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Biology > Biological Molecules > Flashcards

Biological Molecules Flashcards

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1
Q

Test for lipid

A
  • dissolve in ethanol and add water

- milky while emulsion should form

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2
Q

Name of bond between glycerol and fatty acid

A

Ester

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3
Q

Adaptations of starch

A
  • insoluble so does affect water potential of cell
  • helical structure so can be compacted
  • large molecule so cannot cross cell-surface membrane
  • branched so MANY ENDS for enzymes to hydrolyse quickly for energy release
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4
Q

Adaptations of cellulose

A
  • long straight chains of beta glucose
  • successive glucose units are rotated 180 degrees relative to each other
  • many hydrogen bonds
  • provide strength to cell wall
  • form microfibrils which run parallel
  • with hydrogen cross linkages
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5
Q

Test for reducing sugars

A
  • Benedict’s solution goes from blue to brick-red

- heated with reducing sugars

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6
Q

Test for non reducing sugars

A
  • heat with Benedict’s reagent + solution remains blue
  • heat with dilute hydrochloric acid
  • neutralise using sodium hydrogen carbonate as slightly alkaline conditions are required
  • heat with Benedict’s reagent + observe colour change from blue to brick-red
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7
Q

Lipid uses

A
  • energy storage
  • thermal insulation
  • waterproofing
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8
Q

Triglyceride

A

1 glycerol + 3 fatty acids (carboxyl group and R-group i.e. hydrocarbon chain)

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9
Q

Test for proteins

A
  • biuret test
  • add NaOH and CuSO4
  • changes colour from pale blue to purple
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10
Q

Adaptations of glycogen

A

Same as starch

  • less dense and more soluble than starch to fulfil higher metabolic requirement of animals (e.g. run from predators)
  • glycosidic bonds are easily broken so rapid release of glucose
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11
Q

Why is HCl added in test for non reducing sugars

A
  • hydrolyses non reducing sugar
  • into its constituent monosaccharides
  • positive Benedict’s test
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12
Q

Prosthetic groups

A

Inorganic group forming part of quaternary structure of conjugated protein e.g. haemoglobin has iron containing haem groups

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13
Q

Nucleotide components

A

Nitrogenous base
Phosphate group
Pentose sugar

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14
Q

ATP structure

A

Phosphorylated macromolecule

  • adenine
  • ribose
  • three phosphate groups
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15
Q

How does ATP release energy

A

Bonds between phosphate groups are unstable and have a low activation energy so are easily broken to release the potential energy stored in the bond

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16
Q

ATPase

A

Catalyses hydrolysis of ATP into ADP and Pi (inorganic phosphate)

17
Q

ATP Synthase

A

Catalyses condensation reaction between ADP and Pi for reform ADP

18
Q

Compare the structure of starch and cellulose

A

similarities

  • polymers of glucose monomer
  • insoluble
  • contain glycosidic bonds

differences

  • alpha vs beta glucose
  • helical vs long, straight chains
  • monomers same way up vs alternate
19
Q

Name processes in which ATP in produced

A
  • photosynthesis
  • aerobic respiration
  • anaerobic respiration
20
Q

Role of ATP

A
  • active transport
  • cell division (contraction of spindle fibres)
  • synthesis of DNA, proteins etc.
  • muscle contraction
  • nerve impulses (resting potential)
  • phosphorylation
21
Q

Suggest why cells are always producing ATP

A
  • immediate energy source so is unstable

- cannot be stored since it is constantly broken down

22
Q

Suggest why ATP is better than glucose

A
  • involves a single reaction to release energy immediately
  • releases a small amount of energy so is more manageable / less wasted
  • cannot pass out of cell so cells always have supply
23
Q

Suggest why it is important ATP releases energy in small, manageable amounts

A
  • avoids wastage

- overheating

24
Q

Equation to show how energy is released from ATP

A

ATP + H2O -> ADP + Pi

25
Q

Why serial dilution

A
  • without serial dilution you would need to measure very small volumes
  • which is difficult to do accurately
26
Q

