Peptides and Proteins

Question 1

Proteins

Answer 1

are very important biological molecules that play important roles in almost ALL biological processes

Question 2

Proteins provide many essential functions in the body, such as:

Answer 2

• antibodies supporting the immune system
• digestive enzymes help facilitate chemical reactions
• support muscle contraction & movement
• hormones help coordinate bodily function
• provide support to the body
• move essential molecules around the body
• support the regulation and expression of DNA and RNA

Question 3

Proteins are

Answer 3

polymers of amino acids

Question 4

A peptide bond results from the linkage of the

Answer 4

carboxyl group of 1 amino acid to the amine group of its neighbor

Question 5

Water is

Answer 5

eliminated to form a peptide bond

Question 6

Each amino acid links to the next with

Answer 6

a peptide bond

Question 7

Amino acids are connected

Answer 7

head to tail

Question 8

Dipeptide=
Tripeptide=
Polypeptide=

Answer 8

2 joined amino acids
three
many

Question 9

A polypeptide becomes a protein at

Answer 9

50 amino acids

Question 10

Naming peptides

Answer 10

-name from the free amine (
NH3+)
-use -yl endings for the names of amino acids

Question 11

Naming peptides 2

The last amino acid with the free carboxyl group (COO-)

Answer 11

uses its amino acid name

Question 12

Representation of a peptide or protein:

A peptide or protein can be represented using the

Answer 12

3 letter codes of the residues, written in the order in which they are linked together

Question 13

Why do we represent peptides/proteins link this:?

Answer 13

this convention is to orient the sequence of amino acids so that N-terminal residue is on the left and the C-terminal residue is on the right.

Question 14

Many hormones are

Answer 14

peptides

Question 15

Oxytocin has

Answer 15

9 residues

Question 16

Bradykinin has

Answer 16

9 residues

Question 17

Insulin has

Answer 17

30 residue chain + 21 residue chains + glucagon 20 residues

Question 18

Antibiotics polymyxin B is for

Answer 18

grambacteria

Question 19

Bacitracin is for

Answer 19

gram + bacteria

Question 20

Amanitin =
Conotoxin=
Chlorotoxin=

Answer 20

mushrooms
cone snails
scorpions

Question 21

Protein folding is

Answer 21

the physical process by which a protein chain acquires its native 3-dimensional structure, a conformation that is usually biologically functional

Question 22

Protein folding occurs _______ in a cellular compartment called the ______

Answer 22

spontaneously

ER

Question 23

Why is protein folding necessary?

Answer 23

because proteins must be correctly folded into specific, 3D shapes in order to function correctly

Question 24

When does folding occur?

Answer 24

begins during the translation of the polypeptide chain

Question 25

Amino acids interact with each other to produce a ............. The folded protein is known as the -----------

Answer 25

well-defined 3D structure | native state

Question 26

Primary Structure

Answer 26

linear sequence of amino acids

Question 27

Secondary Structure

Answer 27

localized folding

Question 28

Tertiary Structure

Answer 28

overall 3-D structure

Question 29

Quaternary Structure

Answer 29

association of 2 or more protein subunits into a protein

Question 30

Primary structure is the

Answer 30

order in which amino acids are joined together by peptide bonds

Question 31

Secondary structure of protein includes

Answer 31

alpha helix b pleated sheet (3 strands) b turn

Question 32

Alpha Helix

Answer 32

held by H bonds between the H of --N-H group and the -O of C (double bond) O of the fourth amino acid along the chain

Question 33

The alpha helix looks like a

Answer 33

coiled 'telephone cord'

Question 34

The 2 very important secondary structures of proteins are:

Answer 34

a- helix | b-pleated sheet

Question 35

Both of these structures depend on ________ ______ between the _____ H and the _______ O further down the chain or on a parallel chain.

Answer 35

hydrogen bonding amide carbonyl

Question 36

What is a common secondary structure of proteins?

Answer 36

alpha helix (a-helix)

Question 37

The a-helix is a

Answer 37

right hand coiled or spiral conformation

Question 38

What must happen in a alpha helix bond?

Answer 38

every backbone N-H group donates a hydrogen bond to the backbone C=O group of the amino acid 4 residues earlier (hydrogen bonding)

Question 39

Each turn of a-helix contains

Answer 39

3.6 amino acids

Question 40

In a B-pleated sheet

Answer 40

all of the peptide bond components are involved in a hydrogen bonding

Question 41

In a B-pleated sheet , the surface of the sheet appears

Answer 41

pleated

Question 42

All of the carbonyl O and amide H are involved in the __ _____ with the chain are nearly completely ________.

Answer 42

H bonds | extended

Question 43

In a B-pleated sheet, the 2 possible orientations are

Answer 43

parallel | antiparallel

Question 44

What are the differences between B-pleated sheets and A-helix sheets?

Answer 44

- unlike the a-helix, B-sheets are composed of 2 or more peptide chains - the peptide chains of B-sheets are fully extended

Question 45

There are several types of ______ and ________ that hold a protein in its tertiary structure

Answer 45

bonds and forces

Question 46

Quaternary Structure: | Association of

Answer 46

more than one polypeptides

Question 47

Each unit of a quaternary structure protein is called a

Answer 47

subunit

Question 48

Subunits (________) can be identical (__________) or different (__________)

Answer 48

monomers hompolymeric heteropolymeric

Question 49

Hemoglobin is made up of

Answer 49

2 alpha globins | 2 beta globins

Question 50

We can classification of proteins according to

Answer 50

shape and nutritional value

Question 51

According to shape:

Answer 51

globular | fibrous

Question 52

According to nutritional value:

Answer 52

complete protein | non-complete protein

Question 53

Globular proteins 'spherical' shape include:

Answer 53

``` HEMAI Hemoglobin Enzymes Myoglobin Antibodies Insulin ```

Question 54

Fibrous proteins 'long, thin fibers' include:

Answer 54

KEC keratin elastin collagen

Question 55

Complete Proteins

Answer 55

proteins that provide all the essential amino acids (most animal proteins)

Question 56

Incomplete Proteins

Answer 56

proteins that are missing one or more essential amino acids (most plant proteins except soy protein)

Question 57

Incomplete proteins can be served with a

Answer 57

complementary protein to make it complete

Question 58

Why are animal products thought to be higher quality proteins compared to plant products?

Answer 58

because animal proteins are complete proteins

Question 59

Not only do animal proteins contain all of the essential amino acids,

Answer 59

they're in larger amounts and in the proper proportions

Question 60

Can plant proteins provide the human body with all the amino acids needed for optimal growth and development?

Answer 60

yes

Question 61

The proteins in plant proteins are usually in much

Answer 61

smaller amounts

Question 62

Most plant proteins have ____ or ________ ________ acid making them ________ proteins.

Answer 62

one or more limiting amino acid making them incomplete proteins.

Question 63

While most plant proteins are considered to be incomplete amino acid sources, they

Answer 63

may be combined and eaten in proper combinations to provide complete proteins

Question 64

The only protein that is an exception to this rule is

Answer 64

the soybean

Question 65

The soybean is considered a

Answer 65

complete protein and is comparable to animal protein