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biological molecules Flashcards

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1
Q

how much water does our bodies lose, and through what?

A

our bodies lose up to 3l of water daily, mostly through sweat and urine production

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2
Q

how does dehydration occur in humans?

A

it happens when the volume of water lost is not balanced by the water intake through eating and drinking.

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3
Q

what are the symptoms of dehydration?

A

feeling faint, losing focus, dry and irritated eyes, cracked lips and sore throat, constipation, pungent and dark-coloured urine

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4
Q

why is water important in humans in terms of regulating body temperature?

A

-water has a high heat capacity and is used to transport heat around the body
-when water in sweat evaporates,the latent heat of vapourisation removed from the skin helps keep the body cool

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5
Q

why is water important in humans in terms of maintaining blood pressure?

A

water makes up half the volume of blood
-too little water and blood becomes too viscous
-too much water and blood vessels may burst

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6
Q

why is water important humans in terms of medium of transport?

A

water being a universal solvent allows for efficient transport of many soluble substances throughout the body

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7
Q

why is water important in humans in terms of solvent for chemical reactions?

A

water makes up more than half the volume of the cell cytoplasm and is where most chemical reactions occur in the cell

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8
Q

why is water important in humans in terms of lubrication?

A

fluid at the joints and tears on the eye reduce the wear and tear these surfaces experience

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9
Q

why is water important in humans in terms of preventing constipation?

A

undigested food should be passed out in a semi-solid form with some water present

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10
Q

why is water important in humans in terms of excretion?

A

the kidneys remove toxic metabolic waste from the body by diluting it in water and excreting it in urine

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11
Q

why is water important in plants in terms of regulating temperature?

A

when plants lose water vapour via transpiration, the latent heat of vapourisation removed helps keep the plant cool

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12
Q

why is water important in plants in terms of medium if transport?

A

water being a universal solvent allows for the efficient transport of many soluble substances via the xylem and phloem

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13
Q

why is water important in plants in terms of solvent for chemical reactions?

A

water makes up more than half the volume of the cell cytoplasm and is where most chemical reactions occur in the cell

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14
Q

what are carbohydrates, proteins, and fats called, and what do they all contain in common?

A

they are biological molecules
they all similarly contain carbon, hydrogen, and oxygen atoms in varying ratios

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14
Q

in carbs, what are the polysaccharides?

A

starch, cellulose, glycogen

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14
Q

in carbs, what are the monosaccharides?

A

glucose, galactose, fructose

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14
Q

in carbs, what are the disaccharides?

A

maltose, lactose, sucrose

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14
Q

what is the element composition of carbs?

A

carbon, hydrogen, oxygen only
hydrogen and oxygen always 2:1

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14
Q

what is the basic unit in carbs?

A

monosaccharide (C6H12O6)
simplest carbohydrate molecule

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14
Q

what is the role in organism of carbs?

A

all carbohydrates consumed are ultimately broken down into glucose
substrate for cellular respiration
substrate for lipid and amino acid synthesis

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14
Q

what are some examples of glucose?

A

honey, raisins, dates

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14
Q

what are some examples of galactose?

A

honey, celery, plums

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14
Q

what makes maltose and what are some examples of it?

A

glucose+glucose
malt sugar
apples, sweet potatoes, edamame

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15
Q

what are some examples of fructose?

