Biological compounds Flashcards
1
Q
What is an element?
A
A substance made up of only one type of atom
2
Q
What is a molecule
A
Two or more atoms chemically bonded together
3
Q
- What is an organic compound?
A
A compound (two or more elements chemically bonded together) containing carbon and hydrogen and produced by living organisms
4
Q
- What is an ion?
A
A particle with charge
5
Q
- What is an inorganic compound?
A
A compound (two or more elements chemically bonded together) NOT containing carbon and hydrogen, and NOT produced by living organisms
6
Q
- Which ion is a necessary component of chlorophyll?
A
Magnesium Mg2+
(1 of the 4 Macronutrients)
Deficiency causes chlorosis and stunts plant growth due to a lack of glucose from reduced photosynthesis.
7
Q
- Which ion is a component of haemoglobin?
A
Iron Fe2+
(1 of the 4 Macronutrients)
Responsible for oxygen transport
8
Q
- What is the role of calcium ions (1 of the 4 Macronutrients) in plants?
A
Component of the middle lamellae of cell walls
9
Q
- What is the role of calcium ions in animals?
A
Growth and repair of bones and teeth
Deficiency leads to rickets
10
Q
- Name 4 types of molecules that contain phosphate PO4^3-. (1 of the 4 Macronutrients)
A
Adenosine Triphosphate (ATP), Ribonucleic Acid (RNA), Deoxyribonucleic Acid (DNA), and Phospholipid membrane.
11
Q
- What is an anabolic reaction?
A
Building small to larger molecules
12
Q
- What is a Catabolic reaction?
A
Breaking larger to smaller molecules
13
Q
- What does “water is a polar molecule” mean?
A
It has a positive end (H-) and a negative end(O-), but the molecule has no overall charge.
- Makes it a good polar solvent to act as a transport medium.
14
Q
- What type of bonds hold different water molecules together?
A
Hydrogen bonds
15
Q
- What does “high specific heat capacity” mean?
A
It requires a lot of energy to raise the temperature of 1kg of water by 1°C. (Average kinetic energy) 4200J/kg°C
16
Q
- What is the significance of water having a high specific heat capacity?
A
Stable aquatic and cellular environments. Prevents large fluctuations in bodies of water.
17
Q
- What does high latent heat of vaporisation mean?
A
It absorbs a lot of energy when it turns from liquid to gas. It also expels a lot of heat when it changes state from gas to liquid to solid without a temperature change. Lots of energy is needed to break hydrogen bonds.
18
Q
- What is the significance of this property to mammals?
A
Excess heat radiates from the surface of the skin and can be used to evaporate water (sweat), thus cooling the body.
Bodies of water do not dry up easily as it takes large increases in temperature to vaporise.
19
Q
7a. What does water provide for aquatic animals?
A
- High density: Insulating layer of ice so lakes dont freeze and provides buoyancy.
- Cohesion forces = high surface tension for insects to habitat on
20
Q
7b. What does water provide for aquatic plants?
A
- High density: Insulating layer of ice so lakes dont freeze and provides turgidity of plant cells and supports seed dispersal.
- Transparent: Sunlight can reach for photosynthesis.
-Cohesion: Water sticks to each other to create a column on water in the xylem.
-Adhesion: Water sticks to the inside of the xylem wall
21
Q
- Which processes is water a reactant in? (Metabolite)
A
Hydrolysis
22
Q
- Which processes is water a product from?
A
Condensation
23
Q
- Define condensation and hydrolysis. Give example for each
A
Hydrolysis: Water molecules are chemically inserted to break bonds. e.g photosynthesis
Condensation: Water is a product. e.g respiration
24
Q
- What do the terms: monomer, dimer and polymer mean?
A
Monomer: Single Units
Dimer: Two Mono units chemically bonded
Polymer: More than two monomer units chemically bonded
25
2. What is the difference between a structural and a molecular formula?
Structural shows the arrangement of atoms and molecular shows the number of each atom
26
3. What is an isomer?
Molecules with the same molecular formula but different structural formula
27
4. What is the general term for a single sugar unit?
Monosaccharide (sweet soluble sugar)
