Biology 108 Lab Exam Prep Notes
LAB 1: BIOLOGY TOOLS AND TECHNIQUES
1 eyepiece unit (epu) at 10X is 10μm
1 eyepiece unit at 40X is 2.5μm
LAB 2: ORIGIN OF SPECIES: STARTING THE STORY WITH DNA
Species are particular kinds of plants or animals.
The most basic source of change is mutation. (Another important source is natural selection)
The replacement of one nucleotide with another in a DNA strand is called single-base substitution.
Continuous accumulation of mutations has been called a molecular clock.
We can make phylogenies based on phenotypes (observable traits) and also genotypes (genetic traits).
Multiple sequence alignment is a sequence alignment of three or more biological sequences.
A neutral mutation has no effect on fitness.
And the common sense terms:
- Most recent common ancestor
- Phylogenetic tree
LAB 3: DIVERSITY OF PHOTOSYNTHETIC PIGMENTS
Chlorophyta are commonly referred to as the green algae, the Rhodophyta as the red algae and the
Phaeophyta as the brown algae.
Cyanobacteria are a phylum of prokaryotic, photosynthetic bacteria.
Colors in cyanobacteria are due to photosynthetic pigments which capture sunlight for photosynthesis.
Endosymbiosis is the theory that certain organelles originated as free-living bacteria that were taken
inside another cell as endosymbionts. Both benefitted from this relationship and organelles developed.
Angiosperms refer to the flowering plants.
Thin layer chromatography, TLC, separates molecules with different polarities. (^polar, ^distance)
There are three broad classes of photosynthetic pigments: chlorophylls, carotenoids and phycobilins.
The supernatant is the liquid above the pellet after it is removed from the centrifuge.
Chlorophyll a is the primary pigment participating in the chemical reactions of photosynthesis. The
others are all accessory pigments, which capture light at different wavelengths than chlorophyll a, the
transfer the light energy to it. Table 3-1.
Pigment Color Water soluble? Position on TLC Occurs in:
Phycoerythrin Red Yes - Rhodophyta,
Phycocyanin Blue Yes - Rhodophyta,
Carotene Orange No Close to top Rhodophyta,
Xanthophylls Yellow, orange No Midway or lower Phaeophyta,
Chlorophyll a Bluish- green No Close to top Rhodophyta,
Chlorophyll b Yellow-green No Slightly lower than Chlorophyta,
Chlorophyll c Light green No Close to bottom Phaeophyta
LAB 4: PLANTS PART I: PLANT FORM AND FUNCTION
The classic interpretation is that leaves capture light energy (via photosynthesis), stems maintain plant
structure and transport water, nutrients and sugars, while roots function in the absorption of water and
nutrients from the soil.
Buds are where the organs differentiate.
There are three major tissue types:
- Dermal tissues which make up the outside cover of the plant
- Vascular tissue which makes up conducting tissues xylem and phloem
- Ground tissue which is “filler” tissue
The blades of leaves differ in shape;
- Simple leaves have single blades
- Compound leaves are divided into leaflets
The xylem is located on the central part of the vascular bundle and the phloem on the outside.
The stoma is a pore found in the leaf or stems epidermis that is used for gas exchange. This pore is
bordered by guard cells that are responsible for regulating the size of the opening of the stoma.
The radicle is the first part of a seedling to emerge from the seed during the process of germination
If the primary root continues to be the largest and most important root, it is a taproot system.
If many roots are formed the plant has a fibrous root system. Xylem is the water conducting tissue and the phloem is the tissue responsible for the translocation of
the products of photosynthesis to other parts of the plant.
The dermal tissue is composed of the epidermis (outermost layer of cells), and the cuticle (non-mineral,
tough, outer coverings of an organism [like nails for humans]).
The cortex is the tissue region just interior to the epidermis. This region may contain cells that are
specialized for storage of starch, cells that are specialized to add additional support, etc.
The pith is the central part of the stem, composed of loosely arranged storage cells.
Table 4-2. Plant Tissue Cell Types
Tissues or cell type Characteristics of the cell Function
Dermal: Epidermis Variable shape, some contain a waxy guard cells open and close stomata to
substance called cutin; living trichomes retard water loss
Vascular: Xylem: Elongate, tapering and lignified; primary Water conducting cells found in the
Tracheids and secondary wall with thickenings; xylem of nearly all vascular plants
dead at functional maturity
Vascular: Xylem: Elongate but shorter than tracheids, Water conducting cells found in the
Vessel elements primary and lignified secondary walls; xylem of most angiosperms, as well as
join at ends to form long continuous some gymnosperms and a few
vessels, dead at functional maturity seedless vascular plants
Vascular: Phloem: Elongate and tapering; primary cell wall Sugar conducting cells found in the
Sieve-tube only; several in a vertical series constitute phloem of angiosperms.
member a sieve tube; living at maturity but lack a
Vascular: Phloem: Variable shape; generally elongate; living Associated with sieve tube members
Companion cell at functional maturity. and aid in transfer of food
Vascular: Fibers May be present as a crescent shaped cap Protects and supports the vascular
of thick walled cells outside the phloem bundle.