A

honey, pear, mango

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15
what makes lactose and what are some examples of it?
galactose+glucose milk sugar milk, yoghurt, cheese
15
what are reducing sugars?
glucose, galactose, fructose, maltose, lactose
15
what makes sucrose and what are some examples of it?
fructose+glucose table sugar sugar cane, maple syrup, gula melaka
15
what sugar isnt a reducing sugar?
sucrose
15
how to carry out the benedicts test?
if presented with solid sample grind with a mortar and pestle then add distilled water -add 2cm3 of benedicts solution to 2cm3 of the liquid/aqueous sample -heat the mixture for 5 minutes in a boiling bath
16
what do the results of the benedicts test mean?
remains clear blue=reducing sugars absent turns brick-red=reducing sugars present
17
what are polysaccharides made out of?
polysaccharides are made out of many repeating subunits of glucose chemically bound together
18
where is starch commonly found?
starch is the storage in plants
19
where is glycogen commonly found?
glycogen is the storage in animals
20
where is cellulose commonly found?
cellulose is the structural support for the plant cell wall
21
how to carry out the iodine test for starch?
add 3 to 5 drops of iodine solution to the sample
22
what do the results of the iodine test mean?
remains yellowish-brown=starch absent turns blue-black=starch present
23
which class of biological molecules do fats belong to?
lipids (which also include many other important molecules such as phospholipids;cell membrane, and hormones;oestrogen and testosterone)
24
what is the element composition of fats?
carbon, hydrogen, and oxygen no fixed ratio of hydrogen and oxygen
25
what is the basic unit of fats?
one glycerol backbone with three fatty acid tails
26
what is the role in organism in fats?
long-term energy storage, insulation beneath the skin surface, cushion and protect internal organs from impact, major component of cell membrane, solvent for fat-soluble vitamins
27
what are saturated fats?
solid at room temperature, increases risk of heart diseases
28
what are unsaturated fats?
liquid at room temperature, lowers risk of heart diseases
29
how does the ethanol-emulsion test for fats occur?
add the food sample to a beaker of ethanol and shake thoroughly to allow any fats present to dissolve -filter the mixture and pour 2cm3 of the residue to 2cm3 of water
30
what do the results of the ethanol-emulsion test for fats mean?
remains clear and colourless=fats absent cloudy white emulsion formed=fats present
31
what are proteins?
proteins account for more than 50% of the dry mass of most cells and are crucial for the basic functioning of a cell. proteins help to speed up chemical reactions, transport substances, and allow cells to move
32
how are proteins formed?
there are 20 amino acids that can be chemically bound together in various lengths and sequences to form thousands of different proteins
33
for proper functioning, how many proteins does a normal human have?
10000 different proteins for an estimated total of 400000 proteins for proper functioning
34
what do amino acids contain?
they all consist of an amino group, a carboxyl group, and a hydrogen atom.
35
what differs in amino acids?
the variable group that gives rise to the 20 different amino acids
36
what do those 20 different amino acids do?
these 20 different amino acids come together in various lengths and sequences to form polypeptides which subsequently fold to become the proteins essential for life
37
what are some products rich in proteins?
meat and dairy products, as well as leafy vegetables. eggs, nuts and beans
38
what is the element composition of proteins?
carbon, hydrogen, oxygen and nitrogen some amino acids have sulfur and phosphorus
39
what is the basic unit of amino acids?
amino acid
40
what is the role in organism in proteins?
enzymes speed up chemical reactions, antibodies and antigens protect cell from pathogens, hormones regulate various processes, contractile and motor proteins allow for movement
41
how does the biuret test for proteins occur?
-add 2cm3 of sodium hydroxide solution to 2cm3 of the liquid/aqueous sample and shake thoroughly to mix -add a 3 to 5 drops of copper(II) sulfate solution, shaking the mixture between drops
42
what do the results of the biuret test for proteins mean?
remains blue=proteins absent turns violet=proteins present
43
what are enzymes?
enzymes are biological catalysts that speed up the rate of chemical reactions and remain chemically unchanged at the end of each reaction
44
how do enzymes work?
-all enzymes are proteins and function best at their optimal temperatures and pH -enzymes provide an alternative reaction pathway with a lower activation energy -only a small amount of enzymes are needed as they remain chemically unchanged at the end of each reaction and can therefore be reused
