BIOL 2213 Lecture Notes - Lecture 1: Electrochemical Gradient, Membrane Potential, Catabolism

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rubyhedgehog729

27 Apr 2017

School

University of Arkansas

Department

Biology

Course

BIOL 2213

Professor

Dr.Hill

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Document Summary

Proteins often function by binding to ligands; binding enables the protein to do its function (ex: act as enzymes, receptors for hormones) Ability for protein to do it"s function can be turned on, off, or slowed down. When ligand binds to protein it makes it change it"s shape. Allosteric modulation: in addition to the binding site, it will have another site (the allosteric site) where it can bind something else; allosteric site is like a switch that turns it on or off or slows it down. Allosteric activation: green molecule has to bind to the allosteric site to turn on the enzyme. Allosteric activator causes it to change it shape, making it turn on. Allosteric inhibition: binds to the allosteric site and slows down the enzyme. Allosteric molecule can regulate the speed of the reaction. Covalent modulation: second way enzymes/proteins can be regulated. Covalent bond form at another site on the enzyme, usually with the phosphate group.

Related Questions

Explain how the following mechanisms regulate enzyme activity.

Part A

Covalent modification

a)The product of a series of reactions acts as an inhibitor for an earlier reaction.

b)Hormones control the synthesis of enzymes.

c)A regulator binds to the enzyme at a site other than the active site. This binding changes the shape of the enzyme and alters the catalytic ability of the enzyme.

d)An inhibitor binds reversibly to the enzymesubstrate complex, blocking the binding of the second substrate to the active site.

e)The activity of an enzyme is influenced by the addition or removal of a group that is covalently bonded to the enzyme.

f)An inhibitor forms covalent bonds to the active site, permanently blocking it.

Part B

Genetic control

a)The product of a series of reactions acts as an inhibitor for an earlier reaction.

b)Hormones control the synthesis of enzymes.

c)A regulator binds to the enzyme at a site other than the active site. This binding changes the shape of the enzyme and alters the catalytic ability of the enzyme.

d)An inhibitor binds reversibly to the enzymesubstrate complex, blocking the binding of the second substrate to the active site.

e)The activity of an enzyme is influenced by the addition or removal of a group that is covalently bonded to the enzyme.

f)An inhibitor forms covalent bonds to the active site, permanently blocking it

Part C

Allosteric regulation

a)The product of a series of reactions acts as an inhibitor for an earlier reaction.

b)Hormones control the synthesis of enzymes.

c)A regulator binds to the enzyme at a site other than the active site. This binding changes the shape of the enzyme and alters the catalytic ability of the enzyme.

d)An inhibitor binds reversibly to the enzymesubstrate complex, blocking the binding of the second substrate to the active site.

e)The activity of an enzyme is influenced by the addition or removal of a group that is covalently bonded to the enzyme.

f)An inhibitor forms covalent bonds to the active site, permanently blocking it.

Part D

Feedback inhibition

a)The product of a series of reactions acts as an inhibitor for an earlier reaction.

b)Hormones control the synthesis of enzymes.

c)A regulator binds to the enzyme at a site other than the active site. This binding changes the shape of the enzyme and alters the catalytic ability of the enzyme.

d)An inhibitor binds reversibly to the enzymesubstrate complex, blocking the binding of the second substrate to the active site.

e)The activity of an enzyme is influenced by the addition or removal of a group that is covalently bonded to the enzyme.

f)An inhibitor forms covalent bonds to the active site, permanently blocking it

Enzyme Activity

1. Briefly explain the principle of spectrophotometry.

2. Which of the following statements is true about enzymes?(check all correct answers)

		__ enzymes act on (are specific for) one or just a fewsubstrates
		__ enzymes can be denatured (loose their tertiary/quaternarystructure and activity) by extreme conditions such as heat, high orlow pH,or presence of organic solvents
		__most enzymes are DNA
		__ enzymes are protein
		__enzymes perform best at specific conditions of temperature, pHand salt concentration 5. Which enzymes break the following macromolecules? Match the following with their correponding answers: ___ Nucleic acids A. proteases or proteinases such as pepsin ___ Cellulose B. none ___ Triglycerides C. lipases ___ Proteins D. amylases ___ Starch E. nucleases 6.Match the following enzymes totheir products. Answers ___ pepsin, trypsin and other digestive proteases A.Nucleotides ___ salivary and pancreatic amylases and other enzymes B. AminoAcids ___ lipases C. Monosaccharides ___ nucleases D. fatty acids and glycerol 7. Based on experiments, what is the effect of extremeconditions of pH and temperature (boiling tube) on enzymeactivity? 8. ATP stores energy in the form of___ ___ Chemical energy ___ Kinetic energy ___ Thermal energy ___ Activation energy 9. An allosteric site in anenzyme is____ __ the site where reactions occur __ the site that binds aregulator __ the site that binds thesubstrate __ the site that binds the product 10. Enzymes increase the rate of reactions by making thetransition state less stable. __ True __ False 11. Enzymes increase the rate of reactions by placing reactingparts of the molecule in favorable positions. __ True __ False 12. Which of the followingis a mechanism for regulation of enzymes? __ covalent modification __ feedback inhibition __ allosteric regulation __ all of the above 13. Which of the following represents a correct order of eventsin an enzyme catalytic cycle? 1.enzyme changes shape 2.substrate binds to active site 3.substrate is converted to products 4. products are released from activesite __ 1>2>3>4 __ 2>1>3>4 __ 3>2>1>4 __ 2>4>3>1

cyancicada301

Can someone please help me with the following questions.

Question 6

Proteins can be regulated by removing phosphate groups that modify specific amino acids in their sequences. This removal activity is exerted by

	a.	Protein Phosphorylases
	b.	Protein Phosphatases
	c.	Protein Kinases
	d.	Protein Phosphoproteases

Question 7

Proteolytic processing is a(n)

	a.	requirement for protein insertion into membranes
	b.	type of covalently-linked post-translational modification
	c.	irreversible post-translational modification
	d.	type of reversible post-translational modification
	e.	frequent consequence of heat denaturation

Question 8

Allosteric regulation involves

	a.	the binding of a protein to a regulatory subunit
	b.	the binding of a regulatory molecule to the active site on an enzyme
	c.	the binding of a regulatory molecule to a site on an enzyme that is distinct from the catalytic site
	d.	the binding of GTP to an enzyme to regulate its function
	e.	the binding of a Ubiquitin-like protein to an enzyme

Question 9

During N-linked glycosylation, a carbohydrate side chain is attached through a Nitrogen atom at the amino group of Serine or Threonine

True

False

Question 10

The signal sequence that targets proteins for insertion into the Endoplasmic Reticulum is rich in hydrophobic aminoacids and is most frequently located at the N-terminus of the protein

True

False

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BIOL 2213 Lecture Notes - Lecture 1: Electrochemical Gradient, Membrane Potential, Catabolism

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