SPECIALIZED SUBJECT-

STEM

GENERAL BIOLOGY 1
QUARTER 1, MODULE 1

Cell Structure and

Function

1
General Biology 1
Self-Learning Module
1st Semester – Module 1: Cell Structure and Function
First Edition, 2021

Republic Act 8293, section 176 states that: No copyright shall subsist in any work of the
Government of the Philippines. However, prior approval of the government agency or office
wherein the work is created shall be necessary for exploitation of such work for profit. Such
agency or office may, among other things, impose as a condition the payment of royalties.
Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks,
etc.) included in this module are owned by their respective copyright holders. Every effort
has been exerted to locate and seek permission to use these materials from their respective
copyright owners. The publisher and authors do not represent nor claim ownership over
them.

Published by the Division of Romblon

Superintendent: Maria Luisa D. Servando, Ph.D.,CESO VI
OIC-Asst. Superintendent: Mabel F. Musa, Ph.D., CESE

Development Team of the Module

Writer: Fritzie Jane F. Famorcan
Content/Language Evaluator: Melchor M. Famorcan, PhD.
Layout Editor: Marife M. Osorio

Cover Design: April C. Bagnate

Cover Illustrator: Albert Xavier M. Merano
Management Team

Division Management Team:

Maria Luisa D. Servando PhD, CESO VI
Mabel F. Musa PhD, CESE
Melchor M. Famorcan PhD
Apryl C. Bagnate – Project Coordinator
Ruben R. Dela Vega
Leopoldo M. Mago Jr.
Leona Lynn F. Famorcan

Printed in the Philippines by

Department of Education – Region IVB,Schools Division of Romblon
Office Adress :Brgy.Capaclan, Romblon, Romblon
Email Adress :deped.sdoromblon@deped.gov.ph

Lesson Structure and Functions of

2
 Animal Tissues and Cell
Modification

Good Day!

How are you? It is nice to be with you again. Even though I can’t see you still my
feeling is with you, because you are reading this module which I personally prepared
for you. So, what did you learn from the past lesson?

___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
_________________________________________________________________

Thank you for answering my question. Now; I prepared another topic for you which
will give you more information about cell. But before we continue with this lesson,
you have to ask first the guidance of the Holy Spirit to guide you and give you
knowledge and wisdom from above. Close your eyes and say a little prayer to our
Lord.

Welcome to the Structure and Functions of

Animal Tissues and Cell Modification
(These topics are good for two (2) weeks)

Learning Competencies

Be sure that at the end of the week you should be able to;
1. Distinguish prokaryotic and eukaryotic cells according to their distinguishing
features.
2. Classify different cell types ( of plant/ animal tissues) and specify the
function(s) of each
3. Describe some cell modifications that lead to adaptation to carry out
specialized functions (e.g., microvilli, root hair)

3
Prokaryotic Vs Eukaryotic cells

All cells may be classified into two basic cell types, depending on their internal
organization. Prokaryotic cells or prokaryotes lack a true nucleus, while eukaryotic
cells or eukaryotes possess a true nucleus. Prokaryotes contain nuclear material
(DNA) arranged in a single circular structure called nucleid, but they lack membrane-
bound organelles. Organisms belonging to the kingdom Eubacteria and kingdom
Archea. Such as bacteria, blue –green algea, archaeans, and spirochetes, are
examples of prokaryotes. In contrast, eukaryotes possess nuclear materials (DNA)
arranged into chromosomes and its organelles are surrounded by membranes. All
other organisms, except those mentioned above, are called eukaryotes.

Prokaryotes Vs Eukaryotes
Cell Structure Prokaryotes Eukaryotes
Larger
Size Smaller (1-10 mm) in (10- 100 mm in
diameter diameter)
Nuclear envelope Absent Present
Made up of peptidoglycan Made up of cellulose
Cell Wall when present when present
Membrane bound Absent Present
organelles
Double – stranded DNA
Nuclear material Single loop of circular DNA arranged into
chromosomes
Ribosomes Small Large
Cytoskeleton Absent Present
Mitochondria Absent Present
Not found in chloroplasts Found in chloroplasts
Chlorophyll when present
Reproduction Asexual Sexual and asexual

Types of cell (Animal and Plant Cells)

Although animal and plant cells are both eukaryotic cells and are basically composed
of the same structures, they exhibit unique characteristics.

