NAME:__________________________________________
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12
GENERAL BIOLOGY 1
Semester I – Week 1
Cell Structure
and Functions
1
CONTEXTUALIZED LEARNING
ACTIVITY SHEETS
SCHOOLS DIVISION OF PUERTO PRINCESA CITY
General Biology 1 – Grade 12
Contextualized Learning Activity Sheets (CLAS)
Semester I - Week 1: Cell Structure and Functions
First Edition, 2021
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Lesson 1
Cell Structure and Functions
MELC: The learners explain the postulates of cell theory. STEM_BIO11/12-Ia-c-1
The learners describe the structure and function of major subcellular organelles.
STEM_BIO11/12-Ia-c-2
Objectives:
1. Explain the three postulates of the cell theory
2. Describe the structure and explain the function of the different subcellular
organelles
3. Differentiate animal cell from plant cell.
Let’s Try
Directions: Let us try to activate your prior knowledge about this topic by answering the
following questions. Choose and write only the letter of the best answer on the line provided
before the number.
____1. Which of the following is NOT a premise of the cell theory?
I-All cells arise from other cells.
II-All living cells require water for survival.
III- All living things are composed of cells.
A. I only
B. II only
C. I and II
D. II and III
____2. A cell with relatively few energy needs will probably have a relatively small number
of what organelle?
A. ribosomes B. lysosomes C. mitochondria D. chromosomes
____3. Which of the organelles digest worn out substances taken in by the cell?
A. ribosomes B. golgi apparatus C. lysosomes D. smooth endoplasmic reticulum
____4. Which cell organelle is responsible for the formation of vesicles for the bulk transport
of materials out of the cell?
A. golgi body B. vacuole C. ribosomes D. endoplasmic reticulum
____5. Plant cells often have a box-like shape. What structure of the cell is this attributed?
A. nucleus B. cytoplasm C. cell wall D. cell membrane
____6. What is the outermost boundary of an animal cell?
A. the cell wall
B. the cell membrane
C. the cytoplasm
D. the nuclear envelope
____7. What site regulates materials that goes in and out of the cell?
A. cell wall B. plasma membrane C. vacuole D. nuclear membrane
____8. Where is the site of protein synthesis found?
A. nucleus B. ribosome C. lysosome D. mitochondria
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____9. Which is the “brain” of the cell?
A. nucleus B. Golgi bodies C. chloroplast
D. mitochondria
____10. Why do cells are relatively small?
A. as cell size increases, volume and surface area decrease.
B.as cell size increases, volume increases faster than the surface area.
C.as cell size increases, volume and surface area increase at the same rate.
D.as cell size increases, surface area increases faster than the volume.
Let’s Explore and Discover
Unlocking Word
Difficulties
Formulation of Cell Theory in 1838, Theodor Schwann
and Matthias Schleiden were enjoying after-dinner coffee and
talking about their studies on cells. It has been noted that
DNA-genetic
when Schwann heard Schleiden describe plant cells with
material/deoxyribonucleic
nuclei, he was struck by the similarity of these plant cells to
acid
cells he had observed in animal tissues. The two scientists
Organelles- means “little
went immediately to Schwann’s laboratory to look at his
organs” found within the
slides. Schwann published his book on animal and plant
cell
cells (Schwann 1839) the next year, a treatise devoid of
acknowledgments of anyone else’s contribution, including that of Schleiden (1838). These
discoveries of Schleiden and Schwann introduced the cell theory. This theory states that:
1. All living things are made up of one or more cells.
2. The cell is the fundamental, structural and functional unit of all living organisms.
In 1855, third statement on the cell theory was added by Rudolf Virchow. It states
that:
3. All living cells come from pre-existing cells, by division .
All living things are made from one or more cells. A cell is the simplest unit of life
and they are responsible for keeping an organism alive and functioning. There is a massive
variety of different types of cells but they all have some common characteristics. Almost
every different type of cell contains genetic material, a membrane and cytoplasm. Cells also
have many other features such as organelles and ribosomes that perform specific functions.
All cells share three common components. These are the plasma membrane, an outer
covering that separates the cell interior from its surrounding environment; the cytoplasm
consisting of a jelly-like cytosol within the cell in which other cellular components are found.
The nucleus which serves as a control center that contains the genetic material (DNA) of
the cell.
