L6 chroms, genes, DNA

Question 1

LO2: recog struc compons D+RNA.

Answer 1

• gene= code for prot. chrom locat, same in ev indiv. hum 25000. euk v complex.
  -genome= ent dna seq of organism. hum 22 autos and x and y. 3.bn bp.
  -D+RNA nuc acids= polynt= lin polym of nt’s.
  nucleoside=nitrogenous base and sug. nt= base, sug and P by Pdiest bond on C5, neg P interac pos histones.
  pentose sug: ribose RNA has OH on C2. 2 deoxyribose DNA.
  -nitorgenous bases- purine 2 ring A,G. pyrimidine 1 ring C,T,U.
  -nucleotides- eg AMP and CMP ribont= RNA build block. deoxyribont dAMP.
  nomenclature- in rna base adenine, ns adenosine, nt AMP
  dna base adenine, ns deoxyadenosine, nt dAMP.
  -polynt= nt Pdiest bond.

Question 2

LO3: expl polarity of D/RNA chain.

Answer 2

-5’ to 3’ sing str. 5’ free phosphate, 3’ free OH.

Question 3

LO4: imp of H bond and bp in nuc ac secondary struc.

Answer 3

-G purine-C pyrim 3 H bond. alm same dist due to chem compos.
-A purine-T/U pyrim 2 H bond.
- na can form duplex strucs-complem and antipar str. D-D/RNA, or R-RNA. stable or temp. in vitro and vivo.
RNA stemp loops H bond btw antipar complem seqs eg tRNA.

Question 4

LO5: key feats of DNA doub helix.

Answer 4

• sec struc. antipar strs dna. 2nm diam. 3.4nm compl turn. 0.34nm btw each base. R handed. min and maj grooves. asym, furth btw sugs=maj. due to chem struc of bp.

Question 5

LO6: recog and apply conventions in repres D/RNA base seqs.

Answer 5

• top str 5’ to 3’. no need to write doub str, always antipar complem.

Question 6

LO1: how euk dna cond to nucleosome and how rel to chrom.

Answer 6

-2m dna in 6um.
histone octamer core with dna arnd=nucleosome, linker dna btw. = euchromatin, genes exp.
solenoid 30nm diam= heterochromatin, v tight, genes not exp.
chrom- heirarchical solenoid loops lot and scaff prots. 2 chromatids, p and q arms.