shawnkyna

Monday, May 22, 2006

1/4 of the stuff i have to memorize by tuesday, and the rest is more difficult

BOTANY NOTES

Foreunners of simple cells were simple aggregations of molecules called proteinoid micrspheres.

Properties of life: 1. Ability to grow 2. Ability to reproduce 3. Ability to pass on characteristics to future generations. 4. Cellular organization

Monosaccharides function as building blocks and sources of energy.

Monosaccharides are he simplest carbohydrates. Formula (CH2O)n where n can be as mall as 3 or as large as 7: C3H6O3 C7H14O7 A carbon chain with a hydroxyl group attached to every C but one, which is attached to a carbonyl group. Both groups are hydrophilic. Exist in rings and chains.

Disaccharide sucrose is a transport form of sugar in plants.

Sucrose is composed of one alpha-glucose and one beta-fructose bonded in a 1,2 linkage, formed by the removal of a water molecule, dehydration synthesis. The reverse reaction is hydrolysis -- adding a water molecule. Dehydration reactions require an energy input, whereas hydro! lysis releases energy.

Polysaccharide function as storage forms of energy or as structural materials.

Starch -- primary storage polysaccharide in plants, consist of chains of glucose molecules. Two primary forms: 1. amylose -- unbranched, linear chain of alpha-glucose monomers. 2. amylopectin -- branched chain of alpha-glucose monomers.

Cellulose -- primary structural polysaccharide in plants, composed of chains of beta-glucose monomers. Cellulose molecules are long and unbranched. Form microfibrils in the cell wall, combined with pectins and hemicellulose

LIPIDS

fats and fatlike substances hydrophobic -- insoluble in water

Fats and oils are triglycerides that store energy.

Fats and oils contain more energy-rich C-H bonds than carbohydrates, so they contain more chemical energy. Each fat and oil consists of three fatty acid molecules joined to one glycerol molecule

Phospholipids are modified triglycerides that are components of c! ellular membranes.

Composed of fatty acids and a glycerol like tri glycerides are, but the third carbon of the glycerol is occupied by a phosphate group to which another polar group is attached. The phosphate group is negatively charged and hydrophilic (head), while the fatty-acid side is hydrophobic (tail). A phospholipid bilayer forms the structural basis of cellular membranes.

Cutin, Suberin and Waxes are lipids that form barriers to water loss.

Steroids have linked hydrocarbon rings and play a variety of roles in plants.

Four interconnected hydrocarbon rings. Sterol -- hydroxyl group attached at the Carbon-3 position. �-Sitosterol -- most common sterol in green algae and plants ergosterol -- found in fungi cholesterol -- found in animals, trace amounts in plants Sterols are important components of cellular membranes; they stabilize the phospholipid tails. Steroids may also function as hormones.

PROTEINS

All are polymers of Nitrogen-containing molecules called amino acids arranged in a linear sequence. P! rotein molecules are large and complex.

Amino acids are the building blocks of proteins Basic structure = an amino group (-NH2) a carboxyl group (-COOH) and an H atom all bound to a central C atom, which also has an "R" group. The R group determines the identity of each amino acid. Linkage is accomplished by dehydration synthesis where an amino group of one molecule links to the carboxyl group of another forming a covalent peptide bond.

A protein's Structure is described in levels of organization:

1. Primary Structure the linear sequence of amino acids 2. Secondary Structure the way the chain of amino acids folds on itself a. an alpha helix with shape maintained by H bonds b. beta pleated sheet with polypeptide chains lined up parallel in a corrugated tin manner, shape again maintained by H bonds c. Proteins that exist for most of their length like thi! s are termed fibrous proteins. 3. Tertiary Structure a. Found in gl obular proteins b. the way the secondary structure alpha helix folds on itself c. In some proteins, is spontaneous; in others requires a molecular chaperone which inhibits incorrect folding d. caused by R group interactions e. disulfide bridges lock into shape 4. Quaternary Structure The interaction of two or more polypeptides at by combinations of the previous three structural interactions.

Enzymes are proteins that catalyze chemical reactions in cells Enzymes -- large, complex globular proteins that act as catalysts named by adding -ase to the substrate amylase catalyzes amylose (starch) into glucose sucrase catalyzes sucrose into fructose and glucose

NUCLEIC ACIDS

Nucleic acids contain the information for making proteins Nucleotides form changes that make nucleic acids Nucleotides consist of three subunits: 1. phosphate group -- ion of phosphoric acid 2. a 5-carbon sugar a. ribose -- RNA b. deoxyribose -- one fewer O atom than ribose -- DNA ! 3. a nitrogenous base

The molecule ATP is the cell's energy currency

ATP = adenosine triphosphate three phosphate groups attached to ribose ADP = adenosine diphosphate two phosphate groups attached to ribose