1.Cell Membrane- a phospholipid bilayer
with embedded proteins that separate the
internal contents of the cell from its
surrounding environment. A phospholipid is
a lipid molecule with two fatty acid chain
which is hydrophobic and a phosphate
containing group that is hydrophilic. The
plasma membrane controls the passage of
organic molecules ions, water, and oxygen in
2
and out of the cell. Wastes (such as carbon dioxide and ammonia) also leave the cell by
passing through the plasma membrane.
2. Cytoplasm - the cytoplasm is the region of
a cell within the plasma membrane, it is made
up of organelles suspended in the gel-like
cytosol. It is composed of 70-80% water and
other organic substances such as proteins,
sugar, and fatty and amino acids making
semi-solid in consistency.
Figure 1. The cell membrane/phospholipid
molecule
Source:https://www.slideshare.net/jayswan/ch
apter-7-cell-membranes
3. Mitochondria-Fig. 2 are-oval shaped,
double membrane organelles and often called
the “powerhouses” or “energy factories” of a
cell because they are responsible for making
adenosine
triphosphate
(ATP)
through
cellular respiration using glucose and other nutrients. It is important to point out that
muscle cells have a very high concentration
of mitochondria.
4.
Ribosomesare
the
cellular
organelles responsible for protein synthesis
and are considered the protein factories of
the cell. It may appear as clusters
(polyribosomes) or single tiny dots that float
freely in the cytoplasm. They may be
attached to the cytoplasmic side of the
plasma membrane, endoplasmic reticulum,
and outer membrane of nuclear envelope.
Figure 2- The mitochondrion as power house of the
cell
Source:http://mandevillehigh.stpsb.org/teacher
5. Endoplasmic reticulum is a series of
interconnected membranous sacs and tubules
that modifies proteins and synthesizes lipids that
extends from the nucleus to the cell membrane
and takes up quite a lot of space in some cells.
a.
Rough endoplasmic reticulum- RER is
so named because the ribosomes attached to its
cytoplasmic surface give it a studded appearance
when viewed through an electron microscope.
Figure 3- The ribosome
Ribosomes transfer newly synthesized proteins
Source: https://socratic.org/questions
into RER where they undergo modifications and
secreted from the cell (such as protein
hormomes, enzymes). If proteins are not destined to stay in the RER, they will reach their
destinations via transport vesicles that bud from the RER’s membrane. It would be correct
to assume that the RER is abundant in cells that secrete proteins like cells in the liver.
b.
Smooth endoplasmic reticulum-is continuous with RER but has few or no
ribosomes. Function of the SER include synthesis of carbohydrates, lipids and steroid
hormones; detoxification of medications and poisons and storage of calcium ions. In muscle
cells, specialized SER called the sarcoplasmic reticulum is responsible for storage of calcium
ions that are needed to trigger the coordinated contractions of the muscle cells.
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Figure 4- Rough and smooth endoplasmic reticulum(right) and sarcoplasmic reticulum (left)
Source: https://www.slideshare.net/AshishNain/endoplasmic-reticulum-cell-organelle
6. Golgi body (apparatus)- we have already
mentioned that vesicles can bud from RER and
transport proteins elsewhere, but before
reaching their final destination, sorting,
packaging and distribution of proteins take
place in the Golgi apparatus, a series of
flattened membranes. It tags proteins with
phosphate group (phosphorylation), or with
sugar (glycosylation) so that they can be routed
to their proper destination.
Figure 5- The Golgi apparatus
Source: https://alevelbiology.co.uk/notes
7. Lysosomes- a membrane bound organelles
found in many animal cells. They are spherical vesicles and contain hydrolytic enzymes
that breakdown many kinds of biomolecules and destroy pathogens that might enter the
cell. Lysosomes also act as waste disposal system of the cell by digesting obsolete or unused materials in the cytoplasm. Materials from outside the cell is being taken up through
endocytosis while material from inside of the cell is digested through autophagy.
8. Cytoskeleton- If you were to
remove all the organelles from a cell,
would the plasma membrane and the
cytoplasm be the only components
left? No. Within the cytoplasm, there
would still be ions and molecules
plus a network of protein fibers that
helps maintain the shape of the cell,
secure some organelles in specific
positions, allow cytoplasm and
vesicles to move within the cell, and
enable cells within multicellular
organisms to move. There are three
types
of
fibers
within
the
cytoskeleton: microfilaments/actin
filaments, intermediate filaments,
and microtubules.
Figure 6- The three types of cytoskeleton within the cell
Source:
http://www.maths.dur.ac.uk/~dma0bmp/projects_3H/Mo
dellingCytoskeleton
4
9. Vesicles and vacuoles- are membrane-bound sacs that function in storage and
transport. Other than the fact that vacuoles are somewhat larger than vesicles, there is a
very subtle distinction between them. The membranes of vesicles can fuse with either the
plasma membrane or other membranes systems within the cell. The membrane of a vacuole
does not fuse with the membranes of other cellular components.
