P3.2. Protein

Question 1

• naturally-occurring
• unbranched polymer in which the monomer units are amino acids

Answer 1

PROTEIN

Question 2

Elemental Compositon of Protein:

Answer 2

Carbon
Hydrogen
Oxygen
Nitrogen
may also contain Sulfur

Question 3

average nitrogen content of proteins

Answer 3

15.4% by mass

Question 4

Some elemental composition that can be present in proteins are:

Answer 4

Fe, P, and some other metals in some specialized protein

Question 5

a peptide in which at least 40 amino acid residues are present

Answer 5

PROTEIN

Question 6

Several proteins with ____ amino acid residues are known

Answer 6

GREATER THAN 10,000

Question 7

Common proteins contain ____ amino acid residues

Answer 7

400–500

Question 8

Small proteins contain ____ amino acid residues

Answer 8

40–100

Question 9

TRUE OR FALSE?

There can be more than one peptide chain may be present in a protein.

Answer 9

TRUE

Question 10

contains one peptide chain

Answer 10

monomeric protein

Question 11

contains more than one peptide chain

Answer 11

multimeric protein

Question 12

2 PROTEIN CLASSIFICATION BASED ON CHEMICAL COMPOSITION:

Answer 12

Simple Proteins
Conjugated Proteins

Question 13

• only amino acid residues are present.
• more than one protein MAY BE PRESENT, but ALL SUBUNITS contain only AMINO ACIDS.

protein portion - AMINO ACIDS

Answer 13

Simple Proteins

Question 14

A protein that has one or more non-amino acid entities (prosthetic groups) present in its structure

Answer 14

Conjugated Protein

Question 15

1. non-amino acid entities are ____.
2. non-amino acids components may be ____.

Answer 15

1. prosthetic groups
2. organic/inorganic - prosthetic groups

Question 16

Examples of Prosthetic Groups:

Answer 16

• Lipoproteins
• Glycoproteins
• Metalloproteins

Question 17

TRUE OR FALSE?
One or more polypeptide chains may be present in Conjugated Proteins.

Answer 17

TRUE

Question 18

TRUE OR FALSE

Non-amino acid components in Conjugated protein may be organic or inorganic prosthetic groups.

Answer 18

TRUE

Question 19

contain lipid prosthetic groups

Answer 19

Lipoproteins

Question 20

contain carbohydrate groups

Answer 20

Glycoproteins

Question 21

contain a specific metal as prosthetic group

Answer 21

Metalloproteins

Question 22

Four types of Protein Structures:

Answer 22

• PRIMARY STRUCTURE
• SECONDARY STRUCTURE
• TERTIARY STRUCTURE
• QUATERNANRY STRUCTURE

these four dictates the function & defines the morphology of proteins

Question 23

refers to the order [number and sequence] in which amino acids are linked together in a protein

Answer 23

PRIMARY STRUCTURE OF PROTEINS

Question 24

the number and sequence of amino acids linked by the amides/peptide bonds are dictated by?

Answer 24

DNA CODING

Question 25

**sequenced and determined the primary structure** for the first protein hormone - **Insulin** ## Footnote its: - molecular structure - identity - binding capacity/ability

Answer 25

Frederick Sanger (1953)

Question 26

- **interaction of adjacent amino acids** ## Footnote its 3 forms?

Answer 26

SECONDARY STRUCTURE OF PROTEINS ## Footnote 1. alpha-helix [spring] 2. beta-pleated [corugated form] 3. random [without pattern]

Question 27

**The peptide linkages** [in SECONDARY STRUCTURE of Proteins] are essentially ____ thus allows **only two possible arrangements** for the peptide backbone

Answer 27

planar

Question 28

**The peptide linkages** [in SECONDARY STRUCTURE of Proteins] are essentially **planar** thus allows **only two possible arrangements** for the peptide backbone... **ITS REASONS:**

Answer 28

- For **two amino acids** linked through a peptide bond **six atoms lie in the same plane** - The **planar peptide linkage structure** has considerable **rigidity**, therefore rotation of groups about the C–N bond is hindered - **Cis–trans isomerism** is possible about **C–N bond**. - The **trans isomer** is the **preferred orientation** | yung naka-bold lang tandaan HAHAHAHA. Explain in own words na langs~

Question 29

- **single protein chain** - shape: **COILED SPRING [HELIX]** - **coiled helical spring** - **its R-group are outside the Helix** because there is not enough room for them to stay inside. - **H-bonding between same amino acid chains** – **INTRAMOLECULAR** | SAME AMINO ACIDS - HYDROGEN BONDING ## Footnote R-GROUP OUTSIDE!!!

