Term
| where is DNA found in prokaryotic cells? |
|
Definition
|
|
Term
| what is the form of prokaryotic DNA? |
|
Definition
| a single circular ring (mostly) |
|
|
Term
| what holds sister chromatids together in a chromasome? |
|
Definition
|
|
Term
| what is the name of the particular DNA sequence that joins sister chromatids in a chromosome to each other? |
|
Definition
|
|
Term
| what is the part of the cell cycle where mitosis is NOT taking place? |
|
Definition
|
|
Term
| what are the three parts of interphase, and what is happening in each? |
|
Definition
G1 (growth)
S (replication of DNA - the two strands of complimentary base paired DNA separate from each other)
G2 (getting ready to separate) |
|
|
Term
| what is the name for the combination of DNA with proteins? (how DNA exists in all eukaryotic cells) |
|
Definition
|
|
Term
| list the stages of condensation (0-4) |
|
Definition
0: DNA double helix (2nm)
1: (10 nm fiber) - "beads on a string" configuration
2: (30nm fiber) - "beads on a string" twisted into a helix (about 6 nucleosomes/turn)
3: (300nm) loops around scaffold protein
4: (700nm) chromosome |
|
|
Term
|
Definition
| the "beads" in the "beads on a string" 30 nmfiber are histone cores - 2 copies of each histone protein (H2A, H2B, H3, H4) and the DNA wraps around them. The whole configuration is called a nucleosome. |
|
|
Term
why does it make sense that the histone proteins are basic? |
|
Definition
| basic is a positive charge. DNA is acidic and hence has a negative charge. the opposite charges hold the DNA strands to the histone cores |
|
|
Term
| what is the DNA between the histone cores in a 10nm fiber called? |
|
Definition
|
|
Term
| what are N-termini, and what is the function of the N-termini of the histone proteins? |
|
Definition
stick out of the histone core as histone tails.
an N-terminus is the end of an amino acid chain that ends with a free amino group (-NH2)
- these stick to each other in the helixal 30-nm fiber |
|
|
Term
|
Definition
| right outside the histone core, associated with the linker DNA |
|
|
Term
| if you see granular DNA formations under a microscope in interphase, what stage is it likely to be in? |
|
Definition
| 30nm fiber ("beads on a string" twisted into a helix, sticking together by hydrogen bonding on the histone tails) |
|
|
Term
| in the 300nmfiber, what is the name of the looped DNA around the scaffold proteins? |
|
Definition
|
|
Term
| in what stage of mitosis does the DNA finally become condensed into chromosomes? |
|
Definition
|
|
Term
| during what phase of mitosis does the DNA decondense out of chromosomes? |
|
Definition
|
|
Term
| what is DNA expression and how can it happen? |
|
Definition
| gene expression is a gene "coding" for an actual protein; this can't happen unless the DNA is unwound. |
|
|
Term
| when does most gene expression take place? |
|
Definition
|
|
Term
|
Definition
DNA that is very tightly condensed, even during interphase
- never gets expressed |
|
|
Term
|
Definition
| genes in heterochromatin - which is too tightly wound, so they never get expressed. |
|
|
Term
|
Definition
| DNA that isn't tightly wound during interphase and can get expressed |
|
|
Term
|
Definition
| the ends of a chromosome, which are always wound and never get expressed. |
|
|
Term
| how can you affect how condensed or decondensed DNA is? |
|
Definition
| by modifying the histone protiens |
|
|
Term
| what stage is the DNA in during most of interphase? |
|
Definition
|
|
Term
| what are two functions of the cytoskeleton? |
|
Definition
- maintaining the shape of the cell
- motility |
|
|
Term
| what are the three support/motility structures in eukaryotic cells, and the protein that makes up each? |
|
Definition
| microfilaments (actin), intermediate filaments (keratin), microtubules (tubulin) |
|
|
Term
| what form of support structure is responsible for both the cleavage furrow and muscle movement in eukaryotic cells? |
|
Definition
|
|
Term
| how are microfilaments responsible for muscle movement? |
|
Definition
| alternate with a motor molecule in stripes to move the muscle |
|
|
Term
| what is ameboid movement and what form of support structure is involved in it? |
|
Definition
| extending a pseudopodium (lit. false foot) to move and/or change shape - these are microfilaments |
|
|
Term
|
Definition
