PLSCI 1101 Prelim 1

Green Organism, Autotroph, Producer

Organisms that make their own food and are not reliant on other organisms for food. They carry out the complex metabolic process of photosynthesis to capture solar energy and store it in organic molecules that we call food.

Metabolic Processes

Series of chemical reactions carried out by living organisms to build or break downb orgamnic moecules and to store or release energy to power life.

Heterotrophs

Organisms tghat cannot produce their own food so they have to depend on other porganisms for food.

Cellular Respiration

metabolic processes that all organsism use to break down organic molecules and release stored energy. Plants respire too!

Top 5 Crops that make up more than 50% of calories that humans consume

rice, wheat, maize, sugarcane, barley

Domestication

The selection of particular plant characteristics over time that leads to physiological and morphological changes

Why are plants important components of ecosystems?

they provide food and shelter, absorb water and conrtol floods, roots stabilize soil and prevent erosion, roots have partnerships with nitrogen fixing bacteria which converts atmospheric nitrogen into usable forms

What is the purpose of genetically modifying crops?

enhance yield and nutrition in crop plants, ward off pests, disease resistance, and herbicide resistance

Oppositely Arranged

2 leavs from 1 node

Alternate Arrangement

1 leaf from each node

Petiole

Part of plant that attatches the leaf to the stem

Axil

Angle between the stem and the petiole

Sessile

No petiole, leaf is attatched directly to the stem

Terminal bud

bud on the end/top of shoot

Lateral/Axillary Bud

buds on the side of stem, they grow to make branches

Tip

Top of the leaf

Base

bottom of the leaf

Margin

sides of the leaf

Simple Leaf

1 blade attatched to a petiole

Whoreld Arrangement

3 or more lkeaves coming out of a node on a stem

Palmate Leaf

Veins or lobes spread outwards from one central point (ex. sweet maple leaf)

Compound Leaf

A single leaf whose main blade is divided into multiple smaller separate parts called leaflets

Pinnate Leaf

a compound leaf with smaller leaflets arranged in two rows along opposite sides of a central stalk, looking like a feather

Sepal

The leaf looking green parts on the bottom of a flower

Perianth

Consists of the sepal and the petals

Stamen

The male repoductive part of a plant, consists of the filament and the anther.

Pistil

The female reproductive parts of the plant. Contains the stigma, style, and ovary,.

What is in buds and what are their purpose?

Buds contain meristem tissues and tiny primordial leaf and branch tissue that will eventually grow into new branches and leaves. Buds allow the survival of leaves and branch tissue throughout the winter

Bud Scale Scars

Tiny ring shapes marks left on a woody stem or twig each year when the buds grow into new branches. You can tell the age of the branch by looking at the scarring.

Lenticils

white markings on stems that are in bark to allow CO2 out and oxygen in for respiration

Water

main component of life/living cells. Makes up 70-90 % of volume in cells. Water is also the most important solvent because it dissolves molecules and allows them to be absorbed by cells. Water provides aqueous medium for metabolic reations and to move materials in and out of cells. In plants water pressure provides struictural support.

Hydrophtyes

Live in areas with very wet or waterlogged soils, water plants

Mesophyte

land plants in moderate climates, grow in average well drained soils with a balanced supply of water

Xerophyte

drought resistant plants that thrive in very dry arid climates like deserts

Monecious

Plant has male and female flowers on the same plant. ex: corn

Diecious

Plants are either a female plant or a male plant

Perfect Flower

Flower has both male and female parts in the same flower

Terpenoids

A seconary product based on isoprene, largest class of secondary molecules. Ex: Carotenoids - serve a protective role in chloroplasts and show as yellow color in the autumn. Some terpenoids might be defense compounds. Other examples are natural rubber, spices, and pigments. Some are defense compounds.

Phenolics

Secondary products based on phenol a benzene ring with an OH grpup.The most important phenolic in plants is lignin.

Lignin

Phenolic in secondary cell walls that provides rigidity and strength.

Alkaloids

basic (pH) molecules with at least 1 nitrogen atom. They often have significant effects on living organisms, including medicinal properties. Examples include caffeine, morphine, and nicotine. Plants use them as defense against insect feeding and animal grazing.

Flavones and Flavonoids

Polyphenolic pigments. Flavonoids are pigments that attract insects and birds and absorb UV light.

Enzymes

Proteins that have an active sign that catalyze reactions. Substrate molecules bind to the active site and then the enzyme moves in some way for a chemical reaction to occur,

Protein uses in plants

Nitrogen storage, especially in seeds. This is important for seed germination and animal nutrition. Many plant proteins contain the essential amino acids. Plants absorb a lot of nitrogen because it is needed for portein synthesis. Nitrogen is often deficient in soils and must be supplied through fertilzer ir compost. Plant tissues are 3-4% nitrogen by dry weight. Peanuts and soybean are high protein seeds that humans eat.

