Pollination

Many plants favour cross-pollination, so pollen must be transferred to the stigma of another plant if sexual reproduction is to take place. Some flowers rely of the wind to carry pollen grains others rely on insects.

Fertilisation
If the pollen grain lands on a compatible stigma, a pollen tube will grow so that eventually the egg cell, hidden away in the embryo sac, can be fertilised

External fertilization
External fertilization is characterized by the release of both sperm and eggs into an external environment; sperm will fertilize the egg outside of the organism, as seen in spawning.

Internal fertilization
Internal fertilization protects the fertilized egg or embryo from predation and harsh environments,which results in higher survival rates than can occur with external fertilization.

Oviparous
Oviparous is a zoological term that refers to animals that lay eggs which then hatch externally. Oviparous animals may fertilize their eggs either externally or internally.

Cell Differentiation
The multiple cell types within a tissue don’t just have different functions. They also have different transcriptional programs and may well divide at different rates. Proper regulation of these rates is essential to tissue maintenance and repair.

Generative and
a Vegetative cell
The generative cell produces two sperm cells, or male gametes, whereas the vegetative cell produces an elongated pollen tube, a gametophytic cell, to deliver the male gametes to the embryo sac.

Pollination
Pollination leads to the creation of new seeds that grow into new plants. Pollination occurs in several ways. People can transfer pollen from one flower to another, but most plants are pollinated without any help from people. Usually plants rely on animals or the wind to pollinate them.

hybridisation
A hybrid is a cross between two different plants, which are usually two plants within the same species, but can be between two different species or genera. In artificial hybridisation two parent plants are chosen, each of which has required characteristics.

Endosperm
Endosperm, tissue that surrounds and nourishes the embryo in the angiosperm seed. The initiation of endosperm is a definitive characteristic of angiosperms and requires the fusion of at least one nucleus in the embryo sac with a sperm nucleus from the pollen grain.

Male reproductive system
The male reproductive system includes the scrotum, testes, spermatic ducts, sex glands, and penis. These organs work together to produce sperm, the male gamete, and the other components of semen.

Female reproductive system
The female reproductive system includes the ovaries, fallopian tubes, uterus, vagina, vulva, mammary glands and breasts. These organs are involved in the production and transportation of gametes and the production of sex hormones.

Parturition and lactation.
The average duration of human pregnancy is about 9 months which is called the gestation period. Vigorous contraction of the uterus at the end of pregnancy causes expulsion/delivery of the foetus. This process of delivery of the foetus (childbirth) is called parturition
The mammary glands of the female undergo differentiation during pregnancy and starts producing milk towards the end of pregnancy by the process called lactation.

Birth Controls
Essure - Essure is a method of sterilization that requires placement of a tiny coil mechanism into each of the fallopian tubes
IUDs- are placed by a healthcare provider through the vagina and cervix, into the uterus.
Diaphragm- is a shallow, dome-shaped cup made of silicone. it covers cervix and keeps sperm out of uterus.

Vasectomy - Vasectomy is a sterilization procedure for men that surgically cuts or blocks the vas deferens, the tubes that carry sperm from the testes.

Condoms- can protect against sexually transmitted infections (STIs) and they can be used to prevent pregnancy.

STDs

= Bacterial Vaginosis (BV)
= Gonorrhea
= HIV
= Human Papillomavirus (HPV)
= Pelvic Inflammatory Disease (PID)
= Syphilis

infertility

= Primary infertility refers to couples who have not become pregnant after at least 1 year having sex without using birth control methods.

= Secondary infertility refers to couples who have been able to get pregnant at least once, but now are unable.

Gregor Mendel
and inheritance

an Austrian monk named Gregor Mendel introduced a new theory of inheritance based on his experimental work with pea plants. Prior to Mendel, most people believed inheritance was due to a blending of parental ‘essences’, much like how mixing blue and yellow paint will produce a green colour. Gregor Mendel crossed various pure lines of garden peas and, by following their hybrid progeny, observed that traits are inherited as alternate states of independent units of inheritance or genes (“factors”), and that these units come in pairs. Each unit of inheritance can have alternate states (alleles) that segregate at meiosis, with each gamete receiving only one allele.

Law of Segregation
The Law of Segregation states that for any trait, each parent’s pairing of genes (alleles) split and one gene passes from each parent to an offspring. Which particular gene in a pair gets passed on is completely up to chance.

Law of Independent Assortment
The Law of Independent Assortment states that different pairs of alleles are passed onto the offspring independently of each other. Therefore, inheritance of genes at one location in a genome does not influence the inheritance of genes at another location.

genetic disorders
Single-gene disorders: where a mutation affects one gene. Sickle cell anemia is an example.

Chromosomal disorders: where chromosomes (or parts of chromosomes) are missing or changed. Chromosomes are the structures that hold our genes. Down syndrome is a chromosomal disorder.

Complex disorders :where there are mutations in two or more genes. Often your lifestyle and environment also play a role. Colon cancer is an example.

DNA

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA)

The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people.

An important property of DNA is that it can replicate, or make copies of itself. Each strand of DNA in the double helix can serve as a pattern for duplicating the sequence of bases.

