Cellular Reproduction (Grade 8, Quarter 4)

Key idea
2/22/2020 G8Q4L2 - CELLULAR REPRODUCTION 2

Cells divide to produce more
cells. The process involves
the division of the nuclear
materials followed by the
division of cytoplasm.

Chapter topics

1. Cellular Parts involve in
the Cell Division
2. The Cell Cycle
3. Mendelian Genetics

Cellular Parts
Involved in Cell
Division

Scientist
Highlight
Rudolf Virchow
1821 – 1902
Proposed the Cell Theory

Scientist
HighlightRobert Hooke
1635 – 1703
First person who observed a cell.
Also the person who coined the
word “cell”.

Types of Cells

Based on
complexity

Prokaryotes Eukaryotes

Prokaryotes (Prokaryotic Cell)
A prokaryote is a
unicellular organism
(cell). Came from the
Greek work “pro” which
means “before” and
“karyon” which means
nut.

Prokaryotes Eukaryotes

Eukaryotes (Eukaryotic Cell)
A prokaryotic cell have
nucleus and membrane
bound organelles.
Came from the Greek
work “eu” which means
“true/well” and “karyon”
which means nut.

Based on
organism

Plant Cell Animal Cells

Plant Cells
Plant cells are
eukaryotic cells that are
commonly found on
green plants. Unlike
other cells, they can
manufacture their own
food with the help of the
sunlight.

Plant Cell Animal Cells

Animal Cells
Animal cells dominates
most of the animals
(and humans). Because
of the absence of cell
wall, thay can be of any
size or shape.

Review: Parts
of the Cell

Parts of the Cell
The cell is made up of two
main parts
1. Nucleus – the central
part of the cell
2. Cytoplasm – the
liquid substance
where the organelles
are suspended

Nucleus
Nickname: The Control Center
Function: Holds the DNA
Location
• Mostly in the center of the
cell

Nucleus
Sub-parts
• Chromatin - strands that
contain genetic material
(chromosomes)
• Nucleolus - dark spot in the
middle of the nucleus that
helps make ribosomes

Ribosomes
Nickname: Protein Synthesizer
Function: Makes protein
Location
• All over the cell
• Suspended in the cytoplasm

Endoplasmic Reticulum
Nickname: The Freeway
Function: Delivery System of
the Cell
Location

Golgi Complex
Nickname: The Shippers
Function: packages, modifies,
and transports materials to
different location inside/outside
of the cell
Location

Mitochondria
Nickname: The Powerhouse
Function: Makes energy
(transform food into adenosine
triphosphate, ATP)
Location

Vacuoles
Nickname: The Dumpsters
Function: Stores and releases
waste products
Location

Cell Membrane
Nickname: The Walls and
Door
Function: separates the inside
of the cell from its environment.
Also controls what substances
enter and leave cell.
Location
• Around the cell

Nucleus, ribosomes, endoplasmic reticulum, golgi
complex, mitochondria, vacuoles, and cell membrane
are both found on animal and plant cells.

Part exclusive
to animal cells

Lysosomes
Nickname: The Clean-up Crew
Function: break down food
into particles that the rest of the
cell can use and to destroy old
cells
Location

Centrioles (Centrosomes)
Nickname: The Splitters
Function: pull chromatids
apart during cell division
Location
• near the nucleus, still
suspended in the
cytoplasm

Part exclusive
to plant cells

Chloroplast
Nickname: The Foodmaker
Function: site for the
photosynthesis
Location

Chloroplast
Nickname: Green Wall
Function: just like the cell
membrane, it also separates
the inside of the cell from its
environment. It is just harder
than cell membrane.
Location
• Around the cell

Other parts
of other cells

Flagelum
Nickname: The Tail
Function: whip-like structure
that allows a cell to move
Location
• Attached in the tip of the cell

Cellular Parts
involved
in Cell Division

Nucleus

Nucleus
One of the most important
part since genetic materials
are found in the nucleus.
The genetic material is
organized into
chromosomes.

Nucleus
Chromosome are constantly
replicated as the need
arrives in order to give each
daughter cell distinct
number of chromosomes
after the cell divide.

Did you know?
Deoxyribonucleic acid (DNA) are
found in the not only nucleus only.
They are also located in the
mitochondria and chloroplast.

