Cell Division
Bayani Gaba-gaba
You began as one cell. That cell held a full instruction set, and it did something remarkable: it copied every instruction, split in half, and handed a complete set to each of the two cells it became. Those two did it again, and again, and the repetition never really stopped. The skin you shed this morning is being replaced right now by the same process, running quietly in a layer of cells you will never see.
This lesson follows that process in two very different versions. One makes copies so faithful that the new cells are indistinguishable from the old, and it builds bodies and keeps them stocked. The other deliberately halves the instruction set, and without it sexual reproduction would double the chromosome number in every generation until nothing worked. You will learn what a chromosome actually carries, why body cells hold them in pairs, where each kind of division happens, what comes out of it, how fertilisation puts the pairs back together, and why a single fertilised egg can end up producing cells as unalike as a nerve cell and a red blood cell.
Manufura
- The nucleus of a cell contains chromosomes. Chromosomes carry genes that control the characteristics of the body. Each chromosome carries a large number of genes.
- Many genes have different forms called alleles, which may produce different characteristics.
- In body cells the chromosomes are normally found in pairs.
- Body cells divide by mitosis to produce additional cells during growth or to produce replacement cells.
- When a body cell divides by mitosis: copies of the genetic material are made; the cell then divides once to form two genetically identical body cells.
- Cells in reproductive organs divide to form gametes.
- A cell divides to form gametes by meiosis.
- When a cell divides to form gametes: copies of the genetic information are made; the cell then divides twice to form four gametes, each with a single set of chromosomes.
- Gametes join at fertilisation to form a single body cell with new pairs of chromosomes. This cell repeatedly divides by mitosis to form many cells. As an organism develops, these cells differentiate to form different kinds of cells.
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Takardar Darasi
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Nazarin Darasi
Barka da kammala darasi akan Cell Division. Yanzu da kuka bincika mahimman raayoyi da raayoyi, lokaci yayi da zaku gwada ilimin ku. Wannan sashe yana ba da ayyuka iri-iri Tambayoyin da aka tsara don ƙarfafa fahimtar ku da kuma taimaka muku auna fahimtar ku game da kayan.
Za ka gamu da haɗe-haɗen nau'ikan tambayoyi, ciki har da tambayoyin zaɓi da yawa, tambayoyin gajeren amsa, da tambayoyin rubutu. Kowace tambaya an ƙirƙira ta da kyau don auna fannoni daban-daban na iliminka da ƙwarewar tunani mai zurfi.
Yi wannan ɓangaren na kimantawa a matsayin wata dama don ƙarfafa fahimtarka kan batun kuma don gano duk wani yanki da kake buƙatar ƙarin karatu. Kada ka yanke ƙauna da duk wani ƙalubale da ka fuskanta; maimakon haka, ka kallesu a matsayin damar haɓaka da ingantawa.
- How many chromosomes are present in a human gamete? A. 23 B. 46 C. 92 D. 12 Answer: A
- Which statement describes what happens when a body cell divides by mitosis? A. The genetic material is copied and the cell divides twice B. The genetic material is copied and the cell divides once C. The cell divides once and the genetic material is then copied D. The genetic material is halved and the cell divides once Answer: B
- How many cells are produced when one cell divides by meiosis? A. One B. Two C. Four D. Eight Answer: C
- What is an allele? A. A length of DNA that carries many genes B. An alternative form of a gene C. A cell that has developed structures suited to one job D. A pair of matching chromosomes Answer: B
- A plant body cell contains 24 chromosomes. How many chromosomes are present in one of its gametes? A. 6 B. 12 C. 24 D. 48 Answer: B
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Yi aikin wadannan tambayoyi a cikin manhaja
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Yi Aikin Tambayoyin Gwaji
Kana son yin aikin tambayoyin gwaji kan Cell Division? Sauke manhajar Green Bridge CBT don samun tambayoyin gwaji da cikakkun jarrabawa akan wannan batu.
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