1. B12: Plant Reproduction
1.1. Reproduction
1.1.1. Asexual
1.1.1.1. One parent
1.1.1.2. Offspring are identical to each other, and the parent
1.1.1.3. No gametes (sex cells)
1.1.1.4. Vert rapid, very rapid growth
1.1.1.5. Very simple process
1.1.2. Sexual
1.1.2.1. The process involving the fusion of haploid nuclei to form a diploid zygote and the production of genetically dissimilar offspring
1.1.2.2. Involves two gametes
1.1.2.3. Fertilisation where the nuclei fuse together to form a zygote (46 chromosomes, full sets, 2 haploids, form diploid fertilised cell)
1.1.2.4. Genetic variation
1.1.2.5. Male gamete is mobile, moves to stationary female gamete
1.2. Plant Structures
1.2.1. Stamen
1.2.1.1. Anther
1.2.1.1.1. The part of the stamen that produces pollen.
1.2.1.2. Filament
1.2.1.2.1. The stalk of the anther.
1.2.1.3. Male part of the flower, containing the anther and the filament.
1.2.2. Carpel/Pistil
1.2.2.1. Stigma
1.2.2.1.1. Sticky top part of the flower, which the pollen grains get stuck to.
1.2.2.2. Style
1.2.2.2.1. The stalk of the carpel, from which the pollen strands grow down towards the ovary.
1.2.2.3. Ovule
1.2.2.3.1. Houses the female gametes, which become seeds upon fertilisation.
1.2.2.4. Ovary
1.2.2.4.1. Contains the ovule
1.2.2.5. Female part of the flower
1.2.3. Other
1.2.3.1. Petal
1.2.3.1.1. Attract pollinators to the plant, via the bright colours, or the production of nectar.
1.2.3.2. Receptacle
1.2.3.2.1. Houses the flower's organs, at base of flower.
1.2.3.3. Sepal
1.2.3.3.1. Leaf like structures at base, which protect young flower.
1.3. Pollination
1.3.1. Wind Pollination
1.3.1.1. Small, dull petals, no scent or nectar.
1.3.1.2. Large amount of pollen
1.3.1.2.1. Pollen is light and smooth, so that it doesn't clump together
1.3.1.3. Anthers loose and long outside, so that the pollen is more easily released into the wind.
1.3.1.4. Stigma outside the flower to easily catch the pollen.
1.3.1.4.1. Sigma is feathery, net like.
1.3.2. Animal Pollination
1.3.2.1. Large, bright petals, sweet scent, often contain nectar.
1.3.2.2. Moderate quantity of pollen
1.3.2.2.1. Pollen is sticky or spiky to stick to the animals.
1.3.2.3. Anthers firm and inside flower, so that they can brush against the animal.
1.3.2.4. Stigma has sticky coating, so pollen sticks.
1.3.2.4.1. Inside the plant, so the animal rubs against it
1.4. Seed Structure
1.4.1. Non endosperm seeds are seeds with their food reserves within the cotyledon.
1.4.2. Parts
1.4.2.1. Cotyledon
1.4.2.1.1. Seed leaves
1.4.2.2. Testa
1.4.2.2.1. Seed Coat
1.4.2.3. Plumule
1.4.2.3.1. The embryonic shoot
1.4.2.4. Radicle
1.4.2.4.1. An embryonic shoot
1.4.2.5. Embreyo
1.4.2.5.1. Consisting of the young root and the shoot
2. B13: Human Reproduction
2.1. Male Reproductive System
2.1.1. Parts
2.1.1.1. Testes
2.1.1.1.1. Contain narrow, coiled tubes which produce the male gametes (the sperm). Made through meiosis (cell division of the cells in the walls of the tube).
2.1.1.2. Scrotum
2.1.1.2.1. A sac of skin and muscle, containing the testes.
2.1.1.3. Sperm Duct
2.1.1.3.1. A passageway that the sperm travel through one they combine with the fluids produced by the glands.
2.1.1.4. Semen
2.1.1.4.1. The male reproductive fluid which helps carry the sperm from the male to the female's gamete. It provides nutrients, and is either neutral or basic to counter the woman's acidity.
