Objectives describe the specialized structures and functions of
cells in the leaf system explain the transport system in plants
relate a multi-cellular level of organization with cell, tissue,
and system specialization
Slide 3
Multicellular vs Unicellular What are the advantages to having
a large structure with lots of cells? Division of Labour When a
cell is specialized (performs a particular function), it is more
effective and efficient. A single-celled organism must multi-task
(do many jobs).
Slide 4
Multicellular vs Unicellular Size The surface area to volume
ratio and related rate of diffusion restricts growth in unicellular
organisms. Efficient transport systems within multicellular
organisms allow for growth.
Slide 5
Multicellular vs Unicellular Interdependence of Cells A
single-celled organism is dependent on that one cell. If a
multicellular organism loses a cell, the entire organism will not
die. However, a cell not functioning properly (ex. cancerous) can
cause problems for the rest of the organism.
Slide 6
Plant Structure Plants are multicellular: made of many parts,
each with its own function organized in increasing complex levels
of organization Tissues= group of cells performing same function
together Organs= tissues contributing to same function System=
group of interconnected organs (two in plants) Shoot system
everything above ground Root system everything below ground and
aerial roots
Slide 7
Slide 8
What about animals? What are some examples of tissues, organs
and systems in humans? Ex. Heart/cardiac tissue heart circulatory
system
Slide 9
Do now Find the definition/function associated with each of the
following terms (workbook - chart) Meristem Dermal tissue/epidermis
Cuticle Ground tissue Vascular tissue Xylem tissue Phloem tissue
Sieve tube cells Companion cells
Slide 10
How did you do? Meristem- growth areas Dermal tissue/epidermis-
outer layer of cells; responsible for exchange of matter and gases
and protection Cuticle- waxy substance; resists attack and prevents
water loss Ground tissue- majority of plant; strength and support
(stem); food and water storage (roots); site of photosynthesis
(leaves)
Slide 11
How did you do? Vascular tissue- transport of materials; xylem
and phloem Xylem- moves water and minerals from roots to leaves;
thick, non-living, perforated cells Phloem- transports sucrose and
other sugars from leaves to other parts; made of sieve cells Sieve
tube cells- form continuous ducts; perforated Companion cells-
direct activity of sieve tube cells
Slide 12
Plant Growth Cells divide to grow and repair damage. This cell
division is called mitosis. In plants, increase in size results
from the cell division in growth areas called meristems Rapidly
dividing cells - Cell walls thin, nuclei are large, vacuoles, small
or absent
Slide 13
Meristems Onion root tip note different stages of mitosis (cell
division)
Slide 14
Specialization of Cells Once cells are no longer in the
meristem, they will specialize Produce products only for their
function The root and shoot systems are made up of 3 types of
tissues: Dermal Tissue (epidermis) Ground Tissue Vascular
Tissue
Slide 15
Types of Tissue Dermal Tissue Outer layer of cells that covers
all herbaceous (non-woody) plants. Responsible for exchange of
matter and gases into and out of the plant. Also protects the plant
from disease. This is done by the cuticle (waxy substance), which
resists attacks from micro-organisms and helps reduce water
loss.
Slide 16
Types of Tissue Ground Tissue Found underneath epidermis, it
makes up majority of plant. Provides strength and support to the
plant (stem). Involved in food and water storage (roots). Location
of photosynthesis (leaves).
Slide 17
Types of Tissue Vascular Tissue Responsible for transport of
material, which occurs in xylem tissue and phloem tissue
Slide 18
Vascular Tissue - xylem Cells in xylem tissue allow transport
of water Die when differentiate leaving empty tubes Long fibres in
celery are vascular tissue (both xylem and phloem)
Slide 19
Vascular Tissue - phloem Phloem Tissue Formed from long sieve
tube cells (no nuclei), which are connected with companion cells
(nucleated) that direct activity. Transports carbohydrates and
water from the leaves to other parts of the plant.
Vascular tissue From:
http://www.youtube.com/watch?v=4V0VcNCRKTo&feature=related at
4:14http://www.youtube.com/watch?v=4V0VcNCRKTo&feature=related
Slide 23
Vascular Bundles
Slide 24
Sieve tubes
Slide 25
More specialization: Roots Cells in root system will produce
tiny hair-like projections called root hairs Why is this beneficial
for the plant? Increases the surface area for absorption of
water
Slide 26
Root hairs
Slide 27
Slide 28
More Dermal cells in shoot system produce a cuticle Why is this
beneficial? Prevents water loss
Slide 29
And last Lower epidermis in leaves have guard cells Form tiny
pores called stomata for gas exchange Only cells with chloroplasts
Why is this important? Photosynthesis!
Leaf Cross section Can you indentify some of the
structures?
Slide 32
Slide 33
How does water move up the plant? Gravity should pull water
down how does it move up from the roots to the leaves? How do all
these specializations allow for this? Shall be investigating this
in this section. http://www.youtube.com/watch?v=U4rzLhz4HHk&fea
ture=relatedhttp://www.youtube.com/watch?v=U4rzLhz4HHk&fea
ture=related
