paper 2

• homeostasis is the regulation of the internal conditions of a cell or organism to maintain optimum conditions for function
• the human nervous system enables humens to react to their surroundings and coordinate their behaviour
• the human nervous system goes stimulus to receptor to coordinator to effector to reponse
• the stimulus is the change in environment
• the receptor is what detects a stimulus
• effector is what produces a response
• a synapse is the hap btween two neurons
• hormones are chemical messengers that are scrected by the bloodstream to target cells
• reflexes are automatic and rapid
• the pituitry gland is the master gland of the endocrine system located in the brain, it secretes several hormones into the blood in response to body conditions
• glocose in the blood is monitored and controlled by the pancreas which produces the hormone insulin
• if blood glucose levels are too low, the pancreas produces the hormone glucagon that cause glycogen to be converted into glucose
• diabetes is a disease where people cannot control their blood glocuse levels
• follicle stimulating hormone(fsh) causes an egg to mature in one of the overies
• lh stimulates the release of an egg
• oestrogen + progesterone involved in maintaining the uterus lining
• fsh is produced in the pituitry gland
• oestrogen produced in the overies
• Lh produced by thr pituitary gland
• progesterone produced in the ovaries
• ovulation occurs on day 13-15
• the pill is an oral contraceptive that inhibits fsh production so that no eggs mature
• injection, implant + skin patch progesterone is used to inhibit the maturation and release of the egg
• adrenaline is a hormone released by the adrenal glands in times of fear/stress
• thyroxine is a hormone released by the thyroid gland stimulates the basal metabolic rate
• human gametes= sperm + egg cells
• plant gametes= pollen + egg cells
• meiosis: a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores
• meiosis copies the genetic information are made, the cell divides twice twice to form four gametes each with a single set of chromosomes, all gametes are genetically different
• gametes join at fertilisation to restore normal amount of chromosomes
• asexual reproduction involves only one parent and no fusion of gametes
• dna is a polymer a large molecule built from a chain of smaller molecules
• a gene is a small section of dna
• a genome is an entire set of genetic information in an organism
• an allele is a different form of the same gene
• dominant is a n allele that is always expressed
• recessive is an allele that is only expressed if two copies are present
• homozygous have two of the same allele
• heterozygous have two different alleles
• a genotype is the combonation of allleles that you have