Reproduction
Muhtasari
Pull a strawberry plant out of a bed in late summer and you will find it trailing a thin horizontal stem across the soil, with a small rooted plant at the far end. That little plant had no other parent. Every gene it carries came from the plant you are holding. A few metres away, a bee is carrying pollen between two flowers, and the seed that results from that visit will carry instructions from two different individuals. Both events are reproduction, and the difference between them shapes almost everything that follows in genetics.
This lesson takes the two forms apart. You will see what a gamete is and what actually happens when two of them fuse, why that fusion produces offspring that resemble their parents without copying either of them, and why reproduction from a single parent gives you offspring so alike that biologists call them clones. Then you will weigh the two against each other the way an examiner does: not asking which is better, but asking which one wins in a particular field, on a particular farm, in a particular changing climate.
Malengo
- There are two forms of reproduction: sexual reproduction - the joining (fusion) of male and female gametes. The mixture of the genetic information from two parents leads to variety in the offspring; asexual reproduction - no fusion of gametes and only one individual is needed as the parent. There is no mixing of genetic information and so no genetic variation in the offspring. These genetically identical individuals are known as clones.
Ramani ya mawazo
Mada hii imechorwa ili uone jinsi mawazo yanavyounganika.
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Maelezo ya Somo
Dokezo Kamili la Somo Linapatikana kwenye Programu ya Green Bridge
Pata programu ya Green Bridge CBT kwenye simu au kompyuta yako kwa maktaba kamili ya IGCSE: mitihani ya miaka iliyopita, miongozo ya usahihishaji, ramani za mawazo, kadi za marudio na masomo ya sauti.
Tathmini ya Somo
Hongera kwa kukamilisha somo la Reproduction. Sasa kwa kuwa umechunguza dhana na mawazo muhimu, ni wakati wa kuweka ujuzi wako kwa mtihani. Sehemu hii inatoa mazoezi mbalimbali maswali yaliyoundwa ili kuimarisha uelewaji wako na kukusaidia kupima ufahamu wako wa nyenzo.
Utakutana na mchanganyiko wa aina mbalimbali za maswali, ikiwemo maswali ya kuchagua jibu sahihi, maswali ya majibu mafupi, na maswali ya insha. Kila swali limebuniwa kwa umakini ili kupima vipengele tofauti vya maarifa yako na ujuzi wa kufikiri kwa makini.
Tumia sehemu hii ya tathmini kama fursa ya kuimarisha uelewa wako wa mada na kubaini maeneo yoyote ambapo unaweza kuhitaji kusoma zaidi. Usikatishwe tamaa na changamoto zozote utakazokutana nazo; badala yake, zitazame kama fursa za kukua na kuboresha.
- Which statement about asexual reproduction is correct? A. Two parents are needed B. Male and female gametes fuse C. The offspring are genetically identical to the parent D. The offspring show a wide range of genetic variation Answer: C
- A human body cell contains 46 chromosomes. How many chromosomes are in a human sperm cell? A. 11 B. 23 C. 46 D. 92 Answer: B
- What is a clone? A. A cell formed when two gametes fuse B. A group of genetically identical individuals produced from one parent C. A sex cell with a single set of chromosomes D. An offspring produced from two parents of different varieties Answer: B
- Which of these is produced by sexual reproduction? A. A potato plant grown from a tuber B. A strawberry plant at the end of a runner C. A seedling grown from a seed D. A new Hydra formed as a bud on the side of a parent Answer: C
- Why can a population of genetically identical plants be destroyed completely by a new disease? A. The plants are always grown close together B. The plants have no way of reproducing C. No individual differs from the others, so none is likely to be resistant D. Cloned plants grow more slowly than plants grown from seed Answer: C
Fanyia kazi maswali haya kwenye programu
Fanyia kazi maswali haya kwenye programu
Vitabu Vinavyopendekezwa
Fanya Mazoezi ya Maswali ya Majaribio
Ungependa kufanya mazoezi ya maswali ya majaribio kuhusu Reproduction? Pakua programu ya Green Bridge CBT ili kupata maswali ya majaribio na tathmini kamili za mazoezi kuhusu mada hii.
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