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Flashcards in Biological Molecules Deck (30):
1

Covalent bond between two adjacent amino acids in chain of amino acids

Peptide bond

2

Reaction involved in breaking bonds and what happens during reaction

Hydrolysis
H20 added

3

Describe how enzyme such as pepsin breaks down a substrate

1.substrate shape is complementary to active site
2.substrate fits into active site
3.induced fit
4.enzyme-substrate complex formed
5.destabilising/staining of bonds in substrate then forms enzyme-product compex
6.products/amino acids then leave active site

4

Repeats

Improve reliability
Assess spread of results
Allow calculation of mean

5

Pepstatin acts as a competitive inhibitor of pepsin
What can you conclude about the structure of pepstatin

Similar shape to substrate/protein
Complementary to active site

6

Triglyceride

Contains only the the elements carbon, hydrogen and oxygen

Insoluble in water

Contains glycerol

Contains ester bonds

Contains fatty acids

7

Phospholipid

Insoluble in water
Contains glycerol
Contains ester bonds
Important in membrane structure
Contains fatty acids

8

Cholesterol

Contains only carbon, hydogen and oxygen
Insolube in water
Important in membrane structure

9

Describe how to do the emulsion test for lipids and how a positive result would be identified

Mix with ethanol and add water
Goes cloudy

10

Mycoproteins produced by microorganisms
How might lipid content of mycoprotein fiffer from food that comes from animals

Less overall lipid/fat
Less/no saturated fat/lipid
More unsaturated fat/lipid

11

Primary structure

Peptide bonds
Sequence of amino acids

12

Secondary but not primary

Hydrogen bonds
Initial folding of polypeptide chain
(alpha helix AND B pleated sheets)

13

Tertiary but not primary or secondary

Overall 3D shape
Ionic bonds
Supercoiled shape (fibrous)
Or
Spherical shape (globular)

14

Quaternary structure ONLY

a and B subunits
Multiple polpeptide chains arranged to make complete protein molecule

15

Describe formation of hydrogen bonds between 2 molecules of water and explain why water can form these bonds

1. Between O and H (of adjacent molecules)
2. Between, electropositive H and electronegative O
3. Water molecule is polar/has unequal charge distribution

16

Hydrogen bonds allow water to act as a solvent
Why is ability of water to act as a solvent important for survival of survival of organisms

1.medium for reactions
2.allows ionic compounds to seperate
3.transport
4.apoplast-transport of water
5. Organism can absorb minerals
6. Able to dilute toxic substances

17

Name given to sequence of amino acids in a protein molecule

Primary structure

18

Structure if amino acid molecule

NH2 at one end
COOH at oposite end
C in centre bonded to one R and one H

19

One property of collagen that makes it useful component of blood vessel walls

Strength/toughness/insolubility

20

Describe structure of collagen molecule

1.peptide bonds between amino acids
2.every 3rd amino acid is same
3.coil/twist/spiral/helix
4.left handed heliz
5.glycine/small R group allows closeness/twisting of polypeptide chains
6.three polypeptide chains
7.hydrogen bonds between polypeptide chains
8.no/few hydrophilic (R) groups on outside of molecule
9. Adjacent molecules joined by crosslinks
10. Crosslinks/ends of molecules, being staggered
11.fibril

21

Function if haemoglobin

Transport if oxygen

22

3 ways in which haemoglobin differs from that of collagen

Haemoglobin has/is:
1.globular
2.hydrophobic (R) groups on inside/ hydrophilic (R) groups on outside
3. 4 subunits
4. Two alpha and 2 beta chains
5. Alpha helix
6. Proportion of glycine similar to that of other amino acids

23

Testing for proteins

Biuret test
If protein present, colour change form blue to lilac
Add biuret reagent

24

Testing for lipids

Emulsion test
Add ethanol/alcohol
Add distilled water
Cloudy white emulsion indicates presence of lipids

25

Testing for carbohydrates

Starch
Add iodine solution
Starch present
Colour change from yellow-brown to blue-black

26

Reducing sugars

Place sample of food to be tested in a noiling tube
Add benedict's solution then heat in a water bath at 80°c for 3 minutes
Orange-red precipitate indicates a reducing sugar is present (low levels of sugar-contents yellow or green)

27

Functions of triglycerides

Energy source
Energy store
Insulation
Buoyancy
Protection

28

Amylose

Plants
Alpha glucose
1-4 glycosidic bonds
Coiled
Hydrogen bonds
Unbranched

29

Amylopectin

Plants
1-4 and1-6 glycosidic bonds
Coiled
Hydrogen bonds
Branched

30

Gylcogen

Animals
1-4 and 1-6 glycosidic bonds
Branched
Coiled
1-4 bonded chains smaller than amylopectin
Less tendecy to coil
Morw branched
More compact
Easier to remove monomer units as there are more ends