Term
| Chromosomal Theory of Inheritance |
|
Definition
| Thomas Hunt Morgan's Theory: Mendeleain genes have specific positions on chromosomes (linear sequence of genes),(!!!) and it is the chromosome that undergos segrgation and independent asortment |
|
|
Term
| Thomas Hunt Morgan (job / where / what he did / what he found) |
|
Definition
| American geneticist / Professor at Columbia / Studied common fruit fly to test Mendel's principles because it reproduces quickly / found that Mendel's principles applied to other organisms, not just peas! |
|
|
Term
| Morgan's Scientific Inquiry (sex linked experiments) |
|
Definition
wild type = w+ = normal phenotype (red eyes)
mutant type = w = alternative traits (white eyes)
P generation = white eyed (mutant) x red eyed (wild)
F1 generation = 100% red eyes (Rr)
F2 generation = 3:1 phenotype ratio but all white yes were make!
conclusion = eye color is related to gender (gene must be on X chromosome only) |
|
|
Term
|
Definition
| males only expressing 1 trait because they can't express on the Y (doesn't mater if its dominant or recessive) |
|
|
Term
| linkage groups and linked genes |
|
Definition
| genes located on one chromosome form a linkage group that are inherited together (called linked genes) because tehy are close together on the chromosome and there is no crossing over(crossing over causes genetic recombination) to separate linked genes |
|
|
Term
| Morgan's linkage experiments |
|
Definition
wild type = gray bodeis, normal wings
mutants = black bodies, small wings
F1 generation = whild type dihybrids
F2 generation = female dihybrids x male double mutant phenotype (all sperm donated b and vg together (no b+ or vg+) so offspring phenotypes depended on female alleles |
|
|
Term
| evidence of PARTIAL linkage |
|
Definition
| body color and wing size usually inherited together because of higher proportion of parental phenotypes than expected (expected 25%, 25%, 25%, 25% and instead got different numbers) BUT, there were still some nonparental phenotypes because there must be some crossing over aka genetic recombination |
|
|
Term
| parental types vs. recombinants |
|
Definition
parental types = phenotypes like the parent
recombinants = nonparental phenotypes |
|
|
Term
| frequency of recombination (4 things) |
|
Definition
-percentage of offspring that are recombinants
-max 50% because that is equivalent to freq. of genes on two different chromosomes
-related to distance between linked genes
frequency = # of recombinants in offspring / total offspring |
|
|
Term
|
Definition
| used crossing over data to create 1st chromosome map showing relative locations of each known gene of one of the Drosophila (fly) chromosomes |
|
|
Term
| chromosome mapping: genetic map |
|
Definition
| ordered list of genetic loci along particular chromosome (percentage of crossing over between genes is proportional to distance between them on a chromosome, so 2 genes that are separated by crossing over 1% of the time = 1% cross over frequency = distance between genes = 1 MAP UNIT apart = centimorgans |
|
|
Term
| linkage map (type of genetic map) |
|
Definition
| genetic map based on recombiination frequences (does not correspond to actual locations of genes but gives order of genes along chromosome) |
|
|
Term
| discovering sex chromosomes |
|
Definition
| drosophila has 4 pairs of homologous chromosomes but male and females differ in one pair (male's was shorter and hooked where females had 2 indentical ones) so X = female and Y = male |
|
|
Term
| sex determination (how you form into a guy or girl) |
|
Definition
| less than 2 months = generic gonads, then anatomical signs of sex emerge when SRY gene, the sex-determining region of Y, expresses proteins that allow for testis (no SRY = ovaries) |
|
|
Term
| sex linkage (Morgans proposal, 2 things) |
|
Definition
-Morgan proposed that because the X chromosome was larger, it carried more genes than Y
-x linked genes: carried on x chromosome like recessive color vision and blood clotting
-y linked genes: carried on Y chromosome and required for normal testis functioning (SRY gene!) |
|
|
Term
| Morgan confirming X linked traits |
|
Definition
| In drosophila eye color is X linked: most fruit flies have red eyes adn a few males have white, but no femails have white eyes because its rare for female to be homozygous recessive |
|
|
Term
|
Definition
COLORBLINDNESS: most common is inability to distinguish red and green (mostly men because x linked alleles like recessive one for colorblindness are always expressed in males)
HEMOPHILIA: inability of blood to clot because of lack of blood proteins
DUCHENNE MUSCULAR DYSTROPHY: Weakens and progressively destroys muslc etissue dut o lack of muscle protein dystrophin -- rarely live past 20's |
|
|
Term
| x inactivation in femals mammals |
|
Definition
-during embryonic development, one of the X chromosomes is inactivated in femals so that the cells of both males and females have an equally effective dose of x chromosomes
