Practice Exam: In Class

proportion of adenine in human DNA is about 30%, whats the proportion of thymine, guanine, and cytosine?

thymine = 30%, guanine = 20%, cytosine = 20%

also called 5-methyl uracil

thymine

has a ketone C=O group as part of Carbon #6, an amino group off of carbon #2, and is bonded to the sugar deoxyribose from position #9 of the base

guanine

has 2 keto side groups at position 4 and 2; appears in RNA only

uracil

DNA of thermophiles have a G + C content of 70% to what advantage does this provide them?

thermophiles like hot environments, its beneficial b/c theres more hydrogen bonds present which gives a lesser possibility of DNA melting at hot temps

tandem repeat like centromeric DNA

a short DNA sequence is repeated right next to itself over and over again

what is SINE

short interspersed nuclear element; short DNA sequence that has been copied and inserted into many different locations

parainversion

both on the same arm

perinversion

one on each side of the centromere

you want to radioactively label RNA in a growing dividing cell but not its DNA; which unique radioactive base/nucleotdie would you add to the culture medium

uracil

structural or functional differences between RNA and DNA

RNA = ss, U, ribose, catalyst; DNA = DS, t, deoxyribose

T or F inversions and translocations often contribute to infertility and nonviable offspring due to gametes that have many chromosomal aberrations

true

lac +

able to ferment/use lactose as a source of carbon; can grow on media containing lactose

leu-

not able to make leucine; must be supplemented with leucine

prototroph

wild type bacteria; able to conduct most metabolic pathways

auxotroph

mutant bacteria; having one or more nutritional mutations

what is called a circular piece of double stranded DNA separate from the main chromosomes codign for antibiotic resistance

R factor

the process whereby a bacterial virus donates bacterial DNA from 1 host to another, because of mispackaging the bacterial DNA in a viral protein shell

generalized transduction

the process whereby a bacterial virus that undergoes lysogeny and lytic cycles will carry over specific bacterial DNA from 1 host to the next simply by incorporating adjacent DNA to the point of incorporation

specialized transduction

catabolic

breaks down DNA into nucleotides, usually releases energy, considered DNA degradation

anabolic

builds up DNA from nucleotides, usually requires energy, considered DNA replication

a cell bearing the type of fertility factor which also has part of the chromosomal DNA

Hfr cell

the type of bacterial genetic recombination in which any foreign DNA is taken in and incorporated into the cell

transformation

the type of bacteria who are wild type and can synthesize all the biological molecules they need for growth and reproduciton

prototroph

the type of bacteria who are nutritionally deficient and will need supplements for growth and reproduction

auxotroph

the time it takes for a copy of the entire bacterial chromosome to transfer from a donor to a recipient

100 minutes

when recombination occurs within one generation of bacteria, sometimes of different species resulting in sharing of DNA between species, blurring what species represent

horizontal gene transfer

when recombination occurs carrying over the fertility factor and part of the chromosomal DNA

an F’ cell

when viruses carry over DNA adjacent tot heir locus of incorporation; used for mapping bacterial chromosomes

specialized transduction

a cells thats a recipient lacking any fertility factor propertiesf

a cells thats F-

a cell that carries a fertility factor

a cell thats F+

the process whereby a bacterial virus donates bacterial DNA from 1 host to another, because of mispackaging the bacterial DNA in viral protein shell

generalized transduction

when we melth DNA fragments from eukaryotic chromosomes what temperatures should we use? After melting is DNA DS or SS

