ppq notes

• more anthers than stigma in a flower
• pollen tube penetrates the ovule through the micropyle
• ovule wall becomes seed coat / testa
• copulation is sex
• embryo develops in the seed
• mitosis - genetically identical. meiosis - genetically distinct from parent and each other
• twins - ovary releases 2 eggs. identical - before stem cells, embryo divides
• crossing over only in meiosis
• meiosis only in reproductive organs
• foetus is not breathing with lungs so the blood in foetus is not distinctly oxygenated / deoxygenated. blood in heart mixes in the vessels. blood also flows from right atrium to right ventricle so it makes blood flow more efficient.
• FSH stimulates oestrogen which inhibits FSH. oestrogen causes uterus lining to thicken. it stimulates pituitary gland to produce LH which triggers ovulation.
• 1. ovulation when progesterone starts to rise
• progesterone - prolong preserve protect, pregnancy tells body to hold onto the lining
• oestrogen thickens. progesterone maintains the uterus lining
• sperm can last a few days in the female
• plant cell division only takes place in the meristems (eg tips of roots and shoots