Carbohydrates Flashcards

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1
Q

definition of a monomer

A

small, single repeating units that act as the building blocks to create larger molecules

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2
Q

definition of a polymer

A

molecules made up of many monomers, usually thousands, chemically bonded together

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3
Q

examples of monomers

A

monosaccharides, amino acids, nucleotides

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4
Q

examples of polymers

A

starch, dna, proteins

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5
Q

what is needed for monomers to bond together

A

a condensation reaction

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6
Q

explain a condensation reaction

A

involves the elimination of a water molecule
this joins two molecules together with the formation of a chemical bond between the monomers

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7
Q

explain a hydrolysis reaction

A

a water molecule is added between two bonded monomers (within a dimer or polymer) to break the chemical bond

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8
Q

define a dimer

A

2 monomers linked together

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9
Q

define a trimer

A

3 monomers linked together

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10
Q

define carbohydrates

A

key biological molecules that store energy and can provide structural support to plant cells

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11
Q

what are the three groups of carbohydrates

A

monosaccharides, disaccharides, polysaccharides

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12
Q

how can carbohydrates be classified

A

into three groups determined by how many units they are made of

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13
Q

examples of monosaccharides

A

glucose, fructose, galactose

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14
Q

examples of disaccharides

A

maltose, sucrose, lactose

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15
Q

examples of polysaccharides

A

starch, glycogen, cellulose

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16
Q

what are monosaccharides

A

the monomers from which larger
carbohydrates are made

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17
Q

how are disaccharides formed

A

formed by a condensation reaction, releasing a water molecule

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18
Q

what does a condensation reaction between two monosaccharides form

A

a glycosidic bond

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19
Q

what are the two isomers of glucose

A

alpha, beta

20
Q

features of monosaccharides

A

simple sugars
soluble in water

21
Q

function of monosaccharides

A

either to provide energy or to be a building block to create larger molecules

22
Q

what elements do carbohydrates contain

A

carbon, hydrogen, oxygen

23
Q

general formula for a monosaccharide

A

CnH2nOn

24
Q

formula for glucose

A

C6H12O6

25
Q

describe the difference between alpha glucose and beta glucose

A
  • both isomers so have the same molecular formulas but differently arranged atoms
  • OH group is below carbon 1 in alpha and above in beta
26
Q

what is an isomer

A

compounds that have the same formula but the atoms are arranged differently

27
Q

what are disaccharides

A

two monosaccharides joined together with a glycosidic bond

28
Q

what are polysaccharides

A

many monosaccharides joined together with glycosidic bonds

29
Q

how are polysaccharides formed

A

formed by many condensation reactions, releasing many water molecules

30
Q

what is starch

A

an energy store in plant cells

31
Q

what does cellulose do

A

provides structural support

32
Q

what is glycogen

A

an energy store in animal cells

33
Q

describe the structure of starch

A

-polysaccharide of alpha glucose
-some has 1,4-glycosidic bonds so is unbranched (amylose)
-some has 1,6-glycosidic bonds so is branched (amylopectin)

34
Q

describe the structure of glycogen

A

-polysaccharide of alpha glucose
-1,4- and 1,6- glycosidic bonds so is branched

35
Q

how does the structure of starch (amylose) relate to its function

A

-helical - compact for storage in cell
-large, insoluble polysaccharide molecule-cant leave cell/cross cell membrane
-insoluble in water-water potential of cell not affected

36
Q

how does the structure of glycogen (and starch amylopectin) relate to its function

A

-branched → compact / fit more molecules in small area
-branched → more ends for faster hydrolysis → release glucose for respiration to make ATP for energy release
-large, insoluble polysaccharide molecule → can’t leave cell / cross cell membrane
-insoluble in water → water potential of cell not affected (no osmotic effect)

37
Q

describe when starch is made

A

made from the excess glucose created during photosynthesis

38
Q

function of cellulose

A

provides strength and structural support to plant / algal cell walls

39
Q

structure of cellulose

A

● polysaccharide of β-glucose
● 1,4-glycosidic bonds so forms straight, unbranched chains
● chains linked in parallel by hydrogen bonds, forming microfibrils

40
Q

how is the structure of cellulose related to its function

A

● every other β-glucose molecule is inverted in a
long, straight, unbranched chain
● many hydrogen bonds link parallel strands
(crosslinks) to form microfibrils (strong fibres)
● hydrogen bonds are strong in high numbers
● so provides strength to plant cell walls

41
Q

where is cellulose located

A

in the cell wall of plants to prevent cells bursting if they take in excess water

42
Q

properties of cellulose

A

-insoluble due to being a large molecule so doesn’t change water potential and affect osmosis
-very strong due to large number of hydrogen bonds

43
Q

equation for maltose

A

glucose + glucose

44
Q

equation for lactose

A

glucose + galactose

45
Q

equation for sucrose

A

glucose + fructose