Lesson 5: Carbohydrates

Question 1

What is the configurationn of all naturally occuring amino acids

Answer 1

They are in the (L) configuration
-Proteins injested in the body can only be recognised by enzymes if its amino acids are in L configuration
-Active sites of enzymes contain chiral molecules

Question 2

Carbohydtares configuration

Answer 2

They are composed of caron, hydrogen and oxyen in ratio 1:2:1

Question 3

Glucose

Answer 3

-C6H12O6
-They are one of the primary sources of energy for organic organisms and they play a central role in various cellular processes. the role they play are dependant on the type of carbohydrate
-Glucose is an aldehyde as it has an aldehyde functional group and so is known as an aldose, especially an aldohexose

Question 4

Types of carbs

Answer 4

Monosaccaride
Diasaccaride
Polysaccaride

Question 5

Functions of carbs

Answer 5

-Energy Reserves
-Components of other biomolecules- Nucleotides and proteins
-Structure component of cell- Bacterial and plant cell wall (gives cell wall rigidity)
-Involved in signal transduction

Question 6

Monosaccaride

Answer 6

M also known as simple sugars can be defined as a polyhydric alcohols (they have several alcohol groups)
-They can also be defined as poly hydroxy aldehydes and ketones
-Glucose is an example of M and is also essential for cellular respiration

Question 7

Most common glucose isomer

Answer 7

-D-glucose isomer is more common in nature compared to the L-glucose isomer

Question 8

Fructose

Answer 8

F is found in sugar and honey
It is a ketose as it has a ketone functional group, more specifically a ketohexose
-It is a metabolic intermediate

Question 9

Galactose

Answer 9

-It is a component of the milk sugar lactose.
-It is also an aldose due to its aldehyde group
-It is a C4 epimer of glucose which means that glucose and galactose are diastereomers that differ only at the C4 chiral centre
-Galactose and glucose are inter-convertible in a reaction catalysed by an enzyme Apmerase

Question 10

Ribose sugars

Answer 10

-The other M are ribose sugars
0They are compounds of nucleotides and consist of 5 carbons and so are known as pentose
-The deoxy version of R is found in DNA

Question 11

Hasworth projections

Answer 11

-It is the anomeric C1 of glucose that is attacked by the C5 hydroxyl group to form a ring structure
-The open form of glucose reacts with mild acid to form an activated aldehyde

Question 12

B-carbon ribose

Answer 12

It is the ring structure that consists of the hydroxyl group being at the bottom of th structure
-It forms at a rate of 64% compared to alpha carbon
-This is because of the 2 hydroxyl groups on the same side that make it too unstable

Question 13

Chair conformation

Answer 13

-In a glucose molecule, in the pyranose ring structure, there are 2 distinct positions around chiral carbons
-Equitaorial and Axial

Question 14

Equatorial position

Answer 14

It is approxiamtely perpendicular to the plane and is more thermodynamically favourable compared to axial position

Question 15

Axial position

Answer 15

-The subsequent groups extend upwards/downwards from plane/rng
-The groups in the pyranose ring structure are approxiamtely parallel to the plane and are less stable due to steric hinderance

Question 16

Trioses

Answer 16

-Examples are D-glyralaldehyde,Dihydroxyacetone, glycerol
-They consist of aldotroses and ketotrioses
-All 3 sugars are products/intermediates of glucose breakdown in anerobic respiration (Glycolysis)

Question 17

4 carbon sugar

Answer 17

-Biologically NB sugar is D-erthrose
-It is a tetrose and an aldose
It was first isolated from Rhubarb in 19th century and is called erythrose due to red colour
-Erythrose-4-phosphate is an intermediate in the Calvin Cycle found in plants
-It is also an intermediate in biosynthesis of aromatic amino acids: Phe (F), Tyr (Y), Trp (W)
-It can also partcipate in glycation reactions when it reacts with amino acids or nucleotides leading to formation of advanced glycetion End product which is implicated in many age-related diseases

Question 18

Pentose Sugar

Answer 18

-M with 5 carbons
-Ribose sugars are found in nucleotides as either Deoxy or Oxy
-Also M known as ketopentoses due to ketone functional group and 5 C atoms

Question 19

D-Ribulose

Answer 19

pentose
Rare sugar found in the biological systems but it plays essential roles in specific metabolic pathways
eg. Photosynthesis, calvin cycle and other metabolisms in plants

Question 20

D-Xylulose

Answer 20

pentose
-They are intermediates in PPP which functions to produce NADP
NADP and NAD+ are NB cofactors of enzymes involved in redox reactions which is needed for oxidophosphorylation
-It is involved in formation in ribose-triphosphate which is found in nucleotides
-It is also a metabolic intermediate that feeds into glycolysis and glucaneogenesis (synthesis of glucose)
-It is also involved in gene expression/regulation of cell-signaling pathways
-These pathways play a role in glucose and lipid metabolism
-In plants, it is involved in aromatic compounds and other natural products

Question 21

D-Mannose

Answer 21

-It is M and it is an aldose hexose`
-It is NB in urinary tract infection
-D-configuration is most abundant and because it can inhibit adhesion of bacteria, it has antibiotic potential to flush out bacteria from urinary are and reduce bacterial colonisatiom
-cell metobilsim only focuses on D config
-Alos used as energy source

Question 22

Adhesion Inhibiton and signaling

Answer 22

Bacteria contain polysaccacharides in their cell walls and monomers are mannose which it can reduce adhesion.
signaling works by D-mannose attaching to specific receptors to cause a response

Question 23

Glycoproteins

Answer 23

-Manose is a monomer
-Glycosylation is a process where Mannose as well as other polysaccarides are attached to amino acids, expecially asparagine
-In most Eu, more than 50% of proteins are glycolised
-These proteins are made through post translational modifications that add sugars as well as other compounds

Question 24

Summary of D-Mannose

Answer 24

-UTI
-Cell metabolism
-Cell signaling
-Potential to be used as a drug

Question 25

Answer 25

Left is D glucose and right is L glucose can you save Brett from

Question 26

Answer 26

D-Fructose

Question 27

Answer 27

D-galactose

Question 28

Haworth Projection of glucose

Answer 28

Question 29

Answer 29

Chair conformation of glucose

Question 30

Answer 30

Glyceraldehyde

Question 31

Answer 31

Dihydroxyacetone

Question 32

Answer 32

Glycerol

Question 33

Answer 33

D-erthyrose

Question 34

Answer 34

Erthyrose-4-phosphate

Question 35

Answer 35

D-ribose

Question 36

Answer 36

D-Xylulose

Question 37

Answer 37

D-Mannose

Question 38

Answer 38

D-seduheptose
D-glycero-D-alto-heptose