Molecules of life (Chapter 3) Flashcards
What are the Molecules of life?
Molecules of life are metabolic macromolecules that are critical for the functioning of organisms.
Why are metabolic macromolecules important?
They are commercially attractive substances and are used in genetic engineering.
What are the key metabolic processes?
- Existence - to provide energy, building material, etc.
- Propagation - to increase the number of microorganisms
(Live long and prosper)
What is the relationship between niche and metabolic capabilities?
Metabolic capabilities determine the niche in which the microorganisms will be found.
Niche: is a set of conditions where organisms can survive and reproduce.
The niche in which an organism lives resulted in the evolution of key metabolic capabilities.
Physiological features of microorganisms determine what?
Physiological features of microorganisms determine:
- the conversions that these microorganisms can bring in nature or in a process.
- if the microorganisms are advantageous or disadvantageous for a process.
What is important in bioprocesses
In Bioprocesses, it is crucial to evaluate how metabolic capabilities and features can be exploited to maximize process performance and product yield.
What are physiological features?
Dependence on oxygen,
Source of carbon,
Source of energy
What are the three classes of molecules of life that the key elements can be subdivided into?
Macromolecules,
Macro elements,
Trace elements.
List the elements that form part of the macromolecules
Carbon, C = 50% oxygen, O = 20% nitrogen, N = 14% hydrogen, H = 8% phosphorous, P = 3% Sulphur, S = 3%
List the elements that form part of the macro elements:
Magnesium, Mg
Potassium, K
Calcium, Ca
Iron, Fe
List the elements that form part of the trace elements
Mo, Mn, Co, Ni, Cu, Zn, I, Al, B
What are the four major groups of complex organic molecules in life?
Carbohydrates
lipids
proteins
Nucleic acids (DNA and RNA)
The four major groups of complex organic molecules of life usually consist of:
repetitive units such as polymers
Which complex organic molecules are responsible for structural functions?
Carbohydrates and proteins
Which complex organic molecules act as a source of energy?
Carbohydrates and lipids
Which complex organic molecules act as information storage?
Nucleic acids
What are the four most important functional groups that form part of the molecules of life?
Hydroxyl (-OH)
Carboxyl (-COOH)
Amino (-NH2)
Phosphate (-PO4)
What are the features of the functional groups?
- All four groups are polar of charged - important for interactions in an aqueous environment
- All four groups are reactive - readily participate in chemical reactions
What are phosphate functional groups important for?
Phosphate groups
- are important in the role of transferring energy in the cell, and
- act as energy-rich cofactors that promote certain reactions
Isomers
Have the same chemical composition but a different form.
Several biological molecules are isomers
Sugars as isomers
The position of a -OH and the presence of an aldehyde or keto group determines the specific sugar and the role/function of that sugar.
Stereoisomers
Chiral molecules that are enantiomers of each other
non-superimposable/mirror images
or
when molecules are enantiomers - when they have a chiral centre
Specific preferences of life in stereoisomers
Amino acids always in the L-form
Sugars always in the D-form
Diastereomers/diastereoisomers
Stereoisomers that are not enantiomers
different configurations at one or more (but not all) of the related stereocentres
Not mirror images
Anomers
Diastereoisomers that differ in configuration at the carbon closest to the aldehyde or ketone group. (Carbon 1)
What are the most abundant carbohydrates in nature?
Cellulose and hemicellulose (components of wood)
and
starch (general storage source in plants)
Carbohydrates are polymers of
Basic six-carbon sugars (hexoses) - C6H12O6
and
five-carbon sugars (pentoses) - C5H10O5
suffix “-ose” implies sugar
The ratio of elements is carbohydrate polymers
C:H:O = 1:2:1
Name the two forms of sugar
aldoses: contain an aldehyde at the terminal carbon (eg. glucose)
ketoses: contain a ketone at the near-terminal carbon (eg. fructose)
D-aldoses
- all molecules have an aldehyde group
- as the chain length increases, carbon is added closest to the carbonyl group of the aldehyde.
- in D-aldoses all the hydroxyl groups closest to the terminal CH2OH groups point to the right.
- Diastereoisomers (non-superimposable, non-mirror-image isomers) are formed with increasing carbon chain length (the result of adding hydroxide groups to the chain in opposite directions).
D-Glyceralaldehyde
or glyceral is a triose monosaccharide with the chemical formula C3H6O3.
It is the simplest of all common aldoses and plays a key role in central metabolic pathways.
D-ketoses
- all molecules have a ketone group
- as the chain length increases, carbon is added to the closest carbonyl group of the ketone group.
- In D-ketoses all the hydroxyl groups closest to the terminal CH2OH groups point to the right.
- Diastereoisomers are formed with increasing carbon chain length.
Forms of Hexoses and pentoses
Hexoses are usually in the pyranose form (five carbons and oxygen form the ring structure).
Pentoses are usually in the furanose form (four carbons and oxygen form the ring structure).
Some hexoses can also be in the furanose form - have two carbons that are not included in the ring structure
Three different projections of sugar
Fischer, Haworth and Chair projections.
Haworth and Chair projections are more correct since sugars in the aqueous form are more stable in the ring structure.
What form are aldoses and ketoses usually written in in metabolic pathways?
Aldoses and ketoses are usually written in pyrosis (or ring) form in metabolic pathways.
e.g. D-glucose is converted to D-glucopyranose
D-glucopyranose forms
The hydroxyl group on the anomeric C1 can exist either in the alpha (downwards) or beta-form (upwards). (aBove)
Monosaccharides
General sugars are:
hexoses: glucose, fructose, mannose and galactose
pentoses: xylose and arabinose
These sugars appear in the three major carbohydrates/polysaccharides (cellulose, hemicellulose and starch).
Ribose is a basic building block of nucleic acids
Glucose is the primary product of photosynthesis and has a special function in life as the most abundant source of carbon for most life forms.
Disaccharides
Glucose + fructose = Sucrose (table sugar)
galactose + glucose = Lactose (milk sugar)
How are disaccharides formed?
most important disaccharides are formed via condensation (dehydration) reactions between monosaccharides.
What is the most common form of sugar storage?
Sucrose (common table sugar) is the most common form of storage of sugar in plants (e.g. sugarcane and sugar beet). It is formed form a glucose and fructose molecule and is a disaccharide.
Lactose
Lactose is the basic source of carbon and energy in milk and is formed from galactose and glucose.
What is pyranoside?
A pyranoside is a pyranose in which the anomeric OH at C(1) has been converted into an -OR group.
What is a pyranosyl?
One hydrogen substituted for some substituient.