mse

Question 1

precipiation of proteing at their isoelectric point is due to which of the following event?

Answer 1

proteins achieving a zero nett charge.

Question 2

Keq is the equilibrium constant of an enzymatic reaction where the amount of
substrate A and product B are equilibrated after a period of time in a reversible
reaction. Which of the following options is incorrect?

Answer 2

Keq = [B].[A]

Question 3

0. An animal cell that lacks carbohydrates on the external surface of its plasma
   membrane would likely be impaired in which of the following functions?

Answer 3

b. Cell-cell recognition.

Question 4

Which of the following statements correctly describes the property of hydrophobic
substances such as vegetable oil?

Answer 4

Nonpolar substances that repel water molecules

Question 5

Fatty acids are ___________.

Answer 5

long, unbranched hydrocarbon chains

Question 6

The conversion of NAD+ to NADH depicted is classed as what type of chemical
reaction?

Answer 6

reduction

Question 7

a-ketoglutarate -> x -> succinate

= whats the name of metabolite X in the above reaction

Answer 7

succinyl CoA

Question 8

The TCA cycle generates NADH and FADH2. What is the ATP yield generated from
each molecule in the mitochondria?

Answer 8

NADH: 3 ATP and FADH2: 2 ATP

Question 9

In the glycerol phosphate shuttle, which of the following molecules is reduced to
transfer electrons into the mitochondria

Answer 9

DHAP (dihydroxyacetone phosphate)

Question 10

Which one of the following enzymes is unique to gluconeogenesis

Answer 10

Pyruvate carboxylase

Question 11

saturated fatty acids have…

Answer 11

single bonds, packed tightly, solidify at room temp

Question 12

unsaturated fatty acids

Answer 12

double bonds= bends/kinks chain

do not pack tightly
remains liquid at rt

Question 13

list inhibitors of the etc

Answer 13

Cyanide, azide, hydrogen sulphide, carbon monoxide
* React with cytochrome (a + a3) and prevent electron transfer to O2
* Antimycin
* Blocks electron flow from cytochrome b to c1
* Rotenone
* Inhibits NADH oxidoreductase
* Oligomycin
* Potent inhibitor of ATP synthase
* Atractyloside (from Mediterranean thistle)
* A toxic glycoside
* Inhibits translocase proteins

Question 14

Each glucose that is metabolised by glycolysis generates a net gain of four ATP.

Is this statement true or false?

Answer 14

false

Question 15

How efficient is the trapping of energy from glycolysis?

Answer 15

30%

Question 16

The TCA cycle generates NADH and FADH2 but how many of each are produced from one pyruvate molecule?

Answer 16

4 NADH and 1FADH2

Question 17

The equivalent of only one ATP is directly trapped by substrate-level phosphorylation by the TCA cycle.

Is this statement true or false?

Answer 17

true

Question 18

In muscle cells, glucose is metabolised to pyruvate. Under anaerobic conditions, this pyruvate is then converted to lactate. Why?

Answer 18

It re-oxidizes the cytoplasmic NADH generated by glycolysis

Question 19

During glycolysis, NADH is formed in the cytoplasm. Under aerobic conditions, what is the fate of this NADH?

Answer 19

It is re-oxidised to NAD+ by the glycerol-3-phosphate shuttle

Question 20

The ATP yield from 1 mitochondrial NADH under aerobic conditions in a eukaryotic cell would be

Answer 20

3 ATP

Question 20

Respiratory control is the mechanism that ensures that the electron transport chain is not active unless ____
is needed by the cell

Answer 20

ATP

Question 21

ATP synthesis by ATP synthase is powered by a ____ gradient.

Answer 21

proton

Question 22

In the electron transport chain, cytochrome b transfers its electrons to which compound?

Answer 22

Cytochrome c1

Question 23

Glucose and galactose yield the same amount of ATP when they feed into glycolysis. True or false?

Answer 23

true

Question 24

describe the difference between catabolism and anabolism.

Answer 24

Catabolism - Degradative reactions of metbolism - Larger compounds are broken down into smaller ones generating energy Anabolism - Synthetic (building) reactions of metabolism - Smaller compounds are combined into larger ones - Requires energy

Question 25

Distinguish between the reaction types of the seven major classes of enzymes

Answer 25

Class1: oxidoreductase Reaction : catalyses redox reactions (transfer og H O or e-) Example : alcohol, dehydrogenase Class 2: transferase Reaction: transfer a functional groun from one molecule to another Example ; hexokinase Class 3: hydrolase Reaction: hydrolase (breaks bonds) in presence of water Example: glucose-6-phosphatase Class 4: lyase Reaction: remove or add groups to a molecule (breaks bonds, electron rearrangement) Example: pyruvate, decarboxylase Class 5: isomerase Reaction: rearrange functional groups in a molecule (isomers) Class 6: ligase Reaction: join molecules Example: pyruvate, carboxylase Calss 7: translocases Reaction: catalyses movement of ions/molecules across membrane Example: sodium-potassium ATPase pump

