pharmaceutical botany 1 laboratory answers
DESCRIPTION
1st SemesterParts of a MicroscopeBasic Parts of a Plant - college LevelPharmacyTRANSCRIPT
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OUTLINE!
(1) Microscopy A. Dissecting Microscope
B. Compound Microscope
(2) Preliminary Microscopic Work (3) Magnification and Reduction (4) Two Types of Seed Plant (5) Structure of Plant Cells (6) Cell Types and Tissues (7) Mitotic Cell Division (8) Plant Physiology
A. Osmosis
B. Plasmolysis
C. Cell Turgidity
(9) Kinds of Root System (10) Structure of Root Tip (11) Internal Structure of a Monocot Root (12) Internal Structure of a Dicot Root (13) Specialized Roots
Dissecting microscope
live specimens 3D too large or thick Specimens can be physically manipulated under
magnification, since they do not have to be
mounted onto a slide
low magnification, 10x to 80x magnification, the range depending on the make and model
PARTS OF A DISSECTING MICROSCOPE
1. Stereo Head - moveable top portion with two adjustable eyepieces, similar to binoculars.
2. Ocular Lenses 2 eyepieces, viewer looks through. each set at 10x magnification, though it
is possible to upgrade to higher power
magnification levels.
3. Diopter - Since no two eyes are exactly alike, slight adjustments can be made to the ocular lens
to compensate for the differences, using the
rotating diopter ring found on one or both of the
ocular lenses, allowing both eyes to focus on a
single image clearly.
4. Objective Lens - extends down from the head of the microscope, toward the stage.
magnification is determined by the eyepiece and
objective lenses collectively. Often, stereo
microscopes have two separate objectives, each
one connecting to one of the eyepieces.
5. Rotating Objective Turret - magnification of the objective, zoom control knob
6. Focus Knob - The head of the microscope can be moved up and down with the focus knob,
rack and pinion focusing.
7. Stage Plate - viewing. on base of the microscope, directly under the objective lens.
metal stage clips hold a glass slide in place. The
background color of the stage can be alternated
for optimal contrast with the specimen, usually,
with either white or black stage inserts.
8. Lighting - Many microscopes have both top and bottom lighting. Top lighting shines down on the
stage to light up solid specimens with direct
illumination, and bottom lighting is transmitted
up through the stage to highlight translucent
objects.
9. Light Switch - Usually the light switch or switches can be found on the top or back of the
microscope base. A light source should be
turned on before making any adjustments to the
lenses or observing specimen. Often it is
equipped with a dimmer, which allows the user
to set the desired level of illumination.
PLANT STRUCTURE
The "Typical" Plant Body
1. The Root System
Underground (usually) Anchor the plant in the soil Absorb water and nutrients Conduct water and nutrients Food Storage
2. The Shoot System
Above ground (usually) Elevates the plant above the soil photosynthesis reproduction & dispersal food and water conduction
Note: the shoot system includes the leaves and
the reproductive organs
Two Types of Seed Plants
Monocots Dicots
Roots Fibrous Taproot
Growth Primary only Primary and
Secondary
Examples: Grass, Palm,
Orchid
Oaks, Roses,
Sunflowers
Plant Growth Plant growth is a phenomenon different from
animal growth.
1. Animals pattern determinate growth. After fertilization, the zygote cells are rapidly
dividing, undifferentiated cells
after a certain critical stage, the cells differentiate and form tissues.
From this point onward, their developmental fate is sealed
There are exceptions to this (i.e. stem cells in bone marrow)
Most animals have a pre-programmed body plan (i.e. barring mutation or accident, a heart with
four chambers, etc..)
quit growing after a certain age
2. Plants- indeterminate growth The plant retains areas where rapidly dividing,
undifferentiated cells remain all through the life
of the plant
These areas are called meristems
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Meristematic tissue continues to rapidly divide producing undifferentiated cells
which may eventually differentiate to
form the tissue and cell types
Plants do not have a pre-programmed body plan There are constants like leaf shape and
branching patters (opposite, alternate,
etc.) but you can never predict where a
new branch will come about on a tree...
Plants continue to grow throughout their life
CELL TYPES IN THE PLANT BODY
Meristems
The pattern of plant growth depends upon the location of meristems
I. Meristematic Tissues (Meristems) Tissues where cells are constantly dividing, and
produce new cells.
The new cells usually have tiny vacuoles with large nucleus.