45
what is activation energy?
the minimum amount of energy reacting molecules need to have to undergo a reaction. the lower the activation energy, the more easily the reaction proceeds
46
what is the 'lock and key' hypothesis?
substrate molecules have a complementary shape to fit into the active site of an enzyme. enzymes ensure specificity by having a unique active site that can only bind to a complementary substrate molecule. upon forming the enzyme-substrate complex, the substrate now requires a lower activation energy to undergo a reaction and can proceed to form new products by breaking or forming bonds
47
what is the complementary substrate molecules for amylase?
starch
48
what is the complementary substrate molecules for sucrase?
sucrose
49
what is the complementary substrate molecules for protease?
proteins
50
what is the complementary substrate molecules for lipase?
lipids
51
how does temperature affect enzyme-cataylsed reactions?
being proteins, enzymes are sensitive to changes in temperature, and their ability to catalyse reactions will diminish when the conditions are too far from the optimal
52
what is the optimum temperature of enzymes found in the human body?
around 37 degrees celsius
53
what does the point below optimum temperature in the graph mean?
enzymes (and substrates) have insufficient kinetic energy enzymes are inactive and enzyme activity is low
54
what does the point at optimum temperature in the graph mean?
enzymes have the perfect of kinetic energy to bind to substrates and catalyse the reaction
55
what does the point above optimum temperature in the graph mean?
enzymes denature and are no longer complementary to their substrates
56
what does the trend below optimum temperature in the graph mean?
as temperature increases, reacting molecules have more kinetic energy and move faster the frequency of effective collisions increase, causing more enzyme-substrate complexes to form more quickly for a greater rate of reaction
57
what does the trend at optimum temperature in the graph mean?
enzymes are most active and have the greatest rate of reaction
58
what does the trend above optimum temperature in the graph mean?
-too much kinetic energy disrupts the bonds holding the three-dimensional structure of the enzyme -the specific shape of the active site is damaged, and the enzyme is no longer complementary to its substrate -enzymes are denatured and cannot catalyse the reaction
59
what is the effect pH has on enzyme-catalysed reactions?
enzymes are also sensitive to changes in pH, and their ability to catalyse reactions will diminish when the conditions are too far from the optimal
60
what is the pH of stomach enzymes?
2 (very acidic)
61
what is the pH of pancreatic enzymes?
8 ( a little basic/alkali)
62
what does the point below optimum pH in the graph mean? (pH)
enzymes are denatured and no longer complementary to their substrates
63
what does the point at optimum pH in the graph mean? (pH)
enzymes are most active
64
what does the point below optimum pH in the graph mean? (pH)
enzymes are denatured and no longer complementary to their substrates
65
what does the trend below optimum pH in the graph mean?
-deviations from the optimal pH disrupts the bonds holding the three-dimensional structure of the enzyme -the specific shape of the active site is damaged, and the enzyme is no longer complementary to its substrate -enzymes are denatured and cannot catalyse the reaction
66
what does the trend at optimum pH in the graph mean?
enzymes are most active and have the greatest rate of reaction
67
what does the trend above optimum pH in the graph mean?
-deviations from the optimum pH disrupts the bonds holding the three-dimensional structure of the enzyme -the specific shape of the active site is damaged, and the enzyme is no longer complementary
68
how does substrate concentration affect the rate of enzyme-catalysed reactions?
-at low substrate concentrations, enzyme activity increases rapidly when substrate concentration increases -at high substrate concentrations, enzyme activity plateaus as all enzyme active sites are occupied and substrate molecules must wait for a free active site
69
how does enzyme concentration affect the rate of enzyme-catalysed reactions?
-at low enzyme concentrations, enzyme activity increases rapidly when enzyme concentration increases -at high enzyme concentrations, enzyme activity plateaus as all substrates have already formed enzyme-substrate complexes and there are no available substrates
70
how does the size of the sample affect the rate of enzyme-catalysed reactions?
-large chunks of food have small surface to volume ratios, decreasing the effectiveness of enzyme reactions -small pieces of food have large surface area to volume to ratios, increasing the effectiveness of enzyme reactions

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