Download Principles of Biology Lake Tahoe Community College

Botany
Spring 2007
Written by: Sue Kloss
Lake Tahoe Community College
Instructor: Ralph Sinibaldi
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Chapters 1 and 3
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Ch. 1
I. Pervasive importance of plants
A. Waves of light energy reflected by objects causes them to be particular colors
The earth from the moon (240 million miles) looks blue (Fig. 1.1) because of all the water on earth (2/3 of
earth’s surface) and water vapor in earth’s atmosphere, but from 10 miles above earth, it looks green.
1. Plants absorb red and blue but reflect green. Enormous numbers of plants carpet the ground;
red and blue light waves are absorbed and power the process of Ps. Green reflects and we see it
B. Plants are organisms with particular characteristics
1. plants are green, photosynthesizing (Ps) organisms, producing organic sugar and O2 from
inorganic CO2 and H2O
2. plants grow attached to one place
3. plants have cell walls containing cellulose- substance contained by few other organisms.
4. plants have multicellular but simple bodies lacking obvious circulatory, nervous and digestive
systems
5. plant bodies are adapted to the stresses of life on land and can regulate water
6. plants have strengthening tissue that keeps them upright
7. plants can regulate temperature
8. plants reproduce with microscopic, drought tolerant spores
C. The Kingdom Plantae has about 250,000 species of trees, (Fig. 1.3) herbs grasses, ferns, and mosses
1. there are another 250,000 species of plant-like organisms in the Kingdoms Monera (Fig. 1.4),
Fungi and Protista (Algae). Many of these are green and Ps, but some are not. They engulf living
food or feed on dead organisms. Some cannot regulate water loss or have no strengthening tissue.
2. civilizations can rise and fall depending on access to and control of plants (list things plants
used for).
a. lumber for warships
b. fuel
c. cure pottery
d. wealth in form of spices, rubber, olive oil, etc.
3. Currently plants are important for
a. basis of food chain on earth
b. absorb CO2 (imp. In ameliorating global warming)
c. produce O2
d. economic values (eg. Pharmaceuticals, crops, etc)
e. ecosystem services
f. recreational and intrinsic values
4. Conservation began as “wise use” and now encompasses preservation of biological diversity
in growth oriented, techno culture trying to coexist with natural resources
II. Scientific Method (Fig. 1.7)
A. All scientists share a common process called the scientific method
1. Scientists make observations, ask questions, make educated guesses about possible
answers, base predictions on those answers, and devise ways to test predictions
a. observation
b. question
c. hypothesis
d. test
e. evaluate
f. refine hypothesis, start again
2. formally, guesses are called hypotheses or theories, and set of procedures is the scientific
method
3. a theory or hypothesis is never seen as absolute truth, but the best answer that may be
modified in the future
4. the external world, not internal conviction, is the testing ground for science
5. one’s beliefs subconsciously influence one’s science
6. Scientific method has proved to be powerful for advancing human knowledge/understanding
7. Technology is application of information to industrial or commercial objectives. Science and
technology are different, but linked
III. Studying plants from different perspectives
A. Any plant is a product of its genetics plus the effects of its environment (Fig. 1.8)
1. 2 major disciplines dealing with plants are plant genetics and plant ecologists
2. Plant genetics is useful for plant evolution and classification, plant taxonomy or systematics
3. knowledge of ecology is useful for paleoecology (reconstructing past climates and landscapes)
and biogeography (how plants have come to be distributed around the world as they are)
4. genes and the environment interrelate through metabolism (Ps, transport of materials, constuct
molecules, cells and tissues, and use hormones to affect behavior - (plant physiology)
5. genes, environment and metabolism work together to produce an individual plant, which can
be studied in several different ways
a. plant morphology (how a plant develops from a single cell into various tissues and
organs), and plant anatomy or cytology (study of a plant’s diverse internal cells)
6. Plants and plant-like organisms can be studied according to their classification
a. microbiology is the study of bacteria; mycology is the study of fungi; phycology is the
study of algae; and bryology is the study of mosses
7. 5 kingdom classification scheme developed by Robert Whittaker in 1969: Monera, Fungi,
Protista, Plantae and Animalia; protists have been split into many groups, no longer viable divisions.
