Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > Chapter 3 - Proteins > Flashcards

Chapter 3 - Proteins Flashcards

1
Q

The Peptide Bonds
1. What are proteins linear polymers of?
2. What is the carboxyl group of one amino acid linked to?
3. What are the two types of
Linkages?
4. What occurs during the reaction of Glycine and Alanine?

A
  1. Proteins are linear polymers of L-amino-amino acids.
  2. Carboxyl group of one amino acid is linked to the amino group of another amino acid.
  3. Linkages can be either amide bond or peptide linkage.
  4. This reaction is a dehydration reaction as water is released, creating Glycyl-alanine.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Dipeptides

  1. How are dipeptides produced?
  2. What is the amino terminal amino acid of a dipeptide? What is it known as?
  3. What is the carboxyl terminal amino acid of a dipeptide? What is it known as?
  4. How are amino acid structures written?
A
  1. Condensing or dehydrating two amino acids produces a dipeptide.
  2. Amino acid with a free â-NH3+ group, also known as N-terminal.
  3. Amino acid with a free -COO- group, also known as C-terminal.
  4. Amino acid structures are written with the N-terminal on the left.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The Primary Structure of Proteins

  1. What is Primary Structure? What is it the result of?
  2. Do all proteins have similar primary structures?
A
  1. Primary Structure is the amino acid sequence of the polypeptide chain. A result of covalent bonding between the amino acids - the peptide bonds.
  2. No: each protein has a different primary structure with different amino acids in different places along the chain.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

The Secondary Structure of Proteins

  1. When are Secondary Structures formed?
  2. How are Secondary Structures formed?
  3. Do all regions have a clearly defined secondary structure?
A
  1. Secondary structures are formed when the primary sequence of the polypeptide folds into regularly repeating structures.
  2. Secondary Structures results from hydrogen bonding between the amide hydrogen and carbonyl oxygen of the peptide bonds.
  3. Not all regions have a clearly defined secondary structure, some are random or non-regular.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

â-Helix

  1. What type of structure is an â-Helix?
  2. What is the shape of an â-helix?
  3. What is the role of the amide H and carbonyl O in an â-helix? Where are these two linked?
  4. What are H bonds parallel to?
  5. What is the handedness of the helix?
  6. What is the measurement of the repeat distance or pitch?
  7. How many Amino Acids per turn are there?
A
  1. â-helix is the most common type of secondary structure.
  2. An â-helix is coiled and helical.
  3. Each amide H and carbonyl O is involved in H bonds locking the helix in place. Carbonyl O links to amide H 4 Amino Acids away.
  4. H bonds are parallel to the long axis of the helix.
  5. The helix is right-handed.
  6. The repeat distance or pitch is 5.4 angstroms.
  7. 3.6 Amino Acids per turn.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

â-Helices in Fibrils

  1. How are fibrous proteins arranged in a secondary structure?
  2. What is there repeated coiling of?
A
  1. Fibrous proteins are arranged in a secondary structure of fibers or sheets with only 1 type of secondary structure.
  2. Repeated coiling of helices.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

B-Pleated Sheet

  1. What type of structure are Beta-Pleated Sheets? What does it appear similar to?
  2. What is the role of Carbonyl O and amide H within Beta-Pleated Sheets?
  3. What are the two possible orientations?
A
  1. Beta-Pleated Sheets are the second most common secondary structure, appears similar to folds of fabric.
  2. All of the carbonyl O and amide H are involved in the H bonds with the chain nearly completely extended.
    • Parallel: if the N-termini are head-to-head.
      - Antiparallel: if the N-terminus of one chain is aligned with the C-terminus of the other.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Tertiary Structure

  1. What is the tertiary structure?
  2. How is the globular tertiary structure formed and maintained?
  3. What is the function of the tertiary structure?
A
  1. The three-dimensional structure of the entire peptide, which is distinct from secondary structure.
  2. Globular tertiary structure forms spontaneously and is maintained by interactions among the side chains or R groups.
  3. Tertiary structure defines the biological function of proteins.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Types of Interactions Maintaining Tertiary Structures