80 degrees C; SS

if allowed reassociation of the DNA fragments after melting we can see some pieces coming together more quickly than others, which pieces come together more quickly

a. highly repeated

b. unique sequences

c. moderately repeated sequences

highly repeated sequences, then moderately, and lastly unique

which part of the chromosome do you find highly repeated sequences

centromere and telomere; sometimes interspersed along the chromosome

5p- these individuals have facial anomalies, sever mental disability and catlike cry

cru-di-chat

46, t (14,21) these individuals make up on 5% of the Down syndrome cases; inherited due to having a parent being a carrier with a mixed chromosome consisting of the q arm of chromosome 14, and the q arm of chromosome 21

robertsonians translocation

47 + 13 these individuals have facial and brain malformations also dying at an early age

pataus syndrome

47 + 21 these ppl have 3 copies of chromosome 21 and are mentally challenged with large tongues, wide skull, cogential heart defects and early onset of Alzheimers

down syndrome

47 + 18 having clenched fist, overlapping fingers, heart malformations, dying at an early age

edwards syndrome

47, XXY male features develop at puberty, with low fertility, learning disability and subnormal intelligence

klinefelters syndrome

X females lacking a second X chromosome, short, wide chested, with rudimentary ovaries

turners syndrome

reason why older mothers are more likely to give birth to a child with down syndrome

b/c the egg is stuck in suspension in early metaphase longer so theres a greater chance for nondisjunction to occur; causing down syndrome

where to find teleomeric DNA

at the end of the chromosome (its replicated separately)

what is the catalytic part of a telomerase enzyme the protein or the RNA

RNA

list properties of structure limitations of B form DNA

DS, double helical formation, sugar-phosphate backbone, right handed, major and minor grooves, hydrogen bonds b/w bases, 10 bp per turn

autopolyploid cropsf

extra chromosome set comes from the same species (can make larger fruit, flowers, or leaves)

allopolyploid crops

chromosome sets come from different species through hybridization (can combine desirable traits from two organisms)

what is the endosymbiosis

bacteria living inside another cell; mutually beneficial

heteroplasmy…impacts diseases how

a cell contains different mixtures of mitochondria DNA; mitochondrial diseases therefore arent the same in all areas of the body

what is the structure of a nucleosome

around 147 bp of DNA wrapped around a histone of octamer containing 2-H2A, 2-H2B, 2-H3, and 2-H4

why histones

because they’re + charged, package DNA, condense DNA, regulate gene expression

retrotransposons

a transposable DNA elements that move through and RNA intermediate using reverse transcriptase to make a new DNA copy

simple transposons

DNA transposable element that moves to another location using transposes without an RNA intermediate

SMC proteins stands for…and function

structural maintenance of chromosome proteins; they help organize and control chromosomes

two important SMC proteins and their function

cohesion = holds sister chromatids together; condensin= condenses/coils chromosomes

function of topoisomerase

enzymes that relieve twisting and tension in DNA; no grooves or supercoils

ends of transposable elements have

direct and inverted repeats

how many origins of replication in prokaryotic cells

one

epigenetics and ex

changes in gene expression that happen without changing the DNA sequence ex: DNA methylation

genomic imprinting

an epigenetic process where gene expression depends on whether the gene was inherited form the mother or the father

the percent recombination is also = to the _____

map units

translocations occur between

non-homologus chromosomes

diagram how both diseases came about: Turners Syndrome + hemophilia

• father = Xh Y

• daughter = Xh O

mother had to supply nondisjunction for O gamete

phosphodiester bonds

connecting 3’ OH of one sugar to the 5” phosphate for the next molecule

besides forming the backbone of DNA what ionic property do phosphodiester bonds provide

phosphates make DNA neg charged

which nitrogenous base is this

thymine

which nitrogenous base is this

guanine

which nitrogenous base is this

cytosine

which nitrogenous base is this

adenine

heterochromatin vs euchromatin

euchromatin is loosely packed and generally transcriptionally active; heterochromatin is condensed repetitive and generally inactive

copy number variants and what are they used for

differences in the number of copies of DNA segments caused by deletions or duplications; can be used to identify genetic variation and associations with traits or diseases

glycosidic bonds

between sugar and nitrogenous base

hershey and chase experiment

labeled phage DNA with radioactive phosphorus and phage protein with radioactive sulfur. The DNA entered the bacterial cells wile most protein remained outside, showing that DNA is the genetic material

example of genetic imprinting

angelman syndrome