3.1 Biological Molecules Flashcards

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1
Q

define monomers

A

smaller units from which larger units are made

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2
Q

define polymer

A

made from larger no. of molecules joined together

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3
Q

define condensation reaction

A

joins two molecules together
formation of a chemical bond
releasing a molecule of water

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4
Q

define hydrolysis

A

breaks a chemical bond
between two molecules
involves using a water molecule

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5
Q

what are monosaccharides

A

monomers from which larger carbohydrates are made
glucose
fructose
galactose

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6
Q

how are dissacharides formed + list the equations

A

condensation of two monosaccharides
glucose + glucose = maltose
glucose + fructose = sucrose
glucose + galactose = lactose

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7
Q

draw the isomers of glucose

A

search

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8
Q

how are polysaccharides formed

A

condensation of many glucose units

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9
Q

structure + function of glycogen

A

function: energy strore in animal cells
structure: polysaccharide of a glucose
1-4, 1-6 glycosidic bonds
branched

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10
Q

structure related to function of glycogen

A

branched ; lots of active sites to be rapidly hydrolysed by enzymes for quick release of glucose for respiration for energy
large ; can’t leave cell
insoluble ; doesn’t affect water potential of cell

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11
Q

strucutre + function of starch

A

function: energy store in plant cells
structure: a glucose
made of amylose + amylopectin
amylose; 1-4 unbranched
amylopectin; 1-4, 1-6 branched

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12
Q

structure related to function starch

A

helical ; compact for storage
large; can’t leave cell
insouble; no osmostic affect on wp of cell

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13
Q

structure + function of cellulose

A

function: provides strength + structural support to plant cell walls
structure: b glucose
long, straight, unbranched cellulose chains
H bonds link parallel strands to form microfibrils
H bonds strong in numbers
provides strength + structural support to plant cells

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14
Q

benedicts test for reducing sugars

A
  • add benedict’s reagent to food sample
  • heat in boiling water bath
  • positive = brick red ppt
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15
Q

benedicts for non reducing sugars

A
  • add dilute HCL
  • heat in boiling water bath
  • neutralise with sodium bicarbonate
  • normal benedicts
  • positive = brick red ppt
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16
Q

determing glucose conc

A
  • produce dilution series of glucose conc of known conc
  • benedicts test on each sample + remove ppt
  • use calorimeter, measure absorbance, establish calibration curve
  • repeat with unknown sample + compare absorbance
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17
Q

iodine test for starch

A

add iodine dissolved in potassium iodide
shake/stir
positive = blue/black colour

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18
Q

how are triglycerides formed

A

condensation of
1 molecule of glycerol
3 molecules of fatty acids
forming an 3 ester bonds

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19
Q

the R group of a fatty acid can be

A

saturated - no c=c bond in hydrocarbon chain

unsaturated - one or more c=c bond

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20
Q

how are phospholipids formed

A

one of the fatty acids is substituted

by a phosphate group

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21
Q

emulsion test for lipids

A

add ethanol to sample
then shake
then add water
positive = milky/white emulsion

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22
Q

properties of triglycerides related to their structure

A

energy store - high ratio of c-h bonds to c atoms
release more energy than same mass of carbohydrated
insoluble in water - no effect on wp

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23
Q

properties of phospholipids related to their structure

A

form cell membrane - allowing movement of non polar/lipid soluble/small molecules down a conc gradient

24
Q

what are amino acids

A

monomers from which amino acids are made

25
Q

what is a functional protein

A

may contain one or more polypeptides

26
Q

what is the primary structure

A

sequence of amino acids in polypeptide chain

joined by peptide bonds

27
Q

what is the secondary structure

A

h bonding between amino acids
causes folding of polypetide
into a helix or b pleated sheet

28
Q

what is the tertiary structure

A

overall 3D structure of polypeptide
further folding of polypeptide
held by ionic, H bonds and DS bridges

29
Q

what is the quaternary structure

A

proteins made of 2(+) polypeptide chains

held by more H, I bonds and DS bridges

30
Q

biuret test for proteins

A

add biuret solution; sodium hydroxide + copper (II) sulfate
blue to purple
detects presence of peptide bonds

31
Q

what do enzymes do

A

lowers the activation energy of reaction it catalyses
speeds up rate of reaction
biological catalysts

32
Q

induced fit model

A

active site not completely complementary to substrate active site changes shape as substrate binds
enzyme substrate complex forms
stresses/distorts bonds in substrate leading to a reaction

33
Q

explain the specificity of enzymes

A

specific tertiary structure + active site
due to sequence of aminp acids
active site is complementary to a specific substrate
so only this substrate can bind to active site
= enzyme - substrate complex

