Molecular Composition Flashcards
What elements make up 99% of the weight of all living matter
CHNOPS
Most important organic molecules
-Carbohydrates (consist of sugar chains)
-lipids (fatty acids)
-proteins (composed of amino acids)
-nucleic acids (DNA and RNA)
Contain C and H
Proteins gave N and S
Carbohydrates
Monosaccharides
Disaccharides
Polysaccharides
1-glucose, fructose, ribose
-consist of a single sugar subunit
-building blocks, primary sources of energy
2-sucrose, maltose, lactose
-consist of two sugar subunits linked covalently
-energy transfer, transport
Many-cellulose (glycogen, chitin) and starch
-many sugar subunits linked together covalently
-storage, structure
Monosaccharides in a formula
(CH20)n
n can be as small as 3 or as large as 7
Proportions gave rise to the term carbohydrate meaning carbon with water added.
What group do monosaccharides have
Carbonyl group because as ring is formed, carbonyl is turned to a hydroxyl group
Sugars are often transported in plants and other organisms as ____
Disaccharides
Specifically sucrose made from glucose and fructose is the form in which sugar is transported in most plants
Dehydration synthesis/ condensation reaction
Synthesis of a disaccharide from two monosaccharide molecules in which a water molecule is removed and a new bond is formed between the two monosaccharides
Requires energy input
Hydrolysis
Reverse condensation reaction in which water is added and the molecules are split.
Energy yielding
Starch
Primary storage polysaccharide in plants consisting of chains of glucose molecules.
Two forms of starch:
-amylose: unbranched molecule
-amylopectin: branched molecule
Glycogen
Most coming storage polysaccharide in prokaryotes, fungi and animals made up of chains of glucose molecules. Resembles amylopectin but it more branches
What must happen to polysaccharides to be used as energy sources and transported through living systems?
Hydrolysis to monosaccharides and disaccharides
Plants break down starch reserves when needing to grow and develop
Cellulose
What can hydrolysis cellulose?
A polymer composed of monomers of glucose.
Only some microorganisms, certain prokaryotes, protozoa, fungi and few animals (who have these microorganisms in their stomachs aka cows)
Difference in starch, glycogen and cellulose structure
Starch and glycogen are made up entirely of alpha-glucose subunits
Cellulose entirely of beta-glucose subunits. Makes cellulose impervious to enzymes to break down starch and glycogen. Once in plant cell wall, no longer useable by the plant as energy source.
Chitin
Structural polysaccharide and principal component of fungal cell walls/ hard outer exoskeleton of insects and crustaceans
Cutin and suberin
Lipids in plant cell walls that form a matrix in which waxes are embedded. The waxes and lipids form a barrier to prevent water/ molecule loss
Epicuticular wax
The covering over the cuticle of plants
-wax off apples
-cuticular wax is made from cutin
Suberin is a major component of the walls of _____ cells
Cork
Form outermost layer of bark of woody stems and roots
Alternating light and dark layered band appearance
Steroids function in plants
-sterols make cell membranes to stabilize phospholipid tails
-hormones (some plants make estrogen)
How do plants use proteins
In seeds, 40% of dry weight of seeds is protein. Function as storage of amino acids to be used by embryo when it resumes growth upon germination of the seed.
What are nucleotides made up of
Phosphate group, 5 carbon sugar and a nitrogenous base
Sugar can be ribose or deoxyribose
Nitrogenous base can be adenine, cysteine, guanine, thiamine and uracil
Principal energy carrier for life
Adenosine Triphosphate
-3 phosphates bonds are weak and can be broken up for energy release
Primary and secondary metabolites
Molecules that are found in all plant cells and are excess age for the life of the plant-sugars, amino acids, proteins and nuclei acids
Restricted in their distribution, both within the plant and along the different species of plants-chemical signals, defence, pathogens, protection from radiation of sun, aid in pollen and seed dispersal. Stored in vacuoles normally.
Phytoalexins
Antimicrobial compounds produced only after wounding or after attack by bacteria or fungi
3 major types of secondary plant compounds
Alkaloids- pharmalogical or medicinal affects: morphine, caffeine, nicotine, cocaine, atropine (eye dilation)
Terpenoids- in all plants, composed of isoprenes (gas emitted in significant quantities by leaves especially in heat): essential oils, taxol (anti cancer), rubber, cardiac glycosides (heart attack, in milk weed to protect caterpillars/butterflies)
Phenolics- in all plant parts in all plants; flavonoids(can inhibit genetic response, protect from UV), tannins (bitter repellant) , lignins (in cell wall, strength and water proof) and salicylic acid (aspirin, esssential in SAR)
SAR
Systematic acquired resistance
In Response to a localized attack by pathogenic bacteria, fungi, or viruses to protect plant.
