[Science] Injectable Contraceptive, 3 Parent Baby, Twins, Clones, Types of Sexual and Asexual Reproductions in Plants and AnimalsDEVENDRA VISHWAKARMA
- Reproduction: Two Types
- Asexual reproduction: Subtypes
- Sexual reproduction in plants
- Pollinating Agents: Two Types
- Pollination: Two types
- Fruits: Types of
- Sexual reproduction in Animals
- Family planning Methods Classification
- Current Affairs: Injectable contraceptives
- Current Affairs: Three Parent Baby
- Twin Babies- Theory
- Cloning- Theory
- Surrogacy: theory
- “Reproduction” related Current affairs topics in news 1) injectable contraceptive 2) three parent baby.
- And since UPSC combined the preliminary exam of both civil services and forest services- agriculture / plant reproduction related things also need to be prepared.
- इसलिए भगवान का नाम लेके let’s take a look at both theory and current of “reproduction”.
Reproduction: Two Types
|Faster||Slower, because gestation period involved|
|Plants and lower organisms can do it.||Plants and higher organisms do it.|
Asexual reproduction: Subtypes
|Budding||bulb-like projection or outgrowth arises from the parent body and makes new baby. Eg. Hydra, yeast, bryophyllum.|
|Regeneration or Fragmentation||an individual breaks up into two or more parts and each part develops into a complete individual. Examples: Spirogyra, Planaria.|
|Spore formation||Protoplast of the cell divides to form 4–8 spores/ zoospores. E.g. Fungi, Chlamydomonas, Moss, fern, rhizopus.|
|any vegetative part of the plant body like leaf, stem or root develops into a complete new plant. This can happen either naturally or artificially:
Q. What are the characteristics of vegetative propagation?
- All plants produced are genetically similar to the parent plant to have all its characteristics
- It’s possible to replicate plants that have lost capacity to product seeds e.g. banana, orange, rose and jasmine.
- Such reproduced plants bear fruits and flowers faster than the ‘naturally’ cross-pollinated plants.
- All of above.
Sexual reproduction in plants
- Spherical. Produced in male part of flower, and sent to female part.
- Considered to increase performance of athletes and race horses. Hence pollent tablets used as “food supplements” in first world.
- Can cause allergy. e.g. carrot grass (Parthenium) in imported wheat. [given in class-12 NCERT, hence needs to be remembered]
Pollinating Agents: Two Types
Pollination: Two types
|Cross pollination /
In either method: male + female fusion -> fertilization -> Zygote -> endosperm->embryo-> mature ovary-> fruit -> seed.
Fruits: Types of
|False fruit||They are born from parts other than ovaries. E.g. Apple, strawberry, cashew, jackfruit, pineapple.|
|True fruit||They are born only from ovaries. Mango, Maize, Grape|
|Parthenocarpic fruit||Fruits develop without fertilization e.g. Banana, seedless grape-orange-watermelons. This is done via growth hormones and the resultant fruit is seedless.|
Seed dispersing agents
Seed is the final product of sexual reproduction in angiosperms.
|Wind||Drumstick, maple, aak (Madar), sunflower. Their seeds get blown by wind to faraway places|
|Water||Coconuts because they’ve floating ability.|
|Animals||Xanthium and Urena: they’ve hooks that attach to fur of sheep / goat.|
Q. Seed dispersal helps the plants to
- prevent overcrowding
- avoid competition for sunlight, water and minerals
- invade new habitats.
- All of above
Sexual reproduction in Animals
|In vitro fertilization||
|Internal fertilization / in-vivo||
Family planning Methods Classification
|Methods prevent of fertilization and conception. Three types
|If preventive or contraceptive method not used or fails, then fetus destroyed using these methods. Also known as Medical Termination of Pregnancy (MTP)
Current Affairs: Injectable contraceptives
- Injection of Deoxymedroxy progesterone acetate (DMPA).
- Given to the arm or buttock muscle every 3 months.
- It blocks Luteinizing Hormone (LH) –> hence Ovulation doesn’t take place -> egg doesn’t goto ovary -> sperm and egg can’t meet.
- Why in News? Health ministry told parliament that it’ll be given free to Government hospitals and primary health centres (PHC)
Q. Injectable contraceptive contains ___ hormone?
- Luteinizing hormone
- None of the above
Current Affairs: Three Parent Baby
Old topic from 2013-14. But again in NEWs because one such baby born in Q3-2016.
- Mitochondria crucial to the energy supply of cells.
- Defective Mitochondria will disrupt energy supply to muscles, heart, liver and brain.
- In Britain alone, around one in 6,500 children is born annually with a severe mitochondrial disease like muscular dystrophy.
- Mitochondrial diseases are incurable.
- Current methods can only reduce but not eliminate the risk; no treatment is available either.
Solution: mitochondrial transfer/ 3-Parent IVF
|Mom||gives egg but her DNA material has defective genes for Mitochondria. So that part related to Mitochondria is removed.|
|donor (female)||gives DNA that has right ‘codes’ for healthy Mitochondria.|
- Thus, with help of genetic material from ^three people, an IVF baby is created. Embryo transferd to mother and baby is born without any disease related to mitochondria.
- UK government allowed doctor to use this method.
Arguments in favour and against 3-Parent Baby
|Favour||Against 3-parent baby|
Twin Babies- Theory
Happens when either:
- One than 1 egg fertilized by more than 1 sperm. OR
- After fertilization, ovum divides into two or more cells.
|Identical twins||When a fertilized egg divides into two independent sets of cells-> two identical embryos products from same egg.|
|Non-identical or fraternal twins||When two eggs are produced at the same time and a different sperm fertilizes each egg, non-identical or fraternal twins are produced.|
- A clone is a cell or an organism that is produced asexually from an ancestor. (=without sperm meeting egg)
- A Clone cell genetically identical to its ancestor.
- Thus the clone of Lennon, produced today, will be genetically the same John Lennon of the 70s.
Dolly Sheep Cloning (Scotland, 1996)
|Polly (Black face)||they removed genetic material from her egg-cell. Thus her egg remained only an empty reaction vessel.|
|Molly (White face)||they took cells from her udder, extracted genetic material out of it, and planted in Dolly’s empty egg cell. Thus an embrayo created.|
|Holly||they planted above embryo in Holly’s womb. Thus holly served as a surrogate mother.|
Result: Dolly sheep was born. White faced, inherited the genes from Molly only. The only male DNA of Dolly came from Molly’s father’s DNA contained in her somatic cells.
- A Man does not live by body alone. What goes into the brain is interaction with the external world. Culture is not coded in our DNA. Experience, education, environment — all these matter.
- If Cloned Mohandas Gandhi isn’t thrown out of a train going to Pretoria (or face similar racial discrimination), he may not become “Mahatma”.
- Cloned John Lennon will not be an equally good singer-musician like original John Lennon, Cloned Adolph Hitler will not be a mass-murderer, IF they don’t live through similar circumstances like their “fathers”.
- Husband has healthy sperms and Wife has healthy eggs
- but Wife cannot carry a baby to its full term. For example, Aamir Khan’s wife Kiran Rao suffered a miscarriage earlier and had uterine medical problems so the couple opted for surrogacy.
- In surrogacy: Wife’s egg is fertilized with husband’s sperm through in-vitro fertilization (IVF) and an embryo is created. (In Vitro=outside body. In-vivo=inside body.)
- This embryo is implanted in the womb of a “surrogate mother”, she will carry It for nine months and deliver the baby.
- Baby thus produced, will have genetic make-up of the husband and wife (and not that of surrogate mother.)
- Ethical Merits and demerits are given