chapter 3 - biological molecules Flashcards

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1
Q

what are the three main single sugars / monosaccharides?

A
  1. glucose
  2. galactose
  3. fructose

“great girl friends”

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2
Q

what are the three main double sugars / disaccharides?

A
  1. Maltose = glucose + glucose
  2. lactose = glucose + galactose
  3. sucrose = glucose + fructose
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3
Q

maltose = glucose + _____________

A

glucose

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4
Q

lactose = glucose + _____________

A

galactose

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5
Q

why do we need food?

A

the nutrients in the food provide us with energy and materials needed by the body

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6
Q

sucrose = glucose + _____________

A

fructose

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7
Q

galactose is commonly found in _____________

A

milk from mammals

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8
Q

glucose is commonly found in ______________

A

plants and animals

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9
Q

fructose is commonly found in ___________

A

plants
(very rare in animals)

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10
Q

what is the test for reducing sugars?

A

Benedict’s test (using benedict’s solution)

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11
Q

what are the reducing sugars?

A
  1. glucose
  2. galactose
  3. fructose
  4. lactose
  5. maltose
    “great girl friends like me”
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12
Q

if the benedict’s solution remained blue, _______________ reducing sugar

A

no reducing sguar

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13
Q

if the benedict’s solution turned from blue to green, _____________ reducing sugar

A

traces of

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14
Q

if the benedict’s solution turned from blue to yellow/orange, _____________ reducing sugar

A

moderate amount of

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15
Q

if the benedict’s solution turned from blue to red, _____________ reducing sugar

A

large amount of reducing sugar

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16
Q

traces of reducing sugar: benedict’s solution _________

A

turns from blue to green

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17
Q

moderate amount of reducing sugar: benedict’s solution _________

A

turns from blue to yellow/orange

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18
Q

no reducing sugar: benedict’s solution _________

A

remains blue

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19
Q

large amount of reducing sugar: benedict’s solution _________

A

turns from blue to red

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20
Q

what are the three complex carbohydrates / polysaccharides?

A
  1. starch
  2. glycogen
  3. cellulose
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21
Q

what is the main function of carbohydrates?

A

needed as an immediate source of energy

22
Q

what are the chemical elements that make up carbohydrates?

A

carbon, hydrogen, oxygen

23
Q

in carbohydrates, the hydrogen and oxygen atoms are present in the ratio __________

A

2:1

24
Q

starch, glycogen and cellulose are polysaccharides make up of numerous __________ molecules

A

glucose

25
Q

disaccharides are created when _______________

A

two monosaccharides are joined together through a condensation reaction

26
Q

what is the role of starch (2 pts) and where does it occur (1 pt)?

A
  1. a storage form of carbohydrates in plants
  2. digested to glucose when needed
  3. found in storage organs of plants, e.g. potato, tapioca
27
Q

what is the role of glycogen? (2 pts)

A
  1. a storage form of carbohydrates in mammals
  2. digested to glucose when needed
28
Q

what is the role of cellulose? (2 pts)

A
  1. cellulose cell wall protects plant cell from bursting/damage
  2. serve as a dietary fibre that prevents constipation
29
Q

why are glucose and starch used as storage materials?

A
  1. insoluble in water (they are osmotically inactive so they do not change water potential in cells)
  2. large molecules (cannot diffuse across cell membranes, so they will not be lost from cell)
  3. easily hydrolysed to glucose when needed for respiration
  4. have compact shapes (occupy less space than sum of individual glucose molecules)
30
Q

what is the meaning of hydrolysed

A

breakdown in the presence of water

31
Q

starch is broken down by ___________ to form maltose

A

amylase

32
Q

maltose is broken down by _________ to form glucose

A

maltase

33
Q

what is the test for starch ?

A

iodine test (using iodine solution)

34
Q

for solid food samples, crush the food using _____________

A

a mortar and pestle

35
Q

what elements are proteins made up of?

A

carbon, hydrogen, oxygen and nitrogen

36
Q

each protein molecule is made up of smaller basic units called ___________

A

amino acids

(amino acids are the building blocks of protein)

37
Q

amino acids are made up of _________, __________ & _____________.

A

amino group, acidic group & a side chain

38
Q

amino acids ——-> ____________———> _____________

A

polypeptides
proteins

39
Q

what happens when proteins are denatured?

A

they lose their unique 3D shape and lose their ability to function

40
Q

what are the functions of proteins? (5)

A
  1. synthesis of new cytoplasm for growth and repair of worn-out cells
  2. synthesis of enzymes and some hormones
  3. formation of antibodies to combat diseases
  4. source of energy during EXTREME starvation when carbohydrate and fat reserves are depleted.
  5. proteins are used for muscle development.
41
Q

what is the test for proteins?

A

biuret test (using biuret solution)

42
Q

in the absence of protein, the biuret solution will __________________.

A

remain blue

43
Q

in the presence of protein, the biuret solution will _________________.

A

turn from blue to violet

44
Q

what elements are fats made up of?

A

carbon, hydrogen, oxygen

45
Q

unlike carbohydrates, fats contain ________ oxygen compared to hydrogen

A

MUCH less

46
Q

fats can be broken down into ________ & _________ by _________

A

fatty acids & glycerol by lipase

47
Q

what are the functions of fats? (5)

A
  1. a long-term storage of energy
  2. insulating material that prevents excessive heat loss
  3. solvent for fat-soluble vitamins and hormones
  4. they form cell membranes
  5. oily substance secreted by skin glands reduce rate of evaporation and heat loss from skin surface
48
Q

what is the test for fats?

A

ethanol emulsion test (using ethanol + water)

49
Q

during an ethanol emulsion test, in the presence of fats, _________________ is formed.

A

a cloudy white emulsion

50
Q

(ethanol emulsion test) in the absence of fats, ______________

A

solution will remain clear.