The Molecular Composition of Plant Cells Flashcards
substances that cannot be broken down into other substances by ordinary means
elements
make up 90% of the weight of all living matter
Carbon, Hydrogen, Nitrogen, Oxygen, Phosphorus, Sulfur (CHNOPS)
Composed of carbon, hydrogen, and oxygen; follows 1:2:1
carbohydrates
Three principal kinds of carbohydrates:
Monosaccaride, Disaccharide, Polysaccharide
a carbohydrate that functions as building blocks and sources of energy
Monosaccharide
Ribose, glucose, fructose, galactose, and maltose, consist only of one sugar
Monosaccharide
Contain two sugar subunits linked covalently
Disaccharide
the synthesis of a disaccharide where a molecule of water is removed and a new bond is formed between the monosaccharide
Dehydration synthesis or condensation reaction
from hydro, meaning “water”, and lysis, “breaking apart”; the reverse reaction of dehydration synthesis in which a molecule of water is added, the disaccharide is split into its monosaccharide subunits
hydrolysis
glucose + fructose; transport form of sugar in plants
Sucrose
glucose + galactose
lactose
glucose + glucose
maltose
a carbohydrate that function as storage forms of energy or as a structural materials
polysaccharide
Contain many sugar subunits linked together
polysaccharide
common storage polysaccharide in prokaryotes, fungi, and animals; resembles amylopectin but is more highly branched
glycogen
primary storage polysaccharide in plants
starch
Starch have two forms:
amylose – which is an unbranched molecule & amylopectin – which is branched
the principal storage polysaccharides in leaves and stems; consist of the polymers of fructose
fructans
(structural polysaccharide) principal component of fungal cell walls and also of the relatively hard outer coverings, or exoskeletons of insects and crustaceans, such as crabs and lobsters
chitin
(large molecules) that are made up of similar or identical small subunits
macromolecules
(“single parts”) individual subunits of polymers
monomers
(many parts) similar or identical small subunits that made up the macromolecules
polymers
stepwise linking of monomers into polymers
polymerization
Serve as energy-storage molecules – usually in the form of fats or oils – and also for structural purposes
Lipids
triglycerides that store energy
fats and oils
consist of 1 glycerol + 3 fatty acids
fats
tend to stay solid at room temperature and can cause fatty deposits in blood vessels leading to atherosclerosis (“hardening of the arteries”)
saturated fat
Butter, lard, coconut oil, palm oil, etc.
saturated fat
stay liquid at room temperature are less likely to clog your arteries linked by one or more double bonds
unsaturated fat
Safflower oil, peanut oil, corn oil, obtained from oil-rich seeds
unsaturated fat
1 glycerol + 2 fatty acids + 1 phosphate group; modified triglycerides that are components of cellular membranes
phospholipids
cholesterol, lipid-like, sex hormones; stabilize cellular membranes and also function as hormones
Steroid
Most abundant organic molecules
protein
building blocks of proteins
amino acid
consists of an amino group (–NH2), a carboxyl group (–COOH), and a hydrogen atom, all bonded to a central carbon atom; has an “R” group also bonded to the central carbon atom
amino acid
(“R” can be thought of as the “rest of the molecule”) that determines the identity of each amino acid
R group
Four Levels of Protein Organization
Primary Structure
Secondary Structure
Tertiary Structure
Quaternary Structure
protein organization that consists of a linear sequence of amino acids linked together by peptide bonds
primary structure
level of protein organization that exist in two most common structure: alpha helix (spiral) & beta pleated sheet (zigzag)
secondary structure
– Alpha helix may fold to form a three-dimensional, globular (structure) protein
– E.g., membrane proteins, transport proteins
Tertiary Structure
facilitates the process by inhibiting incorrect folding
Molecular chaperones
a level of protein organization wherein it is combination of several polypeptide chain into a single functional molecule
quaternary structure
the unfolding or breaking up of a protein, modifying its standard three- dimensional structure
denaturation
lock and key model—substrate will fit into a specific enzyme
enzymes
- large, complex globular proteins that catalyze chemical reactions (act as catalyst)
- often named by adding the ending -ase to the root name of the substrate
enzyme
substance that accelerate the rate of a chemical reaction by lowering the energy of activation, but remains unchanged in the process
catalyst
the reacting molecule or molecules
