Biology 1002B Lecture Notes - Lecture 6: Anabolism, Cellular Respiration, Endergonic Reaction

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16 Oct 2013

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Metabolic pathways consist of exergonic and endergonic reactions. Metabolism: sum of all chemical reactions that rake place within an organism. Exergonic reaction: releases free energy (delta d is negative) Endergonic reaction: consumes free energy (delta g is positive) Catabolic pathway: energy is released by the breakdown of complex molecules to simpler compounds. (cellular respiration). Anabolic pathways: consumes energy to build complicated molecules from simpler ones. Overall delta g of anabolic pathway is positive. Overall delta g of catabolic pathway is negative. Both pathways have many exergonic and endergonic reactions. According to the second law of thermodynamics, energy transformations are never. Organisms must bring in much more energy than they actually require. So living organisms are defined as having negative delta g and reach equilibrium of delta g being zero only when they die. The breakdown of atp in an aqueous environment is a hydrolysis reaction that liberates free energy and result in formation of adp and orthophosphate ion (inorganic phosphate).

Related Questions

Which of the following is FALSE with respect to coupledreactions?

	they occur in ALL cells (bacteria, plants, animals, etc.)
	enzymes are typically involved
	endergonic reactions power exergonic reactions
	the coupled reaction has a ?G value that is negative
	none of the above (i.e., all of the above are TRUE)

Which of the following reactions is LEAST likely to bespontaneous? One with a:

	very large increase in entropy and a very large decrease inenthalpy
	very large increase in entropy and a very small increase inenthalpy
	very small decrease in entropy and a very large decrease inenthalpy
	very small increase in entropy and a very small decrease inenthalpy
	very small decrease in entropy and a very small increase inenthalpy

Energy of activation refers to the:

A)	?G of a reaction
B)	difference in energy between the transition state and theproduct
C)	difference in energy between substrate and product
D)	net change in free energy
E)	energy input needed to reach the transition state

Homeostasis refers to maintaining a relatively constantenvironment, and is achieved to a large extent by how enzymes areregulated. For example, when the end product of a pathway regulatesan enzyme that acts early in the same pathway, the effect is mostoften:

	stimulation if an anabolic pathway, and inhibition if acatabolic pathway
	inhibition if an anabolic pathway, and stimulation if acatabolic pathway
	stimulation, whether an anabolic or catabolic pathway
	inhibition, whether an anabolic or catabolic pathway

Enzymes function by:

	decreasing the free energy level of the reactants
	decreasing the free energy level of the transition state
	increasing the free energy level of the reactants
	changing delta G from positive to negative
	changing delta G from negative to positive
	increasing the free energy level of the products
	decreasing the free energy level of the products

6.	When carbohydrates are oxidized, the C

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3) The hydrolysis of sucrose to glucose and fructose is exergonic. However, if you dissolve sucrose in water and keep the solution overnight at room temperature, there is no detectable conversion to glucose and fructose. Why?

Select one:

a. The change in free energy of the reaction is negative.

b. The activation energy of the reaction is high.

c. The free energy of the products is higher than the free energy of the reactants.

d. This is a condensation reaction.

e. The change in free energy of the reaction is positive.

5) Competitive inhibition differs from non-competitive inhibition in that the ___1___ site is where we see competitive inhibition, while the non-competitive inhibitor __2___.

1. a. allosteric b. non-active c. active d. hydrophillic e. hydrophobic

2.
a. binds to the active site, thus blocking it
b. binds outside the active site, changing the shape of the enzyme
c. binds outside the active site, and blocks the active site

6) Phosphofructokinase is an enzyme, and as such it __1___ of the reaction. It is part of glycolysis, and is an example of an enzyme controlled by inhibition, as high levels of citrate (an intermediate further down the catabolic pathway) turns the enzyme off
(1)Select one:
a. lowers activation energy
b. lowers the ÎG
c. raises the Free Energy
(2)Select one
a. non-competitivenegative feedback
b. irreversible competitivereversible competitive.

15)The reactions in the pathways of glycolysis and the citric acid cycle harvest the high-energy electrons stored in glucose. Therefore, these pathways _______________.

Select one:

a. take place in animal cells, but not in plant cells
b. are catabolic pathways
c. are anabolic pathways
d. involve the reduction of glucose and its metabolic intermediates

21) In an exergonic chemical reaction, the products have less free energy than the reactants (-ÎG). Endergonic reactions require an input of energy (+ÎG). The addition of starting materials and the removal of end products prevent metabolism from reaching final equilibrium. Instead, the cell exists in a state of dynamic equilibrium.

Select one:
True
False

greyferret515

One feature of a prokaryote that is not found in a eukaryote includes what?

A. a plasma membrane

B. ribosomes

C. lack of nucleus

D. DNA

E. cytoplasm

Which is a series of interconnected membranous tubules that collectively modify proteins and synthesize lipids?

A. endoplasmic reticulum

B. vacuole

C. nucleus

D. lysosome

E. Golgi apparatus

What kind of metabolic pathway takes small molecules and builds them into larger ones, requiring energy?

A. catabolic

B. anabolic

C. bioenergetics

D. metabolism

Why canât cells store extra free energy?

A. it would result in an increase of heat, which would denature enzymes

B. it would result in a lack of space, which would keep out other molecules

C. they can store free energy, which is why we are able to survive

D. it would result in a lowering of heat, which would freeze the cells

Reactions that absorb free energy are called what?

A. potential

B. kinetic

C. exergonic

D. endergonic

Biology 1002B Lecture Notes - Lecture 6: Anabolism, Cellular Respiration, Endergonic Reaction

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