Evolution
Human evolution is the lengthy process of change by which people originated from apelike ancestors. Paleoanthropology is the scientific study of human evolution. Paleoanthropology is a subfield of anthropology, the study of human culture, society, and biology. Early humans first migrated out of Africa into Asia probably between 2 million and 1.8 million years ago. They entered Europe somewhat later, between 1.5 million and 1 million years

Human Health and disease

AIDS is a syndrome caused by the HIV virus. It is when a person’s immune system is too weak to fight off many infections, and develops when the HIV infection is very advanced. This is the last stage of HIV infection where the body can no longer defend itself and may develop various diseases, infections and if left untreated, death.

innate immune system

The innate immune system, also known as the nonspecific immune system or in-born immunity system is an important subsystem of the overall immune system that comprises the cells and mechanisms that defend the host from infection by other organisms.

Autoimmune disorders

An autoimmune disorder occurs when the body’s immune system attacks and destroys healthy body tissue by mistake. There are more than 80 types of autoimmune disorders.

Cancer

Cancer can start any place in the body. It starts when cells grow out of control and crowd out normal cells. There are more than 100 different types of cancer. The spread of cancer from one part of the body to another is called metastasis

Common signs and
symptoms of alcohol abuse

= Repeatedly neglecting your responsibilities at home, work, or school

= Drinking as a way to relax or de-stress.

= Using alcohol in situations where it’s physically dangerous

Green Revolution

The Green Revolution was a period when the productivity of global agriculture increased drastically as a result of new advances. During this time period, new chemical fertilizers and synthetic herbicides and pesticides were created.

Single-cell proteins

Single-cell proteins are the dried cells of microorganism, which are used as protein supplement in human foods or animal feeds. Microorganisms like algae, fungi, yeast and bacteria, utilize inexpensive feedstock and wastes as sources of carbon and energy for growth to produce biomass, protein concentrate or amino acids.

Antibiotics

Antibiotics are powerful medicines that fight bacterial infections. Used properly, antibiotics can save lives. They either kill bacteria or keep them from reproducing. Your body’s natural defenses can usually take it from there.

Microbes and Biogas
Microbes usually produce gases during their growth and metabolism. Based on the organic substrates they utilise, different microbes produce different gases.
Methanobacterium present inside the rumen of cattle digest the cellulose present in grass, and its dung is rich in the same bacteria. The dung or gobar is used to generate biogas in a biogas plant.

Biotechnology
biotechnology is technology based on biology - biotechnology harnesses cellular and biomolecular processes to develop technologies and products that help improve our lives and the health of our planet.
Biotechnology is a broad discipline in which biological processes, organisms, cells or cellular components are exploited to develop new technologies

Genetic engineering
Genetic engineering is the process by which scientists modify the genome of an organism. Creation of genetically modified organisms requires recombinant DNA.
Recombinant DNA is a combination of DNA from different organisms or different locations in a given genome that would not normally be found in nature.

Biotechnology and
Its Appilcations Gene therapy
Gene therapy is an experimental technique that uses genes to treat or prevent disease. In the future, this technique may allow doctors to treat a disorder by inserting a gene into a patient’s cells instead of using drugs or surgery. Researchers are testing several approaches to gene therapy, including:

=Replacing a mutated gene that causes disease with a healthy copy of the gene.
=Inactivating, or “knocking out,” a mutated gene that is functioning improperly.
Introducing a new gene into the body to help fight a disease.

Organism and populations
Mutualism :This is a beneficial relationship to both partners of different species living together.
Commensalism:The association of two or more partners living together, where only one benefits from the partnership and the other remains unharmed.
Parasitism:Parasites are completely dependent on a host for survival. The relationship is beneficial to one, and harmful to the other. Parasites may live outside or inside a host; they are called ectoparasites and endoparasites

Ecosystem
The carbon cycle is very important to all ecosystems, and ultimately life on earth. The carbon cycle is critical to the food chain.
Human activities like heating homes and cars burning fuels give off carbon into the atmosphere. The Carbon dioxide in the atmosphere is absorbed by green plants (producers) to make food in photosynthesis.Carbon dioxide is also given off when plants and animals die.

Biodiversity and Conservation
Conserve biodiversity
Biodiversity is the cornerstone of our existence on Earth. It is also important to conserve biodiversity for the sake of our own curiosity and aesthetic appreciation. Biodiversity is the life support system of our planet- we depend on it for the air we breathe, the food we eat, and the water we drink. Wetlands filter pollutants from water, trees and plants reduce global warming by absorbing carbon, and bacteria and fungi break down organic material and fertilize the soil.

Environmental Issues
Radioactive waste
Radioactive waste is a by product from nuclear reactors, fuel processing plants, hospitals and research facilities. Radioactive waste is also generated while decommissioning and dismantling nuclear reactors and other nuclear facilities. There are two broad classifications: high-level or low-level waste. High-level waste is primarily spent fuel removed from reactors after producing electricity. Low-level waste comes from reactor operations and from medical, academic, industrial, and other commercial uses of radioactive materials.