| a network/layer of microfilaments right on the inside of the plasma membrane in eukaryotic cells |
|
|
Term
| what anchors the nucleus and the organelles? |
|
Definition
|
|
Term
| describe the nucleus, including the role of intermediate filaments |
|
Definition
| a double membrane with nuclear pores in it (these are proteins that let ribosomes and RNA move to the outside of the nucleus). the nuclear lamina anchors the pore proteins and is made of intermediate filaments |
|
|
Term
| what is the nuclear lamina? |
|
Definition
| network of intermediate filaments inside the eukaryotic cellular nucleus. It provides support and also regulates the cell cycle, is involved in DNA replication, chromatin organization and apoptosis |
|
|
Term
| what is the structure of microtubules? |
|
Definition
| 13 columns of tubulin molecules; each column is made up of one alpha tubulin and one beta tubulin (dimers) - to make it long, add more dimers |
|
|
Term
| what are flagella and cilia made of? |
|
Definition
|
|
Term
| what is the structure of a flagella? (anchor, arrangement of tubulin) |
|
Definition
| basal body anchors it to the cell; has a 9+0 arrangement; is actually part of the cell membrane |
|
|
Term
| what is the structure of the tubulin in cilia? |
|
Definition
| 9+2 arrangement (9 doublets arranged in a column around two doublets) with motor proteins and cross-linking proteins |
|
|
Term
|
Definition
| motor proteins in between the tubulin doublets |
|
|
Term
| what keeps the tubulin dimers in flagella from sliding past each other? |
|
Definition
|
|
Term
what area of the cell produces the microtubules and controls thier polymerization and depolymerization? |
|
Definition
|
|
Term
| what are the central rods in the centrosomes? |
|
Definition
|
|
Term
| what is the difference in structure between cilia/flagella and the centrioles? (2) |
|
Definition
cilia/flagella: 9+2 arrangement; doublets of microtubules
centrioles: 9+0 arrangement; triplets of microtubules |
|
|
Term
| what do animal centrosomes have that plant centrosomes don't? |
|
Definition
|
|
Term
| what is the area where the synthesis of ribosomal DNA occurs? |
|
Definition
| nucleolus (dark region in the nucleus) |
|
|
Term
| what happens during prophase? |
|
Definition
1. chromatin starts to condense
2. spindle apparatus (made of microtubules) are synthesized from the centrosomes - centrosomes move away from each other
3. nucleus is still intact, but the nucleolus disappears |
|
|
Term
| what are the two kinds of microtubules? |
|
Definition
|
|
Term
| in what region are sister chromatids joined together? |
|
Definition
|
|
Term
| by what point in the cell cycle does each chromosome consist of two sister chromatids? |
|
Definition
|
|
Term
| what holds the two sister chromatids together in the centromeric region? |
|
Definition
|
|
Term
| what happens during G2 of interphase? |
|
Definition
| organelles are replicated in preparation for mitosis |
|
|
Term
| how many centrosomes are there during G1? G2? |
|
Definition
|
|
Term
| what emerges from the centrosomes during G2? |
|
Definition
| asters (short bursts of microtubules) |
|
|
Term
| what happens to the nuclear envelope in prometaphase? |
|
Definition
| it fragments (pieces later used to form the new nuclear envelope) |
|
|
Term
| what is the first time DNA can be seen as individual (but not fully condensed) chromosomes? |
|
Definition
|
|
Term
| during anaphase, how many chromosomes are there in total? |
|
Definition
|
|
Term
| what is the signal that anaphase has begun? |
|
Definition
| cohesids (that hold the sister chromatids together) start to degrade |
|
|
Term
| during anaphase, what happens to the kinetochore and nonkinetochore (polar) microtubules? |
|
Definition
| kinetochore ones "shorten" (depolymerize) and the nonkinetochores "lengthern" (polymerize) |
|
|
Term
|
Definition
| actin-based motor protein; helps with muscle movement |
|
|
Term
| where do the reformed nuclear membranes come from in telophase? |
|
Definition
| fragments of the original nuclear membrane; also a little bit from the endomembrane system |
|
|
Term
| what happens to any remaining microtubules in telophase? |
|
Definition
|
|
Term
| what's the difference between the ribosomes on the rough ER and those in the cytoplasm |
|
Definition
| rough ER: makes proteins that are secreted outside the cell; the cytoplasm ones make proteins that are secreted inside the cell |
|
|
Term
| what happens to proteins in the ER when they are done being synthesized by the ribosomes in the rough ER? |
|
Definition
| go into the lumen; modified in the smooth ER (also happens to lipids made in the smooth ER); put into a vessicle (made by budding) to get to the golgi apparatus |
|
|
Term
| how does the protein-containing vessicle get to the golgi bodies? |
|
Definition
| attaches itself to a microtubule and transport proteins take it there |
|
|
Term
| what happens if the material inside the golgi body is something you dont want in the cell? |
|
Definition
| the buds become lysosomes, which destroy it |
|
|
Term
| how is the cell plate formed in plants? |
|
Definition
| the vessicles line up along the cell plate line and fuse to each other; these all contain proteins that also fuse to make up the cell wall. |
|
|
Term
| what contracts to form the cleavage furrow in animal cells? |
|
Definition
|
|
Term
| what is the restriction point and when does it take place? |
|
Definition
| the point at which a cell is told to leave the cell cycle and stop dividing or stay in and continue to divide. this happens during G1. |
|
|
Term
| what happens at the G2 checkpoint? |
|
Definition
| the cell makes sure it's ready for mitosis |
|
|
Term
|
Definition
| checks the kinetochores to make sure each has a kinetochore microtubule attatched. |
|
|
Term
|
Definition
| a class of enzymes that phosphorelate (turn on other enzymes by adding a phosphate group). these regulate the stages of mitosis. |
|
|
Term
| in order to pass the G2 checkpoint, what must be present in the cell? |
|
Definition
| cdk (cydin dependant kinase) |
|
|
Term
| what protein activates the cdks? |
|
Definition
|
|
Term
| what are three external cellular growth signals? |
|
Definition
1. growth factors
2. anchorage
3. confluence |
|
|
Term
| density dependant inhibition |
|
Definition
| when cells have covered the whole of the available surface, they will stop dividing (they won't form layers.) |
|
|
Term
| what do you call inserting a plasmid into a prokaryotic cell? a eukaryotic cell? |
|
Definition
| transformation; transfaction |
|
|
Term
|
Definition
| an ordered display of chromosomes |
|
|
Term
| how do you distinguish between chromosomes? |
|
Definition
1. size
2. location of centromeres
3. banding pattern |
|
|
Term
|
Definition
| one chromatid from each chromosome of a homologous pair |
|
|
Term
|
Definition
|
|
Term
| the daughter cells of meiosis I have_________ the chromosomes and __________ the DNA of the original cell. the daughter cells of meiosis II have _____________ the chromosomes and _____________ the DNA of the original cell. |
|
Definition
| the daughter cells of meiosis I have HALF the chromosomes and HALF the DNA of the original cell. the daughter cells of meiosis II have THE SAME AMOUNT of chromosomes and HALF the DNA of the original cell. |
|
|
Term
| what event happens in prophase I of meiosis that doesn't happen in prophase I of mitosis at all? |
|
Definition
| synapsis - homologous chromosomes are stuck together with proteins. this is called a synaptonemal complex. |
|
|
Term
| what is the synaptonemal complex without the cohesids called? |
|
Definition
|
|
Term
| for each tetrad, how many kinetichore microtubules attach? |
|
Definition
| two (the other two are smushed between the two chromosomes) |
|
|
Term
| what is independant assortment of chromosomes? |
|
Definition
| the fact that you can get different assortments of father/mother chromosomes for each homologous pair: f/f, f/m, m/m, m/f |
|
|
Term
| due to independant assortment, how many combinations of chromosomes can we have? |
|
Definition
|
|
Term
|
Definition
| the bits of homologous chromosomal pairs that cross over at the ends |
|
|
Term
| the daughter cells of mitosis are identical to each other and the parent cell; why are the daughter cells of meiosis NOT always identical? |
|
Definition
|
|
Term
| what are the three factors that contribute to genetic diversity? |
|
Definition
1. crossing over
2. independant assortment
3. random fertilization |
|
|
Term
| what is the difference between a phenotype and a genotype? |
|
Definition
| a phenotype is an observed trait; a genotype is the underlying genetic composition that results in that phenotype. |
