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Biology - 2.2 Biological Molecules > Proteins > Flashcards

Flashcards in Proteins Deck (33)
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1
Q

Definitions of Proteins

A

Proteins are polymers; their monomers are amino acids

2
Q

Definitions of dipeptide

A

Its formed when two amino acids are joined together

3
Q

Definitions of Polypeptide

A

Its formed when more than two amino acids join together

4
Q

Describe the structure of amino acids

A

They all have a carboxyl group (-COOH) and an amino group (-NH2) attached to a carbon group which is also attached to a variable group (-R) and a hydrogen atom (-H)

5
Q

What are amino acids linked together by? & what reaction was it?

A

amino acids are linked together by peptide bonds to form dipeptides and polypeptides - its a condensation reaction

6
Q

Definition of a peptide bond

A

peptide bond is a bond formed when two amino acids are joined together b a condensation reaction

7
Q

Definition of Primary Structure

A

primary structure is the sequence of amino acids in a polypeptide chain

8
Q

How does the primary structure affect the protein

A

the number and order of amino acid in a protein chain is important, as changing just one amino acid can alter the function of the protein.

9
Q

Definition of secondary structure.

A

Secondary structure is the coiling or folding of an amino acid chain, which arises often as a result of hydrogen bond formation between the -NH and -CO groups of amino acids in the chain. This makes it automatically coil into a helix or fold into b pleated sheet

10
Q

Definition of tertiary structure

A

Tertiary Structure is the overall three-dimensional shape of a protein molecule. Its shape arises due to interactions including Hydrogen bonding, Disulphide bridges, Ionic bonds and Hydrophobic interactions.

11
Q

Definition of ionic bonds in protein

A

Ionic bonds are attractions between negatively-charged R groups and positively-chafed R groups on different parts of the molecules

12
Q

Definition of Disulphide Bonds in protein

A

Whenever two molecules of the amino acid cysteine come close together, the sulfur atom in one cysteine bonds to the sulfur in the other cysteine, forming a disulphide bond.

13
Q

Definition of Hydrophobic and hydrophilic interactions in protein

A

When hydrophobic (water-repelling) R groups are close together in the protein, they tend to clump together. This means that hydrophilic (water-attracting) R groups are more likely to be pushed to the outside, which affects how the protein folds up into its final structure.

14
Q

Definition of Hydrogen bonds in protein

A

These weak bonds from between slightly positively-charged hydrogen atoms in some R groups and slightly negatively-charged atoms in other R groups on the polypeptide chain.

15
Q

What do Hydrogen bonds do?

A

They are involved in keeping the tertiary and quaternary structure of the protein in the correct shape. The presence of H+ bonds can give protein molecules a lot of strenght .

16
Q

Definition of quaternary structure

A

Quaternary structure is where a protein consists of more than one polypeptide chain e.g. insulin

17
Q

Definition of globular protein

A

Globular protein has a relatively spherical shape, which are soluble in water, and often have metabolic roles within the organism.

18
Q

Describe the structure of globular proteins

A

They are round and compact

19
Q

What makes Globular Proteins soluble

A

In a globular protein, any hydrophobic R groups are turned inwards towards the centre of the molecule, while hydrophilic groups are on the outside. This makes the protein soluble as water molecules can bind to them, and now they’re easily transported in fluids. This is caused by the hydrophilic and hydrophobic interactions in the protein tertiary structure.

20
Q

Give 3 examples of globular proteins

A

> Haemoglobin
Insulin
Amylase

21
Q

Whats the job of haemoglobin and whats type of protein is it known as?

A

> Haemoglobin is a globular protein that carries oxygen around the body in red blood cells.
Its known as a conjugated protein . Each of four polypeptide chain in haemoglobin has a prosthetic called haem

22
Q

Definition of conjugated protein

A

this means its a protein with a non protein group attached to it & the non protein group is called a prosthetic group

23
Q

What does a haem group contain?

A

iron, which oxygen binds to

24
Q

What is insulin and its role?

A

its a hormone secreted by the pancreas. It helps to regulate the blood glucose level

25
Q

Why is the solubility of insulin important?

A

because it means it can be transported in the blood to the tissues where it acts

26
Q

Describe the structure of an insulin?

A

an insulin molecules consists of two polypetide chains, which are held together by disulfide bonds. When they’re in the pancreas, six of these molecules bind together to form a large, globular structure.

27
Q

What is an Amylase

A

Amylase is an enzyme that catalyses the breakdown of starch in the digestive system.

28
Q

What is Amylase made up of?

A

It is made of a single chain of amino acids. Its secondary structure contains both alpha helix and beta pleated sheet sections

29
Q

Definition of fibrous proteins

A

Has a relatively long, thin structure, is insoluble in water and metabolically inactive, often having a tsructural role within an organism.

30
Q

Give three examples of fibrous proteins

A

> collagen
keratin
elastin

31
Q

What is collagen & role of it

A

> Its found in animal connective tissue, such as bone, skin and muscles.
they provide mechanical strenght

32
Q

What is Keratin & role of it

A

> its found in many of the external structures of animals, such as skin, hair, nails
it provides mechanical protection

33
Q

What is Elastin

A

its found in elastic connective tissue, such as skin, large blood vessels and some ligaments. It is elastic, so it allows tissue to return to their original shape after they have been stretched.