2.4 Proteins Flashcards Preview

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Flashcards in 2.4 Proteins Deck (18)
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1
Q

How are amino acids linked together?

A

condensation reactions to form polypeptides chains

2
Q

How many types of amino acids are universal to all living organisms?

A

20 different amino acids are used by the ribosomes to create polypeptides

3
Q

What do the amino acids on ribosomes all contain?

A

an amine, a carboxyl and a R group

4
Q

How are organisms capable of producing a huge range of possible polypeptides?

A

amino acids can be linked together in any sequence giving a huge range of possible polypeptides
three bases code for 1 amino acid

5
Q

What is a peptide bond?

A

the covalent bond between the amino acids

6
Q

What are polypeptides?

A

long chains of covalently bonded amino acids

7
Q

How can polypeptide chains be broken down?

A

hydrolysis reactions

8
Q

How are dipeptides formed?

A

amino acids can be covalently joined together in a condensation reaction to form a dipeptide and water

9
Q

How are peptide bonds formed?

A

formed between the amine and carboxylic acid groups of adjacent amino acids
- amine group loses a hydrogen atom (H) and the carboxylic acid loses a hydroxyl (OH) – this forms water (H2O)

10
Q

Denaturation

A

a structural change in a protein that results in loss of its biological properties

11
Q

What causes denaturation in proteins? (two factors)

A

temperature

pH

12
Q

How does temperature cause denaturation?

A

high levels of thermal enrgy may disrupt the hydrogen bonds that hold the proteins together
when the bonds are broken the protein will begin to unfold and lose its capacity to function as needed

13
Q

How does pH cause denaturation?

A

changing the pH will change the charge of the protein, which in turn will alter the protein solubility and overall shape

14
Q

Gene

A

a sequence of DNA which encodes a polypeptide sequence - three bases of the gene is needed to code for each amino acid in polypeptide

15
Q

What are the functions of protein?

A
catalysis
muscle contraction
tensile strengthening
blood clotting 
membrane transport
16
Q

What are the two three-dimensional conformations of a protein?

A

globular proteins

fibrous proteins

17
Q

What are the six examples of proteins? What is each of its function?

A

Rubisco: enzyme with an active site that catalyses the photosynthesis reactions which fixes carbon dioxide in the atmosphere, providing all the carbon needed by living organisms to make sugars and other carbon compounds
Insulin: hormone that is carried dissolved in the blood and binds specifically to insulin receptors reversibly in the cell membranes, causing the cell to absorb glucose and lower the blood glucose concentration
Immunoglobulin: antibodies that bind to antigens on pathogens, each with a different type of binding site, allowing specific immunity against many diseases
Rhodopsin: pigment that makes the rod cells of the retina light-sensitive; the rod cell sends a nerve impulse to the brain when retinal absorbs a photon of light
Collagen: structural protein with three polypeptides to form a rope-like conformation; used in skin to prevent tearing in bones to prevent fractures, and in tendons and ligaments to give tensile strength
Spider silk: structural protein used to make webs for catching preys; has very high tensile strength and becomes stronger when it’s stretched which resists breakage

18
Q

What are proteomes?

A

All of the proteins produced by a cell, tissue, or an organism
Proteome of each individual is unique because different cells make different proteins, and small differences in the amino acid sequence of proteins
Proteome reveals what is actually happening in the organism