Pollination

Many plants favour cross-pollination, so pollen must bet ransferred 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 fertilized
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 cellt ypes within a tissue don't just have different functions. They also have differentt ranscriptional 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.
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 hybridization 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 reproductives ystem
The male reproductives ystem 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 reproductives ystem
The female reproductives ystem includes the ovaries, fallopian tubes, uterus, vagina, vulva, mammary glands and breasts. These organs are involved in the production andt ransportation 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 cotnraction of the uterus at the end of pregnancy causes expulsion/delivery of the fetus. This process of delivery of the fetus (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.
STDs
• Bacterial Vaginosis (BV)
• Gonorrhea
• HIV
• Human Papillomavirus (HPV)
• Pelvic Inflammatory Disease (PID)
• Syphilis
Infertiltiy

• Primary infertiltiy refers to couples who have not become pregnant after at least 1 year having sex without using birth cotnrol methods.
• Secondary infertiltiy refers to couples who have been able to get pregnant at least once, but now are unable.

Gregor Mendel and inheritance
an Autsrian monk named Gregor Mendel itnroduced 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 thatt raits 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 anyt rait, 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 tsructures that hold our genes. Downs yndrome is a chromosomal disorder.
Complex disorders : where there are mutations in two or more genes. Often your lifetsyle 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 propetry of DNA is that it can replicate, or make copies of itself. Each tsrand 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, socitey, 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 as yndrome caused by the HIV virus. It is when a person's immunes ystem 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 utnreated, death.
Innate immunes ystem
The innate immunes ystem, also known as the nonspecific immunes ystem or in-born immuntiys ystem is an important susbystem of the overall immunes ystem 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 immunes ystem attacks and detsroys healthy body tissue by mistake. There are more than 80t ypes of autoimmune disorders.
Cancer
Cancer can start any place in the body. It starts when cells grow out of cotnrol and crowd out normal cells. There are more than 100 differentt ypes of cancer. The spread of cancer from one part of the body to another is called metastasis
Common signs ands ymptoms of alcohol abuse
• Repeatedly neglecting your responsibilities at home, work, or school
• Drinking as a way to relax or de-tsress.

Green Revolution
The Green Revolution was a period when the productivtiy of global agriculture increased drastically as a result of new advances. During this time period, new chemical fertilizers ands ynthetic 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.
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 subtsrates they utilize, 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.
Genetic engineering
Genetic engineering is the process by which scientists modify the genome of an organism. Creation of genetically modified organisms requires recombinant DNA.
Gene therapy
Gene therapy is an experimental technique that uses genes tot reat or prevent disease. In the future, this technique may allow doctors tot reat a disorder by inserting a gene into a patient's cells instead of using drugs or surgery. Replacing a mutated gene that causes disease with a healthy copy of the gene.
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
Ecsoystem
The carbon cycle is very important to all ecsoystems, 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 photsoynthesis. Carbon dioxide is also given off when plants and animals die.
Conserve biodiverstiy
Biodiverstiy is the cornerstone of our existence on Earth. It is also important to conserve biodiverstiy for the sake of our own curiostiy and aesthetic appreciation. Biodiverstiy is the life supports ystem of our planet- we depend on it for the air we breathe, the food we eat, and the water we drink
Air pollution
Air pollution is a mixture of solid particles and gases in the air. Some air pollutants are poisonous. The leading sources of air pollution are power plants, factories, and vehicles. Fossil fuel and coal are the main cotnributors to air pollution.
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 eletcrictiy. Low-level waste comes from reactor operations and from medical, academic, indutsrial, and other commercial uses of radioactive materials.