Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

AS Biology > 2) Biological Molecules > Flashcards

2) Biological Molecules Flashcards

1
Q

benedict’s test for reducing sugars

A
  • Add Benedict’s reagent (which is blue as it contains copper (II) sulfate ions).
  • Heat the test tube in a water bath/beaker.
  • A positive test result is a colour change somewhere along a colour scale from blue
    (no reducing sugar) to brown/brick-red (a high concentration of reducing sugar)

-This test is semi-quantitative as the degree of the colour change can give an
indication of how much (the concentration of) reducing sugar present

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

iodine test for starch

A

positive : blue-black
negative : orange-brown

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

emulsion test for lipids

A
  • Add ethanol to the sample ,
    shake to mix
    add the mixture to a test tube of water.
  • positive : milky emulsion
    negative : clear
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

biuret test for proteins

A
  • A few drops of copper (II) sulfate solution (which is blue) is added to the sample.

-positive : lilac/purple
negative : remains blue

For this test to work, there must be at least two peptide bonds present in any protein
molecules, so if the sample contains amino acids or dipeptides, the result will be
negative.

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

benedict’s test for non-reducing sugars

A

add hydrochloric acid, and neutralise

  • then add benedicts solution and heat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

colourimeter

A
  • measures absorbance and transmission.
  • the paler the solution, the lower the absorbance, higher the transmission (as more light can pass through the sample).
  • calibration curve used
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

serial dilutions

A

are created by taking a series of dilutions of a stock solution. The
concentration decreases by the same quantity between each test tube

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is a macromolecule ?

A

a large biological molecule (like protein/polysaccharide/nucleic acid)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

define monomer

A

used as basic building block for SYNTHESIS OF POLYMER.

  • many monomers join to form a polymer (usually by condensation reactions)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

define polymer

A

made from many similar repeating subunits joined together in a chain (eg. polysaccharides, proteins, nucleic acids, cellulose)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

define monosaccharide

A

consisting of single sugar unit with general formula (CH2O)n

eg : alpha & beta glucose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

define disaccharide

A

sugar molecule consisting of 2 MONOSACCHARIDES joined together by a GLYCOSIDIC BOND

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

define polysaccharide

A

subunits are monosaccharides joined together by glycosodic bonds.

Eg: cellulose, glycogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

whats a glycosidic bond?

A

bonds between monosaccharides/disaccharides/polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

name 3 monosaccharides

A

-glucose
-fructose
-galactose

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

whats the difference between alpha & beta molecules ?

A

alpha - both OH is on the bottom
beta - rhs OH is above

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

glucose, fructose, and maltose are _______ sugars

A

reducing sugars

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

is sucrose reducing or non-reducing sugar

A

non-reducing sugar

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what are the 2 branches of starch?

A
  • amylose
  • amylopectin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

state bonds joining amylose & whether it has branching

A
  • alpha 1-4
  • no branching
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

state bonds joining amylopectin & whether it has branching

A
  • alpha 1-4 & alpha 1-6
  • yes branching
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

state bonds joining glycogen & whether it has branching

A
  • alpha 1-4 & alpha 1-6
  • yes branching (more than amylopectin)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

state bonds joining cellulose & whether it has branching

A
  • beta 1-4
  • no branching
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