Microtubules
and
microfilaments

Microtubules and Microfilaments
Microtubules and
Microfilaments are
necessary when the cell
starts moving. They also
serve as attachment site for
kinetochore.

Can you determine
the parts in a real
photo of a cell?

#1
#2
#3
#5
#6
#7

Identification
Identify the part of cell
being described in each
sentence

Quiz 2-A
1. Can be found around the
cell, it controls which materials
enter and exit
2. Control center of the cell,
holds the genetic material DNA
3. Delivery system of the cell,
there are two types of this
organelle
2/22/2020 G8Q4L2 - CELLULAR REPRODUCTION Slide 66
Cell Membrane
Centrioles
Chloroplast
Golgi Complex
Lysosomes
Mitochondria
Nucleus
Ribosomes
Vacuoles

Quiz 2-A
4. Found only on animal cells,
it breaks downs food particle
and old cells alike
5. Important organelle that
help in the cell division
6. Only found in plant cell, it is
the site where photosynthesis
happens
Cell Membrane
Centrioles
Chloroplast
Golgi Complex
Lysosomes
Mitochondria
Nucleus
Ribosomes
Vacuoles

Quiz 2-A
7. Packages, modifies, and
transports materials to different
location inside/outside of the
cell
8. Part that store and release
waste products
9. Powerhouse of the cell –
provides energy
10. Site where protein is made
Cell Membrane
Centrioles
Chloroplast
Golgi Complex
Lysosomes
Mitochondria
Nucleus
Ribosomes
Vacuoles

Answer
1. Cell Membrane
2. Nucleus
3. Endoplasmic
Reticulum
4. Lysosomes
5. Centrioles
6. Chloroplast
7. Golgi Complex
8. Vacuoles
9. Mitochondria
10. Ribosomes

The Cell
Cycle

The Cell Cycle
Once a cell is fully grown,
two things may happen:
1. Stop growing
2. Divide and produce more
cell through cellular
reproduction

The Cell Cycle
Cellular reproduction
helps your body
grow and repair/heal
your worn-out
tissues.

The Cell Cycle
Cell follows a patter of
growing and dividing that
is known as cell division.
Everytime a parent cell
undergo the cell cycle, it
produces new daughter
cells.

The Cell Cycle
Therefore, reproduction
will always lead to
increasing number of
cells, or exponential
growth.

Interphase
and Cell Division

Vocabulary
What does the prefixes inter-,
pro-, meta-, ana-, and telo-
means?

Vocabulary
Inter – between/middle/in the midst
Pro – before/front/earlier
Meta – occurring after/later
Ana – in the act of process/in/on
Telo - end

Interphase and Cell Division
There are two main
alternating phases of cell
division
1. Interphase (18 hours)
2. Cell Division (2 hours)

Interphase and Cell Division
Interphase is the non-
dividing stage, which is
devoted largely to cell
growth. Even though it is
called “resting phase”, the
cell is still metabolically
active.

Stages
of Interphase

Stages of Interphase
Interphase spends 90% of
its time in the cell cycle.
Interphase includes three
stages
1. Gap 1 (G1) phases
2. Synthesis (S) phase
3. Gap 2 (G2) phase

Gap 1 Phase

Gap 1 (G1) Phase
This is the period when the
cell increase in size in
preparation for cell division.
• Growth of cell
• Duplication of organelles
• Synthesis of protein

synthesis Phase

Synthesis (S) Phase
genetic material (DNA) and
chromosomes are
duplicated (replicated). Each
strand of the double
stranded chromosome
produced is called sister
chromatid.

Gap 2 Phase

Gap 2 (G2) Phase
cell synthesize proteins and
continues to increase in
size. Cell is preparing for
cell division.

Bonus phase
Gap 0 Phase

Gap 0 (G0) Phase
While at G1, some cells
enter the G0 phase, also
known as the quiescent
stage. Cells that enter G0
stage continues functioning
but stops reproducting, thus
stops growing.

Stages
of Cell Division

Stages of Cell Division
After the interphase, the cell
is now ready to be divided.
Two parts are involved in
the cell division, the nucleus
and the cytoplasm.

