Bio Hw due 9/15

Question 1

A polypeptide is a long unbranched chain of

Answer 1

Amino acids

Question 2

The shape of a protein determines its

Answer 2

function

Question 3

Functions of proteins

Answer 3

• they catalyze chemical reactions
• they transport ions and molecules across the cell membranes
• provide structural support for many animal tissues
• play a key role in the contraction of muscles

Question 4

Proteins are polymers made up of how many different amino acids?

Answer 4

20

Question 5

Which part of an amino acid is ALWAYS acidic?

Answer 5

the carboxyl group

Question 6

the chemical structure of a typical amino acid found in a protein:

Answer 6

A central carbon atom is bound to an amino group, carboxyl group, a side chain, and a hydrogen atom.

Question 7

the 20 common amino acid are classified into 5 chemical classes based on their

Answer 7

R groups

Question 8

What is responsible for linking amino acids together to form polypeptides?

Answer 8

Dehydration synthesis

Question 9

Two _______ joined together by a peptide bond form a dipeptide.

Answer 9

amino acids

Question 10

Where are the peptide bonds located in a polypeptide?

Answer 10

Between the amino group of one amino acid and the carboxyl group of another

Question 11

Proteins that only have a single polypeptide chain what two terms are synonymous?

Answer 11

Protein and polypeptide

Question 12

Each kind of protein has a single unique sequence of

Answer 12

amino acids

Question 13

In general, where are nonpolar and polar amino acid found in a folded protein?

Answer 13

Non-polar - interior

Polar - exterior

Question 14

Type of interaction involves the formation of a covalent bond between two different amino acid side chains?

Answer 14

Disulfide bridge

Question 15

The structure of proteins is usually discussed in terms of a hierarchy of how many levels?

Answer 15

4

Question 16

The amino acid sequence of its polypeptides is

Answer 16

primary structures

Question 17

Altering the sequence of amino acids in a polypeptide chain by just a single amino acid can have drastic effects on which of the following ?

Answer 17

Proteins function and proteins shape

Question 18

What is true about the relationship between enzymes and environmental conditions?

Answer 18

• the optimum conditions for enzyme activity are usually similar to the conditions where the enzyme normally functions
• changing environmental conditions may alter the structure of enzymes
• changing environment conditions may alter the activity of enzymes

Question 19

Best describes the relationship between temp. and enzyme activity?

Answer 19

Each enzyme has an optimum temp. where it functions best

Question 20

Proteins are made up of one or more unbranched chains of

Answer 20

amino acids

Question 21

Denaturation

Answer 21

changes in a proteins environment cause the protein to unfold and lose its shape

Question 22

Primary structure

Answer 22

Amino acid sequence

Question 23

Secondary structure

Answer 23

Hydrogen bonding patterns. Alpha helices and Beta sheets

Question 24

Tertiary structure

Answer 24

folds and links. 3D folding of a single peptide

Question 25

Quaternary structure

Answer 25

interaction between 2 or more polypeptides to form a protein

Question 26

A protein's _____ structure refers to the final 3 dimensional shape of the polypeptide chains make up the protein.

Answer 26

tertiary

Question 27

Interactions that help determine a protein's tertiary structure

Answer 27

- Hydrogen bonds - Disulfide bonds - Ionic bonds - Hydrophobic exclusion

Question 28

When a protein spontaneously refolds back into its natural environment it is called :

Answer 28

renaturation

Question 29

Protein denaturation may be caused by an increase in which of the following?

Answer 29

- Temperature - Ionic concentration - pH

Question 30

Dissociation

Answer 30

observed when individual subunits making up a protein with quaternary structure separate without losing their tertiary structures

Question 31

Dehydration synthesis

Answer 31

responsible for linking amino acids together to form polypeptides

Question 32

The term ______ refers to a single, long chain of amino aicds, while a(n) _____ can be composed of one or more long amino acid chains.

Answer 32

polypeptide, protein

Question 33

In general, where are nonpolar and polar amino acids found in a folded protein?

Answer 33

Non- Polar - interior | Polar - exterior

Question 34

Hydrogen bonds between the amino and carboxyl groups of the polypeptide backbone help determine a proteins ____ structure while hydrogen bonds between the amino acid chains help determine protein _____ structure

Answer 34

secondary, tertiary

Question 35

TRUE OR FALSE A protein's final structure can include either regions shaped like an alpha helix or regions shaped like a B- pleated sheet but not both?

Answer 35

FALSE

Question 36

What are two basic types of secondary structure in proteins?

Answer 36

Alpha helix and B pleated sheet

Question 37

Individual polypeptides within a protein are referred to as which of the following?

Answer 37

subunits

Question 38

Most likely to be found in the interior of a protein:

Answer 38

Valine, Leucine, Phenylanine

Question 39

The alpha helix and b pleaded sheets are maintained primarily by hydrogen bonds between which of the following?

Answer 39

The amino and carboxyl groups within the polypeptide backbone

Question 40

A ____ is a substance or a mixture of substance's pH

Answer 40

buffer

Question 41

A substance that decreases (H+) and increases pH when it dissociates in water is called

Answer 41

base

Question 42

A substance that increases (H+) and decreases pH when it dissociates in water is

Answer 42

acid

Question 43

Disulfide bridge

Answer 43

formation of a covalent bond between 2 cysteine side chains

Question 44

Ionic bond

Answer 44

formation of a bond between groups with opposite charge

Question 45

Van der Waals attraction

Answer 45

weak attraction between atoms due to oppositely polarized electron clouds

Question 46

Hydrophobic exclusion

Answer 46

hydrophobic portions of the protein gather in the interior of the protein

Question 47

Diffusion that is assisted by a channel protein or carrier protein is called ___ diffusion

Answer 47

facilitated

Question 48

channel proteins

Answer 48

have a hydrophilic interior that provides an aqueous channel through which polar molecules can pass when the channel is open

Question 49

TRUE about ions

Answer 49

- They interact well with polar molecules | - They are repelled by the hydrophobic interior of the lipid bilayer

Question 50

Channel proteins that can be opened or closed in response to specific stimilus are called ____ channels

Answer 50

gated