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Definition
| used X-ray diffraction imagery to examine the crystal structure of DNA |
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Definition
| Theory of natural selection; SURVIVAL OF THE FITTEST |
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Definition
Austrian monk
Studied inheritance of pea plants
Developed principles of inheritance
Difference in traits
Suggested each cell contained set paired factors and that each pair determined a specific trait |
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Definition
showed genetic bacteria can be changed
R strain vs S strain in mice with pneumonia
dead smooth cells can make live rough cells pathogenic when rough cells are usually nonpathogenic
-what is transforming material, substance, is dna causing transformation? |
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Term
| Avery, MacLeod, and McCarty |
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Definition
| showed that genetic info in bacteria could be transformed by purified DNA |
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Definition
Determined the 3-D structure of the DNA molecule (double helix)
Stole Rosalind Franklin's work |
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Definition
Used phages labeled with radioisotopes
Protein was labeled with 35S, DNA labeled with 32P
After the virus was introduced with radioactive labels the host had labeled DNA in it
Final proof that DNA was heredity material |
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Term
| Characteristics of functional DNA |
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Definition
chemical complexity + stability
to encode and store genetic info
expression of traits/gene
ability to slowly mutate
genetic diversity
accurately replicate
offspring receive identical copies |
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Term
| Prokaryotes vs Eukaryotes |
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Definition
Prokaryotes- DNA contained in single circular molecules of DNA, no nuclear membrane, DNA not highly condensed during replication
Eukaryotes- contains nucleus, DNA in nucleus, within cytoplasm are organelles |
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Term
| Which organelles contain DNA? |
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Definition
| Nucleus and the mitochondria and chloroplasts contain circular DNA |
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Term
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Definition
phosphate group is attached to 5' carbon of the sugar in nucleoside
(base + sugar + phosphate) |
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Term
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Definition
| nitrogenous base chemically linked to 1 molecule of sugar deoxyribose at 1' carbon (base + sugar) |
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Term
| Difference between pentose sugars of RNA and DNA? |
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Definition
RNA- bottom of 5 membered ring has 2 OH groups
DNA- bottom of 5 membered ring has 1 OH group and 1 H |
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Term
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Definition
adenine and guanine
double ringed |
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Definition
thymine, cytosine, uracil
single ring |
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Term
How many bonds do A and T make?
G and C? |
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Definition
A and T- 2 hydrogen bonds
G and C- 3 hydrogen bonds |
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Term
| What direction are nucleic acids read in? |
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Definition
5' --> 3'
5' is phosphorylated
3' has a hydroxyl group |
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Term
| Semiconservative replication |
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Definition
the mechanism by which DNA is replicated where it produces 2 copies one original strand and one new strand
Meselson and Stahl
Grew e. coli w/N15 for many generations
after experiment started, generation 0 had 100% N15/N15 (N15 in both strands)
After generation 3 strands had half N15/N14 |
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Term
| How was RNA discovered to be the genetic material in some viruses? |
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Definition
by testing if RNA or protein carries the genetic material in Tobacco Mosaic Virus
Took TMVa and combined it with protein and same with TMBb and protein a and each time they got the RNA after replication to be the TMVa with protein a |
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Term
| DNA replication is mediated by: |
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Definition
Polymerase
enzyme specific
add nucleotides to the 3' end |
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Term
| Procedures involving synthesis of leading and lagging strands |
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Definition
starts at origin
multiple origins occur at a time
results in a bubble at each site
initiation- different proteins bind to origin DNA to unwind
UNWINDING- Helicase binds to short stretch of single stranded DNA
Helicases break H bonds
Binds to lagging strand moves toward replication fork
occurs AHEAD of replication fork
elongation- DNA polymerasre elongates the polynucleotide |
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Term
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Definition
| used to break apart H bonds on the rest of the genome |
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Term
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Definition
enzyme that controls the supercoiling during replication
synthesizes a short RNA primer |
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Term
| Single Strand Binding Protein (SSB) |
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Definition
prevents binding of the separated strands
allows them to stay available to be a template |
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Term
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Definition
| delivers primase and necessary proteins to an origin or replcication |
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Term
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Definition
the main DNA synthesizing enzyme
synthesizes new DNA w/a sequence complementary to the template strand as long as there are complementary nucleotides on the template to direct nucleotide addition to the daughter strand |
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Term
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Definition
| large protein complex at replication fork |
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Term
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Definition
| replaces pol III and removes nucleotides of RNA primer one by one and replaces them w/DNA nucleotides |
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Term
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Definition
| after all of the RNA primer is replaced DNA ligase comes inand creates the phosphodiester bonds |
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Term
| why is a primer needed for DNA polymerase? |
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Definition
| a primer is needed because it has a free 3' POH end for the new nucleotodes to bind to it |
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Term
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Definition
enzyme capable of separating the phosphodiester bonds between nucelotides
endonuclease- breaks bonds inside a chain
exonuclease- removes a nucleotides from the end of chain; a built in mechanism for correcting rare errors during DNA synthesis |
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Term
| how does telomerase function to maintain the length of a chromosome? |
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Definition
it contains AACCCC
allows for the extension of the template strand so the alpha polymerase can add an RNA primer that a chromosome end can be replicated |
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Term
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Definition
| two copies of chromosomes that are duplicated in S phase |
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Term
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Definition
identical pair of chromosomes that are inherited from mom and dad
usually illustrated by karyotype |
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Term
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Definition
