Topic 7.5: Proteins Flashcards Preview

HL Biology > Topic 7.5: Proteins > Flashcards

Flashcards in Topic 7.5: Proteins Deck (50):
1

Explain Primary (1°) Structure of Protein (3)

The order / sequence of the amino acids of which the protein is composed
Formed by covalent peptide bonds between adjacent amino acids
Controls all subsequent levels of structure because it determines the nature of the interactions between R groups of different amino acids

2

Explain Secondary (2°) Structure of Protein (4)

The way the chains of amino acids fold or turn upon themselves
Held together by hydrogen bonds between non-adjacent amine (N-H) and carboxylic (C-O) groups
May form an alpha helix, a beta-pleated sheet or a random coil
Secondary structure provides a level of structural stability (due to H-bond formation)

3

Explain Tertiary (3°) Structure of Protein (3)

The way a polypeptide folds and coils to form a complex molecular shape (e.g. 3D shape)
Caused by interactions between R groups; including H-bonds, disulphide bridges, ionic bonds and hydrophilic / hydrophobic interactions
Tertiary structure may be important for the function of the enzyme (e.g. specificity of active site in enzymes)

4

Explain Quaternary (4°) Structure of Protein (4)

The interaction between multiple polypeptides or prosthetic groups that results in a single, larger, biologically active protein
A prosthetic group is an inorganic compound involved in protein structure or function (e.g. the heme group in haemoglobin)
A protein containing a prosthetic group is called a conjugated protein
Quaternary structure may be held together by a variety of bonds (similar to tertiary structure)

5

What is the difference between a fibrous protein and globular protein in respect to shape?

Fibrous: long and narrow

Globular: round/spherical

6

What is the difference between a fibrous protein and globular protein in respect to role?

Fibrous: structural (strength and support)

Globular: functional (catalytic, transport, etc)

7

What is the difference between a fibrous protein and globular protein in respect to solubility?

Fibrous: (generally) insoluble in water

Globular: (generally) soluble in water

8

What is the difference between a fibrous protein and globular protein in respect to sequence?

Fibrous: repetitive amino acid sequence

Globular: irregular amino acid sequence

9

What is the difference between a fibrous protein and globular protein in respect to stability?

Fibrous: less sensitive to changes in heat, pH, etc

Globular: more sensitive to changes in heat, pH, etc

10

What is the difference between a fibrous protein (6) and globular protein (4) in respect to examples?

Fibrous: collagen, myosin, fibrin, actin, keratin, and elastin

Globular: catalase, hemoglobin, insulin, immunoglobin

11

Is collagen a fibrous or globular protein?

fibrous

12

Is myosin a fibrous or globular protein?

fibrous

13

Is fibrin a fibrous or globular protein?

fibrous

14

Is actin a fibrous or globular protein?

fibrous

15

Is keratin a fibrous or globular protein?

fibrous

16

Is elastin a fibrous or globular protein?

fibrous

17

Is catalase a fibrous or globular protein?

globular

18

Is hemoglobin a fibrous or globular protein?

globular

19

Is insulin a fibrous or globular protein?

globular

20

Is immunoglobin a fibrous or globular protein?

globular

21

Explain the significance of polar and non-polar amino acids (4)

Polar amino acids have hydrophilic R groups, whereas non-polar amino acids have hydrophobic R groups
For water soluble proteins, non-polar amino acids tend to be found in the centre of the protein (stabilising structure) while polar amino acids are found on the surface (capable of interacting with water molecules)
For membrane-bound proteins, non-polar amino acids tend to be localised on the surface in contact with the membrane, while polar amino acids line interior pores (to create hydrophilic channels)
For enzymes, the active site specifically depends on the location and distribution of polar and non-polar amino acids as hydrophobic and hydrophilic interactions can play a role in substrate binding to the active site

22

What are the six functions of proteins?

structure, hormones, immunity, transport, movement, and enzymes

23

What is the role of structure proteins?

Support for body tissue

24

What is the role of hormone proteins?

Regulation of blood glucose

25

What is the role of immunity proteins?

Bind antigens

26

What is the role of transport proteins?

Oxygen transport

27

What is the role of movement proteins?

Muscle contraction

28

What is the role of enzyme proteins?

Speeding up metabolic reactions

29

Name three examples of structure proteins

collagen, elastin, keratin

30

Name two examples of hormone proteins

insulin, glucagon

31

Name two examples of immunity proteins

antibodies / immunoglobulins

32

Name two examples of transport proteins

haemoglobin, myoglobin

33

Name four examples of movement proteins

actin / myosin, troponin / tropomyosin

34

Name three examples of enzyme proteins

catalase, lipase, pepsin

35

What type of protein function does collagen serve?

structure

36

What type of protein function does elastin serve?

structure

37

What type of protein function does keratin serve?

structure

38

What type of protein function does insulin serve?

hormones

39

What type of protein function does glucagon serve?

hormones

40

What type of protein function does antibodies serve?

immunity

41

What type of protein function does immunoglobulins serve?

immunity

42

What type of protein function does hemaglobin serve?

transport

43

What type of protein function does myoglobin serve?

transport

44

What type of protein function does actin serve?

movement

45

What type of protein function does myosin serve?

movement

46

What type of protein function does troponin serve?

movement

47

What type of protein function does tropomyosin serve?

movement

48

What type of protein function does catalase serve?

enzymes

49

What type of protein function does lipase serve?

enzymes

50

What type of protein function does pepsin serve?

enzymes

Decks in HL Biology Class (66):