-barr body: inactive X chromosomes that is reactivated later so recessive traits are masked in females
mosaic of cell types: inactivation is random so female has cells with active X from mom or active X from dad |
|
|
Term
| difference between X and Y (4) |
|
Definition
-created in ovum vs. testes
-bigger so it can carry most genes vs. smaller so it can carry less
-everyone gets it vs. determines sex
-causes girl vs. causes boy |
|
|
Term
|
Definition
MUTATIONS: a change in DNA in whole or part of chromosome
MUTAGEN: agents (chemicals, radioactive like radiation, X-rays or UV rays, or something spontanous) that causes mutation
GERM-CELL MUTATION: in gametes, do not affect organism ut can be passed on
SOMATIC CELL MUTATION: in bod cells; do affect organisms and cannot be passed on (skin caner like leukemia)
LETHAL MUTATIONS: cause death, often before birth, which is sad but good because there aren't problems later |
|
|
Term
|
Definition
-loss of a piece of chromosome due to breakage where all info carried by that piece may be lost (genes=letters)
-most deletions lethal or cause serious disorder
-ABCDE-FGHIJ ---> ABDE-FGHIJ |
|
|
Term
|
Definition
-linear chromosomal segment breaks off and then reattaches in reverse orientation to same chromosome
-it is cut out, inverted, and put back in
-ABCDE-FGHIJ ---> ABCDE-FIHGJ |
|
|
Term
|
Definition
-chromosome piece breaks off and reattaches to another nonhomologous chromosome
-reciprocal translocation = segments from nonhomologues switch
-ABC-DEF and GH-IJKLM ---> A-DEF and GH-IJBCKLM |
|
|
Term
|
Definition
-repeated segment
-usually paired with deletion
BELOW: deletion from one homologue causes duplication on the other
-ABCDEFG and ABCDEFG --> ABEFG and ABCDCDEFG |
|
|
Term
| NONDISJUNCTION (4 things) |
|
Definition
-failure of chromosome to separate from its homologue during anaphase
-gives rise to abonrmal chromosome number in gametes
-as you get older, enzymes and proteins don't work as well so nondisjunction probability rises
-ANEUPLOIDY: any abnormal number of particular chromosome once gametes are fertilized
TRISOMIC: 2n+1 chromosome (47) present in triplicate (DOWN SYNDROME)
MONOSOMIC: 2n-1 chromosomes(45), one is missing
POLYPLOIDY:more than 2 sets of chromosomes (3n,4n, usually used in vegies and plants to make them bigger and better, humans won't survive till birth) |
|
|
Term
|
Definition
-affects 1/700 children in US
-result of extra chromosome 21 (called Trisomy 21)
-frequency increases with mother's age (maybe an age-related abnormality in meiosis checkpoints?)
-characteristic facial features, short stature, heart defects, susceptibility to respiratory infection, mental retardation, prone to developing leukemia and ALzheimer's disease, sexually underdeveloped and sterile |
|
|
Term
| ANEUPLOIDY OF SEX CHROMOSOMES (4K, 4T) |
|
Definition
KLINEFELTERS SYNDROME (XXY):
-Inheritance of an extra X chromosome that results mainly from nondisjuction in mother
-tall, sterile males with small testes but normal intelligence
-feminized traits like sparse facial hair, somewhat enlarged breasts
-treated with testosterone injections (XYY men have no syndrome, just are taller)
TURNERS SYNDROME (XO):
-inheritance of one X chromosome only
-98% spontaneously aborted
-short, infertile females, sex organs don't mature, but normal intelligence
-reduced seconday sexual traits (long eyelashes, etc)
-Treated wtih hormones or surgery |
|
|
Term
| structurally altered chromosome disorders |
|
Definition
CRI DU CHAT: cry of the cat- due to deletion in chromosome 5: mental retardation, small head, cry of a destressed cat
CML: chronic myelogenous leukemia- due to translocation between chromosome 22 and 9 |
|
|
Term
|
Definition
| before 1940's scientists didn't know what material caused inheritance (either DNA or proteins, but people pushed for proteins because you'd think DNA with its 4 bases was just too simple) so a series of experiments were conducted to find out waht was the genetic material responsible for inheritance |
|
|
Term
| 1868 / 1928 / 1944 / 1952 |
|
Definition
| Miescher / Griffith / Avery / Hershey-Chase |
|
|
Term
|
Definition
| 1868-isolated DNA by taking white blood cells from puss of soldiers bandages, isolating DNA, and calling it "nuclein" |
|
|
Term
| Griffith experiment (3 things) |
|
Definition
1928
-Attempted to develop a vaccine
-isolated two strains of streptococcus pneumonia (rough strain was harmless, smooth strain was pathogenic and caused disease)
-mice injected with live R don't die and there are no live R cells in their blood
mice injected with live S die and there are live S cells in their blood
mice injected with heat-killed S don't die and there are no live S cells in their blood
mice injected with live R cells plus heat-killed S cells die and there are live S cells in their blood descendents of these transformed R cells were also pathogenic) |
|
|
Term
| Griffith conclusion and year (3 things) |
|
Definition
1928
-although heat-killed s cells are weak, they could still stick their DNA into R cells to transform them and kill the micieys!
