Proteins Flashcards

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1
Q

Functions of proteins

A
Enzymes 
Transport molecules 
Structural 
Hormones 
Storage 
Contraction 
Defence against infection 
Membrane 
Plasma proteins
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2
Q

Draw an amino acid

A

Amino group consisting of N with two h
R group carbon with r group and hydrogen
Carboxyl
Carbon with a double bonded oxygen and a OH group

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3
Q

Structure of protein

A

Polymers made up of many subunits called amino acids

Amino acids are joined together by peptide bonds

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4
Q

Primary structure

A

The sequence of amino acids found in a polypeptide chain

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5
Q

Secondary structure

A

The polypeptide chain can fold to form a Alpha-Helix or a beta pleated sheet

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6
Q

Tertiary structure

A

The overall 3D shape of the polypeptide chain. Folding superimposed on top of the secondary structure held together by bonds between the R groups

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7
Q

Bonds of the tertiary structure?

A

Weak hydrogen bonds
Ionic bonds
Hydrophobic interactions
Strong covalent disulphide bonds

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8
Q

Explain how the sequence of amino acids in a polypeptide determines the 3D shape of a functional protein (3)

A

The sequence of the amino acids determines the sequence of the r groups in the polypeptide
Different bonds form between different r groups e.g ionic between two charged r groups
Hence the order of the amino acids determines the position of the tertiary bonds and hence how the polypeptide chain folds into its 3D shape

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9
Q

Quaternary structure

A

Some proteins have a quaternary structure because they are made up of more than 1 polypeptide chain

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10
Q

Conjugated proteins

A

The non protein part called the prosthetic group eg haem group of haemoglobin

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11
Q

Two types of protein

A

Globular

Fibrous

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12
Q

Biuret test for proteins

A

Add 2cm3 of your sample to a test tube and add an equal volume of sodium hydroxide solution

Holding test tube at 45o use a pipettes to add a small volume of copper sulfate
Negative result stays blue
Positive goes purple

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13
Q

Rf value equation

A

Distance moves by sample/ distance moves by solvent front

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