ANIMAL CELL VERSUS PLANT CELL

Cell structure Animal structure Plant cell
cell wall Absent Present
Chloroplasts Absent Present
Vacuoles Usually numerous and Single and large (usually
small at the center of the cell)
Centrioles Present Absent
Cilia and flagella Present in some Absent in flowering plants
but present in ferns,

4
 cycads, and bryophytes

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv
%3DvqbJqW57TUQ&psig=AOvVaw1SwKRhc2AQUI6Sd4HIfhbm&ust=1629870916776000&source=images&cd=vfe&ved=0CAgQjRxqFwoTCJjx07z8yPICFQAAAAAdAAAAABAJ

CELLS are organized into TISSUES and TISSUES into ORGANS for specific
functions.

Plants are made up two support, metabolism, reproduction

structural systems i.e. The shoot enabling plant growth, and
system and the root system, whereby development. For example, plant cells
the shoot system is made up of are formed at the meristem which
structures that is above the ground multiple and grows to for plant tissues.
including leaves, stems, fruits, flowers
while the root system is made up of
roots, tubers and rhizobial structure
that lie below the ground and it’s the
origin of growth of plants. These
systems are structured differently,
defined by sets of specialized mature
cells that perform a wide range of
functions ranging from protection,

 Dermal tissue – this tissue lies on the surface of plants and it’s made up
of epidermal cells that protect the plants from losing water.
 Ground tissue – This makes up the root vascular and epidermal system
majorly made up of parenchyma, collenchyma and sclerenchyma

5
 cells responsible for plant photosynthesis, storage of water and food and the
plant support system.
 Vascular Tissue – this tissue is made up of xylem, phloem, parenchyma
and cambium cells, with its functions including transportation of water
(xylem), transportation of food (phloem), minerals,
hormones in the plants’ of the plant cells

Cell has Amazing Functions in Plants! Read

and you will know!
Plant cells multiply by cell division, a mechanism
known as Mitosis, which takes place within its
nucleus. This begins at the meristem that is found
at the tip of the root and/or the shoot of vascular
plants. Meristems at the tips are known as apical
and lateral meristems. Apical meristems are
responsible for producing the roots while the
lateral meristems produce secondary growth of
the stem wood and cork.

Besides cell division of the cells that leads to the

formation of tissues that eventually creates a
plant, there are other features of the plant cells
that are of importance to plant growth and
metabolisms.

1. Presence of a cell wall combined with a plasma

membrane. It’s made up of cellulose, hemicellulose, and pectin. The cell wall
gives the cell shape, cell protection and mediation of cellular interactions.

2. They have dynamic single-membranous central vacuoles that are filled with
water to maintain the turgor pressure of the cell, regulate the movement of
cellular molecules within the cytosol, storage of nitrogen and phosphorus and
mediate digestion of stored cellular proteins.

3. They have plasmodesmata, which is a continuous porous structure that

extends from the endoplasmic reticulum, allowing cell-cell communication.

6
 4. Plant cells also have plastids. The most common plastid known
as chloroplasts that are made up of chlorophyll, a green pigment responsible
for capturing light energy and converting it to chemical energy that is used by
the plants in photosynthesis. Other plastids include amyloplast for storage of
starch, elaioplast, for storage of fats and chromoplasts for synthesis and
storage of pigments.

5. The plant cells undergo cell division by forming the phragmoplast template for
building up cell plates in cytokinesis.

6. Unlike animal cells, plant cells notably lack cilia, flagella, and centrioles.

How animal cells are organized into tissues.

Animal cells are the basic unit of life in organisms of the kingdom Animalia.
They are eukaryotic cells, meaning that they have a true nucleus and specialized
structures called organelles that carry out different functions. Animal cells do not
have plant-specific organelles like cell walls, which support the plant cell, or
chloroplasts, the organelle that carries out photosynthesis. Animals, plants, fungi,
and protists are all made up of at least one eukaryotic cell. In contrast, bacteria and
archaea are made up of a single prokaryotic cell. All cells are surrounded by a cell
membrane (also called a plasma membrane).