Phosphate bonds are weak and can be broken easily by hydrolysis ATP + H20 --> ADP + Phosphate Group + Energy

SECONDARY METABOLITES

three classes 1. alkaloids -- medically significant 2. terpenoids -- isoprene units including essential oils, taxol, rubber and cardiac glycosides 3. phenolics -- flavenoids, tannins, lignins and salicylic acid

CHAPTER 3 INTRODUCTION TO THE PLANT CELL

Cell Theory 1. all living organisms are composed of one or more cells 2. the chemical reactions of a living organism, including its energy-releasing processes and its biosynthetic reactions, take place within cells 3. cells arise from other cells 4. cells contain the hereditary information of the organisms of which they are a part, and this informa! tion is passed from parent cell to daughter cell

General Structur e 1. Cell Wall 2. Protoplast a. cytoplasm 1) organelles 2) membrane systems 3) non-membranous structures like ribosomes 4) cytosol 5) vacuoles bounded by tonoplasts b. nucleus 1) controls activities of cell by determining which proteins are produced and when they are produced 2) stores most of the cell's genetic information 3) bounded by two membranes called the nuclear envelope, which is pitted with nuclear pores

Functions of Plasma Membrane 1. mediates transport of substances into and out of the protoplast 2. coordinates the synthesis and assembly of the cell wall cellulose microfibrils 3. receives and transmits hormonal and environmental signals for cell growth and differentiation

Chloroplasts and other plastids -- concerned with photosynthesis and storage

Internally differentiated into a system of membranes, or thylakoids, and a more or less homogenous matrix, the stroma.

Three types 1. chloroplasts a. contain chlorophyll pigments ! and carotenoids b. have elaborate thylakoid systems c. handle photosynthesis 2. chromoplasts a. contain pigment other than chlorophyll b. synthesize and retain carotenoid pigments 3. leucoplasts a. lack pigments b. amyloplasts synthesize starch c. others may form oils and proteins

Proplastids -- precursors to plastids occur in meristematic cells proplastids can develop into any type of plastid, or, in the absence of light, into an etioplastid. All the forms of plastids, in turn, can change into another form.

MITCOCHONDRIA

Mitochondria are bounded by two membranes. The inner membranes is invaginated to form cristae. Mitochondria carry out cellular respiration, and they seem to cluster where energy is needed in a cell. Mitochondria and chloroplasts evolved from bacteria sheltering within larger prokaryotic cells.

Peroxisomes (microbodies)

Peroxisomes are spherical organelles bound by a single membrane enclosing a granular interior contain! ing protein. Some play a role in photorespiration, others (glyoxysome s) convert stored fats to sugars.

Vacuoles

Membrane bound area in the cell filled with a liquid called cell sap. The surrounding membrane is called the tonoplast The principal component of cell sap is water, with other components varying. Maintain internal pressure and tissue rigidity, serve as sites for pigment and toxin deposition, break down and recycle macromolecules.

Oil Bodies

Amorphous, membraneless structures that give cytoplasm a granular appearance. Store fats for energy.

Ribosomes

Small particles made of equal amounts protein and RNA. Site where amino acids are linked to form proteins. Polysomes -- clusters of ribosomes actively involved in protein synthesis, aka polyribosomes.

Endoplasmic Reticulum (ER)

A complex 3-D membrane system. Rough -- flattened sacs, cisternae, containing ribosomes -- protein storage Smooth -- tubular shaped, lacks ribosomes -- lipid synthesis ER functions as a communications system in the he cel! l and as a means of channeling materials to different parts of the cell. ER also crosses from cell to cell via plasmodesmata.

Golgi Complex

Refers to all of the Golgi bodies (dictyosomes) in a cell. Involved in secretion and synthesis of non-cellulosic cell wall polysaccharides, and the secretion of glycoproteins.

Cytoskeleton

A network of protein filaments throughout the cytosol. Two types:

Microtubules -- composed of a helix of a-tubulin and b-tubulin which forms a hollow-cored tube. Important in many aspects -- movement, cell division, cell wall formation, etc .... Actin filaments -- microfilaments composed of the protein actin involved with many activities -- cytoplasmic streaming, cell wall deposition, organelle movement, etc .....

Flagella and Cilia

9+2 pattern of organization

CELL WALL

Distinguishes plant from animal cells. Principal component -- cellulose -- (o_   v1.2a s BO@ 0/0/ FD - 0 OBC 2 0 75.5% <16oct98&! gt;             .---. //\   Hey, I have an album, and you can listen to it at my URL  _/__~0_\_ V_/_  cuth@prysm.net -- http://www.prysm.net/~cuthulu/      (_________)