Class Notes (806,694)
Canada (492,412)
BIOA01H3 (687)

genetics overview and review.docx

6 Pages
Unlock Document

University of Toronto Scarborough
Biological Sciences
Mark Fitzpatrick

Unit 2: Genetics DNA: molecule inside nucleus that gives instructions to make proteins etc. Deoxyribose sugar Phosphate backbone Nitrogenous Bases: Adenine, Thymine, Guanine, and Cytosine Base Pair : AT – Purines – 2 rings Base Pair: CG – Purimidines – 1 ring Gene: segment of DNA that encodes information DNA twists itself, then on histones, then histones twist to form chromatids Chromosomes: Human has 46, 23 pairs, 1 pair of sex chromosomes, 22 pairs of autosomes Homologus: same instructions, but expressed in a different way Homologs: single chromosomes that are similar but not the same Homologus Pairs: pairs of homologs after criss-cross Centromere: middle region of chromosome, attracts spindle fibres Chromosome = 2 sister chromatids held by a centromere = chromatin N = Haploid = # of unique chromosomes = human: 23 2N = Diploid = # of total chromosomes = human:46 Cell Cycle G1: growth, prepares for synthesis S: DNA duplication G2: growth and prepares to divide or rest phase Mitosis: somatic cells, daughter will be identical to parent Interphase: G1, S, G2 + condensing Prophase: Nuclear membrane breaks, migrate to poles Metaphase: lines up in a row in the equator of the cell by spindle fibres Anaphase: centromere splits apart, pulled by spindle fibres Telophase: cell squeezes inwards, nuclear membrane reforms, plant builds a cell wall Cytokinesis: cytoplasm divides. Meiosis: gamete cells, results in cells with half the number of chromosomes, sex cells Meiosis 1: separates homologous chromosomes into 2 cells + criss crossing Interphase1: chromosome duplication, not condensed, risk for mutation Prohase1: condenses chromatid, crossing over, creating Tetrads [Genetic variation]Crossing over (Synapsis): arms of chromatids become tangled Metaphase1: homologous chromosomes align randomly in the centre by spindle fibres [Genetic variation]Independent Assortment: metaphase random centre alignment Anaphase1: sister chromatids split and moved to poles [Genetic variation]Non-Disjunction: failure to split apart into 2 sister chromatids Telophase1: Same as mitosis Cytokinesis1: splits into 2 Intermediate Cells, have double # of original now 46>46*2>4*23 Meiosis 2: Divides the 2 intermediate cells into haploid cells. Pulls sister chromatids Prophase: sister chromatids do not duplicate, they will split in the end. Chromatids condense Metaphase2: spindle fibres attract them to the center side by side on the equator Anaphase2: Spindle fibres pull them apart through their centers Telophase2: nuclear membrane reforms, each daughter cell has haploid chromosomes Cytokinesis2: Parent cell divides 2 intermediate cells into 4 gamete cells or spores in plants Gametes: end result of meiosis Gametogenesis: production of creating a sperm or egg Spermatogenesis: production of turning sperm gamete (spermatogonium) into a sperm cell -Male testes, spermatogonium enlarges size and becomes sperm cells -Happens all year round Oogenesis: process of making egg from an egg gamete (oogenium) -Oogenium not equally divided, has polar bodies, and primary oocyte -1 gamete survives to give nutrients to the rest -eggs are produced till meiosis 1, then frozen until fertilized, where meiosis 2 will finish it off -1 oogenium is released each month Karyotypes: shows all the chromosomes arranged from largest to smallest with centrosmeres lined up -Dyed with Giemsa to reveal G-branding to check the gene segments, but do not show genes Polyploidy: extra chromosome in a cell Aneuploidy: one less chromosome Mixed: translocation of parts of DNA Gregor Mendel: formulated laws that stated how heredity could be brought over Dominant Trait: a characteristic that is always
More Less

Related notes for BIOA01H3

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.