HPS 772 Revision

Chromosomes contain Genes which are made up of DNA

RNA creates proteins from DNA (basically carries out the instructions of DNA). DNA is made of double helixes.

We have 23 pairs (46 in total). They're made up of DNA. One pair is the sex chromosome, the rest are "autosomes".

Genes are a small part of a chromosome, which is a segment of your DNA.

Genotype is what's coded in your genes, phenotype is what actually manifests.

Alleles are all of the possiblities for a gene. E.g. I^A, I^B, and I^O for blood type. Genes can be dominant, recessive or co-dominant. Homozygous means alleles from both parents are the same (e.g. AA). Heterosygous means they're different (e.g. AO).

When one doesn't dominate another, e.g. with blood groups, the A allele is as ‘strong’ as the B allele. So someone with one A and one B has the blood group AB.

From conception to week 2 (when zygote is implanted in the wall of the uterus). Period of rapid cell replication. Ends in Blastocyst with 2 cell layers - trophoblast layer (outer cell mass) and inner cell mass called the "embryonic disk".

Lasts from implantation to about 8 weeks. Period of organogenisis. Embryo starts to responsd to direct stimulation. Ectoderm forms CNS, skin & hair. Mesoderm forms muscles, bones etc, endoderm forms digestive system, lungs etc. Starts to look much more human.

From 8 weeks to birth. Divided into three trimesters. Organs start working ("histogenesis").

Can have sensitive periods. Can be tissue specific. Includes diseases, drugs, alcohol, blood incompatibilities. Dose-response relationships = the more exposure, the higher the chance of an effect.

Axon covered by fatty substance. Speeds up information.

Brains are more or less identical to adult brains, except for a lack of development and myelination in the frontal lobe (planning, reward, motivation, attention etc.). Also growth of limbic system (emotions etc).

Trust vs mistrust

Autonomy vs Shame and doubt

Initiative vs Guilt