Lecture 5

Question 1

functions of proteins

Answer 1

1. Enzymes: catalyze specific reactions
2. Transport proteins: hemoglobin, channel/carrier proteins in cell membranes
3. Structural proteins: ex cytoskeleton
4. Hormonal proteins
5. Receptor proteins
6. Defensive proteins

Question 2

what are proteins made up of

Answer 2

Proteins are made of monomers called amino acids

Question 3

Amino acids are held together by ..?

Answer 3

peptide bonds

Question 4

Peptide bonds are formed by which reaction?

Answer 4

dehydration synthesis reaction

Question 5

proteins get breakdown through which reaction

Answer 5

hydrolysis

Question 6

Can Eating Extra Protein Make Muscles Grow Larger?

Answer 6

No

Hard work, not excess dietary protein, is the trigger for the genes to build more muscle tissue

Question 7

4 levels of Protein structure?

Answer 7

Primary
Secondary
Tertiary
Quaternary: 2 or more polypeptides

All proteins have primary, secondary, & tertiary structures but quaternary structures only arise when a protein is made up of two or more polypeptide chains.

Question 8

what is the Primary Structure?

Answer 8

Amino acid SEQUENCE

Each polypeptide has a unique linear sequence of amino acids

Question 9

what is the Secondary Structure?

Answer 9

Coiling / folding of the 1° structure = secondary structure

Coiled (α-helix): Flexible: H-bonds can be broken so polypeptide can stretch under tension
Folded (ß-pleated): strong

Question 10

what is the Tertiary Structure?

Answer 10

Polypeptide with secondary structure folds on itself giving the protein a three-dimensional shape
All polypeptides have this level

Question 11

what is the Quaternary Structure?

Answer 11

Association of 2 or more polypeptide chains

Question 12

what is a POLYPEPTIDE

Answer 12

polymer of aa with a tertiary structure

Sometimes a polypeptide is a protein: if the polypeptide performs a function without needing to be associated with other polypeptides

Question 13

what is a protein

Answer 13

1 or more polypeptides folded/coiled into a specific shape & performs a function

Proteins made up of > 1 polypeptide have quaternary protein structure

Question 14

what is the Denaturation in proteins

Answer 14

Disruption and possible destruction of both the secondary & tertiary structures of the polypeptide & possibly of quaternary structure if present

Inhibits protein function
Can be reversible or irreversible

Question 15

what are Mutations in proteins

Answer 15

Protein misfolding can occur due to mutations (primary structure), which can lead to changes in secondary & tertiary structure

Question 16

When a protein is denatured, why does it lose its functionality?

Answer 16

Denaturation breaks bonds that hold the protein in its 3-dimensional shape. Without the proper shape, the protein cannot function

Question 17

The primary structure of a protein is determined

Answer 17

by genes

Question 18

what are amino acids made up of

Answer 18

organic compounds made from amine (-NH2) and carboxylic acid (-COOH) functional groups