Answer 29

Alpha-helix (a-helix)

Question 30

- **Completely extended amino acid chains** - **Side chains below or above the axis** - **H-bonding between two different chains** – **INTER or/and INTRAMOLECULAR** | DIFFERENT AMINO ACIDS - HYDROGEN BONDING ## Footnote R-GROUP/SIDE CHAINS - TOP OR BOTTOM!!!

Answer 30

Beta-pleated sheets (b-pleated sheet)

Question 31

- overall **three-dimensional shape** of a protein - **interactions between amino acid side chains** (R groups) that are widely separated from each other - defines the **physical & chemical properties of proteins**

Answer 31

TERTIARY STRUCTURE OF PROTEINS

Question 32

4 types of interactions are observed in Tertiary Structure of Proteins:

Answer 32

1. Disulfide Bond 2. Electrostatic Interactions 3. H-bondings 4. Hydrophobic interactions

Question 33

- covalent - strong - between **two cysteine groups**

Answer 33

Disulfide Bond

Question 34

- **Salt Bridge** between **charged side chains** of **acidic and basic** amino acids

Answer 34

Electrostatic Interactions ## Footnote -OH -NH2 -COOH -CONH2

Question 35

- bonding between **polar, acidic and/or basic R groups** - for this bonding to occur, it must be attach to what elements?

Answer 35

1. H-bonding (Hydrogen Bonding) 2. OXYGEN, NITROGEN, FLUORINE

Question 36

interaction between **non-polar side chains**.

Answer 36

Hydrophobic Interactions

Question 37

- **HIGHEST level** of protein organization. - 2 or more chains/subunits attract to form proteins.

Answer 37

QUATERNARY STRUCTURE OF PROTEINS

Question 38

Most ____ contain an **even number of subunits** (two subunits a dimer, four subunits a tetramer, and so on).

Answer 38

multimeric proteins

Question 39

held together mainly by **hydrophobic interactions between amino acid R groups.**

Answer 39

subunits

Question 40

- example of a protein with quaternary structure. - **oxygen carrying protein in blood** - **tetramer** in which there are **two identical a chains** and **two identical B chains** ## Footnote Each chain in this protein enfolds a ____, the site where oxygen binds to the protein.

Answer 40

Hemoglobin ## Footnote heme group

Question 41

Proteins Classification based on SHAPE:

Answer 41

1. FIBROUS PROTEINS: Collagen 2. GLOBULAR PROTEINS: Myoglobin & Hemoglobin

Question 42

- **Most abundant proteins** in humans (**30%** of total body protein) - **Major structural material** in CONNECTIVE TISSUES [tendons, ligaments, blood vessles, skin] - **Organic component** of bones and teeth - Predominant structure - **TRIPLE HELIX** - **Rich in proline (up to 20%)** – important to maintain structure

Answer 42

COLLAGEN

Question 43

Collagen is rich in what derivatives?

Answer 43

4-hydroxyproline (5%) 5-hydroxylysine (1%)

Question 44

some hydroxylysines are linked to ____ and ____, and their ____ that helps in aggregation of collagen fibrils. | aggregation: cluster

Answer 44

1. glucose 2. galactose 3. disaccharides

Question 45

- **oxygen storage molecule in muscles**. - Monomer - **single peptide chain with one heme unit** - Binds **one O2 molecule** - oxygen serves as a **reserve oxygen source for working muscles**

Answer 45

Myoglobin

Question 46

TRUE or FALSE: myglobin has a **higher affinity for oxygen** than hemoglobin.

Answer 46

TRUE

Question 47

- **An oxygen carrier molecule in blood** - Transports oxygen from lungs to tissues - **Tetramer (four peptide chains)** - each subunit has a heme group - Can transport up to **4 oxygen molecules** at time ## Footnote Iron atom in heme interacts w/...

Answer 47

Hemoglobin ## Footnote Oxygen

Question 48

PROTEINS CLASSIFICATION BASED ON FUNCTION:

Answer 48

1. ability to bind small molecules 2. ability to bind other proteins 3. ability integrated into cell membranes ## Footnote Proteins is the most versatile macromolecule.