Function of lipids in plants
-energy storage in fruits and seeds
-cell membrane component
-protection (cutin, suberin and waxes)
-steroids (cell membrane and hormones)
Function of proteins in plants
Structural and catalytic functions
Primary metabolism is composed of
Most of the dry weight of organisms is made up of four types of organic molecules
Carbs
Lipids
Proteins
Nucleic acids
Most of the dry weight of organisms is made up of four types of organic molecules
Organic molecule
Consists of carbon
Binds to hydrogen
Alpha glucose and beta fructose =
OH on right bottom
OH on right upper side
Fructose
Cellulose is not available as a
Energy source
Is alpha or beta binds easier to digest
Alpha
Takes different enzymes
Amylose
Linear chain of repeated alpha-glucose monomers
Amylopectin
Branched chain of repeated alpha-glucose monomers
Cell walls have no _____ which makes them less fluid and instead more rigid
Cholesterol
Lipids
Long C-H chains that are hydrophobic
Triglycerides
Fats and oils used in energy storage
Phospholipids
Lipids used as main component of cellular membranes
Fatty acid vs phospholipid structure
Fatty acid- glycerol attached to 3 fatty acids
Phospholipid- phosphate group attached to a glycerol which 2 fatty acid tails
Suberin and lignin structural appearance
Suberin has verticals zig zags
Lignin has computer chip look
Sterol
Steroid with OH in carbon 3 position
Protein dry weight in organism and plants
Very abundant component of organisms
~50% of dry weight, but not in plants because of high cellulose content
What type of bond do proteins have
Peptide bonds which are covalent
Protein structure types
Primary- sequence of amino acids
Secondary- chains fold and interact in chain into alpha helix or beta pleated sheet with H bonds
Tertiary- more folding into solid structure
Quaternary-different subunits of tertiary structures together (hemoglobin)
Nucleic acids
Consists of long chains of nucleotides
ATP, ADP, AMP
Nucleotides
Phosphate group, pentode and nitrogen base
Information molecules
AMP is not in energy transport, but acts as a
Secondary messenger
Types of RNA
mRNA, tRNA, rRNA
Which nitrogenous bases go together
Adenine, thymine and uracil
Guanine, cytosine
Purines
Pyrimidines
Adenine, guanine - two ring
Thymine, cytosine, uracil -one ring
Primary metabolites
Molecules found in all plant cells, necessary for cell functions and plant life
-respiration and photosynthesis
Secondary metabolites
Organic molecules of restricted distribution among species and within the plant body
-stored primarily in vacuoles
-chemical signals invoked in response s to biotic or abiotic cues
-anti-herbivore, anti-pathogen, allelochemicals
Allelochemicals
Organic Chemicals released from roots that make it difficult for other plants to grow around it
Major classes of secondary metabolites
Alkaloids
Terpenoids
Phenolics
Phytoalexins
Phytoalexins
-antimicrobial
-produced only after wounding or infection
-different chemical classes: terpenoids, glycosteroids, alkaloids
Alkaloids
Nitrogenous compounds important for pharmacological/ medicinal, physiological, psychological effects
-10,000 different alkaloids known
Alkaloids examples
-caffeine
-cocaine
-nicotine
-morphine
-strychnine
-quinine : malaria treatment
-ephedrine : cough treatment
-atropine
Can caffeine be produced in more than 1 way?
Yes, 5 biochemical pathways to produce caffeine in plants
Result of convergent evolution showing that caffeine is used as a defence against herbivores and insects
Terpenoids structure
-composed of isoprene units (C5H8)
-largest class of secondary metabolites (22,000)
-monoterpenoids (C10)
-sesquiterpenoids (C15)
-diterpenoids (C20)
Terpenoids examples
-essential oils (pollinator attraction)
-taxol
-rubber
Rubber structure
-Largest terpenoid
-400-100,000 isoprene units
Terpenoids functions
-photosynthetic pigments (carotenoids)
-hormones (GA-growth, ABA-senescence)
-membrane structure (sterols)
What terpenoids is a compound in milkweed?
Cardiac glycosides
Phenolics structure
-broad range of compounds with a hydroxyl group (-OH) attached to aromatic ring
-present in most plants and plant parts
Examples of Phenolics
-Tannins
-Flavonoids
-Lignins
-salicylic acid
Flavonoids
Phenolic compounds
-anthocyaninin , flavones and flavonols
-co pigmentation if anthocyanins and flavones joined through complexes with metal ions
Where are tannins located in cells
Vacuoles
Purpose of salicylic acid
Pathogen defence
