Brainscape's Knowledge GenomeTM

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


See full index

Biology A-level > Chapter 2: biological molecules > Flashcards

Chapter 2: biological molecules Flashcards

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

reagent used for reducing sugars

A

Benedict’s reagent

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

reducing sugars test

A
  • Benedict’s reagent contains copper ions
  • when heated with reducing sugars, the copper ions are reduced to copper compounds
  • the colour changes from blue to brown
  • this test can be used for a range of concentrations of sugars
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

reagent used for non-reducing sugars

A

Benedict’s reagent, following acid hydrolysis

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

non-reducing sugars test

A
  • sucrose is a commonly occurring non-reducing sugar
  • when heated with dilute acid, sucrose is hydrolysed into its constituent monosaccarides, glucose and fructose, which are both reducing sugars
  • excess acid is then neutralised by the addition of sodium hydrogen carbonate and the mixture is then tested with Benedict’s reagent. This will show the production of reducing sugars
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

reagent used for starch

A

iodine in potassium iodide solution

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

starch test

A

iodine solution turns from brown to blue black in the presence of starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

proteins reagent

A

biuret reagent

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

‘macromolecule’ definition

A

a large biological molecule

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

‘monomer’ definition

A

a simple molecule which is used as a basic building block for the synthesis of a polymer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

‘polymer’ definition

A

a giant molecule made from many similar repeating subunits joined together in a chain

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

monosaccharides function

A
  • source of energy in respiration

- building blocks for larger molecules

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

monosaccharide definition

A

a molecule consisting of a single sugar unit with the general formula (CH20)n

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

‘disaccharide’ definition

A

a sugar molecule consisting of two monosaccharides joined together vy a glycosidic bond

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

‘polysaccharide’ definition

A

a polymer whose subunits are monosaccharides joined together by glycosidic bonds

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

what is starch made up of?

A

a mixture of amylose and amylopectin

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

what is the storage carbohydrate in animal cells?

A

glycogen

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

why are hydrogen bonds strong?

A

they are individually weak but collectively they provide enormous strength

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

describe the characteristics of cellulose fibres:

A
  • very high tensile strength so that they can withstand the high pressures caused by osmosis
  • freely permeable, allowing water and solutes to reach or leave the cell surface membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what chemical group do fatty acids contain?

A

-COOH

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

acid + alcohol produces what chemical?

A

an ester

21
Q

what is the bond between an acid and an alcohol called?

A

an ester bond

22
Q

what are the most common lipids?

A

triglycerides

23
Q

describe the solubility of triglycerides

A

insoluble in water but soluble in certain organic solvents

24
Q

describe the roles of triglycerides

A
  • energy reserves
  • insulator against loss of heat
  • metabolic source of water
25
Q

describe the unusual property of phospholipids

A
  • one end is soluble in water

- one of the three fatty acid molecules is replaced by a phosphate group, which is polar

26
Q

describe the phosphate group in a phospholipid in one word

A

hydrophilic (water-loving)

27
Q

describe three functions of proteins

A
  • enzymes
  • some hormones (eg insulin)
  • antibodies
28
Q

describe the general structure of all amino acids

A
  • central carbon atom
  • bonded to an amine group NH2
  • and a carboxylic acid group, COOH
29
Q

how do amino acids differ from each other?

A

by the R group

30
Q

when two amino acids join together, they form a…

A

peptide bond

31
Q

what is a polypeptide?

A

a molecule made up of many amino acids linked together by peptide bonds

32
Q

where are polypeptides formed?

A

in the ribosomes

33
Q

‘primary structure’ definition

A

the sequence of amino acids in a polypeptide or protein

34
Q

‘secondary structure’ definition

A

the structure of a protein molecule resulting from the regular coiling or folding of the chain of amino acids

35
Q

‘tertiary structure’ definition

A

the compact structure of a protein molecule resulting from the dimensional coiling of the already-folded chain of amino acids

36
Q

hydrogen bonds form between…

A

strongly polar groups eg -NH-, -CO- and -OH groups

37
Q

disulfide bonds form between…

A

cysteine molecules

38
Q

disulfide bonds are…

A

strong covalent bonds

39
Q

ionic bonds form between…

A
  • ionised amine (NH3+) groups

- ionised carboxylic acis (COO-) groups

40
Q

how are disulfide bonds broken?

A

by reducing agents

41
Q

how are ionic bonds broken?

A

by pH changes

42
Q

weak hydrophobic interactions occur between…

A

non-polar R groups

43
Q

what structure does haemoglobin have?

A

a quaternary structure

44
Q

describe the structure of haemoglobin

A
  • four polypeptide chains
  • each chain is a protein called a globin
  • two chains are alpha-globin, two are beta-globin
  • each chain contains a haem group (a prosthetic group)
  • each haem group contains an iron atoms
  • one 02 molecule can bind with each iron atom
45
Q

describe the structure of collagen

A
  • three polypeptide chains wound round each other
  • every third amino acid in each polypeptide is glycine
  • covalent bonds form between the R groups of amino acids lying next to each other
  • these cross links form fibrils
  • they form fibres
46
Q

water as a solvent

A
  • water molecules are attracted to the ions and polar molecules
  • they collect around and separate them
47
Q

the high specific heat capacity of water

A
  • the amount of heat required to raise its temperature by a given amount
  • hydrogen bonds need to be broken to allow free movement
48
Q

high latent heat of vaporisation of water

A
  • a measure of the heat energy needed to vaporise a liquid, changing it from a liquid to a gas
  • it means that living organisms can use evaporation as a cooling system
49
Q

high surface tension and cohesion of water

A
  • the molecules tend to stick together
  • water can move through long, unbroken columns through the vascular tissue in plants
  • the surface of water is a habitat for small organisms

Biology A-level (18 decks)

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