BCH210- Lecture 15, 16 (intro to metabolism, carbohydrate structure and transport))

lecture 15, 16

explain the difference between catabolism and anabolism

catabolism → oxidative, exergonic, bonds breaking

anabolism → reductive, endergonic, bonds forming

metabolic flux / conversion of metabolites through pathways is influenced by what

gibbs free energy changes (and enzymes)

whats the standard free energy change equation

delta G = -RT In K (eq)

when K(eq) >1, gibbs free energy is ______ and the reaction is 

negative, favourable (exergonic)

when K(eq) <1, gibbs free energy is ______ and the reaction is 

negative, unfavourable (endergonic)

when K(eq) =1, gibbs free energy is ______

reversible

what is the actual free energy change

delta g = delta g not prime + RT ln [p]/[s]

what are standard conditions

delta G not = 1M, 298K, pH 7

what does ATP phosphoryl transfer potential refer to

transferring of phosphates to other molecules

why is the decreasing of phosphates in ATP and ADP favourable

because in organic phosphates can create stability through resonance

energy is not lost when transfering phosphates when…

the compounds have similar phosphoryl transfer potentials

e.g. GTP + ADP → ATP +GDP

delta G = 0, K(eq) =1 

what is the formula for phosphoryl transfer potential in muscles, explain the process

phosphocreatine +ADP + H ←(creatine kinase)→ ATP + creatine

what is the carbohydrate structure formula

(CH2O)n

what is the most simple monosaccharide carbohydrate

triose (1 chiral center)

what is an aldose vs ketose monosaccharide

aldose has C=O on end and ketose has it in middle

how do u number carbohydrates, how do you letter them l/d

from most oxidized (CHO/C=O) to least oxidized (CH2OH), in its linear form

l or d closest to most oxidized anfd the furtherst away gets L or D

how do u determine the number of isomers for a carbohydrate

2^n, where n is the number of chiral centers (C bound to 4 things)

why are aldehydes, ketones and hydroxyl groups very reactive functional groups

the aldehyde/ketone carbonyle undergo nucleophilic attack by hydroxyl groups

what is the aldehyde derivative called, what is the ketone derivative called (carbohydrate cylization)

hemiacetal, hemiketal

what do haworth projections refer to

the OH being up or down- letting u see the cyclic sugars in 3D

is intramolecular cyclization reversible in solution

only through the linear chain

sugars can react with other molecules in what form

intramolecular reaction in linear form

what are possible carbohydrate modifications- all to increase complexity 

sugars can be

• phosphorylated

• methylated

• or have a N-containing functional group added

hydroxyls or carbonyl may be removed

what are isomers

same molecular formula, different strucutre

what are constitutional isomers

different order of functional group bonding

what are stereoisomers- what are the types

same formula and order

• enantiomers

• diasteromers

  • epimers

  • anomers

what are enatiomers

non-superimposable mirror images

what are diastereomers- whar are the types

not mirror images

• epimers

• anomers

what are epimers

differ at one symmetric carbon

what are anomers

differ at a newly formed, asymmetric C in the ring structure

what is a reducing sugar

a carbohydrate that contains a free aldehyde or ketone group- very reactive due to free carbonyl group 

why are reducing sugars imporant

they allow the potential to interact with other molecules by acting as a reducing agent by donating electrons to another molecules in a chemical rxn

how do u determine a reducing sugar

the free OH group on the anomeric carbon indicated the sugar is reducable / can unfold

why are D sugars biologically important

they are the primary form of energy for organisms, serve as fundamental building blocks for vital molecules like DNA and RNA, and are recognized and processed by cellular enzymes.

how does cyclization result in the formation of 2 additional structures

because of the formation of two additional structures called anomers (specifically, the alpha and beta forms). These two structures arise because the cyclization process creates a new chiral center at the former carbonyl carbon atom

what type of reaction is a glycosidic bond formation and what is produced

condensation, H2O is produced

how are monosaccharides linked to form disaccharides

glycosidic bonds

what are the two types of glycosidic bonds

N (NH) or O (O-oxygen) linked- intermolecular glycosidic bonds formed between an amine or hydroxyl and a reactive anomeric carbon 

what is the order of carbohydrate complexity for number of sugars

monosaccharides (1), disaccharides (2), oligosaccharides (3-20), polysaccharides (up to 1000)

what are glycans

another word for polysaccharides

what are homopolymer vs heteropolymer

the same monosaccharides e.g. glycogen and starch

different monosacchardies e.g. sugars found in glycoproteins 

what are the types of starches (complex carbohydrates)

amylose → unbranched glucose units (a1-4 linkages)

amylopectin → linear glucose chains joined by a(1-4) linkages, a(1-6) linkages at branch points once every 30 glucose units

what does a-amylase do

breaks down complex starches

what does cellulose do, how many sugars is cellobiose

it provides a structural role in plants, it is a disaccharide linked by b(1-4)

what is glycogen, what is its strucutre, what side are glucose units added and removed, where can it be found

a storage from of glucose, 

dimer of glycogenin at the centre, linear glucose chains joined by a(1-4) linkages, a(1-6) linkages at branch points once every 8-12 glucose units 

glucose units added/removed from the non-reducing ends

found in the liver and muscle 

what enzymes help cleave disaccharides and make monosaccharides, where are these enzymes found

lactase, maltase, sucrase

found in the microvilli attached to cells to help with monosaccharide absorption 

what is the difference between maltose and lactose , what is similar

the 1-4 bond being in a for maltose and b for lactose , both are disaccharides

why is sugar sequencing more difficult than polymer or DNA sequencing

DNA has 4 possible (AGTC), proteins have 20 possible (AA), carbons have 1000s possible

how do polysaccharides differ - how to tell for sugar sequencing

composition : Glucose vs Galactose

connectivity: 1-4 vs 1-6

configuration: a vs b

how does glucose move throughout the body and bilayers

uses transporters based on the concentration gradient and binding affinity

what type of glucose transporter is SGLT1 and SGLT2

secondary active transport

what type of glucose transporter is GLUT1, GLUT2, GLUT3, GLUT4, GLUT5

facilitated diffusion

what glucose transporter is insulin dependent

GLUT4

if there is a blood glucose concentration < the Km of the GLUT transporter how efficiently does glucose move through the transporter into the bodily location and why

the more above the concentration the transporter is the less it will move into the body part because it moves down its concentration gradient 

if there is a blood glucose concentration > the Km of the GLUT transporter how efficiently does glucose move through the transporter into the bodily location

it will move in quickly because it moves down its concentration gradient