-transforming factor must be gene since it was inherited in daughter cells
TRANSFORMATION: change in genotype and phenotype due to assimilation of external DNA by a cell |
|
|
Term
| Avery (experiment and conclusion) |
|
Definition
1944 - Treated virus cells with protein-destroying enymes and cells still could transform other strains, but when treated with DNA destroying enzymes they couldn't.
conclusion:DNa is the transforming factor |
|
|
Term
| Alfred Hershey and Martha Chase experiments to find out if protein or bacteria enters bacteria and results |
|
Definition
1952 1. label bacteriophages (viruses that infect bacteria) with radioactive sulfur (for protein, not in DNA) and phosphorus (for DNA)
2. allowed labeled viruses to infect bacteria
RESULTS: Protein coat labeled with 35S remained outside cell, whereas DNA labeked with 32P remained inside cell, so genetic material MUST be DNA FOR SURE!
LANDMARK #1 |
|
|
Term
| DNA structure (nucleotide, what DNA is, 4 types of bases) |
|
Definition
nucleotide; deoxyribose sugar, phosphate group, and nitrogen-containing base
DNA: chain of nucleotides linked together
Adenine and Guanine (purines = 2 rings)
Cytosin and Thymine (pyrimidines = single-ringed) |
|
|
Term
|
Definition
| -when not part of Dna strand, nucleotide can actually bond to 2 other phosphates that help link the DNA strands together through deohposphorylation when energy is used from remaining phosphate groups to create covelant (sides) and hydrogen (AT, GC) bonds |
|
|
Term
| Chargaff (his experiment, what he discovered, his 3 rules) |
|
Definition
experiment:A and T each 30%, G and C each 20%..weird!
discovered: the base pairing rules and ratios for different species (complimentary base pairing is a mechanism to avoid mistakes because A and T always bond and C and G always bond)
RULES:
A-T with 2 hydrogen bonds
G-C with 3 hydrogen bonds
base-pairing: bases match across from each other and bind together with hydrogen bonds forming two strands |
|
|
Term
| Franklin and Wilkins (2 things) |
|
Definition
1952ish
-taken first pictures of DNA using X-ray christallization and diffraction patterns
-Wilkins purified DNA to get chrystalography |
|
|
Term
|
Definition
1953=big discovery
background story: Crick wen't to ENgland to see Franklin and Wilkins, and discovered it was helical (2 strands wound around eachother), H bonds hold the strands together, it was uniform width, and it was a twisted ladder.
-built models of DNA where there was a major grove and minor grove (not perfect double helix!)