B. Domains Bacteria and Archaea; Archaea include 3 groups of extremophiles – methanogens in swamps
And animal guts; halophiles in salt areas, and thermophiles in hot pools and vents
Bacteria includes Photosynthetic Bacteria - earliest life forms in fossils, 3-4 byo. Prokaryotes are
microscopic, but collectively, numbers and biomass are astronomical. Occur in extreme environmentshot springs, snow and ice surfaces; confusing bc, all referred to as “Bacteria”, but all are prokaryotes
1. The organisms have prokaryotic cells - lack bounded nucleus, no organelles, very small size,
DNA is circular and not linear.
2. bacteria are beneficial as decomposers and detrimental as pathogens- cause botulism,
bubonic plague, cholera, diptheria, gonorrhea, leprosy, syphilis, tetanus, T.B., and typhoid fever
3. Cyanobacteria (blue-green algae) have chlorophyll in their cells and are capable of Ps;
a. cyanobacteria are surrounded by rigid cell walls and reproduce with spores
b. many cyanobacteria can incorporate inorganic nitrogen gas (N2) from the environment
into organic nitrogen in the form of the ammonium ion (NH4+)
C. Domain Eukarya:
1. The Kingdom Fungi contains decomposers and pathogens Fungi are nonphotosynthetic with
eukaryotic cells (membrane-bound nucleus), organelles,
linear DNA, much larger than prokaryotes; sexual reproduction. Include molds, mildews,
mushrooms, rusts, smuts
a. fungi are typically microscopic and filamentous with cells surrounded by a rigid cell wall
composed of chitin, a substance also associated with some animal groups
b. fungi reproduce sexually and asexually
c. fungi are widely distributed around the world but are mainly terrestrial
d. fungi are ecologically important as decomposers
e. some fungi form mutually beneficial associations with plant roots
f. some fungi important as foods for plants and animals (humans - yeasts, mushrooms,
meds - penecillin)
2. The Kingdom Protista includes grasses of the sea (sea weed) - catchall kingdom; future
differentiation
a. Protists are eukaryotic, simple, often microscopic and usually aquatic organisms; they
reproduce sexually and asexually
b. Some protists are Psing algae; others are slime molds, foraminiferans and protozoans widely divergent groups
1. algae can be single cells or clusters of cells, come in sheets, filaments. Every cell in
algal bodies can carry out Ps, and obtain food and H2O from liquid environment
2. microscopic algae are called phytoplankton and are often referred to as grasses of the
sea
3. phytoplankton form the basis of vast natural food chains and produce half of all the O2
in the atmosphere as a byproduct of Ps
3. The Kingdom Plantae contains complex plants adapted to life on land
a. the kingdom Plantae contains mosses, ferns, pine trees, oak trees, shrubs, vines,
grasses and flowering herbs
b. organisms in this Kingdom are adapted to life on land and are recently evolved. Make
up the biomass of forests, meadows, shrublands, deserts, marshes, woodlands and
grasslands
c. Plants have eukaryotic cells with cellulose walls, store carbohydrates in form of starch,
and have special types of chlorophylls and other pigments
d. plant cells and tissues are more complex than monerans, fungi and protistans. They
often have specialized cells and tissues (tansport, storage, Ps, strength). Plant structures
include leaves, roots, stems, flowers and seeds
e. plants have major ecological and economic importance
4. Domain Animalia
a. multicellular
b. mobile
c. ingest food
Ch. 3.
