Organisms (Continuity and change)
- Reproduction
- Sexual vs asexual
- Identical offspring: existing environment
- Variation: changed environment
- Meiosis and fertilization
- Human systems
- Male gamete travels
- Testis, epididymis, prostate
- Ovary, oviduct, endometrium
- Menstrual cycle
- FSH, LH from pituitary
- Oestradiol, progesterone from ovary
- Positive feedback: LH surge
- Negative feedback: progesterone
- Fertilization and IVF
- Membranes fuse
- Joint mitosis, two diploid nuclei
- Suspend hormones, superovulation
- Flowering plants
- Pollen and ovules
- Pollination, pollen tube
- Cross-pollination methods
- Self-incompatibility
- Seeds
- Dispersal not pollination
- Water, oxygen, temperature
- Mobilize food reserves
- Gametes and puberty HL only
- GnRH triggers LH, FSH
- Spermatogenesis: four sperm
- Oogenesis: one egg
- Pregnancy HL only
- Acrosome and cortical reactions
- Blastocyst implants
- hCG test, placenta
- Progesterone, oxytocin, HRT
- Sexual vs asexual
- Inheritance
- Gametes and crosses
- Haploid gametes, diploid zygote
- P, F1, F2
- Punnett grid
- Peas self-pollinate
- Genotype and phenotype
- Homozygous, heterozygous
- Genes plus environment
- Dominant, recessive
- Phenotypic plasticity
- Alleles in gene pools
- PKU: autosomal recessive
- SNPs, multiple alleles
- ABO: Iᴬ, Iᴮ, i
- Other dominance patterns
- Codominance: AB blood group
- Incomplete: Mirabilis pink
- Sex linkage
- Sperm determines sex
- X carries more genes
- Haemophilia Xʰ
- Pedigree charts
- Continuous variation
- Polygenic: skin colour
- Mean, median, mode
- Box plots, 1.5 × IQR
- Dihybrid crosses HL only
- Segregation, independent assortment
- 9:3:3:1 and 1:1:1:1
- Linkage, recombinants
- Chi-squared, p = 0.05
- Gametes and crosses
- Homeostasis
- Homeostasis
- Preset limits
- Temperature, pH, glucose, osmotic
- Negative feedback both ways
- Blood glucose
- β cells: insulin
- α cells: glucagon
- Target cells via blood
- Diabetes
- Type 1: β cells destroyed
- Type 2: insulin resistance
- Risk, prevention, treatment
- Thermoregulation
- Thermoreceptors, hypothalamus
- Pituitary, thyroxin
- Shivering, brown fat
- Vasodilation, sweating
- Kidney HL only
- Excretion vs osmoregulation
- Ultrafiltration in glomerulus
- Reabsorption in PCT
- Water balance HL only
- Na⁺ pumped in ascending limb
- Osmoreceptors, ADH
- Aquaporins move to membrane
- Blood redistribution HL only
- Arterioles dilate or constrict
- Muscles up in exercise
- Brain constant
- Homeostasis