Did you know?
The nucleus also filled with a
liquid called nucleoplasm. It is
also covered by a membrane call
the nuclear membrane.

Nuclear division (division of
nucleus) is called
karyokinesis. There are
two types of karyokinesis:
1. Mitosis
2. Meiosis

Regardless of karyokinesis
(mitosis or meiosis), it
always involve four stages:
1. Propase
2. Metaphase
3. Anaphase
4. Telophase

Cytoplasmic division
(division of cytoplasm) is
called cytokinesis. In plant
cell, cytokinesis involves the
formation of cell plate,
eventually becoming the cell
wall.

In animal cell, cytoplasmic
division occur with the
formation of cleavage
furrow.
Both animal and plant cells
produce daughter cells.

Vocabulary
Haploid and Diploid Cells
Haploid – a haploid cell, represented by symbol N,
contains only one set of chromosome. Gametes
(sperm and egg) are haploid.
Diploid – represented by the symbol 2N, contains
two sets of chromosomes. Most somatic cells
(body cells) are diploid.

Cell Division:
Mitosis

Review of
important parts

Review of Important Parts
A chromosome is a long,
continuous piece of DNA
which contains the
genetic information for the
cell.

Chromatid is a one strand
of the chromosome after it
has duplicated for cellular
division. The two
chromatids are called
“sister chromatids” and will
eventually split and move to
opposite ends of the cell.

Chromatin is the
building block for a
chromosome. It
consist of DNA and
protein.

The centromere is constricted region of
thechromosomes that holds the sister
chromatids together, the site where
kinetochore forms.

A centriole is a barrel
microtubule structure.
Two centrioles arrange
themselves
perpendicularly to form a
centrosome.

mitosis

Mitosis
It is the process in which
a eukaryotic cell
separates the
chromosomes in its cell
nucleus, into two
identical sets in two
daughter cells.

Mitosis
Mitosis is when the cell
actualy splits into
daughter cells. It has two
parts
1. Mitosis
2. Cytokinesis

Mitosis
The Mitosis part has 4 (other
books says 5) stages:
1. Prophase
2. (Prometaphase)
3. Metaphase
4. Anaphase
5. Telophase

Prophase

Prophase
Duration: 15 minutes
• Chromosomes
condense (get thicker)
and coil, they become
visible under light
microscope.

Prophase
• The two sister
chromatids of
eachchromosomes
attach at a point called
centromere.
• Spindle fibers begin to
form from two
centrosome, and they will
start moving apart.

Prometaphase

Prometaphase
• The nuclear membrane
disappears.
• Kinetochores will get
attached to the centromere.
• The spindle fibers become
attached to the kinetochore.

metaphase

Metaphase
• Chromosomes reach their
most highly condensed
state.
• The spindle fibers begin to
contract to the centromeres
of the chromosomes, which
are now arranged along the
middle of the spindle.

Anaphase

Anaphase
Duration: 3 minutes
• The centromere of each
chromosome splits, allowing
the sister chromatids to
separate.
• The chromatids are then
pulled by the spindle fibers
toward opposite sides of the
cell.

Anaphase
• The two sets of
chromosomes are
identical.
• Cleavage furrow starts
to form.

Telophase

Telophase
• New nuclear membranes
are formed around each of
the two sets of 46
chromosomes.
• The spindle fibers
disappear.
• Chromosomes become
thinner.

Telophase
• Cytoplasm starts
dividing by contractile
ring.
• At the end, we will have
two diploid daughter
cells, which are
identical.

Cytokinesis

Cytokinesis
• the division of the cytoplasm and organelles
• Begin in anaphase and completed by the end
of telophase

SUMMARY
• Interphase (90% of cycle)
• G1 phase~ growth
• S phase~ synthesis of
DNA
• G2 phase~ preparation for
cell division
• Mitotic phase (10% of
cycle)
• Mitosis~ nuclear division
• Cytokinesis~ cytoplasm
• division

Cell Division:
Meiosis

meiosis

Meiosis
Meiosis and mitosis
shares many
similarities. Both
are types of cell
division.

Meiosis
Meiosis and mitosis
also undergo the
same interphase
stages (G1, S
phase, G2).

Meiosis
So what are the
differences of mitosis
and meiosis? For
instance, their
purpose are
different.

Meiosis
Mitosis is for growth
and repair. In the other
hand, meiosis is
responsible for the
production of gametes
(sex cells/sperm and
egg cells).

Meiosis
Meiosis is the form of cell
division by which gametes,
with half the number of
chromosomes, are
produced.
• Diploid (2n) → haploid (n)

Meiosis
• Sex cells divide to
produce gametes (sperm
or egg).
• Gametes have half the
number of chromosomes.
• Occurs only in gonads
(testes or ovaries).

Meiosis
Production of gametes
(sperm cells) in males is
called
spermatogenesis.
Production of gametes
(egg cells) in female is
called oogenesis.

Meiosis
Meiosis also
undergo cell division
twice. The first
division is Meiosis I,
immediately followed
by Meiosis II.

2n=46
human
sex cell
diploid (2n)
n=23
n=23
Meiosis I
n=23
n=23
n=23
n=23
sperm
haploid (n)
Meiosis II

Meiosis I

Meiosis I
• Cell division that reduces
the chromosome number
by one-half.
• Four phases:
oprophase I
ometaphase I
oanaphase I
otelophase I

Prophase I

Prophase I
• Longest and most complex
phase (90%).
• Chromosomes condense.
• Synapsis occurs: homologous
chromosomes come together
to form a tetrad.
• Tetrad is two chromosomes or
four chromatids (sister and
nonsister chromatids).

Did you know?
Homologous cromosomes are pair of
chromosomes (maternal and paternal)
that are similar in shape and size.
Homologous pairs (tetrads) carry genes
controlling the same inherited traits.

Did you know?
Humans have 23 pairs of
homologous chromosomes.
(22 pairs of autosomes and
1 pair of sex
chromosomes). The 23rd
pair is called the sex
chromosome.

Did you know?
The Sex Chromosomes code
for the sex of the offspring.
• If the offspring has two “X”
chromosomes it will be a
female.
• If the offspring has one “X”
chromosome and one “Y”
chromosome it will be a
male.

Prophase I
Crossing over (variation) may
occur between nonsister
chromatids at the chiasmata.
• Crossing over: segments of
nonsister chromatids break
and reattach to the other
chromatid.
• Chiasmata (chiasma) are
the sites of crossing over.

METAPHASE I

Metaphase I
• Shortest phase
• Tetrads align on the
metaphase plate.
• Independent assortment
occurs:
1. Orientation of
homologous pair to poles
is random.
2. Variation

AnAPHASE I

Anaphase I
• Homologous
chromosomes
separate and move
towards the poles.
• Sister chromatids
remain attached at
their centromeres.

TeloPHASE I

Telophase I
• Each pole now
has haploid set
of chromosomes.
• Cytokinesis
occurs and two
haploid daughter
cells are formed.

Meiosis II

Meiosis II
• No interphase II (or
very short - no more
DNA replication)
• Remember:
Meiosis II is similar
to mitosis

Prophase II

Prophase II
Prophase II have
same events like
the prophase in
mitosis.

Metaphase II

Metaphase II
Metaphase II
have same
events like the
metaphase in
mitosis.

Anaphase II

Anaphase II
Anaphase II have
same events like
the anaphase in
mitosis.
• Sister
chromatids
separate.

Telophase II

Telophase II
Telophase II have
same events like
the Telophase in
mitosis.
• Nuclei form.
• Cytokinesis
occurs.

Telophase II
Remember:
four (4) haploid
daughter cells
are produced.

Variation
in meiosis

Variation
Important to population as
the raw material for natural
selection.
Question: What are the
three sexual sources of
genetic variation?

Variation
1. crossing over (prophase I)
2. independent assortment
(metaphase I)
3. random fertilization
Remember: variation is good!

Variation
Question: In terms of
Independent Assortment -
how many different
combinations of sperm
could a human male
produce?

Variation
Formula: 2n
Human chromosomes:
2n = 46
n = 23
223 = ~8 million
combinations

Comparing Mitosis
and Meiosis

Review: Is that you?
Read the word in the piece of paper
distributed in the class.
Then, questions and descriptions will be
shown in the slides.
If you think you are holding the right answer,
pass your strip of paper in front.

A type of cell division that
produce 2 daughter cells
that are identical to their
parent cell. Body cells use
this process in repairing and
growth of the cell.

A type of cell division that
produce 4 haploid daughter
cells. It is the process where
our body produces sperm
cells and egg cells.

A phase in cell division when
the the nuclear membrane
starts to disappear and the
chromosome starts
condensing.

the the chromosomes
attached to the spindle
fibers and they align in the
middle of the cell.

the the chromosome is
divided into two due to the
pull of the spindle fibers.

The last phase in cell division
where the nuclear membrane
starts to form and the cell
finally divided into its
daughter cells.

Also known as the resting
phase, it is when the cell is
not dividing.

A stage of interphase where
the organelles are
duplicated and the cell starts
growing in size.

The replication of
chromosomes and DNA
happen in this stage of
interphase.

Last phase of interphase
where the cells continue to
grow in preparation of the
cell division.

Some cells go into this stage
wherein they stop dividing
but continue to function.

What do you call
this structure
found in the
nucleus?

What do you call
this part of the
chromosome?

What do you call
the chromatid
with same
length?

What is the
middle part of
the chromosome
called?

What do you call the division
of the nucleus?

What do you call the division
of the cytoplasm?

Chromosome with two (2)
sets of chromosomes.

Chromosome with one (1)
sets of chromosomes.

Haploid cells produced in
meiosis. It is commonly
known as the sex cells.

Word Jumble
Build words using the letters provided. The group
will take turns in answering.
The group who will be able to guess a word will
receive points equal to the number of letters.
The group who can guess the longest word will
earn 10 points.

T
G E N I
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N G
G
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G N EE
G E N I E
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N I

Vocabulary
Genetic
• relating to or determined by the origin,
development, or causal antecedents of
something
• relating to, or involving genetics
• relating to, caused by, or controlled by
genes
2/22/2020 198

T I
I N E
H R
I
T
H E
I
T H E N
T
H I
N
H I
R
R E
N
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T
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R
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I N H E R I T
T
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I
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H I R E
H I N T
R
E
N
T
H E I R
T
H
I
NT H E N

Vocabulary
Inherit
• to receive from an ancestor as a right or title
descendible by law at the ancestor's death
• to receive from a parent or ancestor by
genetic transmission
2/22/2020 200

NMI
DN
ATO
M
A D M
I
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A D
A
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N
D O M I N A N T
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A D M I T T O A D
T O M

Vocabulary
Dominant
• prevailing over all others
• very important, powerful, or successful
• relating to, or exerting ecological or genetic
dominance
2/22/2020 202

Scientist
HighlightGregor Mendel
(1822 – 1884)
Responsible for the Laws
governing the Inheritance of Traits

Mendelian Genetics
Gregor Mendel is an
Australian monk that studied
the pattern of inheritance.
He uses pea plants(Pisum
sativum) because they can
be cultivated fast and easy.

Mendelian Genetics
Mendel stated that traits are
inherited as ‘particles.’
Later, these partcles are
known as chromosomes
and DNA.

Terminologies

• Trait - any characteristic that
can be passed from parent to
offspring
• Heredity - passing of traits
from parent to offspring
• Genetics - study of heredity

• Alleles - two forms of a gene
(dominant & recessive)
• Dominant - stronger of two
genes expressed in the hybrid;
represented by a capital letter (R)
• Recessive - gene that shows up
less often in a cross; represented
by a lowercase letter (r)

PunnettSquare

Using Punnett Square
Punnett Square is used to
help solve genetics
problems.
Before using the Punnett
Square, you must know the
genotypes of the parent.

Step 1: Make the grid.
Place the alleles of one
parent on top and the
other parent on left hand
side.

Step 2: Combine the
parent alleles inside the
boxes. The letters will
now show the genotypes
of the offspring. You can
now write the ratio of the
genotypes.

Step 3: Fill in the
offspring. Use the Law
of Dominance to
determine the
phenotype and
phenotype ratio of the
offsprings.

Word Problems
with Punnett
Square

Procedure
1. Each group will be given a paper with word
problems indicated on it.
2. The group will be given 10 minutes to analyze
and solve the problem, and to write their
answer on manila paper or cartolina.
3. The groups will then present their answer.

Cellular Reproduction (Grade 8, Quarter 4)

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