Macromolecules

Question 1

Anabolic vs catabolic reactions

Answer 1

anabolic form complex form simple substances, catabolic form simple substances from complex ones

Question 2

Why do organic substances mostly contain carbon atoms

Answer 2

carbon has maximal coordination (four covalent bonds), can form single, double, and triple covalent bonds, and can create branched and unbranched chains – creates a large diversity of stable compounds

Question 3

Dehydration vs hydrolysis reaction

Answer 3

dehydration/condensation reaction is a polymer formation reaction, it requires E to be invested, releases H2O (removing a hydroxyl group (OH) and one hydrogen from the molecules), and forms a new bond while hydrolysis reaction is a polymer breakdown reaction that releases E, requires H2O to be invested, and bonds are broken

Question 4

Goldilocks principle

Answer 4

a planet orbiting its sub at just the right distance for liquid water to exist on its surface, neither hot nor too cold (+ gravity keeping the water in the atmosphere) – being in the Goldilocks Zone

Question 5

Cohesion vs adhesion

Answer 5

cohesion is the bonding of the same molecules by H-bonds and adhesion is the binding of different molecules by H-bonds

Question 6

Surface tension

Answer 6

the force that tends to decrease the surface of water, due to cohesion (exceptionally strong attraction between molecules on the surface) – can be broken only if other molecules intervene and come between them – water surface is a habitat for some organisms (bugs – Gerris lacustris)

Question 7

Capillarity

Answer 7

the ability of a liquid to „climb up“ narrow tubes, due to cohesion and adhesion – water with minerals can be transported through the plant’s xylem towards the upper parts

Question 8

Being a polar solvent

Answer 8

water dissolves polar and charged (hydrophilic) substances, due to adhesion – glucose, NaCl, a-a (some), urea… can be easily transported in the blood, fat, cholesterol, CO2, O2… need special carriers (lipoproteins) which transport them through body fluids

Question 9

Heat capacity

Answer 9

the amount of heat needed to raise the temperature of a substance – water has a high heat capacity (slow to gain and lose heat) because extra energy needs to be invested to break H-bonds among water molecules to then be able to increase molecular movement and temperature – important for stabilization of body temperature, aquatic habitats are thermally more stable compared to terrestrial

Question 10

Buoyancy

Answer 10

buoyant force is the upward force on the object immersed in water (the density of the object is lesser than the density of water) – if the density of an organism is similar to the water it doesn’t have to spend extra E to float on water (not the air case – since air density is very low, energy needs to be invested to be airborne)

Question 11

Viscosity

Answer 11

the „stickiness“ of the fluid which determines how easily it can flow, it depends on the amount of intermolecular forces – the greater their number the greater the friction and viscosity (fluid doesn’t flow easily) – more difficult to travel through water than air so many animals have special adaptations for swimming. More difficult to swim in salt water than in fresh

Question 12

Thermal conductivity

Answer 12

a measure of a material’s ability to transfer heat. It is determined by how easily energy transfers through the material – can cause hypothermia relatively quickly (doesn’t prevent heat loss) this is why aquatic animals like seals have a thick layer of fat to act as an insulator – thermoregulation, heat transported from muscles through the blood to the surface of the skin and exists in the form of sweat

Question 13

Name and draw monosaccharides

Answer 13

trioses, hexoses (alpha glucose and beta glucose, fructose, and galactose), and pentoses (ribose and deoxyribose) – they have to be in ring form in order to polymerize, …

Question 14

Draw the process of polymerization of two carbohydrate monomers, annotate the diagram (numbering C atoms) and name the bond connecting them

Answer 14

…, glycosidic bond (C1 and C4)

Question 15

List disaccharides and polysaccharides (what are they made of)

Answer 15

maltose (2 glucoses), sucrose (glucose, fructose), lactose (glucose, galactose), starch (alpha glucose), glycogen (alpha glucose), cellulose (beta glucose)

Question 16

Starch

Answer 16

used for short-term energy storage in plants – amylose is not branches (only 1-4 glycosidic bonds), has all gluc molecules with the same orientation, has a compact spiral (helical) shape supported by H-bonds between non-adjacent glucose molecules – difficult to digest so it acts as a dietary fiber (keeps moisture in the bowels) – amylopectin has 1-4 and 1-6 glycosidic bonds (has branches), it is easily digestible because molecules can be more easily loaded and unloaded from attachment points. Natural starch has 70% amylopectin and 30% amylose

Question 17

Glycogen

Answer 17

made out of alpha glucose molecules with the same orientation, is more branched than amylopectin, acts as a short-term energy storage molecule in the animal liver (modifying the content of blood – keeps the level of glucose at a homeostatic level) and muscles – it is insoluble in water and therefore not osmotically active

Question 18

Cellulose

Answer 18

made out of beta glucose molecules with alternating orientation – 1-4 glycosidic bonds and H-bonds between neighboring chains – it is a straight unbranched polymer – cellulose microfibrils run parallel – has great tensile strength so it is the basis for the cell wall (in plants) – has a structural function

Question 19

Groups of lipids

Answer 19

Triglyceride (fats and oils) – glycerol and three fatty acids connected by ester bonds – long-term energy storage (insoluble in water)- more efficient energy storage than c-h because they are more chemically complex (can store twice as much as ch in the same mass)
Phospholipid – glycerol and two fatty acids and a phosphate group – amphipathic molecule that is a constituent part of the plasma membrane
Steroid – have a subgroup called sterols recognizable by their four fused C rings – cholesterol (hydrophobic) only in animal plasma membrane and is a precursor for all steroid hormones (sex), vitamin D, and bile