2.1.1.5. Prostate Gland
2.1.1.5.1. Helps control the flow of urine, and during sex, seminal vessels attached to the prostate gland help produce semen.
2.1.1.6. Penis
2.1.1.6.1. Transport the sperm and semen into the woman's vagina during sex.
2.1.1.7. Urethra
2.1.1.7.1. Tube that carries the semen and sperm.
2.2. Female Reproductive System
2.2.1. Parts
2.2.1.1. Ovary
2.2.1.1.1. Contains thousands of undeveloped egg cells, releases one every 28 days (on average)
2.2.1.2. Fallopian Tube/Oviducts
2.2.1.2.1. Carries the egg to the uterus, where they will embed themselves in the wall. The wall of this part is thin and muscular.
2.2.1.3. Uterus/Womb
2.2.1.3.1. Where the baby develops. It provides mechanical protection and nutrients to the embreyo. When the morula (hollow ball of cells) embeds itself in the uterus wall, it forms a blastocyst
2.2.1.4. Cervix
2.2.1.4.1. Muscular tube that keeps the baby in place. 4 cm long
2.2.1.5. Vagina
2.2.1.5.1. 3 inches long, ends the birth canal. This is where the sperm being their journey to the egg.
2.3. Gamete
2.3.1. Male
2.3.1.1. Very small, numerous (millions). Produced 24/7, 0.01mm.
2.3.1.2. Sperm
2.3.1.2.1. Small cell, with a nucleus and a tail. ONe of the smallest in number, and is very numerous. Mobile and can move. 0.01mm
2.3.1.3. Sperm Cell
2.3.2. Female
2.3.2.1. Egg
2.3.2.1.1. Only one, large, not mobile. Released every 28 days. Cannot produce more
2.3.3. Female
2.3.3.1. Egg
2.3.3.1.1. Only one released, quite large. Made up of cytoplasm and nucleus.
2.4. Birth
2.4.1. Amniyotic Sac
2.4.2. Breast Feeding
2.4.2.1. Advantages
2.4.2.1.1. Free
2.4.2.1.2. Correct amount of nutrients
2.4.2.2. Disadvantages
2.4.2.2.1. Cannot be measured
2.4.2.2.2. Transfer of pathogens
2.4.3. Placenta
2.4.3.1. Placenta: - Separate, circular organ - Oxygen and nutrients from blood - Bacteria protection
2.4.3.2. Umbilical Cord: - Attaches the placenta to the fetus. Made of three blood vessels.
2.5. Menstruation Cycle
2.5.1. Oestrogen
2.5.1.1. Repair the lining of blood vessels, nutrients, and cells
2.5.2. Progesterone
2.5.2.1. Maintain the lining
2.5.3. 1. Menstruation 2. Follicular Phase 3. Ovulation Phase 4. Luteal Phase
2.6. HIV/AIDS
2.6.1. How it effects the immune system
2.6.1.1. HIV destroys billions of CD4+ T cells in a person who is infected by HIV. By doing so, it overwhelms the immune system of a person, This is done through a number of methods: Killing cells directly - Large amount of the HIV virus infects the cell, causing it to bud out onto the cell surface, through the membrane, killing the cell. Cell suicide (Apoptosis) - Programmed cell death due to contamination and destruction by the HIV virus. Death of bystander cells - Mistakenly destroyed by CD8 T cells - Mistakenly targeted and destroyed by body due to resemblance of CD4+ T cell - Uninfected cells might still undergo apoptosis. Destruction of immune persecutor cells HIV also affects these cells, which grow to become deformed. Also affects the bone marrow, and thymus, preventing them from regenerating.
2.6.1.2. The CD4+ T cells initiate the body’s response to an infection by secreting lymphokines, which stimulate killer T cells.