10. Peroxisomes- are small, round organelles enclosed by single membranes. They carry
out oxidation reactions that break down fatty acids. They also detoxify many poisons that
may enter the body. Many of these oxidation reactions release hydrogen peroxide (H2O2)
which would be damaging to cells; however, when these reactions are confined to
peroxisomes, enzymes safely breakdown the H2O2 into oxygen and water. For example,
alcohol is detoxified by peroxisomes in liver cells.
11. Nucleus- typically, the nucleus is
the most prominent organelle in a
cell. It houses the cell’s DNA and
directs the synthesis of ribosome
subunits and proteins. It has
nuclear
envelope,
chromatin,
chromosomes, and nucleolus.
12. Cell wall- Fig. 8.A structure
external to the cell membrane. A
rigid covering that gives protection,
provides structural support and
gives shape to the cell. The major
organic molecule in the plant cell
wall is cellulose, a polysaccharide
made up of glucose units. It is the
Figure 7: The Nucleus
Source: https://www.dreamstime.com/animal-cellnucleus-anatomy
pressure of water against the cell wall that
creates the stiffness that give the crunch in
fruits and vegetables.
13. Centrosomes- is a microtubule- organizing
center found near the nuclei of animal cells. It
contains a pair of centrioles, two structures
that lie perpendicular to each other.
Figure 8- Cell wall of plants
Source:
https://www.assignmentpoint.com/science/bi
ology/cell-wall.html
Figure 9- The centrosome consists of two centrioles
that lie at right angles to each other.
Source: https://www.expii.com/t/centriolesstructure-function-10131
5
14.
Chloroplastslike
the
mitochondria, they too have their own
DNA and ribosomes; but chloroplast have
an
entirely
different
function.
Chloroplasts are plant cell organelles that
carry
out
photosynthesis.
Like
mitochondria, chloroplasts have outer
and inner membrane but within the inner
membrane is a set of interconnected and
stacked fluid-filled membrane sacs called
thylakoids are found. Each stack of
thylakoids is called a granum. The fluid
enclosed by the inner membrane that
surrounds the grana is called the stroma.
Figure 10- Chloroplast in plant’s cell
Source:https://www.nature.com/scitable/topicpage/
plant-cells-chloroplasts
15. Central Vacuole- If you look at
Figure 11, you will see that plant cells
have a large central vacuole that
occupies most of the area of the cell.
It plays a key role in regulating the
cell’s concentration of water in
changing environmental conditions.
Have you ever noticed that if you
forget to water the plants for a few
days, it wilts? That’s because as the
water concentration in the soil
Figure 11- The large central vacuole occupy most of the
becomes lower than the water
area of a plant cell.
concentration in the plant, water
Source:https://venngage.net/p/155855/central-vacuole
moves out of the central vacuoles and
cytoplasm. As the central vacuole
shrink, it leaves the cell wall unsupported. This loss of support to the cell walls of plant
cells results in the wilted appearance of the plant.
(Source: Belardo,Gisselle M.,Yael Avissar et.al General Biology 1
Textbook Vibal Group Inc 2016.)
6
Let’s Practice
ACTIVITY 1
Directions: Research each cell organelle to determine its function and write its function
down in the space provided. Below you will find the list of the cell organelles and city
analogies. Be creative and think outside the box.
Cell organelles
Cell wall
Organelle function
chloroplast
cytoplasm
Endoplasmic reticulum
Golgi body
lysosomes
mitochondria
nucleus
Plasma membrane
ribosomes
vacuole
City analogies
City wall or border of
protection
Solar energy plants
Air and lawns
Highway or road system
Post office
Waste disposal/recyclers
Energy plants
City hall
River surrounding the
city
Factories and farmlands
Groceries and
supermarkets
ACTIVITY 2
Directions: Complete the table below. Identify all organelles that belong to each category.
Membrane bound organelles
Non-membrane bound organelles
Think!!!
Why do non-membrane bound organelles don’t need a membrane?
7
Let’s Do More
ACTIVITY 1
Directions: Fill in the Venn diagram with the name of organelles found in animal cell (left)
and in plant cell (right), at the middle write all organelles that are found both in plant and
animal cell.
ACTIVITY 2
Directions: Label the parts of an animal and plant cell. Write your answer on the space
provided.