Question 20

Saturated vs unsaturated fatty acids

Answer 20

saturated have only single covalent bonds between C atoms and form straight chains, mono-unsaturated have just one double/triple bond and poly-unsaturated have multiple double/triple bonds (bent chains) – unsaturated have lower melting points (rounded shape – oils)

Question 21

Proteome vs genome

Answer 21

proteome is all proteins produced by a cell, tissue, or organism (they differ among tissues) and genome is all DNA material of a cell (the genome of all cells in the same organism is the same)

Question 22

Draw and annotate the structure of one amino acid and then a dipeptide

Answer 22

…, zwitterion model – common group (central C, carboxyl group COOH, amine group NH3), and R/radical/functional group that is different for all a-a and it gives them their specific characteristics – peptide bond

Question 23

According to what are a-a grouped, how many polypeptide chains can be made from 20 a-a, classification of polypeptides according to the no. of a-a

Answer 23

according to their chemical properties: polar, non-polar, positively charged (basic), or negatively charged (acidic)
number of different polypeptides that can be made with 20 types of a-a is 20n (n is the number of a-a in the chain)
oligopeptide (less than 20 a-a), peptide (less than 40 a-a), and polypeptide (more than 40 a-a)

Question 24

Primary protein structure

Answer 24

the sequence and number of amino acids in a polypeptide chain

Question 25

Secondary protein structure

Answer 25

formation of patterns (structures) as a result of H-bonds forming between CO and NH groups of non-adjacent a-a along a single polypeptide chain: random coils (no specific pattern), alpha helix and beta pleated sheets

Question 26

Tertiary protein structure

Answer 26

additional folding of the polypeptide chain due to interactions between R-groups of non-adjacent a-a: ionic bonds (positive-negative a-a), hydrophobic interactions, H-bonds (polar a-a), and disulfide bridges (S-S covalent bond – a-a cysteine) – the sum of all these interactions results in a specific shape of the chain

Question 27

Quaternary protein structure

Answer 27

the way more polypeptide chains fit together in a protein – prosthetic groups (not protein) in conjugated proteins (hemoglobin and Fe) – lysozyme has only one polypeptide chain, Hb, insulin, collagen, antibodies have more

Question 28

Protein denaturation, how are pH and temp related

Answer 28

or protein coagulation is the permanent alteration of the protein's conformation due to factors like pH and high temperature which disrupts (causes it to lose) its biological function – high temperature increases molecular movement which breaks intramolecular bonds (secondary and tertiary structure) – too low or too high pH causes an excess of H+/OH- ions which intervene with H-bonds in secondary structure (break them)

Question 29

Essential vs non-essential a-a

Answer 29

essential have to be obtained from nutrition because the body does not synthesize them, non-essential are synthesized by the organism, and conditionally essential are those with limited synthesis (in premature babies, stress…)

Question 30

Cause and consequences of protein malnutrition

Answer 30

unbalanced diet or starvation, lack of essential a-a so the body can't synthesize some proteins – liver can't produce clotting factors, bone marrow can't make Hb, muscles can't synthesize myosin

Question 31

Scurvy

Answer 31

caused by a lack of vitamin C (which aids in the production of collagen by converting a-a proline to a-a hydroxyproline) – symptoms like swollen and bleeding gums, hair loss, and easy bruising

Question 32

Fibrous vs globular proteins

Answer 32

F are long and narrow and G are round (spherical), F have a structural purpose and G functional, F are less sensitive and G more sensitive to changes in pH and temp, F are insoluble in water and G are soluble – examples of F are collagen, myosin, fibrin, elastin, keratin – examples of G are enzymes, Hb, antibodies, hormones

Question 33

Enzymes

Answer 33

proteins that work as catalysts in living organisms, they speed up chemical (metabolic) reactions by binding to substrates and converting them into products without being changed themselves

Question 34

Active site

Answer 34

a region on an enzyme's surface to which substrates bind – shape and chemical properties of the active site are complementary to the shape and chemical properties of the substrate – S is converted into P while inside the enzyme

Question 35

Enzyme substrate specificity models

Answer 35

lock and key model and the induced fit model (when S combines with enzymes it induces a conformational change of the active site – some enzymes can react with a range of similar substrates)

Question 36

Activation energy and enzymes

Answer 36

the energy needed for the destabilization and breaking of bonds within the substrate – enzymes speed up chemical reactions by lowering the activation E by destabilizing the bonds within the S; the strength of attraction forces between the S and active site overpowers the strength of bonds within the substrate (this is called the transition state)

Question 37

Factors affecting enzymatic activity

Answer 37

substrate concentration (proportional – the more S there is the more collisions occur and more products are formed – but there is a saturation point, all active sites are occupied) pH (if it differs from the ideal pH level of that enzyme it’ll cause conformational changes in it and reduce the reaction rate) temperature (proportional – molecular movement increased – until temp causes denaturation (molecular vibrations overwhelming for intramolecular bonds), then the rate drops suddenly) inhibitors

Question 38

Inhibitors, draw the r/C(S) graph with diff inhibitors

Answer 38

substances that reduce enzymatic activity – competitive (same shape as S, competing for the active site) which are affected by C(S), and noncompetitive (bind to the allosteric site and change protein conformation) which are not affected by C(S), …

Question 39

Allosteric interaction

Answer 39

the interaction between an enzyme and the chemical that binds to its allosteric site – negative allosteric regulation (non-competitive inhibition) and positive allosteric regulation (activators that increase an enzyme's affinity for a S)

Question 40

End product inhibition

Answer 40

when the end product acts as an inhibitor for the first enzyme along the linear metabolic pathway that produces that product – e.g. once the required concentration of a-a isoleucine is reached it inhibits its further production by reversibly binding to the enzyme to prevent its unnecessary buildup in the body