The cell membrane is the boundary that separates the inside of the cell from
the outside of the cell. The plasma
membrane encloses all the cell
components, which are suspended in a gel-
like fluid called the cytoplasm. The
cytoplasm is the location of the organelles.

Eukaryotic cells are distinguished

from prokaryotic cells by the presence of a
defined nucleus and other membrane-
bound organelles, such as
the mitochondria, endoplasmic reticulum,
and Golgi apparatus. Prokaryotic cells do not
have a defined nucleus (instead, a region of the
cytoplasm – called the nucleotide – holds the genetic
material). They also lack membrane-bound organelles.

Animals are all multicellular, meaning multiple

cells work together to form the whole organism. In
complex organisms, such as humans, these cells can
be highly specialized to perform different functions. As
such, they often look and function very differently from one another, even though
they are all human cells.

7
These are the specialized cells of an animal

Animal cells are organized (cells grow, mature and undergo cell differentiation
in multicellular organisms. As a result of cell differentiation, tissues are formed.)

A. Epithelial Tissue - this type of tissue is commonly seen outside the body
as coverings or as linings of
organs and cavities. Epithelial tissues are characterized by closely-joined
cells with tight junctions (i.e., a type of cell modification). Being tightly
packed, tight junctions serve as barriers for pathogens,
mechanical injuries, and fluid loss.

Cells that make up epithelial tissues can have distinct arrangements:

1. cuboidal - for secretion
2. simple columnar - brick-shaped cells; for secretion and active absorption
3. simple squamous - plate-like cells; for exchange of material through diffusion
4. stratified squamous - multilayered and regenerates quickly; for protection
5. pseudo-stratified columnar- single layer of cells; may just look stacked
because of varying height;
for lining of respiratory tract; usually lined with cilia (i.e., a type of cell
modification that sweeps the mucus.)

8
 B. Connective Tissue - These tissues are composed of the following:

BLOOD - made up of plasma (i.e., liquid extracellular matrix); contains water, salts,
and dissolved proteins; erythrocytes that carry oxygen (RBC), leukocytes for defense
(WBC), and platelets
for blood clotting.

CONNECTIVE TISSUE PROPER (CTP) - made up of loose connective tissue that is

found in the skin and fibrous connective tissue that is made up of collagenous fibers
found in tendons and ligaments. Adipose tissues are also examples of loose
connective tissues that store fats which functions to insulate the body and store
energy.

CARTILAGE - characterized by collagenous fibers embedded in chondroitin sulfate.

Chondrocytes are the cells that secrete collagen and chondroitin sulfate. Cartilage
functions as cushion between bones.

BONE - mineralized connective tissue made by bone-forming cells called

osteoblasts which deposit collagen. The matrix of collagen is combined with calcium,
magnesium, and phosphate ions to make the bone hard. Blood vessesl and nerves
are found at a central canal surrounded by concentric circles of osteons

9
Figure 2: Connective Tissue (Source: Reece JB, U. L. (2010). Campbell Biology 10th. San Francisco (CA):.)

C. Muscle Tissue - These tissues are composed of long cells called muscle
fibers that allow the body to move voluntary or involuntary. Movement of
muscles is a response to signals coming from nerve cells.

In vertebrates, these muscles can be categorized into the following:

1. Skeletal lstriated; voluntary movements

2. Cardiac – striated; with Intercalated disk for synchronized heart contraction;
involuntary
3. Smooth - not striated; involuntary

10
Figure 3: Muscle Tissue (Source: Reece JB, U. L. (2010). Campbell Biology 10th. San Francisco (CA):.)
Nervous Tissue - These tissues are composed of nerve cells called neurons and
glial cells that function as support cells. These neurons sense stimuli and transmit
electrical signals throughout the animal body. Neurons connect to other neurons to
send signals. The dendrite is the part of the neuron that receives impulses from other
neurons while the axon is the part where the impulse is transmitted to other neurons.

Figure 4: Neurons and Glial Cells (Source: Reece JB, U. L. (2010). Campbell Biology 10th. San Francisco (CA):.)

What is a cell modification?

Are specialized or modifications re-acquired by the cell after cell division

that helps in different beneficial ways.

Apical Modification
Cell modification found on the apical surface of the cell.