The pattern of plant growth depends upon the location of meristems
3 types of Meristems:
1. Apical Meristems - are located at or near the tips of
roots and shoots. The growth increase in length. (grow
up for shoots and down for roots) Located at the tips of
roots and shoots supply cells for the plant to increase in
length .
growth in this direction is primary growth primary growth in monocot &dicot, the vertical
growth of roots and shoots
Example: Growth of tree in height
2. Lateral Meristems - account for secondary growth
in plants. (cambium)
located near the periphery of the plant, usually in a cylinder
supply cells for the plant to increase in girth growth known as as secondary growth found in all woody& some herbaceous plants lateral meristems and secondary growth found only
in dicots
- Secondary growth is the horizontal growth
Example: Growth of tree in girth
3. Intercalary Meristems a region of dividing cells at each internode that allows the stem to grow rapidly. It is
responsible for the regrowth of cut grass
II. Permanent Tissues (Nonmeristematic Tissues) Tissues that do not actively produce new cells. It is made of cells that are produced by the
meristems and are formed to various shapes and
sizes depending on their intended function in the
plant.
2 Types of Permanent Tissues: A. Simple Tissues - one type of cell
A.1 Epidermis
forms a protective covering over herbaceous roots and stems, leaves, and other plant
structures.
functions - prevent entry of pathogenic organisms into the plant ; to prevent excessive
water loss.
Very important in regulating passage of water and gases into and out of the plant.
Cells in the Epidermis:
Trichome a hairlike extension of a dermal cell
Stoma (plural, stomata) a pore in a leaf regulated by two guard
cells; controls the movement of water
vapor, CO2 and O2.
Guard cell one of the two epidermal cells on either
side of a leaf pore
Ground cell at maturity lack chloroplast, and can
produce Cutin, a fatty substance, which
forms a waxy protective layer called the
cuticle. It prevents water loss.
A.2 Parenchyma
Least specialized plant cells Thin and somewhat flexible cell walls Living at maturity Carry on most of the plant's metabolic functions
food and water storage, photosynthesis, gas exchange, maintenance of turgor
pressure, and wound repair.
Generally have a large central vacuole Most parenchyma cells have the ability to
differentiate into other cell types under special
conditions
During repair and replacement of organs after injury
A.3 Sclerenchyma
Thick secondary cell walls Dead at functional maturity More expensive for plants to produce because of
the added cellulose needed to provide the
secondary cell walls
Less common in smaller plants than parenchyma and collenchymas.
Cannot increase in length - occur in parts of the plant which have quit growing in length
Two types - fibers and schlerids Fibers - long, slender cells with a more
or less regular secondary cell wall
reinforced with lignin w/c make them
flexible and strong
Example - hemp fibers for making rope
(stems, trunk of a tree)
Schlerids - shorter cells with an irregular shape (cubical and spherical in shape)
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Example - stone cells in pears and hard
nut and seed shells (rough texture/gritty
sand like texture)
*Lignin substance which act as a binder for the cellulose fibers in wood and certain plants and adds
strength and stiffness to the cell walls
A.4 Collenchyma
Thicker primary cells walls (usually with uneven thickness)
These cells have a living protoplasm, like parenchyma cells, and may also stay alive for a
long period of time.
Distinguishing difference from parenchyma cells is the increased thickness of their walls.
Found just beneath the epidermis Living at maturity Role in support of herbaceous plants
Example - the "strings" of celery
B. Complex Tissues - several types of cell / mixed types
of cells; primary functions include the transport of water,
ions and soluble food substances throughout the plant.
XYLEM
Thick secondary cell walls, often deposited unevenly in a coil-like pattern so that they may
stretch
Dead at functionally maturity. Involved in conduct of water and ions in the
plant
Two types - tracheids and vessels Tracheids - long, slender cells connected
to each other by pits. Found in all
vascular plants which are long cells with
tapered ends which are considered water
conducting cells of ferns, conifers and
other non-flowering vascular plants
Vessels - shorter, larger diameter cells with completely perforated cell wall
ends. Found only in Angiosperms
which are water-conducting cells of
most flowering plants and can transport
water and minerals more rapidly than
tracheids. Vessel elements are wider,
shorter and less tapered than tracheids.
PHLOEM
The food-conducting tissue Involved in transport of sucrose, other
organic compounds, and some ions
contains companion cells which has a nucleus and provides proteins to a sieve-tube member
adjacent to it.
Living at functional maturity Protoplast may lack organelles and
nucleus, though
Endwalls connect to each other via sieve-plates Two types of cells in the phloem - sieve-tube
members and companion cells
Sieve-tube members - actual conduit for sucrose transport
Companion cells - has a nucleus that may also control the sieve-tube element
and may aid in sucrose loading
TISSUE ORGANIZATION IN ANGIOSPERM
Dermal Tissue Generally a single layer of cells The "skin" of the plant Primarily parenchyma cells Main role is protection of the plant
Ground Tissue Makes up the bulk of the plant Predominately parenchyma, but collenchyma
and schlerenchyma cells are found
Diverse functions including photosynthesis, storage, and support
Vascular Tissue Involved in the transport of water, ions,
minerals, and food
Also has a secondary role in support Composed of xylem, phloem, parenchyma,
schlerenchyma
MITOTIC CELL DIVISION
Mitosis is nuclear division plus cytokinesis, and
produces two identical daughter cells during prophase,
metaphase, anaphase, and telophase.