  1. What are Disulfide bridges made between?
  2. What are Salt bridges made between?
  3. What are hydrogen bonds made between?
  4. What are hydrophobic interactions?
A
  1. Disulfide bridges are ONLY made between two cysteine residues.
  2. Salt bridges are made between ionic side chains COO- and NH3+. (Positive and Negative charges)
  3. Hydrogen bonds are made between polar residue side chains.
  4. Hydrophobic interactions: Two non-polar groups are attracted by a mutual repulsion of water.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The Quaternary Structure of Proteins

  1. What does the functional form of many proteins consist of?
  2. What is the Quaternary Structure? How is it maintained?
  3. What is a subunit?
A
  1. The functional form of many proteins is an aggregate of several globular peptides.
  2. The arrangement of subunits or peptides that form a larger protein. Quaternary structure is maintained by the same forces which are active in maintaining tertiary structure.
  3. Subunit: A polypeptide chain having primary, secondary, and tertiary structural features that is a part of a larger protein.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Proteins Requiring Prosthetic Groups

  1. What is the Prosthetic Group and Example of Nucleoprotein?
  2. What is the Prosthetic Group and Example of Lipoprotein?
  3. What is the Prosthetic Group and Example of Glycoprotein?
  4. What is the Prosthetic Group and Example of Phosphoprotein?
  5. What is the Prosthetic Group and Example of Hemoprotein?
  6. What is the Prosthetic Group and Example of Metalloprotein?
A 
1. Prosthetic Group: Nucleic Acid 
Example: Viruses
2. Prosthetic Group: Lipids 
Example: Serum lipoproteins
3. Prosthetic Group: Carbohydrates 
Example: Mucin in Saliva
4. Prosthetic Group: Phosphate groups 
Example: Casein in milk
5. Prosthetic Group: Heme 
Example: Hemoglobin, cytochromes
6. Prosthetic Group: Iron, Zinc 
Example: Ferritin, hemoglobin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Overview of Protein Structure and Function/Interrelationships

  1. What sequence is involved in a Primary structure? What is this the result of?
  2. What two things does a Secondary structure include? What two things do the hydrogen bonds occur between?
  3. What is folded in a Tertiary structure? What interactions occur within a tertiary structure?
  4. What are quaternary structures concerned with? What is involved in this type of structure?
A
  1. Amino acid sequence. Results from formation of covalent peptide bonds between amino acids.
  2. Includes α-helix and β-sheet. Hydrogen bonding between amide hydrogens and carbonyl oxygens of the peptide bonds.
  3. Overall folding of the entire polypeptide chain. Interactions between different amino acid side chains
  4. Concerned with topological, spatial arrangement of two or more polypeptide chains. Involves both disulfide bridges and noncovalent interactions.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Protein Functions Follow Shape

  1. What are 3 characteristics of Fibrous proteins?
  2. What are 3 characteristics of Globular proteins?
A
  1. Mechanical strength, structural components, movement.

2. Transport, regulatory, Enymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Myoglobin and Hemoglobin

  1. What is hemoglobin?
  2. What is myoglobin?
  3. Why is oxygen transferred from hemoglobin to myoglobin?
A
  1. Hemoglobin is the oxygen-transport protein of higher animals.
  2. Myoglobin is the oxygen storage protein of skeletal muscle
  3. Oxygen is transferred from hemoglobin to myoglobin as myoglobin has a stronger attraction for oxygen than hemoglobin does.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Heme and oxygen Binding

  1. What is a heme group?
  2. What ion in the heme group is the oxygen binding site?
  3. What does each hemoglobin contain?
  4. What makes fetus hemoglobin unique?
  5. What does sickle cell do to RBCs?
A
  1. A Heme group is an essential component of the proteins hemoglobin and myoglobin
  2. Fe2+ ion in the heme group is the oxygen binding site.
  3. Each hemoglobin contains a heme group which can hold 1 molecule of oxygen.
  4. A fetus has a unique type of hemoglobin with slightly greater affinity for oxygen than typical hemoglobin
  5. Causes red blood cells to appear altered.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Proteins in the Blood