-Everyone but Franklin got the nobel prize because she was a women and she died from the X rays |
|
|
Term
|
Definition
-.34 base pairs per turn
-3.4 nm per turn
-hydrogen sticking out randomly is a perfect place for hydrogen bonds with histones and other enzymes
-5' end has phosphorus where nucleotides can't be added onto. 3' end has OH on the C3 (C1 is the one attached to the nitrogen base, then clockwise)
-5' and 3' bond together to create strands
-opposite sides of laddar are upside down because that's the way it fits (so when they replicate, new strands also must be ANTIPARALLEL to template strands) |
|
|
Term
|
Definition
| single circular DNA mulecule in cytoplasm vs. chromosomes in nucleus |
|
|
Term
| chromatin vs. histones vs. nucleosome |
|
Definition
| DNA and protein tightly backed together vs. proteins tht DNA coils around in chromatin vs. DNA and histones |
|
|
Term
| how many: chromosomes, base pairs, hours to copy DNA, errors |
|
Definition
| 46, 6 billion, a few hours, 1 per 10 billion nucleotides |
|
|
Term
| 4 steps of DNA replication |
|
Definition
1. origin of replication
2. priming DNA synthesis
3. Elongating the leading strand
4. Elongating the lagging strand |
|
|
Term
| origins of replication / bubble / REMEMBER |
|
Definition
stretch of DNa where replication begins with specific series of nucleotides / proteins recognize and attach to origin to separate strands (many bubbles in eukaryotic cells, one in prok cell)
REMEMBER: DNA replication proceeds in both directions |
|
|
Term
| DNA replication enzymes (6 things) |
|
Definition
- Enzyme helicase unwinds DNA producing replication forks (sites where separation and replication of strands occur)
- DNA Polymerases are enzymes that adds new bases
- 400 nucleotides per sec in bacteria, 50/sec in humans
-topoisomerase: relieves tension and strain caused by unwinding DNA
-single-strand binding proteins (SSBs): bind to unwound DNA strands and stabalize them until they are templates for replication
-DNA ligase: enzyme that joins sugar-phosphate backbone of fragments |
|
|
Term
|
Definition
| DNA polymerases add nucleotides ONLY to free 3' end of growing DNA strand (So elongation 5' --> 3' direction) and polymerase can't start the process of okasaki fragments which is why primers are needed |
|
|
Term
|
Definition
PRIMER: 5-10 nucleotide chain of RNA nucleotides that initiates DNA synthesis
PRIMASE: enzyme that joins RNA's together to produce a single primer at 5' end of leading strand or Okazaki fragment
DNA polymerase 3: adds nucleotides to 3' end of RNA primer and continues to add nucleotides to leading strand or Okazaki fragments (also helps PPP --> P by cutting ot off)
DNA polymerase 1: removes primer from 5' end of leading strand or Okazaki fragment and replaces it with DNa thats added to the 3' |
|
|
Term
| leading vs. lagging(called lagging because it takes longer DUHR) |
|
Definition
pol 3 adds nucleotides to make it vs. made going away from replication fork by a series of segments called Okazaki fragments that are 1000-2000 nucleotides long and each need to be primed separately
(REMEMBER: overall direction is 3' --> 5' on parent, but each individual is added in opposite direction) |
|
|
Term
| OVERALL REPLICATION (GOOD LUCK!) |
|
Definition
1. parent DNA just chilling: template 1 is 5' to 3' left to right, template 2 is 3' to 5'
2. Helicase unwinds DNA at replication fork and puts tension on strands before replication fork (topoisomerase relieves this tension and SSBs are proteins that stabalize the unwound strand)
3. LEADING STRAND (T1): 1 primer (that has an OH for nucleotide to bond to) attaches, then nucleotides are added from 3' (rightmost) --> 5' (leftmost) of parent strand but from 5'-3' of new daughter strand (just kept added on to previous nucleotide towards replication fork - Poly 3 is the main enzyme that adds on nucleotides)
4. LAGGING STRAND: read the strand and add nucleotides left to right on parent (3' -> 5') but happens in chunks to the left (3' -> 5' on daughter strand which is why primers are needed)
for lagging:
-primase is an enzyme that joins RNA nucleotides together to make primer and goes on 1st nucleotide after replication fork
-primer has OH for nucleotides to bond and then once nucleotide attached to parent through, the other 2 parts of okasaki can attach to the OH on the previos
-DNA polymerase 1 removes primers, 2 fills in gap with nucleotides, and ligase joins the fragments |
|
|
Term
| conservative vs. semiconservative vs. dispersive model |
|
Definition
| two parental strands reassociate after being templates vs. two strands of parental molecule separate and each functions as template for syntehsis of a new complementary strand (DNA) vs. each strand of both daughter molecules contains a mixture of old and newly synthesized DNA |