Question 26

how to differenciate between rogh and smooth ER

Answer 26

rough is ribosome dotted

Question 27

what do lysosomes do

Answer 27

- Single membrane bouns vesicle produced from golgi complex - Functions:  Stores enzyme (lysozyme, hydrolase  Destroys lyses material in vesicles  Breakdown macromolecules (proteins)  Recycles cell contents (aging organelles)

Question 28

LLO1.5 Distinguish plant cells from animal cells based on their cellular features

Answer 28

Things that plant cels have that animals do not: Cell wall - Provides structural support - Made up of cellulose microfibrils in a matrix of polysaccharides and proteins  Flexible and extensible - Cell walls connected by plasmodesmata (openings)  Membrane lined  Allows for water and small solutes to pass Chloroplast - Inner and outer membrane - Third membrane system  Granum: stacks of flattened sacs called thylakoids  Tubular membranes: stoma thylakoids which connects sacs together - Functions:  Site of photosynthesis (in stroma)  Light driven process( solar energy and CO2)  Produce sugar and organic compounds Vacuoles - Single membrane bound - Function:  Temporary storage and transport  Phagocytosis  Storage and intracellular digestion  Maintains turgor pressure Peroxisomes - Specialized peroxisomes: Glyoxysomes  Crystalline core: enzyme catalase   Germination: converts fats into carbs Involves in photorespiration

Question 29

draw an amino acid

Answer 29

- Made up of  A (alpha) carbon  Hydrogen atoms  Carboxyl group (carboxylic acid) (COO)  Amino group (Amine( NH3)  R group

Question 30

non polar aa are hydrophobic r hydrophillic

Answer 30

hydropobic

Question 31

describe the primary structure of a protein

Answer 31

- Linear sequence of aa in polypeptide  Aa linked by peptide bonds - Sequence determines higher order of structures

Question 32

describe the secondary structure of a protein

Answer 32

Secondary structure - Backbone of polypeptide  Linear sequence fold upon itself - Structure stabilized by H bonds  Intermolecular (between CO and NH groups of AA of 2 different poly peptides)  Intramolecular (between CO and H+NH groups of aa of the SAME poly peptide - Structural patterns  A heliex  B sheet - Motifs - Combinations of a helices and b sheets  Connected via looped regions varying lengths (random coils)  Examples B-a-B , hairpin loop and heliet turn heliec motifs

Question 33

describe the tertary structure of a protein

Answer 33

Tertiary structure - Higher order of folding  Poly peptide chain folded back on itself to form a condensed structure  Depends on interation between the side chains - - Stabilized by  Disulphide bonds  Hydrogen bonds  Ionic bonds  Van der Waals interaction  Hydrophobic interaction - Two main classes  Fibrous protein vs globular proteins

Question 34

describe the quaternary structure

Answer 34

- Between multile polypeptides - Held together by same bonds of tertary structure - Example :HAemagblobin  Multimeric protein = tetramer  = 4 polypeptides= 2a and 2b subunits

Question 35

Describe how pH that affects the charge of proteins

Answer 35

pH affects proteins by changing the protonation state of the charged residues - affects H+ bonds and ionic bonds Acid - Low pH - Increase H+ - + charge Neutral - Uncharges - Isoelectric point/pI Alkaline/ basic - High pH - Decreased H+ - - charge

Question 36

Describe what denaturation does to the protein structure

Answer 36

Protein denaturing - Structures must be maintained for biological function - Agents may casue loss of structures (2 (secondary), 3 (tertiary) and/or 4 (quaternary) by disrupting bonds - Loss of structure + function= denaturation Factors causing denaturation - Organic solvents- disrupts H bonds (2,3,4) - Detergents – distrupts hydrophobic bonds (3,4) - pH extremes – disrupts H bonds (,3,4) and ionic (electrostatic) bnds (3,4) - heat – increase kinetic energy and disrupts all non-covalent bonds (2,3,4)

Question 37

Describe the types of lipids and proteins in membranes

Answer 37

1. Phospholipids (most abundant) - Consists of a back bone - They have a polar head: contains phosphate group variable R group such as chlorine and is charged so therefore hydrophilic (polar) - Backbone = glycerol and sphingosine - Non-polar tails: fatty acids, long unbranched hydrocarbon chain with arbon,y grounp - Saturated or unsaturated - Hydrophobic 2. Glycolipids * Lipid with carbohydrate group * E.g., Glycoglycerolipids & glycosphingolipids 3. Sterols * Have four-ringed hydrocarbon * E.g., Cholesterol & phytosterol (plant)