Metabolism / Enzymes / Biological specimens / Chromatography / Accuracy and Precision (W13)

Question 1

what is metabolism

Answer 1

all the enzyme catalysed chemical reactions in a cell (includes both anabolic and catabolic)

Question 2

what are anabolic pathways, and what are 4 characteristics of them

Answer 2

the process of building up complex organic molecules
- it is biosynthesis
- it is reductive (requires electrons)
- it requires energy
- the pathway is usually divergent

Question 3

is the process of making large molecules from a selection of small molecules oxidation or reduction

Answer 3

reduction (it requires electrons)

Question 4

what are catabolic pathways and what are 4 characteristics of them

Answer 4

it is the degradation of larger complex substances into smaller molecules, while generating energy
- degradative
- oxidative
- yields energy
pathway is usually convergent

Question 5

is the process of breaking larger molecules into smaller molecules oxidation or reduction

Answer 5

oxidation

Question 6

how to the rates of anabolic and catabolic reactions compare

Answer 6

the rate of degradation = rate of synthesis
in a dynamic steady state
also the energy-yielding catabolic pathways are balanced by the anabolic pathways

Question 7

what are 4 characteristics of enzymes

Answer 7

• they are mostly proteins (some are RNA molecules)
• they are reaction specific
• highly regulated
• essential for the proper function of cells

Question 8

why are enzymes essential

Answer 8

without them the reactions needed in the body would progress too slowly for life

Question 9

what are 3 reasons why we would study enzymes

Answer 9

• clinical pathologies (monitor and diagnose disease)
• design and development of new drugs
• gain understanding of how cells work

Question 10

define chemical reaction and rate of reaction

Answer 10

a chemical reaction is any chemical change that produces at least one new substance
the rate of this is the rate that reactants are being used or products are being formed

Question 11

what is the transition state during a reaction

Answer 11

it is the arrangement of atoms that requires the highest energy, and this must be overcome before converting into products

Question 12

what is the free energy of activation

Answer 12

the minimum energy to get to the transition state from the reactants (activation energy)

Question 13

how does the free activation of energy affect the speed of the reaction

Answer 13

high activation energy = low rate (slower reaction)
low activation energy = high rate (faster reaction)

Question 14

how much can an enzyme increase rates of reaction

Answer 14

by up to 10ˆ20

Question 15

define enzyme rate

Answer 15

the rate that an enzyme can catalyse a reaction

Question 16

how are enzymes usually names

Answer 16

• according to function
• and ending in -ase, -me, -in

Question 17

what are enzyme’s active sites complementary to

Answer 17

the transitional state of the reaction

Question 18

what are 4 factors that can affect enzyme activity

Answer 18

• temperature
• pH
• concentration of enzyme
• concentration of substrate

Question 19

what do the graphs look like for concentration of enzyme and substrate compared to enzyme activity

Answer 19

concentration of substrate: plateaux at Vmax
concentration of enzymes: increases linearly

Question 20

Where is Km (michaelis constant) on a graph

Answer 20

on a substrate concentration graph it shows the strength of association between the enzyme and substrate.
it is where the reaction rate is half of the max

Question 21

what are 6 examples of common biological specimens

Answer 21

• blood
• urine
• faeces
• solid tissue
• cerebrospinal fluid
• swabs

Question 22

what are some of the components of whole blood (8)

Answer 22

cellular components:
- RBCs
- WBCs
- platelets

plasma components:
- Water
-Albumin
- immunoglobulins
- coagulation proteins
- electrolytes
etc.

Question 23

what 4 things are needed for blood clotting to occur

Answer 23

• damage to blood vessels
• Ca2+
• platelets
• Clotting proteins

Question 24

how is a sample of serum obtained

Answer 24

whole blood is taken and clot is formed (serum is the remaining liquid component)

Question 25

how are serum and plasma different

Answer 25

given that plasma is the liquid component of blood, serum is basically plasma minus the clotting proteins

Question 26

how is a sample of plasma obtained

Answer 26

whole blood is taken from the vein and mixed with anticoagulant (no no clot forms) then it is spun to separate the cell components from the plasma

Question 27

what are the 5 types of anticoagulant and how do they each work

Answer 27

Heparin : inhibits clotting proteins
EDTA : complexes divalent cations ( removes Ca2+)
Sodium citrate : chelates calcium reversibly
Oxalate : chelates calcium irreversibly
Sodium fluoride : preserves glucose

Question 28

state and describe 7 things to look out for when working with biological specimens

Answer 28

TACSIPP
-if plasma, correct anticoagulant? correct amount and thoroughly mixed?

• correct collection my phlebotomist (venous or arterial sample? or swabbing the right way)
• identification (labelling samples correctly etc.)
• Separation (correct centrifugation?)
• preservation and storage
• transport (quickly and safely)
• Patient (is the sample taken at the right time)

Question 29

what is chromatography

Answer 29

a process to separate or isolate molecules based of a difference in size, charge, etc.

Question 30

what are the 5 types of chromatography and what state are each of the phases

Answer 30

• adsorption - solid S and liquid M
• partition - liquid S and liquid or gas M
• ion exchange - solid S and liquid M
• size exclusion - liquid S and liquid M
• affinity - stationary ligand and liquid M

Question 31

how does ion exchange chromatography work

Answer 31

resin is charged (pos or neg)
so molecules with different charges move through at different speeds
eg. with a negatively charged matix more negatively charged molecules will move through faster. pos charger molecules will spend more time drawn to the stationary phase and will move slower

Question 32

how does size exclusion / gel filtration chromatography work

Answer 32

resin bead acts as a matrix (consists of strands of cross linked polymers)
- larger molecules move through faster and avoid beads whereas the smaller molecules get trapped for longer in the bead and taker longer to move through

Question 33

describe affinity column chromatography

Answer 33

• column contains polymer bound ligands that are specific to the protein of interest.
• protein of interest binds to the ligand and and unwanted substances move through
• then ligand solution is put through to detach the proteins from the ligand

Question 34

define accuracy and precision

Answer 34

accuracy - how close the value is to the true value
precision - how close values are to each other