11
Cilia and flagella
Cilia are usually short, hair-like structures that move in waves
Flagella are long whip-like structures
Formed from microtubules

Villa and Microvilli

Villi are finger like projections that arise from the epithelial layer in some
organs. They help to increase surface area allowing for faster and more
efficient absorption.
Microvilli are smaller projections that arise from the cell’s surface that
also increase surface area allowing faster and more efficient absorption.

Pseudopods
Temporary, irregular lobes formed by amoebas and some other
eukaryotic cells
Bulge outward to move the cell or engulf prey.

Extra Cellular Matrix

Compound secreted by the cell on its apical surface
Cell wall is the extracellular structure in plant cells that distinguishes
them from animal cells.
Glycoprotein is the main ingredient of ECM in animal cells.

Basal Modification
Cell modification found on the basal surface of the cell.

Desmosomes/Hemi desmosomes
Anchoring junction on the basal surface of the cell

Rivet – like links between cytoskeleton and extracellular matrix

componentssuch as the basal lamina that underlie epithelia
Primarily composed of keratin, integrins and cadherins.

12
Lateral l Modification
Central modification found on the lateral surface of the cell.

Tight Junction
Act as barriers that regulate the movement of water and solutes
between epithelial layers
Prevent leakage of ECF

Adhering Junction
Anchoring junction on the lateral surface of the cell
Very similar to the anchoring junction of the basal surface of the cell
Fasten cells to one another

Gap Junction
Also known as communicating junctions
Closable channels that connect the cytoplasm or adjoining animal cells
Presence of connection that allow direct exchange of chemicals between
the cytoplasm of two cells.

Activity 1:1
Answer the following questions briefly.
1. In what ways are cells similar? In what ways are they different? Make a
Venn diagram

2. You have learned that plant cells have chloroplast but animals do not.
What do you think are the advantages that chloroplast give to plant cells?
13
Activity 1: 2
Answer the following questions briefly:

1. What is the importance of having a tissue level in the hierarchy of

biological organization? (2 points)

2. What do the varying shapes and arrangement of epithelial tissue

suggest? (2 points)

3. What is the general function of connective tissues? What function is

common to all types of connective tissues? (2 point)

4. What are the functions of voluntary and involuntary muscles? (2

points)

5. What is the importance of glial cells in nervous tissues? (2 points)

14
 6. Identify three (3) cell modifications and describe their respective
functions. (2 points each)

Explain the statement “A cell is a living unit greater than the sum of its parts.” Give an
example.

Choose the letter of the best answer.

1. Which of the following muscles is voluntary and can be moved at will?

a. Smooth muscle
b. Cardiac muscle
c. Skeletal muscle
d. All of the above
2. Since animals can move around to search for water, their cells can afford to
have _________
a. Centrosome
b. No cell walls
c. No chloroplasts
d. Smaller vacuoles
3. Which of the following terms are incorrectly matched?
a. Skin: epithelial tissue
b. Muscle: cardiac tissue
c. Tendon: dense connective tissue
d. Cartilage: loose connective tissue
4. Bones provide strength and support because their intercellular matrix consist
of _______

a. Protein fibers
b. Calcium carbonate
c. Salts of calcium phosphate
d. All of the above
5. Which combined tissues are directly involved when a boy kicks, a frog leaps
or a bird flies?
a. Bones and nerves
b. Blood and muscles

15
 c. Muscles and bones
d. Nerves and muscles
Answer the following questions briefly.
1. Use specific examples to show that particular functions are closely related to
the structural characteristics of:
a. Animal cells
b. Animal tissues
2. How do connective tissues support the body?
3. Recall what you know about cell parts. What is the advantage of muscle cell
containing numerous mitochondria?

Create a model of an animal cell with common materials found at home. Get a
plastic bag to represent a membrane. Use other materials that you collected to
represent the structure or function of the cell organelles. Record your explanation
through video and send it to my account in facebook. 4-5 minutes will do! But if there
is no signal in your place. You can take a photo of your work and print it together
with your explanations. Send it together with your module during retrieval.

Liliana C. Joaquin,Ph.D. Catherine Genevieve B. Lagunzada,Ph.D. Functional

Biology Modular approach Vibal Publishing House Inc. 2010
Jonnie Donnie A Ramos and Anna cherylle Morales – Ramos Exploring Life Through
Science Biology Phoenix Publishing House 2004

16
-

17