28
5. How many carbons do the following sugars have: triose and pentose
3 and 5
29
6. What is the general formula for a monosaccharide?
(CH2O)n
30
7. Name: a triose two pentose and three hexose sugars.
Triose: Glyceraldehyde
Pentose: Ribose/ATP and Deoxyribose
Hexose: Glucose, fructose, galactose
31
8. Name two molecules that contain ribose and one that contains deoxyribose.
Ribonucleic acid and Adenosine Triphosphate
32
9. What is the function of triose and hexose sugars?
Respiration
33
10. Why are glucose galactose, and fructose described as isomers of each other?,
They all have the same molecular formula: C6H12O6
34
1. Describe the difference between alpha and beta glucose.
Alpha -OH is below C1 and Beta -OH is above C1
35
2. Which two monomers make up: sucrose, maltose and lactose?
Sucrose: Alpha Glucose and Fructose
Maltose: Two Alpha glucoses
Lactose: Alpha glucose and Galactose
36
3. What is the function of sucrose?
Transport in phloem (energy)
37
4. Describe the reaction that is involved in joining two monosaccharides.
Condensation reaction/elimination of water: -OH lost off one and a -H from the other, thus forming a 1,4-glycosidic bond
38
5. What is the precise term for the bond that links two alpha-glucose molecules together in maltose?
α-1,4-glycosidic bond
39
6. Describe how you would test for the presence of a reducing sugar?
Dissolve sugar into a solution and test this solution with Benedict's reagent and heat strongly. Colour change blue to brick-red if positive.
40
7. Why is this test termed semi-quantitative?
Differences in colour change/ppt can be used to estimate the concentration of reducing sugar in the sample (None,low, medium,etc.)
41
8. Describe what you would do to test for a non-reducing sugar. (Splitting into monosaccharides)
No brick red ppt initially.
Heat strongly in dilute HCl to a fresh sample and boil for 2- 3 minutes.
Then add NaOH to neutralise or preferably slightly alkaline. Carry out the reducing sugar test again.
Colour change: Blue to Brick-red.
42
9. What is the general formula for a disaccharide?
C12H22O11
43
10. Where is lactose found?
Milk
44
1. Starch consists of two polymers, what are their names?
Amylopectin and Amylose
45
2. Which isomer of glucose is the monomer of starch?
α-glucose
46
3. What makes starch useful as a storage compound of glucose?
-Insoluble (does not draw water into or out of the cell by osmosis)
-Compact: Amylose coiled (a lot can be stored in small spaces)
-Hydrolyses to α-glucose, which is easily transported and used in respiration.
47
4. Where is glycogen stored?
Animal equiv. of starch.
Insulin converts excess glucose into glycogen and stores it as granules in liver and muscle cells.
48
5. What is the significance of the highly branched nature of glycogen?
Shorter 1,4-glycosidic bonds and more side branches linked by 1,6-glycosidic bonds. This allows stored glucose to release quickly.
49
6. Which isomer of glucose is the monomer of cellulose?
β glucose
50
7. What properties of cellulose make it suitable for the cell wall of plants?
- Long chain of alternating 180° β-glucose monomers.
Results in very long, very straight chains. Many run parallel and form hydrogen bond crosslinks => Microfibrils => Macrofibrils (high mechanical strength) => Cellulose fibres not aligned but crisscross for strength and rigidity. Prevents plant cells from bursting.
51
8. What are the similarities and differences between chitin and cellulose?
Similarities: Both have alternating through 180° units. Form hydrogen cross links between adjacent chains. Lightweight and strong (chitin is much stronger)
Differences: Chitin has an N-acetyl group attached to the C2 of glucosamine (NH-CO-CH3), whereas cellulose is glucose monomers. Chitin is waterproof.
52
9. Where would you find chitin?
Fungi cell walls and insect exoskeletons
53
10. Describe the test for starch.
Add Iodine solution: Brown to Blue-black
54
1. What are the constituent molecules in a lipid/triglyceride?
Glycerol (Polar w/ alcohol group) and Fatty acids (Non-polar w/ carboxyl group) =>Forms an ester
(Carbon, Hydrogen, Oxygen)
55
2. What are the differences between a triglyceride and a phospholipid?
Triglycerides have 3 fatty acid tails attached to the glycerol. Phospholipids have 2 fatty acid tails and a Phosphate ion.
56
3. Distinguish between a saturated and unsaturated fatty acid.
Saturated: only have single C-C bonds. Tightly packed and solid at normal temp. (Animal lipids)
Unsaturated: Have double C=C bonds, which cause kinks in the tail. Cannot align uniformly so liquid at normal temps (oil).
57
4. List the functions of lipids.
Steroids
Waxes reduce water loss
Phospholipid bilayer Triglycerides: Energy store, Thermal insulation, Buoyancy, Metabolic water, Physical protection.
58
5. Give two reasons that lipids are a good energy store.
- It yields about twice as much energy as the same mass of carbohydrate. Halves the mass needed for the same amount of energy, which is important to flying organisms.
- Not as easily accessible, so preferred for long-term storage.
59
6. What is the general formula for a saturated fatty acid?
CH3-(CH2)n-COOH
60
7a. Why is consumption of too many saturated fats considered unhealthy?