Interphase is often included in discussions of mitosis,
but interphase is technically not part of mitosis, but
rather encompasses stages G1, S, and G2 of the cell
cycle.
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1. INTERPHASE
The cell is engaged in metabolic activity and performing its prepare for mitosis (the next four
phases that lead up to and include nuclear
division). Chromosomes are not clearly
discerned in the nucleus, although a dark spot
called the nucleolus may be visible. The cell
may contain a pair of centrioles (or microtubule
organizing centers in plants) both of which are
organizational sites for microtubules.
2. PROPHASE Chromatin in the nucleus begins to condense and
becomes visible in the light microscope as
chromosomes. The nucleolus disappears.
Centrioles begin moving to opposite ends of the
cell and fibers extend from the centromeres.
Some fibers cross the cell to form the mitotic
spindle.
3. METAPHASE The nuclear membrane dissolves, marking the
beginning of prometaphase. Proteins attach to
the centromeres creating the kinetochores.
Microtubules attach at the kinetochores and the
chromosomes begin moving. Spindle fibers
align the chromosomes along the middle of the
cell nucleus.
This line is referred to as the metaphase plate. This organization helps to ensure that in the next
phase, when the chromosomes are separated,
each new nucleus will receive one copy of each
chromosome.
4. ANAPHASE The paired chromosomes separate at the
kinetochores and move to opposite sides of the
cell. Motion results from a combination of
kinetochore movement along the spindle
microtubules and through the physical
interaction of polar microtubules.
5. TELOPHASE Chromatids arrive at opposite poles of cell, and
new membranes form around the daughter
nuclei. The chromosomes disperse and are no
longer visible under the light microscope. The
spindle fibers disperse, and cytokinesis or the
partitioning of the cell may also begin during
this stage.
6. CYTOKINESIS Cytokinesis (kytos = hollow vessel = cell, and
kinesis = movement)
the two daughter cells become independent. During cytokinesis (example in Bellevalia) that
follows up the actual mitosis, the cytoplasm of
the daughter cells is divided by a cell membrane
(and in plants also a cell wall) in two single
compartments.
In animal cells the separation of the new cells involves a cleavage furrow that pinches the cell
membrane.
In plants, this process is characterized by the formation and growth of a cell plate (example
in Solanum sp.) that expands from the space
between the two daughter nuclei towards the cell
periphery. Sometimes remants of the spindle
(phragmoplast) are involved in the attachment of
this new wall.
TERMS IN MITOSIS
kinetochore - is the protein structure on chromatids where the spindle fibers attach during cell division to
pull sister chromatids apart.
chromatin - combination of DNA and proteins that make up the contents of the nucleus of a cell.
centromere - part of a chromosome link sister chromatids
chromatid - is one copy of a duplicated chromosome, which generally is joined to the other
copy by a centromere for the process of nuclear
division
Biological importance of mitosis
Growth Asexual reproduction Cell replacement
PLANT PHYSIOLOGY
A. Osmosis
The net movement of water across a partially permeable membrane from a region of high
solvent potential to an area of low solvent
potential, up a solute concentration gradient.
It is a physical process in which a solvent moves without input energy across a semi permeable
membrane separating two solutions of different
concentrations.
Osmosis releases energy and can be made to work as when growing tree root splits a stone.
B. Plasmolysis
A solution that is separated from another solution by a semi-permeable membrane can
have three osmotic states:
In an isotonic solution is the pressure at both sides of the membrane the same.
A hypotonic solution has a lesser number of solute particles than the solution to which it is
compared, while
a hypertonic solution has a higher number of solute particles. At equilibrium is a solution
always isotonic
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C. Cell Turgidity
turgor pressure - When a plant cell stores ions, sugars
and other solutes in its vacuole, this causes an influx of
water. The influx of water results in a large turgor
pressure exerted on the plant cell wall. This makes plant
cells to become turgid, thus, helping the plants to stand
upright, and do not wilt.
KINDS OF ROOT SYSTEMS
1. TAP ROOT SYSTEM The taproot is usually relatively large in
diameter and extends more deeply than the
plant's other roots, and often has additional
lateral (secondary) roots
The easiest designation of taproot is the carrot (Daucus carota), where the lateral (secondary)
roots are very thin, so it has a single, thick
central root.
Common in dicots develops from an embryonic root called the
radicle
perennial and undergo secondary growth examples of plants having a tap root system:
carrots, beets, radishes and sunflowers
2. FIBROUS/ADVENTITOUS Fibrous roots are typically thought of as slender,
mass of similarly sized roots and often with few
or no lateral roots.
