Chapters 1.1-1.3 Biological Molecules Flashcards

mix of info with summary q

1
Q

Monomers

A

smaller units from which larger molecules are made.

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2
Q

polymers

A

molecules made from a large number of monomers joined together

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3
Q

Polymerisation

A

the process by which polymers are formed

Condensation reaction occurs whenever polymerisation takes place

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4
Q

Condensation reaction

A

a reaction involving the removal of a water molecule to create a chemical bond between two molecules

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5
Q

Hydrolosis

A

a reaction involving the addition of a water molecule to break a chemical bond between two molecules

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6
Q

Large molecules often contain carbon. Explain why this is.

A

carbon atoms readily link to one another to form a chain

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7
Q

1.glucose+_glucose____——> _________+water

2.glucose+_galactose____——> _________+water

3.glucose+_fructose____——> _________+water

the reactants side = monosaccharides
products side = disaccharides

A
  1. maltose+ water
  2. Lactose +water
  3. Sucrose +water

These are all DISACCHARIDES (2monosac. joined to form them)

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8
Q

properties of monosaccharides and formula?

A

1. sweet tasting
2. soluble
3. ALL are reducing sugars
3. General formula (CH2O)n

n= any no. 3—>7

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9
Q

what reaction do monosaccharides undergo to form disaccharides

A

condensation

Making LARGER molceules= COND.

BREAKING LARGER molecules into SMALLER molecules= HYDROLYSIS

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10
Q

Monomers= MyAuntieNever(Acts Good)

state 4 monomers and the polymers they form

A
  1. Monosacc= carbohydrates
  2. Amino A= proteins
  3. Nucleotides= DNA and RNA
  4. Alpha Glucose= starch, cellulose, glycogen

beta glucose = makes cellulose

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11
Q

reducing sugar

A

a sugar that can donate e- to another chemical, in this case benedict’s reagent

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12
Q

reduction

A

a chem reaction involving the gain of e- or hydrogen

in this case, benedict’s reganet is gaining e- from a reducing sugar

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13
Q

explain how to carry out the benedict’s test

A
  1. Add 2cm3 of food sample in tt. If the food sam. is not alr liquid, grind it with water
  2. Add equal volume of ebnedcit’s reanget to the same test tube
  3. Heat gently in water bath (boiling) for 5 minutes. If a reducing sugar is present then the solution will turn brown-orange
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14
Q

explain why benedict’s reagernt turns red when heated with a reducing sugar

A

sugar donates e- that reduce BLUE copper (II) sulfate to ORANGE copper (I) oxide

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15
Q

suggest a way, other than comapring colour changes, in which different concentrations of red. sugars can be estimated

A
  1. dry the percipitate in each sample
  2. weight it
  3. the heavier it is- the more red sugar is present
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16
Q

explain why its not possible to distinguish between very concentrated samples, even when the concentrations are different

A

once all the copper (II) sulfate has been reduced to copper (i) oxide, further amounts of red. sugar cannot make a difference

17
Q

how polysacc formed via the condensation of many gluc units?

A

2 monosac. undergo a condensation reaction, where a water molecule is removed to form a GLYCOSIDIC BOND (alpha 1,4 glyco bond) between the molecules (forming a disacc). This reaction is repeated until a polysacc is formed.

18
Q

how to carry out a test for non reducing sugars

A
  1. Carry out benedict’s test first = if there is no colour change there are no reducing sugars present
  2. 2cm3 of food sample in a new tt and add 2cm3 of dilute HCL and heat in gently boiling water bath for 5 mins (this will hydrolyse any disaccharide presentinto its constitunent monosacc.)
  3. slowly add sodium hydrogencarbonate to tt as this will neutralise the HCL (bc benedict’s r. cannot work in acidic conditions). Use pH paper to test that the sol is alkaline.
  4. Re-test the resulting sol by heating it with 2cm3 of benedict’s reagent in a gently boiling water bath.
  5. If the sol turns orange-brown then a non-red sugar was present in the og sample; this is bc the reducing sugars are now produced after hydrolysing the non-red sugars
19
Q

non red sugars

A

e.g sucrose = they dont change the colour of benedict’s reagent when they’re heated with it

20
Q

Starch= Iodine

how do u carry out a test for starch

A
  1. Add 2cm3 of sample being tested to tt
  2. Add 2 drops of iodine solution and stir or shake
  3. Yellow——> blue-black in the presence of starch
21
Q

why does the temp have to be lower (40”c) if hydrolysis is being carried out via an enzyme

A

enzymes denature at high temp
therefore preventing them from functioning