Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > Proteins > Flashcards

Proteins Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What re the functional groups of amino acids

A
  • amino group
  • R group
  • carboxyl group
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the R group

A
  • variable functional group that changes depending on the type of amino acid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How are dipeptides made?

A
  • condensation reaction
  • peptide bond formed
  • chemical reaction joining two amino acids with a peptide bond forming a dipeptide and releasing a water molecule
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the similarities between all dipeptides

A
  • all contain carboxyl group
  • all contain amino group
  • all have two R groups
  • all contain C and H and N and O
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the role of proteins

A

Enzymes - These proteins are used to breakdown and synthesise molecules

Antibodies - These proteins are involved in the immune response.

Transport - Some proteins can move molecules or ions across membranes.

Structural components - Proteins like keratin and collagen are used to create strong fibres.

Hormones - Some of these are proteins that act as chemical messengers in the body.

Muscle contraction - Muscles are made up of proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the structure of an amino acid

A
  • central carbon
  • amino group (NH2)
  • carboxyl group (COOH) opposite the amino group
  • R group opposite hydrogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the different structures of proteins?

A
  • primary
  • secondary
  • tertiary
  • quaternary
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the primary structure

A
  • sequence of amino acids in the polypeptide
  • bonded by covalent peptide bonds
  • DNA of a cell determines the primary structure of a protein
  • specific for each protein (one alteration in the sequence of amino acids can affect the function of the protein)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

describe the secondary structure

A
  • interactions between localised sections of polypeptide chain
  • 2 chains: alpha helix and beta pleated sheets
  • held in place by hydrogen bonds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

describe the hydrogen bonds in a secondary structure

A
  • weak negatively charged nitrogen and oxygen atoms interact with the weak positively charged hydrogen atoms to form hydrogen bonds
  • can be broken by pH and temp
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe alpha helix structure

A
  • hydrogen bonds form between every fourth peptide bond
  • between the oxygen of the carboxyl group and the hydrogen of the amine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe beta pleated sheet structure

A
  • when the protein folds so that two parts of the polypeptide chain are parallel to each other
  • enabling hydrogen bonds to form between parallel peptide bonds
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe tertiary structure

A
  • overall 3D shape of polypeptide
  • Further conformational change of the secondary structure
  • additional bonds forming between the R groups (side chains)
  • shape varies in the 20 amino acid structures that determine function
  • bonds: hydrogen, ionic, hydrophobic interactions, disulphide bridges
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are disulphide bridges?

A
  • occurs between cysteine amino acids
  • type of covalent bond
  • R group has SH group -> sulphur atoms are bonded and hydrogen atoms are lost
  • strong and broken by reducing agents (chemicals)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what are hydrophobic interactions?

A
  • between non polar R groups
  • hydrocarbons are hydrophobic (R groups have hydrocarbons) amongst amino acids
  • very weak + easily broken
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is a quaternary structure?

A
  • made of >1 polypeptides chain
  • formed by interactions between polypeptides
  • work together as a functional macromolecule
  • each individual polypeptide chains refer to as subunit

bonds: hydrophobic interactions, hydrogen, ionic, disulphide bridges

17
Q

what is ionic bond here?

A
  • Ionic bonds form between positively charged (amine group -NH3+) and negatively charged (carboxylic acid -COO-) R groups
  • Ionic bonds are stronger than hydrogen bonds but they are not common
  • These bonds are broken by pH changes
18
Q

What are globular proteins

A
  • compact, water soluble, spherical
  • formed form overall 3D folded structure into tertiary structure
  • bc of non polar hydrophobic R groups oriented toward centre
  • bc of polar hydrophilic R groups oriented towards aqueous surroundings
19
Q

Explain the solubility property of globular proteins

A
  • important physiological roles
  • can be transported easily
  • involved in metabolic processes
20
Q

Explain the folding of the protein

A
  • due to interactions between R groups
  • have specific shapes
  • enables important physiological roles

e.g. enzymes, immunoglobulins respond to specific antigens

21
Q

What is a conjugated protein

A
  • type of globular protein
  • contains non polar component = prosthetic group
22
Q

What is a prosthetic group

A
  • non protein part of a protein molecule
  • permanently attached to the molecule
  • vital for normal functioning of molecule
23
Q

what are the different types of prosthetic groups?