- Leads to higher levels of low-density lipoproteins (made from protein and lipids absorbed in the small intestine) building up, which causes atheroma in coronary arteries beneath the endothelial lining, restricting blood flow (atherosclerosis).
- Atheroma absorbs calcium and hardens into plaque, narrowing the lumen and increasing blood pressure (arteriosclerosis).
1) Thrombosis: Atheroma breaks through the endothelium and causes it to become rough and sticky, further narrowing the lumen. A blood clot, called a thrombus, forms, which may block the vessel and potentially cause an embolism (blocking another artery).
2) Aneurysm: Arteriosclerosis can cause the inner layers to separate, leaving only the outer layer. This can lead to swelling and may burst (haemorrhage), resulting in loss of blood. A brain aneurysm can lead to a stroke, resulting in cell death
3) Myocardial infarction: A blocked coronary artery interrupts blood flow to the cardiac muscle; a lack of oxygen leads to fatigue and may kill the cells.
61
7b. Why is a higher proportion of consumption of unsaturated fats better than saturated?
Unsaturated makes more High-density lipoproteins which carry away harmful fats from tissues to the liver for extraction. Protecting arteries from heart disease by knocking LDL off reducing the risk of atheroma.
62
8. Which part of a phospholipid is hydrophilic and which is hydrophobic?
hydrophilic: Phosphate-glycerol head
hydrophobic: Fatty acid tail
63
9. What is the bond called between a fatty acid and glycerol?
Ester Bond
64
10. Describe the test for a lipid.
Shake with ethanol then add cold water. Positive: White emulsification
65
1. What is the monomer of a protein?
Amino Acid
66
2. What is the bond called between two amino acids?
Peptide Bond
67
3. What is the formula of the carboxylic acid group of an amino acid?
-COOH
68
4. What is the formula of the amine group of an amino acid?
-NH2
69
5. What property does the amine group have? Extension
Zwitterions at specific pH.
Acts as a buffer
70
6. State what is meant by the R group of an amino acid.
Variable group: Different for all amino acids
71
7. The carboxylic acid amino and R groups are all bonded to a central carbon. What other atom is bonded to the central carbon?
Nitrogen
72
8. How many naturally occurring amino acid types are there?
20 types
73
9. Describe the test for a protein.
Biuret reagent added to the food sample
Positive: Blue to Purple
74
1. Define the primary structure of a protein.
The number and sequence of amino acids in a polypeptide chain
75
2. What bonds hold the shape of an alpha helix or beta pleated sheet?
Hydrogen bonds
76
3. What level of structure do alpha helices and beta pleated sheets have?
Secondary: Coiling or folding of polypeptides
77
4. Name two secondary structure proteins.
α-helix
β-pleated sheet
78
5. How are secondary structure proteins termed that relates to their function?
α-helix: Held by hydrogen bonds every 3rd amino acid
β-pleated sheet: Polypeptides lies parallel to each other but runs in opposite directions. Folds/pleats like a fan to have a more complex shape. NH2 group (+) bonds to -COOH(-) of another chain.
79
6. Name the four types of bond that can form between R groups in a tertiary structure protein?
Hydrogen bonds
Disulphide bridges
Ionic bonds
Hydrophobic interactions
80
7. Give an example of a tertiary structure protein.
Most Globular proteins
E.g Carboxypeptidase found in pancreatic juice in Duodenum
81
8. The complex 3d shape of a tertiary structure protein is critical for its function. What term is applied to tertiary structure proteins?
Specific shape
82
9. What is a quaternary structure protein?
Two or more polypeptide chains chemically bonded together
83
10. Name two quaternary structure proteins and give their function.
Globular Protein Haemoglobin
- Conjugated protein: 4 Haem groups (w/ Fe2+)
-P: 4 polypeptide molecules
-S: alpha helix
-T: Each chain is folded into a precise chain
Q: 2 alpha and 2 beta chains bonded together
- Can carry 4 O2 molecules.
-Able to change affinity
-Compact, spherical and water soluble for metabolic functions
Fibrous Protein Collagen
- Simple protein
- P: 3 polypeptide chains
-S: alpha helix
-T: Chains twisted into a second helix
-Q: 3 Polypeptide chains wound together like a rope => Microfibrils called tropocollagen held together by hydrogen bonds => Fibrils =>Collagen fibres
-Collagen fibres are staggered to add to mechanical strength (like bricks)
- Insoluble, structural fibres
84
Extra: Describe the structure of insulin
-Small globular protein
- Made of 2 polypeptide chains held together by disulphide bridges at neighbouring cysteine molecules
