Meiosis | Cell Division | Grade 11 General Biology 1 Tagalog
Summary
TLDRThis educational video script discusses meiosis, a type of cell division crucial for the production of reproductive cells. It explains how meiosis reduces genetic information, leading to the formation of haploid gametes with half the number of chromosomes. The script outlines the stages of meiosis, including prophase, metaphase, and telophase, emphasizing the significance of genetic variation introduced through crossing over. It distinguishes meiosis from mitosis and highlights the processes of gametogenesis in males and females.
Takeaways
- 🌟 Meiosis is a type of cell division that occurs in reproductive cells and is crucial for sexual reproduction.
- 🧬 It reduces genetic information in reproductive cells, ensuring that offspring inherit a complete set of chromosomes from each parent.
- 🔗 Human sex cells, or gametes, contain half the total number of chromosomes, which is 23, not the full 46 found in somatic cells.
- 🌱 Meiosis produces haploid gametes, which are essential for creating a new organism with the correct number of chromosomes.
- 📉 Meiosis involves two divisions: Meiosis I and Meiosis II, which together halve the chromosome number in the parent cell.
- 🌼 Gametogenesis is the process of producing gametes or sex cells, with oogenesis being the production of egg cells in females and spermatogenesis for sperm cells in males.
- 🔬 The stages of meiosis include prophase, metaphase, anaphase, and telophase, each with distinct cellular activities.
- 🧵 Synapsis during prophase I is the pairing of homologous chromosomes, leading to the formation of tetrads, which are crucial for genetic recombination.
- 📉 Meiosis I is known as the reduction division, as it reduces the chromosome number by half, resulting in two daughter cells with 23 chromosomes each.
- 📚 After Meiosis I, Meiosis II further separates sister chromatids, resulting in four haploid daughter cells, each with 23 chromosomes.
- 🌐 The process of meiosis ensures genetic diversity through mechanisms like crossing over and independent assortment, contributing to the uniqueness of each individual.
Q & A
What is meiosis?
-Meiosis is a type of cell division that occurs in the reproductive cells of our body, reducing the amount of genetic information and producing haploid gametes for sexual reproduction.
How does meiosis differ from mitosis?
-Meiosis differs from mitosis by having two divisions, meiosis I and meiosis II, and it results in four daughter cells with half the number of chromosomes of the parent cell, making them haploid.
What is the significance of the reduction in chromosome number during meiosis?
-The reduction in chromosome number during meiosis is significant as it ensures that when the sperm and egg cells combine during fertilization, the resulting offspring has the normal diploid number of chromosomes.
What are the stages of meiosis I?
-The stages of meiosis I include prophase I, metaphase I, anaphase I, and telophase I, which involve the pairing and separation of homologous chromosomes.
What happens during prophase I of meiosis?
-During prophase I of meiosis, homologous chromosomes pair up in a process called synapsis, forming a tetrad, and crossing over occurs, leading to genetic variation.
What is the role of the centromere and kinetochore during meiosis?
-The centromere is the point where sister chromatids are attached, and the kinetochore is a protein structure that connects the chromatids to the spindle fibers, facilitating their separation during cell division.
What is the result of meiosis I?
-The result of meiosis I is two daughter cells, each with 23 chromosomes and 46 chromatids, which are still connected as pairs, thus being haploid.
What is the purpose of cytokinesis following meiosis I?
-Cytokinesis following meiosis I is the process that physically divides the cytoplasm and cellular contents into two separate daughter cells, each with a set of chromosomes.
What is the difference between the chromosomes in a gamete before and after meiosis II?
-Before meiosis II, each gamete has 23 chromosomes and 46 chromatids. After meiosis II, the chromatids separate, resulting in four haploid daughter cells, each with 23 single chromatids or chromosomes.
How does meiosis contribute to genetic diversity?
-Meiosis contributes to genetic diversity through the process of crossing over during prophase I, where segments of non-sister chromatids are exchanged, and through the independent assortment of chromosomes during metaphase I.
Outlines
🧬 Introduction to Meiosis
This paragraph introduces the process of meiosis, a type of cell division that occurs in reproductive cells. It explains that meiosis reduces genetic information in reproductive cells, allowing for the transmission of traits from one generation to another. The script mentions that human sex cells, or gametes, are haploid, meaning they contain half the total chromosome number of a human being. The process is divided into two stages: meiosis I and meiosis II, with further subdivisions into prophase, metaphase, and telophase. The paragraph also discusses the preparation stages before meiosis begins, including DNA replication and the doubling of centrosomes.
🌿 Stages of Meiosis I
Paragraph 2 delves into the stages of meiosis I, starting with prophase one where chromosomes condense and synapsis occurs, leading to genetic variation through crossing over. The script describes the five substages of prophase one: leptotene, zygotene, pachytene, diplotene, and diakinesis. It then explains metaphase one, where homologous chromosomes align at the metaphase plate, and telophase one, where chromosomes migrate to the poles and cytokinesis occurs, resulting in two daughter cells with 23 chromosomes each. This paragraph highlights the reduction division aspect of meiosis I, where the chromosome number is halved.
📚 Completion of Meiosis
Paragraph 3 covers the final stages of meiosis, focusing on meiosis II. It begins with interkinesis, a brief phase where the cell prepares for the second division. The script describes prophase two, where chromosomes condense again, and metaphase two, where sister chromatids separate and migrate to opposite poles. Telophase two is detailed, with the formation of two groups of chromosomes and cytokinesis resulting in four haploid daughter cells, each with 23 chromosomes. The paragraph concludes with a summary of the entire meiosis process, emphasizing the reduction from 46 chromosomes to four haploid cells, each with 23 chromosomes, and encourages viewers to continue learning about this essential biological process.
Mindmap
Keywords
💡Meiosis
💡Chromosomes
💡Gametes
💡Oogenesis
💡Spermatogenesis
💡Prophase
💡Metaphase
💡Anaphase
💡Telophase
💡Cytokinesis
💡Haploid
Highlights
Meiosis is a type of cell division that occurs in reproductive cells.
Meiosis reduces genetic information in reproductive cells to pass traits from one generation to another.
Sex cells or gametes have half the total chromosome number of a human being.
Meiosis produces haploid gametes, resulting in 92 chromosomes instead of the normal human number.
Gametogenesis is the process of producing gametes or sex cells.
Oogenesis is the process of producing egg cells in females, occurring in the ovary.
Spermatogenesis is the process of producing sperm cells in males.
Meiosis involves two divisions: Meiosis I and Meiosis II.
Meiosis I includes stages like prophase one with five substages: leptotene, zygotene, pachytene, diplotene, and diakinesis.
Synapsis, the pairing of homologous chromosomes, occurs during prophase one.
Crossing over leads to genetic variation during pachytene stage.
Metaphase one involves the alignment of tetrads at the metaphase plate.
Anaphase one separates sister chromatids, resulting in two daughter cells with 23 chromosomes each.
Meiosis I is also known as reduction division due to the reduction of chromosome number.
Meiosis II is similar to mitosis but involves haploid cells from Meiosis I.
Meiosis II results in four haploid daughter cells, each with 23 chromosomes.
The final result of meiosis is four haploid cells, each with 23 chromosomes and 23 chromatids.
Meiosis ensures genetic diversity and the correct number of chromosomes in offspring.
Transcripts
Hello mga kabuhay ang topic natin ay
tungkol sa meiosis na isang uri po ng
cell division na nagaganap po sa
reproductive cell ng ating katawan first
ang meiosis reduces the amount of
genetic information sa reproductive cell
Dito po naipapasa ng magulang ang mga
traits from one generation to another
Generation ang dala-dala po ng ating mga
sex cells or gamits ay kalahati lang po
ng total chromosome ng isang human being
ang meiosis it produces haploid gamits
kung 46 chromosomes po ang dala-dala ng
sperm cell at nafti po ito o nagun doun
sa egg cell na may 46 chromosomes So
ilan po yung total 92 chromosomes it is
not the normal number of a human being
kalahati lang po dapat para mabuo po
Iyung 46 chromosomes na complete number
or the normal number of a human ang
meiosis din po ay nag-i ng four daughter
cells with half the number of
chromosomes of the parent cell
gametogenesis it is the process of
producing gamits or Sex cells sa female
tinatawag pong oogenesis it is the
process of producing egg cells in femal
so Saan po nagpo-produce ang oocyte no
which is the egg cell dito po sa loob ng
ovary ng isang female spermatogenesis it
is the process of producing sperm cells
in males So saan naman po ito
napo-promote
mga kabuhay bago po mag-start ang
meiosis there're still the interface
stage Just Like In mitosis kaya lang po
ang pagkakaiba ang meiosis Meron po
itong two division Ito po ang meiosis 1
and meiosis two so first po interface na
nandito ang gap one synthesis and gap
two so nagkakaroon ng preparation cell
growth nagpe-prepare na po para
mag-produce ng mga sex cells at sa
synthesis nagkakaroon po ng DNA
replication or Iyung number ng
chromosomes still the same pero Iyung
chromatid
nagre-repack poo din kung
cental spares nag-double po ba yan or
the centrosomes mga kabuhay 46
chromosomes po meron ang isang human
being so mga kabuhay kapag
nag-recommend bilang ng ating
chromosomes after interface so we have
still 46 chromosomes the chromatids
nag-recruit ng meiosis 1 is prophase one
ang prophase one has been subdivided
into five substages so we have the
leptonema zygoma pinem dipon and
diakinesis first po is the leptonema
from a Greek words meaning Tin threads
so during the lepto Tin stage the
replicated chromosomes begin to condense
and become visible with the light
microscope so nagiging condensed
nagiging thicker Nakikita na po ito with
an an ordinary light microscope Ilan po
ang chromosomes do sa prophase 1 46
chromosomes pero ang chromatid natin is
92 second substages po ng prophase one
ay tinatawag pong zyg nema or the
zygotic stage so Dito na po nag-start
yung tinatawag po nating synapsis ang
synapsis po is the pairing of the
homologous chromosomes it is consist of
four chromatids So it is referred to as
bivalent tetrad kaya caput tetrad
meaning apat na chromatids and bivalent
meaning two pairs the third stages p
kinema or pakiing stage Iyung synapsis
is already complete so synapse meaning
Iyung pairing po natin at this point mga
kabuhay sobrang shorter and thicker
yyung mga chromosomes nagkakaroon po ng
crossing over so meaning po yyung non
sister chromatids halimbawa Ito po yung
isang homologous chromosomes and yung
kulay blue yung another sister
chromatids So makikita po natin yung
part ng chromatid inner part nagkakaron
po ng cruising over so nagkakaroon po ng
exchanging of their segments nagkakaroon
po ng genetic variation ang pang-apat po
na substages sa propes one ay tinatawag
na diona or diploe stage from the word
dipl or in fold So it is the longer sub
phase of prophase one wherein the
chromosomes in each pair now stay mve
away from each other so yung synapsis or
the synaptonemal
Complex unti-unti po itong nawawala o
nag-disappear
[Musika]
nadi-discover R are even more condensed
and the chasma often terminal or move
down the chromatids to the end dito po
sa diakinesis yung nucleolus yung
nuclear membrane ay nawawala na po kaya
Makikita po natin ang mga chromosomes so
Naandito po sa cytoplasm so after po ng
diakinesis Ready na po para sa second
phase which is the metaphase one mga
kabuhay ano po ang naganap sa metaphase
one yung mga hus chromosomes na tetrad
pa rin po no naka-air up pa rin pero
hindi na ho sila talaga magkadikit Sila
po ay nag-move at naka-align sa
tinatawag po nating metaphase plate or
the equatorial plate at itong spindle
fiber na which is the polar microtubules
na pino-produce ng centrosome and the
centrioles ay naka-attach po dito sa
kinet Cor ng bawat chromosomes So kaya
meron din po tayong tinatawag na
kinetochore microtubules pair up po
natin which is the tetrad homologous
chromosomes natin
naka-orange nakadikit pa rin po yung
kanilang centromere then last spas po
which is called The telophase One hindi
na po bivalent tetrad ang tawag kasi '
ba naghiwalay na po doun sa anape one
ang tawag na po natin dito ay diads So
it is complete their migration to the
pole so nahati po Iyung ating
chromosomes dito po sa tepace one in
most species cytokinesis follows so
nagkakaroon din po ng cleavage foro
contractile ring hanggang sa maghiwalay
produce po tayo ng two daughter cells At
tandaan po natin mga kabuhay each cell
containing only one set of chromosomes
kaya ito pong first phase ng meiosis 1
tinatawag po itong reduction division
mga kabuhay ito po yyung result ng
number ng chromosomes and chromatids po
after meiosis 1 kaya tinatawag po itong
reduction division wherein yung 46
chromosomes po natin from the start and
after interpace nahati po ito sa dalawa
So meaning yyung two daughter cells na
na-produce natin after telophase 1 and
cytokinesis so nagkaroon po tayo ng 23
chromosomes doon sa isang cell and
another cell is 23 chromosomes kaya lang
po mga kabuhay Ilan po Iyung chromatids
still 46 po iyan so meaning po ang
naghiwalay lang iung pair up po natin sa
anaphase one so Yung isa po napunta dun
sa North Pole at yung isa naman po sa
opposite pole kasi kasi naka-align po
sila as tetrad bivalent so still naka
intact pa rin yung kanilang sister
chromatids h chromosomes so 23 * 2 na
chromatids is we have 46 chromatids pa
rin po pero 23 chromosomes na kasi hindi
na po siya pair yung isang ka pair po
niya napunta dito sa isang cell na
na-produce natin after meiosis 1 kaya po
tinawag na reduction division mga
kabuhay after po ng tepace 2 which is
the meiosis 1 may Kaunti lang pahinga
Then after po non mag-start na ulit ng
meiosis 2 so tinatawag po natin Ong
interkinesis so dito po sa meiosis 2 mga
kabuhay similar na po ito sa nagaganap
sa mitosis except lang po yung number ng
chromosomes kasi haploid po ang
cell na na-produce natin sa meiosis 1 so
dito po sa prophase 2 yung chromosomes
po nagiging condense ulit the nuclear
membrane and also the nucleolus
magdi-date iyan and at ang spindle fiber
na pino-produce ng centrosome unti-unti
po itong mafo-fall
plate or tinatawag po nating metaplas
plate and then divide mga kabuhay
spontaneous po ito no Sabay yung
dalawang daughter cells na na-produce po
natin sa miosis 1 so naka-align na po
ang mga chromosomes at naka-attach ang
spindle fiber dito sa kinetochore and
the centromere ng bawat chromosomes at
makikita po natin ang sister chromatids
nagpi-prepare na po ito para mag-move
away to each other next po natin is
anape 2 so The Sister chromatids po ay
nag-start na ho na mag-saya po ang tawag
na natin is monads and they start to
migrate to the opposite pose of the
spindle fiber so ito po ang kanilang
picture So makikita po natin na each
Sister chromatids no moves away to the
opposite Ces dala-dala po ng
reproductive cell yung mga traits na
pwede ho nating mamana sa ating mga
magulang and last phas po sa meiosis 2
is the telophase 2 wherein the monads
are the poles forming two groups of
chromosomes so Dito po mga kabuhay
kasabay po ng tepase 2 ay ang
cytokinesis so magkakaroon po ng
cleavage farrow contractile ring
hanggang sa
mag-seryoso
po sa meiosis 2 or the end of the cell
division which ay four haploid daughter
cells Bakit po haploid kasi nagdadala po
ito ng 23 chromosomes each and also so
23 chromatids each so mga kabuhay ito na
po yung summarization natin So after po
ng meiosis 2 so ' ba dito po tayo
nag-stop wherein sa meiosis 1 nagkaroon
po tayo ng 23 chromosomes each two
daughter cells at meron po itong tig 46
na chromatids pero after po ng meiosis 2
nahati po ulit ito from four haploid
daughter cells wherein Meron na pong
each daughter cells non na 23
chromosomes at Ilan pong chromatids 23
din mga kabuhay Maraming salamat sa inyo
pong patuloy na pagsubaybay sa aking mga
tutorial video kaya kung Bago pa lang po
kayo sa aking channel so don't forget to
like and subscribe at marami pa po
tayong mga topic I hope na naintindihan
po natin Yung naganap dito po sa
tinatawag nating meiosis or the redu
division kaya mga kabuhay stay healthy
at Good luck sa inyong mga pag-aaral God
bless every one bye
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