A
  • lipids or carbohydrates combine with proteins -> lipoproteins or glycoproteins
  • metal ions + molecules derived from vitamins can form prosthetic groups
24
Q

what is haemoglobin

A
  • conjugated protein, found in red blood cells
  • transports oxygen from lungs to body tissues
25
Q

What is the structure of haemoglobin

A
  • made of 4 polypeptide chains (quaternary structure)
  • 2 alpha globin, 2 beta globin
  • has prosthetic group iron ion (Fe^+2) = called haem group
  • one oxygen molecule bonds to each haem group (Each haemoglobin transports oxygen = maximises amount transported)
  • haem group is able to reversibly combine with an oxygen molecule forming oxyhaemoglobin and results in the haemoglobin appearing bright red
26
Q

what is insulin

A
  • hormone made + secreted by pancreas
  • helps maintain blood glucose levels
27
Q

What is the structure of insulin

A
  • 2 polypeptide chains: alpha and beta
  • joined by disulphide links
28
Q

explain the features of insulin

A
  • shape allows it to specifically bind to receptors on cell membranes –> lower BGLs
  • has hydrophilic R groups on outside –> soluble in water –> insulin can dissolve in blood + get transported round the body
29
Q

Describe pepsin

A
  • catalyses digestion of proteins
  • found in stomach (Acidic env, low PH)
30
Q

describe structure of pepsin

A
  • primary structure, very few basic R groups
    = prevents tertiary structure being impacted by low PH
  • tertiary structure kept stable by hydrogen bonds + disulphide links
31
Q

why does enzymes get denatured at low PH

A
  • bc of amino acids with basic R group
  • basic group acts as base -> accepts Hydrogen ions –> becomes positively charged
  • basic R group becomes +vely charges -> changes structure
  • affects ionic and hydrogen bonds –> denature protein + alter function
32
Q

What are fibrous proteins?

A
  • long strands of polypeptide chains
  • have repeating sequences of amino acids
  • have long cross linkages due to hydrogen bonds
  • have little or no tertiary structure
  • amino acids have non polar R groups –> insoluble in water (suitable for structural roles)
  • polypeptide chains form fibres –> tough and strong protein
33
Q

Describe collagen

A
  • forms strong fibres
  • connective tissue sound in skin, tendons, ligaments, biomes, blood vessels
  • found in artery walls to prevent vessels from from high pressure
  • used to make tendons which connect muscle to bone = allows skeleton to move
  • used to make bone
  • provide structural support and stable and flexible and tough
34
Q

what is the structure of collagen?

A
  • formed from three polypeptide chains closely held by hydrogen bonds
  • triple helix shape (not alpha helix)
  • every 3rd amino acid in primary structure = glycine
35
Q

Describe keratin role

A
  • hard, strong
  • makes up nails, horns, hooves, hairs, feathers
  • protects epithelial cells
  • strengthens skin + internal organs
  • controls hrowth of epithelial cells
  • maintains elasticity in skin
36
Q

what is the structure of keratin

A
  • primary structure = high amounts of of cysteine (amino acid sulfur)
  • disulphide links between two polypeptide chains = hard + strong
  • intertwined to form coils, join to make a-keratin / pleated sheets (beta pleated sheets)
37
Q

Describe the role of elastin

A
  • elastic properties = stretch + recoil (bc of coiling and crosslinks that keep them together
  • found in lungs –> to inflate and deflate
  • in arteries –> easier to pump blood for heart
  • in bladder –> expand and hold urine
  • in blood vessels –> maintain pressure by stretch and recoil
38
Q

what is the structure of elastin?

A
  • many molecules of large flexible molecules
  • made of tropoelastin
  • many amino acids
  • grouped in short, repeated sequences of 3-9 amino acids
  • hydrophobic amino acids –> hydrophobic domains

Biology (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions