L13 -DNA Chromosome Structure

in _____, no one knew what molecule constituted genetic material

1949

what are the 4 things genetic material must be able to do?

contain complex info, replicate faithfully, encode the phenotype, and have the capacity to vary

what does having the capacity to vary have to do with evolution?

variation = diversity which is needed for evolution

all life starts from ___ cell(s)

1

in ____ Hersey and Chase demonstrated that DNA is a genetic material in bacteriophage

1952

mendel's work was rediscovered in _____

1900s

when was mendel's work 1st published?

1866

in ____ Avery, MacLeod, and McCarty, demonstrated that th e transforming principle is DNA

1944

avirulent

bacteria strain unable to procure a capsule , appear rough

virulent

bacteria strain that produces a capsule, appear smooth

Griffifth's Experiment

radiolabeling

using radioactive isotopes of sulfur and phosphorus to radioactively label protein and DNA

blenders

smooth surface attached bacteriophage

the centrifugation technique

spins samples at high speed, to separate to bacteria sediment and phage stays liquid

bacteria are _____ than phage

larger

polymer

chain maid up of many repeating units linked together

______ are relating units of DNA

nucleotides

_NA contains a hydroxyl group at the 2' position

RNA

_NA contains a hydrogen group at the 2' position

DNA

nitrogenous bases

attach to the c1 position above ribose to provide the genetic code

what are the nitrogenous bases?

Adenine, Guanine, Cytosine, Thymine, and Uracil

DNA phosphate group is

acidic and negatively charged

DNA exists as a

antiparallel polynucleotide with two complementary strands

what are phosphodiester bonds?

covalent bonds that connect nucleotides

what do hydrogen bonds do?

link bases on opposite strands

what are stacking ineractions

interactions between bases that stabilize the DNA molecule

purine

double ring structure

pyrimidine

single ring structure

what is the primary site for DNA interactions?

the major groove

what is super coiling

when the (circular) bacterial genome twist onto itself to take up less space

why do we need negative super coiling?

it makes separating the two strands of DNA easier during replication and transcription

topiosomerases

enzymes that control degree of supercoiling

most topoisomerase are …

essential for life

nucleoid

region of bacteria that contains most or all of the genetic material and associated proteins

chromatin

complex of DNA and associated proteins in eukaryotes

condensation

packing

decondensation

unpacking

euchromatin is a type of chromatin, what is its relation to condensation?

undergoes the normal process of condensation and decondensation in the cell cycle

heterochromatin is a type of chromatin, what is its relation to condensation?

stays in a highly condensed state throughout the cell cycle

what are histones? what do they do?

small + proteins that compact and condense dna

histone function

to compact and condense DNA

nucleosome

basic repeating unit of chromatin

high order chromatin structure

the result of nucleosomes folding onto themselves