The Plant Cell
Session 2: The Plant Cell
Total Session Time: 120 minutes
Prerequisites
Learning Tasks
By the end of this session students are expected to be able to:
Resources Needed:
SESSION OVERVIEW
|Step |Time |Activity/ |Content |
| | |Method | |
|1 |05 minutes |Presentation |Introduction, Learning Tasks |
|2 |25 minutes |Buzzing/ |Introduction to Plant Cells |
| | |Presentation | |
|3 |60 minutes |Brainstorming/|Functions of Internal structures |
| | |Presentation |of a plant cell |
|4 |20 minutes |Presentation |The plant cell wall |
|5 |05 minutes |Presentation |Key Points |
|6 |05 minutes |Presentation |Evaluation |
SESSION CONTENTS
STEP 1: Presentation of Session Title and Learning Tasks (5 minutes)
READ or ASK students to read the learning objectives and clarify
ASK students if they have any questions before continuing.
STEP 2: Introduction to Plant Cells (25 minutes)
|Activity: Buzzing (5 minutes) |
| |
|Ask students to brainstorm on the following question: |
| |
|What is a plant cell? |
| |
|ALLOW few students to respond? |
| |
|WRITE their responses on the flip chart/ board |
| |
|CLARIFY and SUMMARISE by using the content below |
[pic]
o The Nucleus
o Nucleolus
o Centrosome
o Ribosomes
o Rough Endoplasmic Reticulum
o Smooth Endoplasmic Reticulum
o Golgi Complex (Golgi apparatus or Golgi body)
o Mitochondria
o Plastids
o Proplastids
o Etioplasts
o Chloroplasts
o Chromoplasts
o Leucoplasts
o Nucleoids
o Vacuoles
STEP 3: Internal Structures of a Plant Cell (60 minutes)
|Activity: Brainstorming (5 minutes) |
|Ask students to brainstorm on the following question: |
| |
|What are the functions of these organelles? |
| |
|ALLOW few students to respond? |
| |
|WRITE their responses on the flip chart/ board |
| |
|CLARIFY and SUMMARISE by using the content below |
o Spherical body containing a nucleolus
o Surrounded by the nuclear membrane
o Contains DNA (genetic material in chromosomes)
o An organelle within the nucleus where ribosomal RNA is produced
o It controls many of the functions of the cell (by controlling protein
synthesis)
o It is a small body located near the nucleus that forms and
organizes microtubules
o Microtubules are important in cell division (mitosis)
o Are small organelles composed of RNA-rich cytoplasmic granules that are
sites of protein synthesis
o Endoplasmic reticulum is a system of interconnected, membranous,
infolded and convoluted sacks located in cytoplasm (the ER is
continuous with the outer nuclear membrane)
o It transports materials through the cell and produces proteins
o Smooth Endoplasmic Reticulum are smooth (i.e. no ribosomes on surface)
membrane proteins
o Is a flattened, layered, sac-like organelle that looks like a stack of
pancakes, located near the nucleus
o It packages and transports materials (proteins and carbohydrates) to
different locations inside/outside cell
o Spherical to rod-shaped organelles with a double membrane that
generates energy for the cell
o Are structures responsible for photosynthesis, storage of products like
starch and for the synthesis of many classes of molecules such as fatty
acids etc. needed as cellular building blocks and/or for the function
of the plant. There several types; proplastids, etioplasts,
chloroplasts, chromoplasts, leucoplasts and leucoplasts specialized for
different functions in the plant body.
o Are regions bound by membrane and filled with cell sap and surrounded
by the tonoplast
o In mature living cells may compose 90 – 95% of cell volume
o Storage site for variety of (ergastic) substances such as:
STEP 4: The Plant Cell Wall (20 minutes)
(lamellae)
o Each cell secretes its own wall
o Junction between the walls is the Middle lamella
o Cell wall is penetrated by plasmodesmata connecting neighbouring cells
o Cell walls are primarily composed of sugar polymers i.e.
polysaccharides
o The architecture, mechanics, and function of plants depend crucially on
structure of cell wall
o Regulates cell volume by limiting protoplast size preventing cell
rupture
o Determines cell shape
o Involved in cell-cell adhesion; provide support to cells and whole
plant
o Forms specialized structures for:
o Primary cell wall:
pectin, cellulose molecules: Unbranched glucose chains and
hemicellulose – a highly branched molecule of sugars and sugar
derivatives
galacturonic acid
o Primary wall/Middle Lamellae
o Secondary Cell Wall
completely elongated
cell stops growing
cuticle waxes, suberin and minerals
STEP 5: Key Points (5 minutes)
in synthesis and storage of drugs
the cell
STEP 6: Evaluation (5 minutes)
References
Trease, G. E., Evans, W. C., & Evans, D. (2009). Trease and Evans
pharmacognosy. London: Saunders.
Joanne Barnes et al (2002), Herbal medicines 3rd Edition: Pharmaceutical
Press
Wallis, T. E. (2005). Textbook of pharmacognosy. New Delhi: CBS.
Robbers, J. E., Speedie, M. K., Tyler, V. E., & Tyler, V. E. (1996).
Pharmacognosy and pharmacobiotechnology. Baltimore: Williams &
Wilkins.
Heinrich, M., Kinghorn, A. D., Maizels, D., Gibbons, S., & Phillipson, J.
Churchill Livingstone/Elsevier.
Unataka kutumiwa notes hizi kupitia WhatsApp?Kwa notes zilizopangiliwa vizuri kwa kusoma offline au PDF, bonyeza kitufe hapa chini. Ujumbe wenye Level, Semester, Module na Topic utaandaliwa moja kwa moja.TUMIWA NOTES WHATSAPP