34
Q

effect of enzyme conc on rate of enzyme controlled reaction

A

increasing enzyme conc

  • rate of reaction increases
  • enzyme conc - limiting factor
  • more enzymes = more active sites
  • more successful E-S collisions + complexes

after, rate of reaction plateaus
-subsstrate conc = limiting factor

35
Q

effect of substrate conc on enzyme controlled reactions

A

increasing sub conc

  • increases rate of reaction
  • sub conc = limiting factor
  • not enough active sites
  • more successful E-S collisions + complexed

after, rate of reaction plateaus

  • enzyme conc =limiting dactor
  • active sites saturated
36
Q

effect of temperature on enzyme controlled reactions

A

increasing temp

  • rate of reaction increases
  • increase in KE
  • more successful E-S collisions + complexes

above optimum

  • enzymes denature
  • tetiary structure + active site change shape
  • H and I bonds break
  • substrate no longer binds
  • enzyme denatures
37
Q

effect of pH on enzyme controlled reaction

A

above/below optimum

  • enzymes denature
  • tertiary structre + active site change shape
  • H and I bonds break
  • complementary substrate no longer binds
38
Q

effect of competitive inhibitors on enzyme controlled reactions

A

decrease rate of reaction

  • similar shape to substrate
  • competes for/binds to/blocks active site so substrate cant bind
  • fewer E-S complexes
  • increasing sub conc reduces inhibitor effect
39
Q

effect of non competitive inhibitors on enzyme controlled reactions

A

decrease rate of reaction

  • binds away from active site (allosteric site)
  • enzyme tertiary structure/active site changes shape so substrate cant bind to active site
  • fewe E-S complexes
  • increasing sub conc has no effect on rate
40
Q

role of DNA and RNA

A

DNA - holds genetic info

RNA -transfers genetic info from DNA to ribosomes

41
Q

a condensation reaction between two nucleotides

A

a phosphodiester bond

42
Q

DNA vs RNA`

A

DNA- deoxyribose RNA-ribose
DNA-thymine RNA-uracil
DNA- double stranded RNA- single stranded
DNA - longer RNA- shorter

43
Q

DNA structure

A

2 anit-parallel strands
joined by H bonds
between specific complementary base pairs

44
Q

structure of DNA related to its function

A

larger no of weak H bonds between complementary bases - stable/strong

double helix - protects bases/ H bonds

long - stores lots of genetic info

double stranded- semi conservative replication, as both strands act as templates

complementary base pairing - accurate replication/identical copies

coiled - compact

45
Q

process of DNA replication

A

-DNA helicase breaks H bonds between bases, unwinds double helix= two strands which can act as templates
-free floating DNA nucleotides attracted to exposed bases via specific complementary base pairing
H bonds form
-DNA polymerase joins adjacent nucleotides on new strand via condensation forming phosphodiester bonds
-

46
Q

how does DNA polymerase move

A

has specific shaped active site
which can only bind to substrate with complementary shape
only the 3’ end

47
Q

what is ATP and what is it formed of

A

a nucleotide derivative

molecule of ribose, adenine + 3 phosphate groups

48
Q

ATP hydrolysis

A

ATP –> ADP + Pi

catalysed by ATP hydrolase

can be coupled to energy requiring reactions within cells
-bonds between Pi bonds are high energy bonds so breaking bonds releases small amount of energy

Pi released used to phosphorylate other compounds to make them more reactive

49
Q

ATP condesation

A

ADP + Pi –> ATP

catalysed by ATP synthase

happens during respiration or photosynthesis

phosphorylation of ADP

50
Q

why is ATP a suitable source of energy

A
  • releases energy in small,manageable amounts so no energy wasted
  • immediate release
  • cannot leave cell
  • quick to resynthesise
51
Q

roles of water

A

metabolite in many metabolic reactions
-water is reactive

solvent
-water is polar molecule

high heat capacity

  • absorbs large amounts of heat before temp changes
  • buffers temp changes
  • helps maintain constant body tep

large latent heat of vaporisation

  • absorbs large amounts of heat before evaporation
  • cooling effect with little loss of water via evaporation
  • constant body temp

strong cohesion between water molecules

  • molecules stick together
  • column of water doesn’t break
  • provides surface tension
52
Q

where do inorganic ions occur

A

in solution in cytoplasm + body fluids of organisms
some in high conc others in low conc
each ion has specific role depending on its properties

53
Q

phosphate ions

A
  • attached to other molecules as a phosphate group

- form the phosphate groups of DNA/RNA nucleotides

54
Q

hydrogen ions

A

maintains pH levels in body

affects rate of enzyme controlled reactions

55
Q

iron ions

A

component of haem group in red blood cells
transports o2 around body
o2 temporarily binds to it, becomes fe3+

56
Q

sodium ions

A

co transport of glucose + amino acids across cell membranes