Biological Molecules Flashcards
(39 cards)
1
Q
Test for lipid
A
- dissolve in ethanol and add water
- milky while emulsion should form
2
Q
Name of bond between glycerol and fatty acid
A
Ester
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
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
5
Q
Test for reducing sugars
A
- Benedict’s solution goes from blue to brick-red
- heated with reducing sugars
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
7
Q
Lipid uses
A
- energy storage
- thermal insulation
- waterproofing
8
Q
Triglyceride
A
1 glycerol + 3 fatty acids (carboxyl group and R-group i.e. hydrocarbon chain)
9
Q
Test for proteins
A
- biuret test
- add NaOH and CuSO4
- changes colour from pale blue to purple
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
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
12
Q
Prosthetic groups
A
Inorganic group forming part of quaternary structure of conjugated protein e.g. haemoglobin has iron containing haem groups
13
Q
Nucleotide components
A
Nitrogenous base
Phosphate group
Pentose sugar
14
Q
ATP structure
A
Phosphorylated macromolecule
- adenine
- ribose
- three phosphate groups
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
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
Why serial dilution
- without serial dilution you would need to measure very small volumes
- which is difficult to do accurately
26
Give examples of nucleotides
- ATP
- DNA
- RNA
27
Condensation
- reaction which joins two molecules together with the formation of a chemical bond
- involves elimination of water molecule
28
Hydrolysis
- reaction which breaks a chemical bond between two molecules
- involves use of water molecule
29
State which monosaccharides the following disaccharides are made of:
- maltose
- sucrose
- lactose
maltose - glucose x2
sucrose - glucose + fructose
lactose - glucose + galactose
(glycosidic bond formed between them)
30
Explain how the structure of triglycerides are related to their function
- 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
Explain how the structure of phospholipids are related to their function
- 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
Give examples of inorganic ions
- iron
- hydrogen
- sodium (potassium)
- phosphate
- nitrate
33
Explain the biological importance of iron
- 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
Explain the biological importance of sodium/potassium ions
- 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
Explain the biological importance of nitrate ions
- 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
Explain the biological importance of phosphate ions
- 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
Explain the biological importance of hydrogen ions
- 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
Explain the biological importance of water
- 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
Difference between alpha and beta glucose
position of H and OH group on carbon 1 inverted for beta