structural description of amylose

A
  • helical
    -long
  • compact
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
structural description of amylopectin
- helical - compact
26
structural description of glycogen
- helical - compact
27
structural description of cellulose
- long straight chains - every other glucose is inverted 180 (flipped) - bonded via hydrogen bonds - make microfibrils
28
functions of amylose
- cellular storage of energy - does not affect osmotic potential - found in plants
29
functions of amylopectin
- cellular storage of energy - does not affect osmotic potential - found in animals - hydrolysed faster than amylose
30
functions of glycogen
- cellular storage of energy - does not affect osmotic potential - found in animals - hydrolysed faster than amylose
31
functions of cellulose
- high tensile strength - insoluble but permeable to water - strong cell wall for support + prevent osmotic damage
32
branching = 1-6 bonds
branching = 1-6 bonds
33
what does non-polar mean ?
hydrophobic - lack complete/partial charges on their atoms - insoluble in water - cannot form hydrogen bonds with water
34
what does polar mean ?
hydrophilic - possess regions of positive & negative charge
35
triglycerides are polar or non-polar?
non-polar hydrophobic
36
functions of triglycerides
- energy storage (insoluble in water). - waterproofing of hair/feathers (oily secretions of glands). - electrical insulation - insulates body against heat loss. - increases ability to float well.
37
describe the molecular structure of a phospholipid
- polar phosphate head - non-polar fatty acid tail
38
explain primary structure
- the number, type, and sequence of amino acids
39
explain secondary structure
- COILING - often folds/ curls up. - 3D shape : alpha helix + beta-pleated sheet. - held in shape by hydrogen bonds.
40
explain tertiary structure
- 3D globular shape. - intramolecular bonding. - 4 types of bonds that hold it in place: hydrogen bond, disulphide bond, ionic bond, hydrophobic interactions - bonds between R groups are on same polypeptide
41
explain quaternary structure
- 2 or more polypeptides - intramolecular bonding - same 4 bonds as tertiary (hydrogen, disulphide, ionic, hydrophobic interactions) - can have prosthetic group - bonds between R groups are on different polypeptides
42
what's a prosthetic group?
proteins w non-polypeptide structure = conjugated proteins
43
describe the 4 types of bonding that holds tertiary and quaternary structures in place. (bonding is between..?)
- hydrogen bonding : between polar R groups. - ionic bonds between charged R groups. - hydrophobic interactions between non-polar R groups. - disulfide bonds between cysteine.
44
describe the structure of haemoglobin.
- globular protein - quaternary structure (from 2 alpha chains, 2 beta chains, 1 haem group) - intramolecular bonding
45
what is a haem group?
prosthetic group
46
globular proteins
- soluble - physiological roles
47
fibrous proteins
- insoluble - structural roles
48
examples of fibrous proteins
keratin(in hair), collagen (in bone)
49
examples of globular proteins
enzymes, haemoglobin, insulin, antibodies
50
difference of shape between fibrous and globular proteins
fibrous - long and narrow globular - round
51
difference of acid sequence between fibrous and globular proteins
fibrous - repetitive amino acid globular - irregular amino acid sequence
52
difference of durability between fibrous and globular proteins
fibrous - less sensitive to changes in temp, pH. globular - more sensitive
53
explain the high specific heat capacity of water
- a lot of heat capacity has to be added to water to raise its temp. - much of the heat energy is used to break hydrogen bonds between water.
54
explain why high specific heat capacity of water is beneficial for fish
-As it takes so much energy to raise the temperature of the lake water, the temperature will remain relatively stable despite the fluctuating external environment preventing their enzymes denaturing
55
Polar molecules dissolve in water e.g NaCl (salt). Explain how this works in terms of the ions
Na+ ions are attracted to the oxygen in water -Cl- ions are attracted to the hydrogen in water
56
What is meant by the latent heat of vaporisation? b) Why is it high for water?
energy required to convert water from a liquid to a gas b) a lot of energy is needed to break the hydrogen bonds
57
How does the high heat of vaporisation of water favour us when we sweat?
- a large amount of heat is removed from your skin to break the hydrogen bonds to turn it into a gas - provides a cooling effect for our skin
58
glucose + fructose = ?
sucrose
59
how is sucrose made
glucose + fructose
60
how is maltose made
glucose + glucose
61
how is lactose made
glucose + galactose
62
differentiate between saturated and unsaturated atoms
saturated = only single bonds unsaturated = atleast one double bond
63
differentiate between semiquantitative & quantitative
- semiquantitative = ESTIMATION of their approximate concentrations. - quantitative = ACCURATE determination of their concentrations.
64
differentiate between simple & serial dilutions
- simple = singlestep process - serial = when the steps are repeated
65
3 facts about collagen
- every 3rd amino acid is glycine (repeating sequence = makes tightly held together). - 3 polypeptide chains = quaternary structure. - fibrous protein. - held by hydrogen bonds

AS Biology (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions