General Biology 1 Quarter 1 Module 6 PDF Philippines

GOVERNMENT PROPERTY NOT FOR SALE 11 GENERAL BIOLOGY 1 Describe the Stages of Mitosis/Meiosis given in 2n=6 Quarter 1 DEPARTMENT OF EDUCATION...

GOVERNMENT PROPERTY NOT FOR SALE 11 GENERAL BIOLOGY 1 Describe the Stages of Mitosis/Meiosis given in 2n=6 Quarter 1 DEPARTMENT OF EDUCATION Republic of the Philippines 1|P age General Biology I  WHAT I NEED TO KNOW What is mitosis/meiosis? Describe the stages of mitosis/meiosis? At the end of the module, you will be able to; ✓ Describe the stages of mitosis/meiosis given 2n=6 (S8LT-IVD-16-FIRST QUARTER- MEIOSIS) WHAT I KNOW Before you go deeply to our lesson, let us first find out what you’ve already know about this topic. Read the questions carefully and answers it to the best as you can. Good luck!!! Direction: Read the questions carefully and encircle the letter of your choice. 1. DNA sequence that control traits are called? a. Proteins b. Enzymes c. Characteristics d. Genes 2. Meiosis is a type of cell division that will produce? a. Packets of pollen to be transferred between the abdomen of insects b. The male and female sex cells c. 2 new somatic cells d. Exact copies of the parent cell 3. During the process of____________, 2 daughter cells will be created with identical DNA. a. DNA Replication b. Meiosis c. Mitosis d. Protein Synthesis 4. When is DNA duplicated in germ line cells? a. In G1 phase b. In S phase c. In G2 phase d. During meiosis 5. During the process of __________ 4 daughter cells will be created with different DNA pattern. a. Protein synthesis b. Mitosis c. Meiosis d. DNA Replication 6. How many chromosomes are found in the human body? a. 26 b. 46 c. 72 d. 23 2|P age General Biology I  7. How many chromosomes are found in human sex cell? a. 26 b. 46 c. 72 d. 23 8. Synapsis is the process whereby? a. Homologous pairs of chromosomes separate and migrate toward a pole b. Homologous chromosomes become closely associated c. The daughter cells contain half of the generic material of the parent cell d. Homologous chromosomes exchange chromosomal materials 9. Mitosis results in two ________ cells, while meiosis results in __________ haploid cells a. Haploid /four b. Haploid/two c. Diploid/two d. Diploid/four 10. In this phase the centrioles are at the opposite poles of the cells? a. Metaphase I b. Anaphase I c. Metaphase II d. Anaphase II GOOD JOB!!!!! I think it’s time for you to learn and discover more about our lesson. WHAT’S IN Now let’s get started……label the parts of the cell cycle. GREAT PERFORMANCE!!!!! It’s a time for us to go to our lesson….. 3|P age General Biology I  WHAT’S NEW The cell (from Latin cella, meaning "small room") is the basic structural, functional, and biological unit of all known organisms. A cell is the smallest unit of life. Cells are often called the "building blocks of life" A cell cycle is a series of events that takes place in a cell as it grows and divides. A cell spends most of its time in what is called interphase, and during this time it grows, replicates its chromosomes, and prepares for cell division. The cell then leaves interphase, undergoes mitosis, and completes its division. Our chromosome number is 46 for the existence of any space chromosome number should be maintained we inherited the genetic program from our parents 23 chromosomes derived from father and 23 from mother that is why we have many characters similar to our parents often use them “hereditary” to call this similarity but maintain the chromosome number to 46, a vital process has occurred reduction is chromosome number to half egg and sperm. What is Mitosis? MITOSIS a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth. "the single large egg cell subdivides by repeated mitosis. What happen during mitosis? During mitosis, a eukaryotic cell undergoes a carefully coordinated nuclear division that results in the formation of two genetically identical daughter cells. Mitosis itself consists of five active steps, or phases: prophase, prometaphase, metaphase, anaphase, and telophase PHASES OF MITOSIS PROPHASE Prophase is the first stage of cell division in both mitosis and meiosis. Beginning after interphase, DNA has already been replicated when the cell enters prophase. The main occurrences in prophase are the condensation of the chromatin and the disappearance of the nucleolus. 4|P age General Biology I PROMETAPHASE Prometaphase is the phase of mitosis following prophase and preceding metaphase, in eukaryotic somatic cells. In prometaphase, the nuclear membrane breaks apart into numerous "membrane vesicles", and the chromosomes inside form protein structures called kinetochores. Kinetochore microtubules emerging from the centrosomes at the poles (ends) of the spindle reach the chromosomes and attach to the kinetochores, throwing the chromosomes into agitated motion. [ Other spindle microtubules make contact with microtubules coming from the opposite pole. Forces exerted by protein "motors" associated with spindle microtubules move the chromosomes toward the centre of the cell. Prometaphase is not always presented as a distinct part of mitosis. In sources that do not use the term, the events described here are instead assigned to late prophase and early metaphase. METAPHASE Metaphase is a stage of mitosis in the eukaryotic cell cycle in which chromosomes are at their second- most condensed and coiled stage (they are at their most condensed in anaphase) These chromosomes, carrying genetic information, align in the equator of the cell before being separated into each of the two daughter cells. Metaphase accounts for approximately 4% of the cell cycle's duration. Preceded by events in prometaphase and followed by anaphase, microtubules formed in prophase have already found and attached themselves to kinetochores in metaphase. In metaphase, the centromeres of the chromosomes convene themselves on the metaphase plate (or equatorial plate), an imaginary line that is equidistant from the two centrosome poles. This even alignment is due to the counterbalance of the pulling powers generated by the opposing kinetochore microtubules, analogous to a tug-of-war between two people of equal strength, ending with the destruction of B cyclin. In certain types of cells, chromosomes do not line up at the metaphase plate and instead move back and forth between the poles randomly, only roughly lining up along the middle line. Early events of metaphase can coincide with the later events of prometaphase, as chromosomes with connected kinetochores will start the events of metaphase individually before other chromosomes with unconnected kinetochores that are still lingering in the events of prometaphase. One of the cell cycle checkpoints occurs during prometaphase and metaphase. Only after all chromosomes have become aligned at the metaphase plate, when every kinetochore is properly attached to a bundle of microtubules, does the cell enter anaphase. It is thought that unattached or improperly attached kinetochores generate a signal to prevent premature progression to anaphase, even if most of kinetochores have been attached and most of the chromosomes have been aligned. Such a signal creates the mitotic spindle checkpoint. This would be accomplished by regulation of the anaphase-promoting complex, securin, and separase. 5|P age General Biology I ANAPHASE Anaphase is the stage of mitosis after the process of metaphase, when replicated chromosomes are split and the newly-copied chromosomes (daughter chromatids) are moved to opposite poles of the cell. Chromosomes also reach their overall maximum condensation in late anaphase, to help chromosome segregation and the re-formation of the nucleus. Anaphase starts when the anaphase promoting complex marks an inhibitory chaperone called securin for destruction by ubiquinylating it. Securin is a protein which inhibits a protease known as separase. The destruction of securin unleashes separase which then breaks down cohesin, a protein responsible for holding sister chromatids together. At this point, three subclasses of microtubule unique to mitosis are involved in creating the forces necessary to separate the chromatids: kinetochore microtubules, interpolar microtubules, and astral microtubules. The centromeres are split, and the sister chromatids are pulled toward the poles by kinetochore microtubules. They take on a V-shape or Y-shape as they are pulled to either pole. While the chromosomes are drawn to each side of the cell, interpolar microtubules and astral microtubules generate forces that stretch the cell into an oval. Once anaphase is complete, the cell moves into telophase. TELOPHASE Telophase is the final stage in both meiosis and mitosis in a eukaryotic cell. During telophase, the effects of prophase and prometaphase (the nucleolus and nuclear membrane disintegrating) are reversed. As chromosomes reach the cell poles, a nuclear envelope is re-assembled around each set of chromatids, the nucleoli reappear, and chromosomes begin to decondense back into the expanded chromatin that is present during interphase. The mitotic spindle is disassembled and remaining spindle microtubules are depolymerized. Telophase accounts for approximately 2% of the cell cycle's duration. 6|P age General Biology I  Cytokinesis typically begins before late telophase and, when complete, segregates the two daughter nuclei between a pair of separate daughter cells. Telophase is primarily driven by the dephosphorylation of mitotic cyclin-dependent kinase (Cdk) substrates. What is Meiosis? MEIOSIS is a special type of cell division in which chromosomes duplicate only once, but the cell divides twice. So one parental cell produces 4 daughter cells, each having half the chromosome number and DNA amount than the normal parental cell. So meiosis is called “Reductional Division” 7|P age General Biology I  MEIOSIS I It is also called as Reductional division or Heterotypical division. It involves the formation of two daughter cells which have chromosome number half to those of parental cell It divided into three part; A. INTERPHASE B. KARYOKINESIS It involves 4 phases Prophase I Metaphase I Anaphase I Telophase I C. CYTOKINESIS A. INTERPHASE a. Prior to meiosis, all chromosomes are duplicated in a process similar chromosome duplication prior to mitosis. b. Outside the nucleus of animal cells are centrosomes, each containing a pair of centrioles. The two centrosomes, each containing a pair of centrioles. The two centrosomes are produced by the duplication of a single centrosome during premeiotic interphase. The centrosomes serve as microtubule organizing centers (MTOCs). Microtublues extend radially from centrosomes. Forming an aster. c. Gap 1 (G1) This is the phase in which the cell undergoes normal growth and cell function synthesizing high amounts of proteins. The cell increases in size and volume as more cell organelles are produced. The cell can only move to the next phase, S after synthesizing enough ribosome. As the phase is almost done, the mitochondria of the cell fuse into a network of mitochondria for effective energy production for cell processes.If the cell cannot divide again, it enters the G0. d. Synthesis, S phase This is the phase when the cell synthesizes and doubles its DNA. During doubling, the number of chromosomes remains constant, a process is known as semi conservative replication. Additionally, new packaged proteins known as histones, wrap around the DNA copies to make it stable. During the S phase, more phospholipids are produced which make up the cell membrane and the membranes of the cell organelles. e. Gap 2 (G2) During this phase, the cell continues its growth phase as it prepares for cell division. Mitochondria will divide and continue to grow until the start of mitosis. Also, the plant chloroplast also divides in this phase. At the end of Gap 1 (G1), the cell is controlled by a checkpoint known as the G1/S whereby, the cell is scrutinized on whether to undergo replication or not. It is at this checkpoint that DNA damages or errors are checked to ensure that cell division thrives. 8|P age General Biology I  During checking, various proteins interact with the DNA a mechanism known as molecular switching. The molecular switch is an on and off process and it continues through the S phase which allows the damaged cells to undergo apoptosis (programmed cell death).At the G2 phase again, a second checkpoint takes place after the synthesis of DNA in the S phase. The second checkpoint uses kinase enzymes which control various stages in cell division cycles. A typical example of a kinase enzyme in cell division is the Cyclin- Dependent Kinase (CDK) which uses cell signals to switch cell mechanisms especially when a genetic mutation is detected. The Cyclin-Dependent Kinase is activated by regulatory protein complexes (tumor suppressors) that control cell growth and induce apoptotic mechanisms of errored cells. In the case of a genetic mutation in the regulatory proteins at the checkpoint, a permanent molecular switch is turned on leading to uncontrolled cell multiplication which may lead to carcinogenesis or development of tumors. Additionally, in case the cell misses on the second checkpoint, cancer cells may develop for example neoplasia develops due to unchecked cell division. B. KARYOKINESIS PROPHASE I It is a long process during which homologous chromosomes pair closely and interchange hereditary material. It is divided into 5 sub-stages: a. Leptotene - each chromosome is attached at both of its end to the nuclear envelope - each chromosome replicate into two sister chromatids b. Zygotene - It begins as pairing between the two members of each homologous chromosome pair is initiated by synapsis. - The homologous chromosome comprises one chromosome derived from each parent - As the result of synapsis each gene is brought together through synaptonemal complex - The chromosome produced is called tetrad 9|P age General Biology I  c. Phacytene - The exchange of genes or CROSSING- OVER between the non-sister chromatids of the homologous chromosomes occurs at points called RECOMBINATION NODULES which appear at intervals on the synaptonemal complex. - The non-sister chromatids twist around and exchange segments with each other. This process is known as Generic Recombination. d. Diplotone - It is the longest duration - Nuclear membrane and nucleoli start disappearing - Separation of paired homologous chromosomes - Homologous chromosomes however remain attached at one more points where crossing over has occurred. These points of attachment are called chiasmata. - As desynapsis proceeds, the chiasmata start moving towards the ends of the chromosome. This is called TERMINALIZATION. - e. Daikinesis - It involves complete disappearance of nuclear membrane and nucleoli - Formation of spindle - Termination of chiasmata - RNA synthesis stops and the chromosomes condense, thicken and become attached to nuclear envelope. - Each pair of sister chromatids is attached to nuclear envelope. - Each pair of sister chromatids of homologous chromosome are in contact with each other at or near their telomeres. _____________________________________________________________________________________ METAPHASE I The centrioles are at the opposite poles of the cell. The bivalents arrange themselves in two parallel equatorial plane called (METAPHASE PLATES). Each of the homologous chromosomes has two KINETOCHORES. These both kinetochores of a chromosome are joined to the spindle fibers of the same side pole. _____________________________________________________________________________________ 10 | P a g e General Biology I  ANAPHASE I At Anaphase I, two duplicated homologous separate from each other and move to opposite poles of the spindle. Notice that in anaphase I the sister chromatids remain attached at their centromeres and move together toward the poles. A key difference between mitosis and meiosis is that chromatids remain joined after metaphase in meiosis I, whereas in mitosis they separate. _____________________________________________________________________________________ TELOPHASE I The homologous pairs complete their migration to two poles as a result of the action of the spindle. Now a haploid set of chromosomes is at each pole, with each chromosome still having two chromatids. The nuclear membranes are formed during this stage by endoplasmic reticulum around the group of daughter chromosomes. One nucleus appears in each nucleus. The formation of two daughter cell with haploid number of chromosomes. It the time of the disappearance of centrosome. The chromosomes undergo decondensation by hydration and change into long and thread-like chromatin fibers. _____________________________________________________________________________________ 11 | P a g e General Biology I  C. CYTOKINESIS Cell divides by cell- furrow formation. Meiosis I does not produce daughter cells with a haploid amount of DNA. Because the sister chromatids behave as one unit, each daughter cell of this division inherits two copies of one of the homologous. The two copies are identical except where genetic recombination has occurred. The two daughter cells therefore, contain a haploid the number of chromosomes (due to disjunction) but diploid amount of DNA. _____________________________________________________________________________________ MEIOSIS II Formation of actual number of variants is very much greater because of a second cell division, division II of meiosis, without further DNA replication. It is called eaquational division (similar to mitosis). Meiosis II is divided into: INTERKINESIS, KARYOKINESIS II and CYTOKINESIS II A. INTERKINESIS It is the period between telophase I of meiosis I and prophase II of meiosis II. It involves only protein and RNA synthesis and there is no DNA synthesis. B. KARYOKENISES II It involves disappearance of nuclear membrane and nucleolus. It involved only protein and RNA synthesis and there is no DNA synthesis. 12 | P a g e General Biology I  PROPHASE II It involves disappearance of nuclear membrane and nucleolus. Condensation of chromatin fibers into a definite number of chromosomes. _____________________________________________________________________________________ METAPHASE II Each of the daughter cells complete the formation of the spindle apparatus. It involves arrangement of duplicated chromosomes on equatorial plane. Centromeres lie at the equator while the other arms are directed towards the poles. For each chromosome, the kinetochores of the sister chromatids face the opposite poles, and each is attached to a kinetochore microtubule coming from that pole. _____________________________________________________________________________________ ANAPHASE II The centromere divided and two chromatids of each chromosome separate and move toward the poles. After separation each chromatid becomes chromosome. _____________________________________________________________________________________ 13 | P a g e General Biology I  TELOPHASE II Disappearance of spindle fibers. The four groups of chromosomes become organized into four haploid nuclei. The endoplasmic reticulum forms the nuclear envelope around the chromosomes and nucleolus appears. Each nucleus at this stage contains the haploid number of chromosomes and forms four cell. _____________________________________________________________________________________ C. CYTOKINESIS II Cytokinesis II takes place, by cell furrow formation, producing four daughter cells( gametes, in animals), each with haploid set of chromosomes. _____________________________________________________________________________________. 14 | P a g e General Biology I  WHAT’S MORE A. The diagram below shows six cells in various phases of the cell cycle. Note the cells are not arranged in the order in which mitosis occurs and one of the phases of mitosis occurs twice. Use the diagram to answer questions 1-6. 1. Cells A and F show an early and a late stage of the same phase of mitosis. What phase it is? __________________________________________________________________________ 2. Which cell is metaphase? __________________________________________________________________________ 3-4. Which cell is in the first phase of mitosis? (2 possible answers) __________________________________________________________________________ 5. In cell A, what structure is labeled X? __________________________________________________________________________ 6. What cell is “in between” phase of mitosis? __________________________________________________________________________ B. On the lines provided, order the different stages of meiosis I through meiosis II, including interphase in the proper sequence. _____________7. Homologous chromosome line up in the center of the cell. _____________8. Spindle fibers pull homologous pairs to ends the cell. _____________9. 4 haploid (N) daughter cells form. _____________10. Cells undergo around of DNA replication. _____________11. Sister chromatids separate from each other _____________12. 2 diploid (N) daughter cells form. _____________13. Spindle fibers attach to the homologous chromosome pairs _____________14. Individual chromatids move to each end of the cell. _____________15. Crossing-over (if any) occurs. 15 | P a g e General Biology I  WHAT I HAVE LEARNED The cell (from Latin cella, meaning "small room") is the basic structural, functional, and biological unit of all known organisms. A cell is the smallest unit of life. Cells are often called the "building blocks of life" A cell cycle is a series of events that takes place in a cell as it grows and divides. A cell spends most of its time in what is called interphase, and during this time it grows, replicates its chromosomes, and prepares for cell division. The cell then leaves interphase, undergoes mitosis, and completes its division. Our chromosome number is 46 for the existence of any space chromosome number should be maintained we inherited the genetic program from our parents 23 chromosomes derived from father and 23 from mother that is why we have many characters similar to our parents often use them “hereditary” to call this similarity but maintain the chromosome number to 46, a vital process has occurred reduction is chromosome number to half egg and sperm. ✓ MITOSIS a type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth."the single large egg cell subdivides by repeated mitosis. ✓ During mitosis, a eukaryotic cell undergoes a carefully coordinated nuclear division that results in the formation of two genetically identical daughter cells. ✓ Mitosis itself consists of five active steps, or phases: prophase, prometaphase, metaphase, anaphase, and telophase ✓ MEIOSIS is a special type of cell division in which chromosomes duplicate only once, but the cell divides twice. So one parental cell produces 4 daughter cells, each having half the chromosome number and DNA amount than the normal parental cell. So meiosis is called “Reductional Division” ✓ Meiosis I ✓ It is also called as Reductional division or Heterotypical division. ✓ It involves the formation of two daughter cells which have chromosome number half to those of parental cell ✓ It divided into three part; INTERPHASE, KARYOKINESIS (It involves 4 phases: Prophase I, Metaphase I, Anaphase I, Telophase I and CYTOKINESIS. ✓ Meiosis II ✓ Formation of actual number of variants is very much greater because of a second cell division, division II of meiosis, without further DNA replication. ✓ It is called eaquational division (similar to mitosis). ✓ Meiosis II is divided into: INTERKINESIS, KARYOKINESIS II and CYTOKINESIS II 16 | P a g e General Biology I  WHAT CAN I DO Directions. Fill in the blanks using the word bank below. ______________1. In what phase does the cell begin to split the cytoplasm and daughter cells first become visible in mitosis? ______________2. During what phase of mitosis do centromeres divide and the chromosomes move toward respective poles. ______________3. What is the phase where chromatin condenses to form chromosomes? ______________4. What is the name of the structure that connects two sister chromatids? ______________5. In a chromosome pair connected by a centromere, what is each individual chromosome half called? ______________6. What is the step of cell division where 2 identical daughter cells are formed? ______________7. Which phase of the cell cycle occurs when the cell is preparing to divide so it grows in size making organelles and copying DNA. ______________8. What forms across the center of a plant cell near the end of telophase? ______________9. What is the division of the cytoplasm called? ______________10. During this phase chromosomes line up in the middle. ASSESSMENT A. Match the term to the description. I= INTERPHASE P= PROPHASE M= METAPHASE A= ANAPHASE T= TELOPHASE ______1. The sister chromatids are moving apart. ______2. The spindle fiber is formed. ______3. Chromatids line up along the equator. ______4. The chromosomes are located at the equator of the cell. ______5. Cytokinesis begin. B. Answer the following brieftly. 1. Compare the number and type of cells that result from meiosis vs mitosis. MITOSIS:__________________________________________________________ MEIOSIS:__________________________________________________________ 2. How do the genetic contents of cells resulting from mitosisand meiosis differ? MITOSIS:__________________________________________________________ MEIOSIS:__________________________________________________________ 17 | P a g e General Biology I  ADDITIONAL ACTIVITIES Match the term to the description. L= LEPTOTENE Z= ZYGOTENE P=PHACYTENE D= DIPLOTENE DA=DAIKINESIS __________1. It begins as pairing between the two members of each homologous chromosome pair is initiated by synapsis. __________2. It involves complete disappearance of nuclear membrane and nucleoli __________3. Each chromosome replicate into two sister chromatids. __________4. Nuclear membrane and nucleoli start disappearing. __________5. The non-sister chromatids twist around and exchange segments with each other. 18 | P a g e General Biology I ANSWER KEY: WHAT I KNOW 1. A 6. B 2. B 7. D 3. C 8. B 4. C 9. D 5. B 10. A WHAT’S IN A. PROPHASE B. METAPHASE C. ANAPHASE D. TELOPHASE E. INTERPHASE 1. Centriole ( aster) 6. Cell membrane 2. Spindle fiber 7. Nucleulos 3. Chromatids 8. Centrioles 4. Daughter cells 9. Chromosome 5. Chromatin 10. Nuclear membrane WHAT’S MORE A. B. 1. PROPHASE 7. METAPHASE I 2. C 8. ANAPHASE 3.-4. A( 1ST Prophase) D( 1ST Interphase) 9. TELOPHASE 5. CENTRIOLES 10. INTERPHASE 6. D 11. ANAPHASE II 12. TELOPHASE I 13. PROPHASE I 14. ANAPHASE II 15. PROPHASE II WHAT CAN I DO 1. Telophase 6. Cytokinesis 2. Anaphase 7. Interphase 3. Prophase 8. Cell plate 4. Centromere 9. Cytokinesis 5. Sister chromatids 10. Metaphase ASSESSMENT A. Answer will found at page 13 B. 1. A 2. P 3. M 4. M 5. T C. 1. MITOSIS: 2 identical cells MEIOSIS: 4 non identical cells 2.MITOSIS: 2n( diploid)(full set of chromosome) MEIOSIS: n(haploid)(half of set of chromosome) 19 | P a g e General Biology I ADDITIONAL ACTIVITIES 1. Z=ZYGOTENE 2. DA=DAIKINESIS 3. L=LEPTOTENE 4. D=DIPLOTENE 5. P=PHACYTENE References: Albert (2020). What is the Difference Between Meiosis I and Meiosis II?. https://www.albert.io/blog/difference-between-meiosis-i-and-meiosis-ii. Shannan Muskopf(2018). Cell Cycle Labeling. https://www.biologycorner.com/2018/06/11/cell-cycle-labeling/ https://www.pinterest.ph/pin/502855114645134968/ https://en.wikipedia.org/wiki/Mitosis https://www.yourgenome.org/facts/what-is-meiosis https://www.khanacademy.org/science/ap-biology/cell-communication-and-cell-cycle/regulation-of-cell- cycle/a/cancer https://www.nature.com/scitable/topicpage/mitosis-and-cell-division-205/ https://ib.bioninja.com.au/standard-level/topic-3-genetics/33-meiosis/stages-of-meiosis.html 20 | P a g e General Biology I