| (gap 1) gene expression continues as normal, cell prepares for DNA synthesis |
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Term
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Definition
| (G zero) a semiperpetual G1, like state in which cells express their genetic material but don't progress through cell cycle and eventually leads to cell death |
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Term
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Definition
| DNA replication takes place and chromosome duplication takes place |
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Term
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Definition
when cells prepare for division
last phase of interphase |
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Term
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Definition
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Term
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Definition
half of mitosis spent in this phase
centrioles start to form to the poles
chromtid structure starts to form
spindle fibers being to form |
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Term
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Definition
nuclear membrane disappears
spindle fibers begin to make contact with chromosomes |
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Term
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Definition
chromosomes are fully condensed
they are aligned on metaphase plate
sister chromatids ready to be separated |
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Term
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Definition
shortest stage of mitosis
sister chromatids migrate away from each other and move towards opposite ends of the cell |
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Term
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Definition
last stage
cytokinesis takes place chromsomes un coil and become chromatin
nuclear membrane reforms |
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Term
| Similarities of mitosis and meiosis |
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Definition
interphase for all cells is same
functions of centrosomes and microtubules are same |
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Term
| Differences of mitosis and meiosis |
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Definition
mitosis produces identical cells, meiosis produces genetically different gametes for sexual repro
mitosis consists of 1 round of replication, meiosis has 2
in mitosis, homologous chromosomes don't pair and don't undergo recombination
in meiosis, they synapse during prophase I and recombine during prophase II
mitosis produces 2 identical cells, meiosis produces 4 HAPLOID DIFFERENT cells |
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Term
| What is the result of DNA synthesis? |
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Definition
| produces sister chromatids |
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Term
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Definition
| the close approach and contact between homologous chromosomes during early prophase I (meiosis) |
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Term
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Definition
| the breakage and reunion of homologous chromosomes that result in reciprocal combination? |
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Term
| Where do spindle fibers attach to pull apart sister chromatids? |
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Definition
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Term
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Definition
| chromosome region containing chromatin that is not densely compacted; most expressed genes are located within euchromatic regions of chromosomes |
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Term
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Definition
| a chromosome region containing densely compacted chromatin and few if any expressed genes |
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Term
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Definition
random assortment of chromosomes means that during metaphase I when the chromosomes line up in a random matter before crossing over takes place
non-disjunction- when homologous chromosomes don't split
can cause mutations, most of the time it is lethal (TRISOMY!) |
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Term
| Gamete maturation: oogenesis and spermatogenesis |
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Definition
oogeneis- creation of egg cells
spermatogenesis- creation of sperm cells |
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Term
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Definition
development of the embryo sac in plants
4 haploid cells produced in meiosis- megaspores
only one is carried forward and 3 degrade |
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Term
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Definition
pollen grain development
four haploid cells produced during meiosis called microspores
microspore nucleus will divide mitotically forming 2 nuclei within the original spore wall
tube nucleus- pollen tube growth
two generative nucleus divides again producing two sperm nuclei
the entire structure is a pollen grain |
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Term
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Definition
embryo is diploid
endosperm is triploid
2 fertilization events:
-embryo = n + n = 2n
-polar nuclei = 2n + n = 3n total |
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Term
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Definition
| chromosomes reach the poles and cytokinesis occurs |
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Term
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Definition
| homologous chromosomes migrate to opposite poles |
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Term
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Definition
| interaction with the spindle fibers allows homologous chromosome pairs to align on the equatorial plate |
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Term
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Definition
chromatin/chromosomes begin to condense
Part 1 of prophase I |
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Term
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Definition
chiasma form and homologous chromosomes have began to separate
4th part of prophase |
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Term
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Definition
homologous chromosomes are repelling, and held together only by the chiasma
5th part of prophase I |
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Term
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Definition
| after meiosis I the chromosomes recondense |
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Term
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Definition
| sister chromatids align on the equatorial plane, and spindle fibers attach to the chromatid cetromeres |
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Term
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Definition
crossing over occurs
3rd part of prophase I |
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Term
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Definition
| sister chromatids migrate to opposite poles |
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Term
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Definition
homologous chromosomes pair
2nd part of prophase I |
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Term
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Definition
| he failure of one or more pairs of homologous chromosomes or sister chromatids to separate normally during nuclear division, usually resulting in an abnormal distribution of chromosomes in the daughter nuclei |
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Term
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Definition
| a point at which paired chromosomes remain in contact during the first metaphase of meiosis, and at which crossing over and exchange of genetic material occur between the strands |
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Term
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Definition
| Homologous chromosomes are chromosome pairs of approximately the same length, centromere position, and staining pattern, with genes for the same characteristics at corresponding loci. One homologous chromosome is inherited from the organism's mother; the other from the organism's father |
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