Ground: Many sided, may have thin cell walls; Storage of food; participate in
Parenchyma living at maturity; metabolic processes – photosynthesis
near outside of stem, water balance
and wound healing.
Table 4-3. Leaf tissue cell types.
Tissue or cell type Characteristics of the cells Function
Dermal: Epidermis: Outer layer of cells on the upper Protection; prevents desiccation
Upper surface of the leaf
Dermal: Epidermis: Outer layer of cells on the lower
Lower surface of the leaf
Dermal: Epidermis: Two guard cells surround stoma Gas exchange
Stomata and Guard cells
Vascular: Xylem and Water, nutrients and conduction of food
Phloem material respectively
Ground tissue: Palisade Dense layer of elongated cells Primary site of photosynthesis
mesophyll directly under upper epidermis
Ground tissue: Spongy Cells below the palisade layer, Photosynthesis and gas exchange
mesophyll separated by large air spaces The following is a cross section of a sunflower stem: Plantae Magnoliophyta (Domain, Kingdom/Phylum):
1. Calculation of the sample mean
2. Calculation of the sample variance
3. Calculation of the t-statistic and the two-sample t-test
4. Comparing t-statistic to critical value
LAB 5: PLANTS PART II: REPRODUCTION IN LAND PLANTS
Alterations of generations: Homospory is when only one kind of spore develops in the sporangia (structures on the sporophyte in
which spores develop)
Heterospory is when two types of spores develop in two different types of sporangia.
Table 5-1. Summary of information gathered in ‘gametophytes and sporophytes’ exercise.
Plant Group What What is Where does How are the Where does What are the
environ the meiosis and spore spores fertilization take modifications
ment(s) domina production occur? dispersed? place? for
do nt reproductive
these generati success?
Bryophyta Moist, Male/Fe Sporangia Wind Archegonium of the Rely on water
(mosses) Cold, male female gametophyte for sperm to
Shady gameto swim
Pterophyta Moist, Mature Sporangia Wind In the archegonium Rely on water
(ferns) Shady Sporoph of the male for sperm to
yte gametophyte swim
Coniferophyta Cold, Mature Microsporangium Wind In the female One tree has
(conifers) Grassy, Sporoph and megasporocyte gametophyte where both Micro and
Dry yte of the the egg nucleus is Megasporangiu
Anthophyta Diverse Mature Microsporangium Direct contact In the embryo sac Direct contact
(flowering habitats Sporoph and megasporocyte between (female increases
plants) yte of the anther and gametophyte) within success
megasporangium stigma the pollen tube
Diagram: Fern - hermaphrodite gametophyte and male gametophyte with emerging sperm Diagram: Fern Alternations of Generations
Diagram: Structures of a flower LAB 7: KINGDOM FUNGI
Sexual reproduction in fungi typically involves three distinct phases. The first phase is the fusion of
cytoplasm (known as plasmogamy) from two haploid hyphae of opposite mating types. This brings
haploid nuclei from each parent together into one cell. These nuclei pair up but do not fuse, forming a
dikaryon. Eventuall in the second phase of reproduction, the two nuclei fuse, uniting into a diploid
zygote nucleus. The fusion of the two nuclei is termed karyogamy. The diploid nucleus or zygote
undergoes meiosis to produce four haploid nuclei, which restores the haploid condition (the third
Diagram: Penicillium sp.
Ascomycete mycelia can produce
asexual spores called conidia borne on
the tips of modified hyphae known as
A yeast is simply a unicellular fungus that reproduces asexually by budding. A bud is just a small
outgrowth of the parent cell, which grows and eventually forms a new cell. Mycorrhizae are mutualistic symbiotic associations between fungi and roots of vascular plants. Although
some mychorrhizal fungi appear to be more beneficial than others it is believed that without these
associations most plants would not be able to survive in the competitive communities found in natural
Lichens are a mutualistic symbiotic association between a fungal partner and a population of algae or
cyanobacteria cells, developing into a unique morphological form quite distinct from either partner. The
three most common growth forms are:
a) Crustose – thallus forms a thin, flat crust that adheres by the margins to the substrate
b) Foliose – thallus is flat with leaf-like lobes, attached to the substrate with rhizines, or circ