation
	An electron transport chain
	Pyruvate oxidation
	Glycolysis
	All of the above

The primary purpose of catabolism is

	generation of ADP.
	generation of ATP.
	oxidation of NADH to NAD⁺.
	degradation of organic molecules.
	biosynthesis.

What is a fate of pyruvate during alcoholic fermentation byyeast?

	It is reduced to lactic acid.
	It is oxidized to form glucose and carbon dioxide
	It is cleaved to form acetylaldehyde and carbon dioxide.
	It is catabolized in glycolysis.
	It is oxidized to form lactic acid and carbon dioxide.

Electrons needed to reduce an oxidized electron acceptor areprovided by

	a) externally provided compounds such asH<sub>2</sub>, lactate or formate.
	b) an intermediate electron carrier such as NADH.
	c) 0<sub>2</sub>.
	d) Both a and b
	e) All of the above

How are aerobic respiration and anaerobic respirationsimilar?

	Both use oxygen as a terminal electron carrier.
	These are other names for glycolysis.
	Both utilize inorganic molecules as terminal electronacceptors.
	Neither receives electrons from glycolysis.
	Anaerobic respiration does not exist in microbes.

The conversion of phosphoenolpyruvic acid (PEP) topyruvate

	a) releases CO<sub>2</sub>.
	b) involves the conversion of ADP and ATP.
	c) involves substrate-level phosphorylation.
	d) Both a and b
	e) Both b and c

Which of the following is the best definition offermentation?

	The reduction of glucose to pyruvic acid
	The complete catabolism of glucose to CO₂ andH₂O
	The oxidation of a carbohydrate with organic molecules servingas electron donors and acceptors
	The production of ATP from glucose
	The production of ethanol from glucose

A reaction that yields energy has a

	positive ?G_o?.
	negative ?G_o?.
	positive ?E_o?.
	negative ?E_o?.
	negative ?H_o?.

Oxidation and reduction reactions are always coupledbecause

	a) electrons generally accompany protons.
	b) protons generally accompany protons.
	c) electrons cannot exist free in solution.
	d) Both a and b
	e) All of the above

10.

Which of the following is true of aerobic respiration?

	It involves the reduction of oxygen.
	It involves the oxidation of oxygen.
	It involves the reduction of lactic acid.
	It involves the oxidation of lactic acid.
	It does not generate ATP.

plumgnu195

BSC 300 Lecture 9: 2-8-18

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