substrate
catalyzes the hydrolysis of amylose (starch) into glucose molecules
amylase
catalyzes the hydrolysis of sucrose into glucose and fructose
sucrase
Consist of long chains of molecules known as nucleotides
nucleic acid
consist of three components: phosphate group, a five-carbon sugar, and a nitrogenous base
nucleotides
five different nitrogenous bases occur in the nucleotides that are the building blocks of nucleic acids:
adenosine, guanine, thiamine, cytosine, & uracil
Double-stranded
Deoxyribose
ATCG
Carries genetic information
DNA
single stranded
ribose
AUCG
Participate in protein synthesis
RNA
component of the ribosomes (protein + RNA)
rRNA (ribosomal RNA)
to carry amino acid during translation of protein synthesis
tRNA (transfer RNA)
blueprint of the DNA during protein synthesis
mRNA (messenger RNA)
molecules that are found in all plant cells and are essential to life
amino acids, sugars, proteins, and nucleic acids
Primary Metabolites
antimicrobial compounds produced only after wounding or after attack by bacteria or fungi
phytoalexins
only produced if the plants are stressed
restricted and not even in their distribution
serve as chemical signals that enable the plant to respond to environmental cues
known to be important for the survival and propagation of the plants that produce them
Secondary Metabolites
Three Major Classes of Secondary Plant Compounds (Secondary Metabolites)
Alkaloids
Terpenoids
Phenolics
among the most important compounds in terms of their pharmacological or medicinal aspects
Alkaloids
alkaline nitrogenous compounds that include morphine, cocaine, caffeine, nicotine, and atropine
alkaloids
first alkaloid to be identified in 1806 from the opium poppy (Papaver somniferum)
- used today in medicine as analgesic (pain reliever) and cough suppressant
morphine
comes from coca (Erythroxylum coca) lessen hunger pangs and fatigue while working in this harsh environment
cocaine
a stimulant found in such plants as coffee (Coffee arabica), tea (Camellia sinensis), and cocoa (Theobroma cacao)
caffeine
caffeine released by the seedling apparently inhibits germination of other seeds in the vicinity of the seedling, preventing the growth of competitors
allelopathy
containing extracts from the Egyptian herbane
- used today as a cardiac stimulant, a pupil dilation for eye examination, and an effective antidote for some nerve gas poisoning
atropine
(Nicotania tobacum) functions as phytoalexin
Nicotine
– Also called terpenes, occur in all plant cells are by far the largest class of secondary metabolites, with over 22,000 terpenoid compounds described
terpenoids
a gas emitted in significant quantities by the leaves of many plant species and is largely responsible for the bluish haze that hovers over wooded hills and mountains in summer
- made in chloroplast from carbon dioxide recently converted to organic compounds by photosynthesis
Isoprene
– monoterpenoids and sesquiterpenoids, they contribute to the fragrance, or essence, of the plants that produce them
- produce by the leaves of some plants deter herbivores, some protect against attack by fungi or bacteria, while others are known to be allelopathic
- the terpenoid of flower fragrances attract insect pollinators to the flowers
essential oils
known to have anti-cancer properties
taxol
large quantities of volatile monoterpenoids (menthol and methone) are both synthesized and stored in glandular hairs (trichomes), which are outgrowths of the epidermis
Mint (mentha)
can result in slower and strengthened heartbeat when used medicinally
cardiac glycosides
largest known terpenoid compound
rubber
Hydroxyl group (–OH) attached to an aromatic ring (a ring of six carbons containing three double bonds)
Almost universally present in plants and are known to accumulate in plant parts (roots, stems, leaves, flowers, and fruits)
phenolics
range in color from red through purple to blue
anthocyanin
yellowish or ivory-colored pigments and some are colorless; can alter the color of a plant part through the formation of complexes with anthocyanins and metal ions. This phenomenon, called co-pigmentation.
flavones & flavonols
- against herbivore (i.e. bitter taste)
- anti-bacterial (denature protein in leather)
tannins
adds compressive strength and stiffness to the cell wall
lignins
active ingredient in aspirin; essential for the development of systemic acquired resistance, commonly known as SAR. SAR develops in response to a localized attack by pathogenic bacteria, fungi, or viruses
salicylic acid
makes up more than half of all living matter and more than 90 percent of the weight of most plant tissues
water
