MOLGEN 4500 Study Guide - Fall 2018, Comprehensive Midterm Notes - Rna, Dna, Acid
12 Oct 2018
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MOLGEN 4500
MIDTERM EXAM
STUDY GUIDE
Fall 2018
GENETICS LECTURE SLIDES NOTES
[Module 1.1]
mitosis- when the non-gametic (sex cells) body (somatic) cells replicate, they start out as diploid
(2n=46) and double the number of chromosomes to 4n=92 and then divide to form two identical
daughter cells that are diploid (2n=46), just like the parent cell.
meiosis- forms gametes, or sex cells (sperm and egg cells) through a process of two divisional steps
where the chromosomes are doubled and distributed. The parent cell doubles the number of
chromosomes from 46 to 92 and then divides (4n to 2n) and then each of those cells divide again to
form 4 daughter cells that are different from the parent cell and are haploid (n=23).
DNA
• carrier of genetic information
• atipaallel ’→’ aoe ’→’
• double-stranded helix
• made of nucleotides (A,T,C,G) hagaff’s la: A-T. C-G.
Monomer
• nucleotide consisting of a sugar (deoxyribose)
• bonded to a phosphate
• also bonded to either A,T,C, or G
Central Dogma
• DNA → RNA → Protein
• proteins are the end product of gene expression
• protein action or location in a cell produces phenotype(s)
• 20 different amino acid building blocks
CH2
Eukaryotic DNA Replication
Prokaryotic DNA Replication
2 major processes (mitosis and meiosis
Need to replicate DNA with each cell division
No nuclear membrane
Generally circular DNA molecule (plasmid)
metacentric- centromere is in the center of the chromosome
submetacentric- centromere is between the middle and the end of the chromosome
arcocentric- centromere is close to the end of the chromosome
telocentric- centromere is at the end of the chromosome
MITOSIS
• occurs in embryo and during organ development
• in adults happens in renewable tissues that have stem cells
➔ epidermis, GI tract, mammary glands, lung, blood forming tissue, testes and ovaries
0) G0 – cell differentiates, and leaves the cell cycle
find more resources at oneclass.com
find more resources at oneclass.com
1) prophase- centriole migration
2) metaphase- chromosomes lining up
3) anaphase- chromosomes migrate to opposite poles
4) telophase- daughter chromosomes at opposite ends, cytoplasm then divides (cytokinesis)
Kinetochores and Centromeres
• centromeric DNA (tandem repeated sequences) allows binding by centromeric proteins
• kinetochore proteins bind to centromeric proteins
• allows attachment to spindle fibers (made of alpha, beta, and gamma tubulin) which facilitates
the transport of chromosomes to opposing poles
Cell division cycle (cdc) mutations
• involve kinase enzymes
• G1/S (assesses DNA damage) [p53] and G2/M (assesses incomplete DNA synthesis or DNA
damage)
• kinases bind to cyclins to attain active form (CDKs- cyclin dependent kinase)
• cyclin levels vary during cell cycle
• mutant p53 allows for proliferation of mutant cells and tumor formation instead of causing the
cell to undergo apoptosis
p53
• has two forms: active and inactive
• normally the inactive form is the predominant form, but things like chemical damage to DNA,
dsDNA breaks, or UV light damage, among other things, can lead to an increase in the active
form.
• phosphorylation or acetylation of p53 activates it
• when p53 is activated, it acts as a transcription factor to turn on other genes
• initiates two responses to DNA damage
1) halts the cell cycle for DNA repair
2) apoptosis
• can act at S, G2/M
MEIOSIS
• Prophase I stages:
1) Leptonema
2) Zygonema
3) Pachynema- crossover at chiasma occurs
4) Diplonema- crossover at chiasma occurs
5) Diakinesis
• anaphase – dyads move to each pole for the reductive stage (telophase)
• disjunction- separation of chromatids
• independent assortment- paired chromatids can go in either direction
Human Egg cells
• all present at birth, resting during diakinesis stage of cell cycle
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Dna: a(cid:374)tipa(cid:396)allel (cid:894)(cid:1009)" (cid:1007)" a(cid:271)o(cid:448)e (cid:1007)" (cid:1009)"(cid:895, double-stranded helix, made of nucleotides (a,t,c,g) (cid:272)ha(cid:396)gaff"s la(cid:449): a-t. c-g. Monomer: nucleotide consisting of a sugar (deoxyribose, bonded to a phosphate, also bonded to either a,t,c, or g. Central dogma: dna rna protein, proteins are the end product of gene expression, protein action or location in a cell produces phenotype(s, 20 different amino acid building blocks. Need to replicate dna with each cell division. Mitosis: occurs in embryo and during organ development in adults happens in renewable tissues that have stem cells. Binomial theorem: 2 alternative outcomes, probability based on # of trials, p=(n!/s!t)*(a^s*b^t) p=probability n=# of trials a=probability of event a b=probability of event b s=# of times of outcome a t=# of times of outcome b. Incomplete dominance- neither allele is dominant and an intermediate phenotype is present for heterozygotes. Codominance- both alleles are dominant, and both traits will appear in the heterozygote organism (like in human blood types a,b,o)
