proteins (biomols)

Question 1

what elements make up proteins

Answer 1

carbon, hydrogen, oxygen, nitrogen, and soemtimes sulphur

Question 2

what monomers make up proteins

Answer 2

amino acids

Question 3

describe structure of an amino acid

Answer 3

amino group (NH2) and carboxyl group (COOH) and r group

Question 4

how many diff amino acids are there

Answer 4

20, each carrying a different R group

Question 5

how many amnio acids are non essential, conditionally essential, essential

Answer 5

5=non essential
6= conditionally essential
9=essential

Question 6

what reaction is needed to join amino acids

Answer 6

a condensation reaction

Question 7

what is a dipepetide

Answer 7

2 amino acids joined tg

Question 8

What is a polypeptide

Answer 8

Many amino acids joind together

Question 9

How do amino acids join together

Answer 9

Its a reaction between the amino group of 1 amino acid and the carboxyl group of another amino acid. As it is a condensation reaction the H20 is lost

Question 10

What is the bond between amino acids

Answer 10

Peptide bonds

Question 11

What enzyme is involved in joining amino acids together

Answer 11

Peptidyl Transferases

Question 12

Where are protein mades

Answer 12

ribosomes

Question 13

How do you turn dipeptide back into amino acids

Answer 13

Do a hydrolysis reaction

Question 14

When does a polypeptide become a functional protein

Answer 14

When polypeptide chains twist and fold into different shapes

Question 15

What is the primary structure of a protein

Answer 15

This is the precise number and sequence of amino acids in the polypeptide chain

Question 16

How is the precise number and sequence of amino acids in a polypeptide chain determined

Answer 16

It is detemined by the genetic code in the DNA

Question 17

Describe the structure of a polypeptide chain

Answer 17

At one end of the polypeptide, theres a carboxyl(COOH) group and at the other end of the chain there will be an amino/NH2 group sticking out.

Question 18

What is the secondary structure of a protein

Answer 18

The hydrogen/oxygen/nitrogen in the polypeptide primary structure interact (not the R- groups) to form hydrogen bonds. holding the structure in a secondary shape. Hydrogen bonds form at various points along the polypeptide chain, pulling the chain into regularly arranged shapes - either ALPHA HELIX or BETA-PLEATED SHEET

Question 19

What is a tertiary structure of a protein

Answer 19

This is how the protein folds up into its specific 3D shape. Again, this is only involves ONE POLYPEPTIDE. This involves the R-GROUPS of different amino acids in the secondary structure interacting with each other when they are close enough to do so.

Question 20

When do hydrogen bonds form in the tertiary structure

Answer 20

These will form whenever there are 2 R- groups close together with the following atoms; one with a slightly positive hydrogen atom, and one with a slightly negative oxygen atom

Question 21

When do ionic bonds form in the tertiary structure

Answer 21

These will form when oppositely charged R-groups are positioned close together in the amino acid chain

Question 22

When do disuphide bonds form in the tertiary structure

Answer 22

These will form whenever there are 2 CYSTEINE amino acids close together - these R- groups contain SULPHUR atoms, and when 2 are close together, they form a strong bond.

Question 23

What is the quaternery structure of a protein

Answer 23

Quaternery proteins have more than one polypeptide joined together. Quaternery structures are held together by the same types of bond that hold together the tertiary structures.

Question 24

What are two quaternary structure proteins

Answer 24

Collagen and Haemoglobin

Question 25

What is the structure of collagen

Answer 25

Collagen is a long rigid structure in which three alpha chain polypeptides are wound around one another in a triple helix

Question 26

What is the structure of Haemoglobin

Answer 26

Haemonglobin is made from four polypeptides , two alpha, two beta. Each chain has an iron containing “HAEM” group, which pick up O2.

Question 27

How is it possible to have thousands of different proteins with all different shapes

Answer 27

The sequence of amino acids in the chain determines how the chain will fold up to makee protein

Question 28

What is the test for proteins

Answer 28

Biuret test
Two centimetres of sample and two centimetres of biuret
If protein is present it will change from blue to purple

Question 29

What are the characteristics of globular proteins

Answer 29

• compact, water soluble, usually spherical
  -hydrophilic R group, on the outside of thr protein = protein soluble in water
• easily transported around organism
• usually have metabolic roles (hormones, enzymes, transport proteins

Question 30

What are the three examples of globular proteins

Answer 30

-Haemoglobin
-Insulin
-Amylase

Question 31

What is haemoglobin and what is its structure

Answer 31

Haemoglobin is made from 4 polypeptide chains joineed together.
It carries oxygen around the body in RBC
Its known as a conjugated protein - this means its a protein with a non-protein group attached
Non - protein = prosthetic group
Each of the four polypeptide chains in haemoglobin has a prosthetic group called haem. Haem group contains iron, which oxygen binds to.

Question 32

What is insulin and what is its structure

Answer 32

Insulin is a hormone secreated by the pancreas that regulates blood glucose level.
It consists of two polypeptide chains which are held together by disulfide bonds. When they are in the pancreas, six of these molecules bind together to form a large, globular structure

Question 33

What is amylase and what is its structure

Answer 33

Amylase is made from one polypeptide chain twisted and folded.
Amylase is an enzyme that catalyses the breakdown of starch in the digestive system. The secondary structure of this protein contains both sections of alpha helix and beta-pleated sheets.

Question 34

What are the characteristics of fibrous proteins and why do they have these characteristics

Answer 34

• long,thin structures
  -insoluble in water (as they have small hydrophobic R group)
  -metabolically inactive
  -often have structural roles
  -strong
  They have these characteristics because they contain a limited range of amino acids and have a repetitive primary sequence.

Question 35

Why are fibrous not water soluble

Answer 35

They contain alot of amino acids with small hydrophobic R- groups

Question 36

What are three examples of fibreous proteins

Answer 36

Keratin/Elastin/Collagen

Question 37

What is the structure of Keratin

Answer 37

It is strong and inflexible. This protein is made from two parallel alpha helices twisted arond each other.It has alot of cysteine( the sulphur containing amino acid). this results in strong disulfide bonds forming strong, inflexible and insoluble

Question 38

What determines the flexiblity of Keratin

Answer 38

The amount of disulfide bonds. Fewer bonds = more flexible.

Question 39

What is Elastin and its structure

Answer 39

Its a fiberous proteins found in elastic fibres in the walls of blood vessels and surrounding the alveoli. Elastin is made up of stretchy proteins fibres called tropoelastin. Tripoelastin has the ability to stretch and recoil.

Question 40

What is collagen and what is its structure

Answer 40

Its a fibreous protein.Its a connective tissue found in skin, tendons, ligaments and the nervous system. There are a number of different forms but all are made up of three polypeptides wound together in a long and strong rope like structure. Like rope, collagen has flexibility. Many of these triple helices then form cross bridges between each other & join to form collagen fibrils, then many of these join to form collagen fibres.

Question 41

What level of protein structure do keratin/elastin/collagen all show

Answer 41

They’re all quarternary protein structures, made from more than one polypeptide chain.

Question 42

Computer modeling systems that predict the structure of a protein base on the amino acid sequence. What are the two modeling systems called

Answer 42

AB initio protein modeling; the computer interprets the phscial & electrical prpoerties of the atoms of each amino acid present. It then uses the infomation to predict the possible outcomes in terms of the secondary & tertiary structure of the final protein. Sometimes these several possible outcomes!
Comparative protein modeling/protein threading; this scans amino acids sequences against a daata base of known protein structures & produces models of what the final structure of the protein might be. Again, there may be more than one possible outcome.