300838 Lecture Notes - Lecture 8: Pentose Phosphate Pathway, Comparative Physiology, Blood Sugar

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amberhippopotamus661

31 Mar 2019

School

UWS

Department

University of Western Sydney

Course

300838

Professor

anonymous

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Document Summary

Comparative physiology 8: glucose is a key metabolite in human metabolism, and we will spend a good bit of time on the various pathways that are concerned with the utilization, storage, and regeneration of glucose. The first step in the degradation of glucose is glycolysis, which breaks down glucose to pyruvate. The main purpose of glycolysis is the generation of energy (atp). Both atp and nadph are needed in every cell, and accordingly both glycolysis and the hexose monophosphate shunt are ubiquitous: glycogen is a polymeric storage form of glucose, not unlike starch, which is found in plants. Glycogen is most abundant in the liver and in striated muscle, although some is found in other tissues also. Glycogen is synthesized when glucose supply is high, and its degradation helps to maintain the blood glucose level when we are fasting. When glycogen is depleted, more glucose is synthesized from scratch in gluconeogenesis.

Related Questions

1. Consider all the pathways of carbohydrate metabolism discussed in biochemisty. List all the reactions that are:

a. unique to glycolysis (1)

b. unique to gluconeogenesis â give enzyme names (1)

c. shared between glycogen synthesis and glycogenolysis â give enzyme names (1)

2. Consider the enzyme hexokinase.

d. Hexokinase activity is regulated by glucose-6-phosphate by the process of _________________________. (1)

e. The liver isozyme of hexokinase, called glucokinase, is not susceptible to this type of regulation. Explain why this makes sense, considering the role of the

liver in maintaining the glucose balance for the organism. (2)

f. Glucokinase has a much higher Km for glucose than does hexokinase. How does this property help the liver act as a glucose storage organ? (2)

3. Lactate is a waste product in rapidly contracting muscle, but a fuel for resting muscle. Explain, with reference to the metabolic pathways through which lactate proceeds in each

case. (2)

g. When lactate is used as a fuel by muscle, how much ATP can the muscle obtain by complete oxidation of lactate? (1)

byzantiumsquirrel336

The complete set of reactions carried out by an organism is called:

a. anabolism

b. catabolism

c. metabolism

Value: 2

The breakdown of starch is broken down to glucose is an example of:

a. anabolism

b. catabolism

c. metabolism

Value: 3

For the following statement, determine which description best describes the process: DNA is synthesized from free nucleotides.

a. anabolism

b. catabolism

c. metabolism

Value: 4

Fill in the blank: Catabolic reactions result in the synthesis of molecules of .............via cellular respiration. This is then used to power anabolic reactions.

Value: 5

The energy in organic molecules is released in a series of steps because:

a. it is not possible to release it in a single step.

b. more total energy is released in multiple steps than would be released in a single step

c. less total energy is released in multiple steps than would be released in a single step.

d. more energy can be harvested for cellular use in multiple steps than from a single step.

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photosynthesis

1-The light reaction of photosynthesis does not include

a. chemiosmosis

b. oxygen liberation

c. glucose synthesis

d. electron transport

Value: 2

Photosynthesis takes place in the membranes of small sacs called

a. thylakoids

b. photosystems

c. stroma

d. photons

Value: 3

During what stage of photosynthesis is O2 produced?

a. the light-dependent reactions involving photosystems I and II

b. carbon fixation

c. the Krebs cycle

d. O2 is not produced during photosynthesis

Value: 4

The pigment molecules responsible for photosynthesis are located in the

a. mitochondria

b. cytoplasm of the cell

c. stroma of the chloroplast

d. thylakoid membrane of the chloroplast

Value: 5

During what stage of photosynthesis are ATP and NADPH converted to ADP + Pi and NADP+?

a. the light-dependent reactions

b. the light-independent reactions

c. both of the above

d. none of the above

Value: 6

What energy-rich organic compound is produced as a result of the Calvin cycle?

a. ATP

b. NADPH

c. glucose

d. H2O

Value: 7

During photosynthesis, photons raise electrons to higher energy levels. These excited electrons belong to what compound?

a. water

b. ATP

c. chlorophyll

d. electron transport chain

Value: 8

Which of the following statements accurately describes the relationship between photosynthesis and cellular respiration?

a. photosynthesis occurs only in autotrophs; cellular respiration occurs only in heterotrophs

b. photosynthesis uses solar energy to convert inorganics to energy-rich organics; respiration breaks down energy-rich organics to synthesize ATP

c. photosynthesis involves the oxidation of glucose; respiration involves the reduction of CO2

d. the primary function of photosynthesis is to use solar energy to synthesize ATP; the primary function of cellular respiration is to break down ATP and release energy

300838 Lecture Notes - Lecture 8: Pentose Phosphate Pathway, Comparative Physiology, Blood Sugar

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