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Greetings
Good Afternoon class

Prayer
Heavenly Father up above
Please give us wisdom, strength and love
Keep us always in the right track
And open Your door every time we knock
This wisdom is for our study sake
The strength is for the trials We will take
Your love is to everyone to share
AMEN.

THE CELLS
(Plant Cell & Animal Cell)
Structure and Functions

Terminologies
• Organelles
- internal compartments
- discrete structures of specific
functions
- provide a “division of labor” that
makes a plant more efficient
- examples: nucleus, vacuole

Terminologies….
• Cytoplasm
- the materials inside the cell
membrane but outside the nucleus
• Cytosol
- the semifluid matrix that surrounds
and bathes the organelles outside
the nucleus

Terminologies…
• Protoplast
- the entire plant cell from the cell
membrane inward
• Cell Wall
- assembles from cellulose and other
polymers produced by the plant cell
(cell product)
- considered to be extracellular; outside
the protoplast

Plant Cell Structures and Functions
• The Cell Membrane
- a highly remarkably changeable and
multipurpose membrane
- supports and defines the plant cell
protoplast
- regulates the flux of molecules into and
out of the cell interior
- selectively permeable

- receives chemical and environmental
signals from outside the cell
which can change cellular
activities
- accepts raw materials from the
membranes inside the cell and
directs the assembly of these
materials into cell walls

• The Nucleus
- surrounded by a double membrane called
the nuclear envelope which has pores to
allow passage
of materials in and out of the nucleus
- contains most of the cell’s DNA
(chloroplasts and mitochondria contain
some DNA), which occurs with proteins
in threadlike structures called
chromosomes

Chromosomes – contain genes, which are
sequences of DNA; that directs most
of the activities of the cells via the
synthesis of RNA.

• Endoplasmic reticulum (smooth and rough)
- rough ER is a major region of protein
synthesis in a cell
- smooth ER helps make phospholipids and
assemble new membranes
- extends from the nucleus through
cytoplasm in any one cell and from one
cell to the next through protoplasmic
connections (plasmodesmata)

• Golgi Bodies (Dictyosomes)
- concerned with cellular
secretions
- their activity is associated with
new cell walls when they are laid
down as a partition between two
newly divided cells

• Vacuoles
- help regulate the water content of the plant
cells and contain numerous enzymes and
pigments
- its membrane is called tonoplast
- as plant cell grows, most of their enlargement
results from the absorption of water by vacuoles
- pigments in vacuoles such as red and blue
anthocyanins impart bright colors to flowers, fruits
and other plant parts
- some plant vacuoles harbor toxic chemicals that
will deter insects and other animals from eating
plants that contain them

• Ribosomes
- the workbench for protein synthesis
- very small and consist of
approximately equal amounts of
protein and RNA
- unlike nucleus and other organelles
ribosomes are not surrounded by
membranes thus some biologists do not
considered them as organelles

• Mitochnodria
- organelles of energy conversion needed for
cellular metabolism
- considered as the powerhouse of the cell
because it converts energy stored in the sugars
produced during photosynthesis to ATP that
powers much of the work of the cell
- contains a small amount of DNA and RNA and
ribosomes that synthsize some of the enzymes
specific to each organelle
- grow and divide on their own

• Chloroplasts
- an organelle of energy conversion
- sites of photosynthesis in plant cells
- the chlorophylls in them trap the light to
fix (capture and integrate) carbon
dioxide into sugars
- use light energy to make amino acids and
fatty acids from carbon fixed via
photosynthesis

• Lysosomes
- contains various enzymes
- act as cellular scavengers, digesting
cytoplasmic particles such as
mitochondria which have passed
usefulness
- they may also bring about dissolution
of entire cells

• The Cytoskeleton
- very tiny structures which can only be seen
under an electronic microscope
- forms a network and support system within the
cell
- performs the following:
a. help maintain organelle position and
organization within the cell; direct cell
expansion and control the movement of
chromosomes during nuclear division; and
b. transports large molecules within the cell
(for some filaments)

Activity
Given the following words in the box. Put
each word in the Venn Diagram that
correspond to the correct answer.
Cell Wall Endoplasmic Reticulum Golgi Complex
Centrioles Chloroplast Cell
Membrane Lysosome Cytoplasm
Vacoule
Ribosomes Mitochondria
Nucleus

Evaluation
A. Choose the letter of the best answer. Write
the chosen letter on a ½ crosswise sheet of
paper.
1. Where is the site of protein synthesis?
a. Nucleus c. ribosome
b. lysosome d. mitochondria
2. Plant cells often have a box-like shape because
of the
a. nucleus c. cytoplasm
b. cell wall d. cell membrane

3. Which of the following is found in the nucleus?
a. vacuoles c. mitochondria
b. chloroplasts d. chromosomes
4. Digestive enzymes or hydrolytic enzymes are
terms associated with
a. ribosomes c. golgi apparatus
b. lysosomes d. smooth ER
5. What site regulates what goes in and out of
the cell?
a. cell wall c. cell membrane
b. Vacuole d. nuclear membrane

B. Draw and label the different part of
the cell either plant cell or animal cell.

Assignment
Thought Questions:
1.What is the selective advantage of the
small size of cells compared to the large
size of organisms?
2. What is the evolutionary advantage of
secondary cell walls?

Prepared by
Joy Clearth A. Padro
BSEd 3.02
Biological Sciences

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Chapter 3.cell structures and fuctions

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