|
|
Term
|
Definition
| the location of a given gene on a chromosome |
|
|
Term
|
Definition
| Law of Segregation - when a plant makes its own gametes, each gamete gets only one of the two alleles; and which it gets will be random. |
|
|
Term
|
Definition
cross between two heterozygotes at one genetic locus
(Aa)x(Aa) |
|
|
Term
| linked vs. non-linked genes |
|
Definition
| linked genes are on the same chromosome; non-linked genes are not. |
|
|
Term
| law of independant assortment |
|
Definition
| whether you have A or a on one gene won't affect whether you have B or b on another gene - unless they're linked (on the same chromosome) |
|
|
Term
| what is the phenotypical ratio in a dihybrid cross? |
|
Definition
|
|
Term
| if you know the probability of each independant event, how do you figure out the probability of them both happening simultaneously? |
|
Definition
| multiply the two probabilities |
|
|
Term
| if you have two independant events, and you want to know the probability of EITHER happening, what do you do? |
|
Definition
|
|
Term
|
Definition
| both alleles in a heterozygote are being expressed |
|
|
Term
|
Definition
| a mix of genotypes produces a mix of phenotypes - something in the middle |
|
|
Term
|
Definition
| the genotype at one genetic locus effects the expression of the phenotype at another genetic locus |
|
|
Term
|
Definition
| if a trait isn't either/or, but is a mix of many factors - a summation effect (like height or skin color) |
|
|
Term
|
Definition
| one gene affecting multiple traits |
|
|
Term
| if a woman is colorblind, what does that tell us about her parentage? |
|
Definition
| her father MUST have been colorblind |
|
|
Term
| in a test cross between a dihibrid and a homozygous recessive, if the parental type is disproportionately present, what does that tell us about the location of the two traits? |
|
Definition
|
|
Term
|
Definition
| in anaphase (I or II) of meiosis, there is a mechanistic failure and BOTH chromosomes of a pair are pulled to one side of the cell. |
|
|
Term
| if nondisjunction happens in meiosis I, what will the four daughter cells look like? |
|
Definition
| two will have n+1 chromosomes, and two will have n-1 chromosomes |
|
|
Term
| if nondisjunction happens in meiosis II, what will the four daughter cells look like? |
|
Definition
| two will be normal (n), one will be n-1 and one will be n+1 |
|
|
Term
|
Definition
| when a zygote has an abnormal number of chromosomes |
|
|
Term
|
Definition
| the sex of the contributing parent is a factor in the expression of a gene |
|
|
Term
| what are the three structural components of DNA? |
|
Definition
1. nitrogen-containing base (A/T/C/G)
2. pentose sugar (deoxyribose)
3. phosphate group |
|
|
Term
| purine (A and G) structure |
|
Definition
|
|
Term
| pyrimadene (T and C) structure |
|
Definition
|
|
Term
|
Definition
| links nucleotides - links the carbon 3' of one nucleotide to the carbon 5' of the next |
|
|
Term
| why does the G-C hydrogen bonding take more heat to denature than the A-T? |
|
Definition
| it's actually three hydrogen bonds; A-T is only two. |
|
|
Term
| semiconservative vs. conservative DNA replication model |
|
Definition
semiconservative: each of two new synthesized helixes of DNA would have one of the original strands
conservative: the new synthesized helixes would NOT have the original DNA strands, which would stay together in their original helix |
|
|
Term
|
Definition
| untwists the strands of the double helix at the replication forks |
|
|
Term
| what keeps the unpaired DNA strands from snapping back together? |
|
Definition
|
|
Term
|
Definition
| untwists the strands of DNA outside of the replication fork and keeps them from tangling as the bubble expands |
|
|
Term
|
Definition
| synthesizes RNA primers from the base DNA template |
|
|
Term
|
Definition
| an enzyme that takes monomers and builds them on one another to become polymers |
|
|
Term
| exonuclease vs. endonuclease |
|
Definition
exonuclease cuts repeatedly on the ends of DNA strands
endonuclease looks for specific sequences and cuts there |
|
|
Term
|
Definition
| acts as an exonuclease to RNA; deletes each RNA sequence - and also as a polymerase, filling in the gaps with DNA! (connecting 5' to 3' ends) |
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|