I. Introduction to eukaryotic cells - Organelles of the Endomembrane system
A. Nucleus - genetic control center
1. chromatin - long threads of DNA and proteins
2. chromosomes - during cell division
3. nuclear envelope - pores to allow flow of material in and out
4. nucleolus -chromatin DNA, RNA and proteins - ribosomes components are made here
B. Endomembrane system - organelles enclosed in membranes that forma cytoplasmic network.
1. many organelles work together in synthesis, storage and export of imp. molecules within this
system
2. endoplasmic reticulum (Gr - network within cell)
a. 2 types, rough and smooth, membranes that form them are continuous;
b. membranes of rough er also contiguous with nuclear envelope
c. dividing the cell into various compartments is one of the main functions of this system
C. Endoplasmic reticulum
Continuous membrane constitutes:
1. rough er - studded with ribosomes; interconnected membrane in flattened sacks
a. produce more membrane and proteins that are inserted into membrane for metabolism
b. produce proteins secreted by cell (e.g. antibody - defense protein made by wbc)
1. ribosomes make polypeptides assembled inside rough er
2. attach sugar = glycoprotein
c. transport vesicle takes glycoprotein to golgi apparatus for further processing
2. smooth er - contnuous with rough er
a. interconnected tubulers that lack ribosomes
b. much enzyme activity from enzymes in membranes
c. synthesis of lipids
C. Golgi apparatus - close partner to ER - looks like pita bread not connected like er
1. receives and modifies substances produced by ER, then ships them
2. substances sent to correct destination via plasma membrane in transport vesicels
a. destinations may be inside cell - become part of another organelle e.g. lysosome
b. out of cell - antibody
D. Lysosomes (Gr. - breakdown body)
1. produced by ER and Golgi apparatus
2. consists of digestive enzymes in a membranous sack
3. digestive functions
a. food
b. harmful bacteria or pathogens
c. recycle damaged organelles
E. Vacuoles function in genl maintenance - central vacuoles in plant cells only
1. may serve as a large lysosome
2. aid in growth by absorbing water
3. store vital chemicals or waste products, pigments, poisons for discouraging grazing
4. water balance - expel water
II. Organelles that convert energy
A. Chloroplasts - convert light to chemical energy in plants and some protists and algae
1. stroma - thick fluid in organelle
2. granum - stacks of interconnected hollow disks
3. inner and outer membrane
4. 3 compartments for chemical work
B. Mitochondria - convert chemical energy from one form to another e.g. food to ATP
1. ATP main currency of all work in cell
III. Cytoskeleton - meshwork of fine fibers for structure and movement
A. Microfilaments - solid helical rods of actin 1. help cells change shape by adding subunits at one end and losing them at the other end
B. Intermediate filaments - varied group - fibrous proteins, ropelike structure
1. hold certain organelles in place eg. nucleus
C. Microtubules -straight hollow tubes composed of globular proteins ,
1. anchor organelles
2. act as tracks for organelle movement eg. lysosome moves to food vaculole on microtubule
3. guide movement of chromosomes in cell division
IV. Cilia and flagella move when microtubules bend
A. Cilia - short numerous appendages on protists or on cells of multicelled orgs 1. eg. paramecium and human windpipes
B. Flagella - longer less numerous for propulsion
V. Cell Surfaces and Junctions
A. Cell walls in plants 10 - 100x thicker than plasma membranes
1. cellulose embedded in matrix of polysaccharides and proteins
2. several layers - sticky polysaccharides glue cells together (Dark brown)
B. Cell junctions connect one cell to another
1. Plasmodesmata in plants - channels between adjacent plants
a. circulatory and communication channels
b. water, nourishment and chemical messages
Chapter 1 and 3 Homework Qs/Lesson Objectives
1. List the Domains and their main characteristics.
2. What traits do plants share with members of Kingdoms Protista, Fungi, and Animalia? What traits of plants are
different from members of each of those Kingdoms?
3. Distinguish all prokaryotes from all eukaryotes, and from protists in particular. Give examples of each of these
groups.
4. What is taxonomy?
5. Describe the scientific method. What steps are used in the scientific method? Why is it important, and how is it
used?
6. Describe some of the important aspects of plants to humans.
7. Draw a plant cell, label all organelles and give functions for each.
8. Distinguish meiosis from mitosis.