2
Let’s Sum It Up
Activity
Directions: Answer the following questions and write your answer in the space provided.
1. State the three postulates of the Cell Theory.
2. Enumerate all parts/organelles found within the cell and state the function of each.
3
Let’s Assess
Directions: Let us see how well you learned the lesson by answering the following
questions. Choose and write only the letter of the best answer on the line provided before
the number.
____1. What is the outermost boundary of an animal cell?
A. the cell wall
B. the cell membrane
C. the cytoplasm
D. the nuclear envelope
____2. What site regulates the going in and out of the cell?
A. cell wall B. plasma membrane C. vacuole D. nuclear membrane
____3. Where is the site of protein synthesis found?
A. nucleus B. ribosome C. lysosome D. mitochondria
____4. Which is the “brain” of the cell?
A. nucleus B. golgi bodies C. chloroplast
D. mitochondria
____5. Why do cells are relatively small?
A. as cell size increases, volume and surface area decrease.
B.as cell size increases, volume increases faster than the surface area.
C.as cell size increases, volume and surface area increase at the same rate.
D.as cell size increases, surface area increases faster than the volume.
____6. Which of the following is NOT a premise of the cell theory?
I-All cells arise from other cells.
II-All living cells require water for survival.
III- All living things are composed of cells.
A. I only
B. II only
C. I and II
D. II and III
____7. A cell with relatively few energy needs will probably have a relatively small number
of ____________.
A. ribosomes B. lysosomes C. mitochondria D. chromosomes
____8. Which of the organelles digest worn out substances taken in by the cell?
A. ribosomes B. golgi apparatus C. lysosomes D. smooth endoplasmic reticulum
____9. Which cell organelle is responsible for the formation of vesicles for the bulk transport
of materials out of the cell?
A. golgi body B. vacuole C. ribosomes D. endoplasmic reticulum
____10. Plant cells often have a box-like shape because of the ________________.
A. nucleus B. cytoplasm C. cell wall D. cell membrane
I hope you enjoyed and learned something new!
4
Answer Key
Let’s Practice
Activity 1
Organelle function
Protects the cell
Produce sugar using sun’s energy
The fluid component of the cell
Gives intstruction of the overall activity of
the cell
Intracellular highway
Packaging center of the cell
Remove unwanted substance into the cell
Powerhouse of the cell
Control center of the cell
Regulates what comes in and out of the
cell
Manufacture proteins for the cell
Storage of the cell
Let’s Practice Activity 2
MembraneMembranebound
bound
organelles
organelles
Nucleus
ribosomes
Smooth ER
centrosomes
Rough ER
Cytoskeleton
Golgi apparatus
mitochondria
Vacuoles and
vesicles
chloroplasts
lysosomes
peroxisomes
Non-membrane bound organelles are more solid structures that
are not fluid-filled, so they have no need for a membrane.
Let’s Do More- Activity 1
Animal cell
Centrioles
Lysosomes
Cilia
Flagella
Let’s Try
1. B
2. C
6. B
7. B
Both animal
and plant
Nucleus
Smooth and
Rough ER
Mitochondria
Golgi apparatus
Cell membrane
Cytoplasm
Cytoskeleton
Vesicle
Vacuole
Ribosomes
Peroxisomes
3. C
8. B
4. D
9. A
Animal cell
1Centrioles 2 chromatins
3 nucleolus 4nucleus 5
lysosomes 6smooth ER
7golgi body 8.rough ER
9 ribosomes 10
cytoplasm 11 plasma
membrane 12.
Mitochondrion 13
cytoskeleton
Plant cell
Plastid
Cell wall
chloroplasts
Let’s Assess
1. B 2. B
6. B 7. C
5. C
10. B
Plant cell
1 wall of adjascent cell 2.
Cytoskeleton 3 golgi
body 4.central vacuole
5.chromatin 6.nucleolus
7.nucleus 8. Smooth ER
9. Ribosome 10.rough
ER 11. Cell wall
12.chloroplast 13.plasma
membrane 14.
Mitochondria 15.
Cytoplasm 16.
Peroxisome
3. B
8. C
4. A
9.D
5. B
10.C
References
Book
Dela Pena, Renato A., Daniel E. Gracilla, and Christian R. Pangilinan. General Biology
Combined Book 1 & 2. JFS Publishing Services. 2016.
Belardo, Gisselle M., Yael Avissar, Jung Choi, Jean Desaix, et. al General Biology 1
Textbook Vibal Group Inc 2016
5
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