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A level Bio > biological molecules > Flashcards

biological molecules Flashcards

(66 cards)

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1
Q

What is cohesion

A

hydrogen bonding between water molecules

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2
Q

how is surface tension created

A

cohesion means water moves as 1 mass
provides a habitat for insects

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3
Q

what is adhesion

A

forces of attraction between water molecules and different substances

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4
Q

what is present in carbohydrates

A

carbon, hydrogen, oxygen

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5
Q

what’s present in lipids

A

carbon, hydrogen and oxygen

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6
Q

whats present in proteins

A

carbon, hydrogen, oxygen, nitrogen, sulfur

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7
Q

whats present in nucleic acids

A

carbon, hydrogen, oxygen, nitrogen and phosphorus

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8
Q

what are the monomers in carbohydrates

A

sugars (saccharides)

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9
Q

what are the monomers in proteins

A

amino acids

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10
Q

what are polar molecules

A

molecules that have regions of negativity and regions of positivity

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11
Q

what are hydrogen bonds, are they strong or weak

A

when polar molecules interact with each other as positive and negative regions of the molecule attract each other
they’re weak interactions but occur in high numbers

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12
Q

characteristics of water

A
  • usually high boiling point
  • small molecule
  • liquid at room temperature
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13
Q

why is water a liquid at room temperature

A

due to the hydrogen bonding between water molecules, it takes a lot of energy to increase the temperature of water and cause it to become gaseous

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14
Q

why does water become less dense when it turns to ice

A

due to the hydrogen bonds, as water is cooled, the hydrogen bonds fix the positions of the polar molecules slightly further apart than the average distance in the liquid state
this produces a giant, rigid but open structure

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15
Q

what does it mean that water has cohesive properties

A

it moves as one mass because the molecules are attracted to each other (cohesion)
this means wawter can draw water up their roots

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16
Q

what does it mean that water has adhesive properties

A

water molecules are attracted to other materials

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17
Q

why is water essential for life

A
  • acts as a medium for chemical reactions
  • acts as a very efficient transport medium
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18
Q

what are carbohydrates

A

molecules that only contain the elements carbon, hydrogen and oxygen

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19
Q

what is a monosaccharide + examples

A

a simple sugar unit
e.g. glucose, fructose and ribose

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20
Q

what is a disaccharide + examples

A

when two monosaccharides link together e.g. lactose, sucrose

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21
Q

what is a polysaccharide + examples

A

when two or more monosaccharides are linked e.g. glycogen, cellulose and starch

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22
Q

chemical formula for glucose

A

C6H12O6

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23
Q

difference between alpha glucose and beta glucose

A

the hydroxyl group (OH) are in opposite positions
in Beta glucose, OH group is aBove the ring
in Alpha glucose, OH group is below the ring