Nucleotides

A 5 carbon sugar, an organic base, and a phosphate.

Nucleic Acids

Linear chains of nucleotides

Purines

Organic bases in nucleotides with 2 ring structure. This is adenine and guanine.

Pyrimidine

Organic bases in nucleotides with single ring structure. This is cytosine and thymine, and uracil

ATP

One of the most important molecules in all of metabolism. It is a nucleic acid that stores lots of energy in phosphate bonds and provides energy for metabolism in organisms.

Sterols

Have unique chemical structures that distinguish them from other lipids. They are made up of 4 interconnected hydrocarbon rings that may have a hydrocarbon chain attatched to one of the rings.

Sitosterol

The most abundant sterol found in membranes of plants, it stabilizes the hydrophobic tails in the bilayer

Phospholipids

structural basis of all cell membranes that contains 2 fatty acid chains and a modified phosphate group attached to glycerol. In the membrane, the phosphate end and attatched tails are oriented to give 2 different chemical regions. Heads are hydrophilic and tails are hydrophobic. The degree of unsaturation affects the fluidity of the membrane. They are many kinds of phospholipids as other groups can link to the phosphate and there are different kinds oif fatty acids.

Proteins

Long chains of animo acids that create complex 3D molecules. They are used for structure, nitrogen storage, and enzymes.

Amino Acids

These make up proteins. They all have N,C,O, and H. The R group is the functional group which gives different amino acids different chemistry. This group determines what amino acid it is abn properties like pH and polarity.

Protein Primary Structure

The chain of amino acids. The peptide bonds link the carboxyl group of one amino acid to the amino group of another one.

Secondary Protein Structure

The amino acid sequence then leads to molecular scale coiliung, spiraling, and pleating. Common structures are alpha helix and beta pleated sheets.

Tertiary Protein Structure

The secondary structure leads to further folding which is the teritary structure. This structure can move and change shape. Basus of catalysis of biochemical reactions.

Quaternery Protein Structure

Combination of multiple subunits

Staurated Fatty Acid

The molecule is rigid and only has single bonds between the carbons. It is solid at room temperature like butter.

Unsaturated Fatty Acid

The molecule can flex as it has at least 1 double bond between the carbons. It is a liquid at room temperatue like oil.

Lipids

Fats and fat like substances. They are hydrophobic. They are molecules with long hydrocarbon chains and many are based on glycerol. They are important in cell membrane structure and energy storage in seeds.

Role of Proteins in the Cell Membrane

Half of the weight of the membrane is protein. They can be on, in, or span the membrane and can be enzymes, ion channels, and electron transport.

Fatty Acid

A lipid with an organic acid group at the end. They can be staurated or unsaturated.

Triglyceride

3 fatty acids linked to a glycerol

Carbohydrates

hydrates of water and carbon. can be mono, di, poly, or oligo saccharides.

Carbohydrate uses in plants

They are formed by photosynthesis in plants. Plants are rich in C, H, and O, and depend on these elements for structure and energy storage. Plants used CHOs to move carcon from leaves to roots, flowers, abnd fruit.

Monosaccharides

Sugars that have 3,4,5,6 carbons in them. Hexoses have 6 carboins abd examples are glucose and fructose.

Glucose

The most important hexose. It has 3 structural forms, 2 ring forms and 1 chain form. In water, all 3 forms can exist at the same time. Alpha and beta carbon determine the forms. The alpha glucose has OH facing down and the beta glucose has OH facing up. Only the ring glucose is involved in metabolism.

Disaccharides

Two sugars (each usually 5 or 6 carbons) linked together. Sucrose is an example, it is glucose and fructose together(hexoses), and it is table sugar. It is obtained from sugarcane and sugar beets. This is the most common sugar in plants. Other examples are lactose and maltose.

Oligosaccharides

4-7 sugars linked together.

Starch

A polysaccharide that is identically chemically to cellulose as it is a glucose polymer. It has alpha 1,4 bonds instead of beta. Starch branches, unlike celluloe. Starch is easily broken down and metabolized. It is produced during photosynthesis and used at night by that plant.

Cellulose

A polysaccharide siminlar to starch but it does not branch and has beta linkage in the 1,4 carbon instead of alpha. It is very difficult to break down and is in plant cell walls. It is a major challenge for biofuels since it is so hard to break down.

Pectin

Another important polysaccharide. It is poly galacturonic acid. It gives plasticity and flexibility to cell walls. It is important for fruit firmness and it used to thicken fruit jams.