  1. How many proteins in g/L does blood plasma contain?
  2. What is the most abundant protein in the blood?
  3. What is the second most abundant? What does it consist of?
  4. What is the third most abundant? What does it consist of?
  5. How much percent of blood plasma do Fibrinogens make up?
  6. What synthesizes γ-globulins?
  7. What are the rest of plasma proteins synthesized by?
  8. What is the hallmark of liver disease?
A
  1. Blood plasma contains 60-80 g/L of proteins, separated in 5 classes: α through γ.
  2. The most abundant is albumin, a nonspecific transport molecule for poorly soluble metabolites such as bilirubin, Ca2+, and fatty acids.
  3. The α-globulins are the next most abundant and include glycoproteins, high and very low density lipoproteins, ceruloplasmin, and prothrombin.
  4. Next are β-globulins which include transferrin and low-density lipoproteins.
  5. Fibrinogen, a protein involved in coagulation of blood, makes up 7% of plasma protein.
  6. γ-globulins are synthesized by the B lymphocytes.
  7. Most of the remaining plasma proteins are synthesized in the liver.
  8. A hallmark of liver disease is reduced amounts of one or more of the plasma proteins.
17
Q

Denaturation of Proteins

  1. What is Denaturation? Does it alter Primary structure?
  2. What two things have a drastic effect on protein conformation?
A
  1. Denaturation is the loss of organized structure of a globular protein. Does not alter primary structure.
  2. Extremes of temperature and pH have a drastic effect on protein conformation
18
Q

Denaturation vs. Hydrolysis

  1. Why are proteins are very susceptible to changes in conditions?
  2. What is Hydrolysis? What 3 things does hydrolysis effect?
  3. What is Denaturation? What 5 things does it effect?
A
  1. Because structure and 3-D shape matters in activity.
  2. Hydrolysis: breaking down into smaller peptides or amino acids. Affects changes in pH, Enzymes and Temperature.
  3. Denaturation: breaking up the 3-D shape. Affects temperature, Heavy metals, Detergents, Organic Solvents, and Mechanical Stress.
19
Q

The Effect of Temperature on Proteins

  1. What is the first effect on proteins as the temperature of a solution of proteins increases?
  2. What happens next as the temperature increases?
  3. What happens eventually?
A
  1. The first effect is the increase in the rate of molecular movement of the individual molecules within the solution.
  2. The temperature increases further, the bonds within the proteins vibrate more violently.
  3. Eventually, the weaker hydrogen bonds and hydrophobic interactions are disrupted, and the characteristic three-dimensional conformation of the protein is disorganized.
20
Q

The Effect of pH on Proteins

  1. How does pH affect proteins?
  2. What does this interfere with?
  3. What are other denaturation agents?
A
  1. When the pH of the solution containing a protein is changed dramatically, the acid or base will change the charge of the protein.
  2. This interferes with the salt bridges and hydrogen bonds that stabilize the tertiary structure.
  3. Organic solvents, detergens, heavy metals (Hg2+ and Pb2+), and mechanical stress
21
Q

Dietary Protein and Protein Digestion

1. What 3 dietary purposes do proteins have?

A
    • Oxidize to provide energy
      - Amino acids liberated by hydrolysis can be used in biosynthesis
      - Amino acids which can not be made in the body are essential amino acids
22
Q

Essential and Nonessential Amino Acids

  1. What two amino acids are essential for infants but not for adults?
  2. What are cysteine and tyrosine are considered to be? Who requires these amino acids?
A
  1. Histidine and arginine are essential amino acids for infants but not for healthy adults.
  2. Cysteine and tyrosine are considered to be semiessential amino acids. They are required by premature infants and adults who are ill.

Biochemistry (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions