BSC 2010 Lecture Notes - Lecture 5: Peptide, Living Systems, Sucrase

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30 Aug 2013

School

University of Florida

Department

Biology - Biological Sciences

Course

BSC 2010

Professor

Oppenheimer

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Document Summary

Concept 3. 2 proteins are polymers with important structural and metabolic roles. Oligopeptides or peptides short polymers of 20 or fewer amino acids (some hormones and signaling molecules) Polypeptides or proteins range in size from insulin, which has 51 amino acids, to huge molecules such as the muscle protein titin, with 34,350 amino acids. Amino acids are linked in condensation reactions to form peptide linkages or bonds. Polymerization takes place in the amino to carboxyl direction. There are four levels of protein structure: 1. Primary- held together by peptide bonds/ covalent bonds: 2. Secondary- held by hydrogen bonds: 3. tertiary, 4. Secondary structure: regular, repeated spatial patterns in di erent regions, resulting from hydrogen bonding. There are 2 major types of secondary structure: 1. (alpha) helix right-handed coil, 2. (beta) pleated sheet two or more polypeptide chains are extended and aligned. Tertiary structure is the nal, folded, 3-d shape of a polypeptide.

Related Questions

1. A sequence of amino acids in a certain protein is found to be â Ser â Gly â Pro â Gly â

The sequence is most probably part of a(n):

a. beta turn

b. antiparallel beta sheet

c. alpha-helix

d. parallel beta-sheet

e. alapha-sheet

2. Which statement about peptides bonds is NOT TRUE?

There is perfectly free rotation about the peptide bond.

The peptide bond has partial double-bond character.

The peptide bond is shorter than a normal carbon-nitrogen single bond.

The peptide bond usually has a trans configuration with respect to the alpha-carbons of the two amino acids involved in the peptide bond.

Peptide bonds are made via condensation of an amine and a carboxylic acid with loss of water.

3. Which of the following statements about proteins is FALSE?

	Active proteins are generally very loosely structured.
	In water-soluble proteins, hydrophobic amino acid residues are generally buried and not exposed to water.
	Primary structure determines tertiary structure.
	Secondary structure is regular, recurring arrangements in space of nearby amino acid residues in a polypeptide.
	Quaternary structure involves the interaction of subunits in a protein with more than one polypeptide chain.

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1. What is an organic molecule?

2.Name three hydrocarbons and be able to draw their structural formulas.

3. What is an isomer? List and describe the three types (structural, geometric, and enantiomers).

4. Be able to recognize and describe the properties of these functional groups: aldehyde, ketone, hydroxyl, sulfhydryl, carboxyl, amino, and phosphate groups.

5. What is a monosaccharide? Give two examples of these molecules and their functions.

6. Describe these chemical reactions: dehydration synthesis (condensation reaction) and hydrolysis (rehydration).

7. What is a disaccharide? List two and give their functions.

8. What is a polysaccharide? List two storage forms and two structural forms. How are they formed and what is their specific function?

9. How do the pancreatic hormones insulin and glucagon regulate blood sugar levels?

10. What is molting and why is it necessary in certain animals?

11. What four molecules are bonded together to form a triglyceride or fat? Why are fats nonpolar? What are some functions of fats as well as other lipids such as oils and waxes?

12. How do saturated and unsaturated fats differ? Discuss bonding patterns and possible sources of these fats. Which type is healthier for you? Why?

13. Why do animals store most of their excess glucose as fats or oils rather than as glycogen or protein? Give two reasons.

14. What are phospholipids? Identify parts of the phospholipid bilayer that are hydrophobic or hydrophilic? What important cell structure do these molecules help create?

15. Describe the structure of a steroid. How is cholesterol used in beneficial ways in your body?

16. What are LDLs and HDLs? Which is considered good or bad cholesterol? What condition could result from high blood pressure?

17. What are four ways to either reduce high blood cholesterol or maintain a safe level?

18. What is the composition of an amino acid? Why would they be considered nonpolar, polar, acidic, or basic?

19. Define dipeptides and polypeptides.

20. Describe the primary structure of a protein. What type of bonding creates it?

21. What is the secondary structure of a protein? Name two types of secondary structure and indicate what type of bonding holds them together. List three fibrous proteins.

22. What is the tertiary structure of a protein? What types of bonds or chemical interactions allow a protein to maintain this structure? List three globular proteins.

23. What is the quaternary structure of a protein? Describe a hemoglobin molecule.

24. What are the subunits of nucleic acids and what is their composition? How are these subunits bonded together? What is DNS's basic shape?

25. List three differences between DNA and RNA.

Question 401 pts

Kinetic energy is the stored energy that can be used for motion.

True

False

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Question 411 pts

When an electron is transferred from one atom to another, and the two atoms are then electrically attracted to one another, a(n) ________________ bond is formed.

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Question 421 pts

Changing the number of ____________ of an atom would change the chemical properties of the atom.

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Question 431 pts

Forming molecules and breaking down molecules in biological organisms usually requires the use of _________ to help the reaction proceed faster.

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Question 441 pts

Organic molecules have a core composed of .

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Question 451 pts

The building blocks of carbohydrates are

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Question 461 pts

Water molecules crossing a membrane from high to low concentration is .

active transport

cell fate

facilitated diffusion

osmosis

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Question 471 pts

Choose the membrane molecule responsible for the passage of polar molecules and ions into and out of the cell.

phospholipids

transmembrane channel proteins

cell surface proteins

carbohydrate chains

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Question 481 pts

The simplest cells are .

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Question 491 pts

Which of the following membrane bound organelles are found inside bacterial cells:

nucleus

organelles are not found in prokaryotic cells

mitochondria

chloroplasts

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Question 501 pts

Which of the following is a specialized components of the cell, is associated with the rough endoplasmic reticulum, and is responsible for making proteins.

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Question 511 pts

Proteins are sorted, modified, and packaged by the _____________ and later transported to the outside of the cell.

ribosomes

golgi bodies (golgi apparatus)

nucleus

mitochondria

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Question 521 pts

Dehydration synthesis is a process of linking two smaller subunits together to form a polymer. Which of the following statements below is true of dehydration synthesis?

Oxygen is consumed.

A water molecule is removed from the molecules.

A water molecule is added to the molecules

Carbon dioxide is given off.

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Question 531 pts

Proteins are made up of _________ held together by peptide bonds.

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Question 541 pts

Which of the following gives an amino acid its properties?

NH2

R Group or functional group

COOH

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Question 551 pts

The final three-dimensional shape of a protein that includes the bonding of two or more polypeptide chains is call its _____ structure.

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Question 561 pts

How do DNA and RNA differ?

all statements are differences between DNA and RNA.

DNA is double stranded while RNA is single stranded.

They have different sugars.

Thymine is present in DNA but not in RNA.

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Question 571 pts

Which of the following is a component of a DNA nucleotide?

phosphate

a nitrogen containing base

All are components of a nucleotide.

5-carbon sugar

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Question 581 pts

Cell membranes are made up of several different types of molecules. Select the membrane molecule below that is made up of a polar region and two non-polar fatty acid tails.

transmembrane proteins

carbohydrate chains

phospholipids

cell surface proteins

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Question 591 pts

Two organelles which are believed to have once been free-living bacterial cells are ____________ and ______________.

chloroplasts and mitochondria

golgi apparatus and endoplasmic reticulum

ribosomes and nucleolus

peroxisomes and lysosomes

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