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24
Q

what is amylose

A

formed by alpha glucose molecule joined together only by 1-4 glycosidic bonds

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25
what is the function of glucose
glucose contains a large number of bonds that can be broken down into simpler molecules in respiration. Respiration produces energy used to make ATP broken down into carbon dioxide and water
26
why is only alpha glucose used in respiration
animals and plants have enzymes that break a-glucose only
27
what is sucrose made of
glucose + fructose
28
what is lactose made of
galactose + glucose
29
what is maltose made of
glucose + glucose
30
properties of starch
- storage in plants - insoluble in water so doesn't lower water potential - made of two forms - amylose and amylopectin
31
properties of amylose
long unbranched chain of alpha a-glucose glycosidic 1-4 bonds straight chain what often coils
32
properties of amylopectin
- a-glucose - has alpha 1-4 and alpha 1-6 glycosidic bonds - branched molecule
33
properties of glycogen
- highly branched - formed as storage product in liver and muscles
34
properties of cellulose
- long chains of beta glucose joined together by b1-4 glycosidic bonds - unbranched and insoluble - structural support - cellulose cell wall - alternate b-glucose molecules must be rotated/flipped 180 degrees to each other to form the b1-4 glycosidic link
35
what makes cellulose so stable
hydrogen bonding between the lines of cellulose
36
what are fibrils
hydrogen bonds form between parallel chains of cellulose - forming fibrils - which are linked by hydrogen bonds to form macrofibrils - gives high tensile strength
37
what are cell walls made of
cellulose chains make up cell wall macrofibrils which are embedded in pectin
38
what is an amino acid made of
- an amine group (NH2) - a carboxyl group (COOH) - R group
39
how is a peptide bond formed
between two amino acids condensation reaction water released as a bio product joins C----N
40
primary protein structure
sequence of amino acids held together by strong covalent peptide bonds
41
secondary protein structure
chain of amino acids coils or folds to form alpha helix or a beta pleated sheet. hydrogen bonds hold the structure together
42
tertiary protein structure
final 3D hydrogen bonds disulfide ionic hydrophobic interactions
43
quaternary protein structure
more than one polypeptide chain joined together e.g. haemoglobin
44
properties of a fibrous protein
S -long and narrow P- structural A - repetitive amino acid sequence D - less sensitive to changes in pH, temp etc E - collagen, fibrin, keratin, elastin S - generally insoluble in water
45
properties of a globular protein
S - round spherical P - function A - irregular acid sequence D - more sensitive to changes E - haemoglobin, enzymes , insulin S - generally soluble in water
46
what does SPADES stand for (types of protein)
Shape Purpose Acid sequence Durability Examples Solubility
47
what is a simple protein
contains only amino acids
48
what is a conjugated protein
consists of a simple protein combined with a non protein component (prosthetic group)
49
structure of collagen and what type of protein
fibrous protein 3 polypeptide chains
50
what is an intracellular enzyme + an example
an enzyme that functions within the cell in which it was produced e.g. catalase which converts hydrogen peroxide into water and oxygen
51
what is an extracellular enzyme + example
an enzyme that is secreted by the cell in which it was produced and functions outside that cell e.g. amylase - converts carbohydrates into simple sugars
52
what are triglycerides made of
one molecule of glycerol and 3 fatty acid chains
53
what is a glycerol molecule made of
three carbon atoms each of these has a hydroxyl (OH) group attached
54
unsaturated and saturated meaning
unsaturated - at least double bond between carbons saturated - single c-c bond
55
when are ester bonds formed
link between the glycerol molecule & each fatty acid
56
function of triglycerides
energy store - hydrophobic so water can be stored energy source - repired to release energy and generate ATP insuslation - seals blubber
57
what is a phospholibid made of
- two fatty acids - a phosphate group
58
why are phospholipids polar
phosphate group has a negative charge, attracting to water - **hydrophilic** whereas fatty acid tails are non-polar and repelled by water - **hydrophobic**
59
functions of phospholipids
- the composition of phospholipids contributes to the fluidity of the cell membrane - if there are mainly saturated fatty acid tails <- membrane will be less fluid - if there are mainly unsaturated <-- membrane will be more fluid - phospholipids control membrane protein orientation
60
function of cholesterol
synthesised in the liver and transported via the blood - steriod hormones testosterone, oestrogen are made from cholesterol - binds to the hydrophobic tails of the phospholipids, causing them to pack more closely together - prevents phospholipids solidifying at low temps and being too fluid at high temps
61
what is the test for reducing sugars + positive result
benedicts reagent blue --> brick red
62
test for starch + positive result
iodine solution orange --> blue black
63
# [](http://) test for lipids + positive result
emulsion (add ethonal and shake, pour into water) colourless--> cloudy
64
how to test for non-reducing sugars
- add hydrochloric acid - add sodium hydrogen carbonate - carry out benedicts test (for reducing sugars)
65
test for proteins (peptide bonds) + positive result
buiret purple
66
why is the ability of water to act as a solvent important for the survival of organisms
- can act as a medium for metabolic reactions <- because it allows iconic compounds to seperate - transport medium (e.g. xylem and phloem) - able to dilute toxic substances

A level Bio (12 decks)

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