Fibrous roots do not arise on pre existing roots and they are not radicles thus they are called
adventitious roots.
Common in monocots do not undergo secondary growth examples of plants having a fibrous root system
are wheat, rice, corn, and sweet potatoes;
important in stoloniferous and rhizomatous
plants
DIFFERENCE OF A YOUNG PLANT FROM A
MATURE PLANT A young dicot plant has a few leaves and a small root
system, the narrow trunk with a few vascular bundles
can conduct water and nutrients between them. A mature
dicot has more leaves and a larger root system, the stem
has more wood and bark, which increases the capacity to
conduct water and sugar. Monocots do not undergo
secondary growth so a mature monocot does not have a
stem that is wider than the young monocot.
Consequently, the mature monocot has no more leaves
or roots than the young monocot.
STRUCTURE OF ROOT TIP
Primary Growth in the Root
a. Root Cap
Thimble-like covering which protects the delicate apical meristem
Produced from cells derived from the root apical meristem
Secretes polysaccharide slime lubricates soil Constantly sloughed off and replaced
b. Apical Meristem
Region of rapid cell division of undifferentiated cells
Most cell division is directed away from the root cap
c. Quiescent Center
Populations of cells in apical meristem which reproduce much more slowly than
other meristematic cells
Resistant to radiation and chemical damage Possibly a reserve which can be called into
action if the apical meristem becomes
damaged
d. The Zone of Cell Division - Primary Meristems
Three areas just above the apical meristem that continue to divide for some time
Protoderm - outermost primary meristem - produces cells which will become dermal
tissue
Ground meristem - central primary meristem - produces cells which will
become ground tissue
Procambium - innermost primary meristem - produces cells which will become vascular
tissue
e. The Zone of Elongation
Cells elongate up to ten times their original length
This growth pushes the root further downward into the soil
f. The Zone of Maturation
Region of the root where completely functional cells are found
INTERNAL STRUCTURE OF A MONOCOT
ROOT
Epidermis Dermal tissue Protection of the root
Cortex Ground tissue Storage of photosynthetic products Active in the uptake of water and minerals
Endodermis cylinder once cell thick that forms a
boundary between the cortex and the stele
Even more distinct than dicot counterpart Contains the casparian strip the innermost tissue of the cortex in many
roots and stems.
Stele The cylindrical central vascular portion of the
axis of a plant that is made up of the pericycle,
conducting tissues and the pith.
Pericycle A thin layer of parenchyma or sclerenchyma
cells that surrounds the stele in most vascular
plants.
Vascular Tissue Xylem and Phloem Forms a ring near center of plant
Pith Center most region of root
INTERNAL STRUCTURE OF A DICOT ROOT
Epidermis Dermal tissue Protection of the root
Cortex Ground tissue
Storage of photosynthetic products
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Active in the uptake of water and minerals
Endodermis Cylinder once cell thick that forms a boundary
between the cortex and the stele
Contains the casparian strip, which will be explained later when we discuss water uptake
the innermost tissue of the cortex in many roots and stems.
Pericycle found just inside of the endodermis
may become meristematic
responsible for the formation of lateral roots
Vascular Tissue Xylem and Phloem
Forms an X-shaped pattern in very center of root
SPECIALIZED ROOTS
1. NODAL ROOTS 2. AERIAL ROOTS
Orchids are epiphytes. Epiphyte is a plant that derives its moisture and nutrients from the air
and rain and grows usually on another plant.
Roots spread along the surface of the bark and often dangle freely in the air.
The root epidermis of orchids is called the velamen. The velamen acts as a waterproof
barrier, not permitting water to leave the sides of
the root.
3. PROP ROOTS Banyan tree (genus Ficus) produce adventitious
roots which provide increased support and
absorptive capacity.
Palm tree produce adventitious root near the base of the stem and provides extra absorptive capacity and
extra stability.
Screwpine is able to produce extremely long adventitious prop roots that not only stabilize the
large, heavy trunk but laos bring water and minerals
into the stem.
4. BUTTRESS 5. CONTRACTILE
a. The root is firmly fixed to the soil and the stem is pulled downward so that the base of
the shoot is either kept at soil level or, in the
case of bulbs, actually buried deeper.
b. Root contraction is the means by which the shoot becomes anchored in the soil.
c. Common in bulbous plants
6. PNEUMATOPHORES 7. CAUDEX/LIGNOTUBERS 8. HAUSTERIAL
a. A number of angiosperms are parasites because their substrate is the body of
another plant.
b. These roots adhere firmly to their host either by secreting an adhesive or by growing
around a small branch or root.
c. Host-Parasite relationship - Parasitism, they live in another plants body in order to
survive; Mostly attack the xylem but the
parasite carries out its own photosynthesis.
9. STRANGLING ROOTS 10. ROOT TUBERS