Give examples of nucleotides

A
  • ATP
  • DNA
  • RNA
27
Q

Condensation

A
  • reaction which joins two molecules together with the formation of a chemical bond
  • involves elimination of water molecule
28
Q

Hydrolysis

A
  • reaction which breaks a chemical bond between two molecules
  • involves use of water molecule
29
Q

State which monosaccharides the following disaccharides are made of:

  • maltose
  • sucrose
  • lactose
A

maltose - glucose x2
sucrose - glucose + fructose
lactose - glucose + galactose
(glycosidic bond formed between them)

30
Q

Explain how the structure of triglycerides are related to their function

A
  • good source of energy due to long hydrocarbon chains which have many energy-containing C-H bonds
  • poor conductors of heat so acts as thermal insulators
  • large/uncharged hence insoluble in water so can be stored without affecting water potential of cells
31
Q

Explain how the structure of phospholipids are related to their function

A
  • hydrophilic head due to negatively charged phosphate group so face outwards
  • hydrophobic tail due to non-polar hydrocarbon chain so face inwards
  • form a bilayer in cell membranes
32
Q

Give examples of inorganic ions

A
  • iron
  • hydrogen
  • sodium (potassium)
  • phosphate
  • nitrate
33
Q

Explain the biological importance of iron

A
  • Fe3+ attached to haem groups in haemoglobin of red blood cells
  • each Fe3+ binds to one oxygen molecule when partial pressure for oxygen is high at lungs
  • rapid saturation of oxygen to make oxyhaemoglobin
  • unloads oxygen when partial pressure is low at muscles
  • oxygen necessary for aerobic respiration which produces more ATP than anaerobic
34
Q

Explain the biological importance of sodium/potassium ions

A
  • sodium potassium pump maintains resting potential
  • influx of sodium ions allows for passage of action potential
  • hyperpolarisation due to excess potassium ions results in refractory period so action potential is unidirectional and discrete
  • sodium-potassium pump creates concentration gradient for sodium so it co-transports glucose/amino acids into epithelial cells from lumen of ileum
35
Q

Explain the biological importance of nitrate ions

A
  • nitrogen-fixing bacteria in root nodules convert atmospheric nitrogen into nitrogen-containing compounds
  • nitrifying bacteria in soil convert ammonium to nitrite then nitrate in two stage oxidation process
  • nitrate taken up by roots in active transport and lower water potential in root hair cells so water enters by osmosis
  • nitrates used for amino acids, DNA/RNA and ATP
36
Q

Explain the biological importance of phosphate ions

A
  • phosphate requires for production of DNA/RNA
  • oxidative phosphorylation to produce ATP from ATP synthase
  • substrate level phosphorylation of glucose during glycolysis to produce triose phosphate from more reactive phosphorylated glucose
  • phospholipid bilayer for cell-surface membrane which is selectively permeable
37
Q

Explain the biological importance of hydrogen ions

A
  • concentration of hydrogen ions affects pH which controls enzyme action since it interferes with ionic bonding of R groups of amino acids
  • enzymes have conformational change of active site based on pH so can catalyse multiple reactions under different conditions
  • hydrogen ions and electrons reduce NADP in LDR
  • NADPH reduces glycerate-3-phosphate in Calvin cycle to TP
  • creates electrochemical gradient during oxidative phosphorylation so moves through ATP synthase resulting in a change in shape so it catalyses ATP production
38
Q

Explain the biological importance of water

A
  • reactive (metabolite) for hydrolysis and condensation reactions plus raw product in photosynthesis
  • cohesion-tension theory in xylem and surface tension for skaters
  • high latent heat for cooling with little water loss
  • high specific heat capacity so acts as a buffer against sudden temperature changes/ maintain homeostasis
  • UNIVERSAL solvent for reactions occur faster in solution /removal of waster products
  • ice has lower density so floats and insulates aquatic organisms during winter
39
Q

Difference between alpha and beta glucose

A

position of H and OH group on carbon 1 inverted for beta

Biology (14 decks)

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