|
|
Term
| Meselon and Stahl (experiment and result) |
|
Definition
1958
1. culture bacteria in medium containing 15N
2. Bacteria transferred to medum with 14N
3. DNA sample centrifuged after 20 min (1st replication)
4. DNA sample centrifuged after 40 min (second replication)
RESULTS: 1st generation had both semiconservative, 2nd generation had homogeneous and heterogeneous (50/50 meaning each replication has to be semiconservative) |
|
|
Term
| damaged DNA, proof-reading and repairing: (5 things) |
|
Definition
-reactive chemicals, radioactive emissions, X-rays, UV light, and spontaneous chemical cnahges can all damage DNA
-DNA polymerases profread each base pair during replication (if there is an error, polymerase fizes it)
-If polymerase dones't get it, then cellls use special DNA repair enzymes (mismatch repair) to fix incorrectly paired nucleotides
-nuclease: enzyme that cuts and removes damaged DNA strand
-DNA polymerase and ligase fill in the gap with correct nucleotides |
|
|
Term
| thymine dimers, xeroderma pigmentosum |
|
Definition
THYMINE DIMERS: Uv light rays damages DNA that cuases thymine dimers (covelant linking of adjacent thymine bases causing DNA to buckle and interferes with replication)
XERODERMA PIGMENTOSUM: caused by defect in nucleotide excision repair (causes hypersensitivity to sunlight, mutations in skil cells can lead to cancer) |
|
|
Term
|
Definition
-specific sequences that predict end of DNA strand (like plastic thing at end of shoelace)
-we can all live forever if telomeres don't get shorter as we age (won't lose any gene function?), and we can use them to kill cancer cells |
|
|
Term
| 2 major steps of protein synthesis |
|
Definition
1. transcription: DNA is copied to form mRNA in the nucleus (too dangerous for DNA to leave the nucleous)
2. translation: mRNA is translated to form proteins in ribosomes in cytoplasm |
|
|
Term
| prokaryotic vs. eukaryotic protein synthesis |
|
Definition
| no nucleus and simultaneous transcription and translocation vs. nucleus and cytoplasm with rna, etc |
|
|
Term
| Structure of RNA and wobble effect |
|
Definition
-single stranded chain of nucleotides
-made of 3 parts:
RIBOSE SUGAR: not deoxyribose
PHOSPHATE GROUP
BASES: same as DNA except tymine is now uracil
wobble effect: leniency with 3rd nucleotide in amino acid because of redundancy in table |
|
|
Term
|
Definition
| single chain of uncoiled nucleotides that carries protein-building instructions from DNA to ribosomes vs. nucleotides in globular form (most abundant RNA) that is a major component that makes up ribosomes vs. single chain of nucleotides in hairpin shape that delivers amino acids to ribosomes to form protein chain |
|
|
Term
| RNA polymerase / promoters / DNA template / mRNA transcript |
|
Definition
-binds to DNa and separates dNA strands and adds nucleotides in 5' to 3' direction (does NOT need a primer)
-specific sequences on DNA where RNA polymerase binds to and begins transcription
-one strand of DNA which serves as the model to make a complementary strand of RNA
-final chain of RNA nucleotides produced in transcription that travels out of nucleus to cytoplasm |
|
|
Term
| differences between RNA and DNA: |
|
Definition
| Uracil vs. Thymine, single strand vs. doule strand, can vs. can't leave nucleus, |
|
|
Term
| TRANSCRIPTION (synthesis of RNA transcript: initiation (3) elongation (1) termination (1)) |
|
Definition
1. Initiation:
-Tata box: promoter DNA sequence to which promoter binds
-Transcription factors: mediates binding of RNA polymerase to promoter
-Transcription Initiation Complex: assembly of transcription factors and RNA polymerase and promoter (tata box) that causes DNA to unwind
Elongation: RNY polymerase moves along DNa template and unwinds and adds RNA nucleotides to 3' end (60 n/sec)
Termination: polymerase detaches from template and pre-mRNA released |
|
|
Term
|
Definition
5' cap: guanine caps 5' end of mRNA
poly-a tail: 50-250 adenines added to 3' end
(functions: help export mature mRNA out of nucleus, protect mRNA from hydrolytic enzymes, help ribosome attach to 5' end of mRNA |
|
|
Term
|
Definition
| sequences of nucleotides in DNA that are NOT used to make proteins (noncoding) vs. sequences that are used (introns CUT OUT of mRNA by RNA splicing) |
|
|
Term
|
Definition
snRNPs (small nuclear ribonucleotides) Rna and proteins that recognize splice sites at end sof introns and say "dude this is what needs to be cut out"
Splicosome: snRPSs and proteins taht release introns and join two adjacent extons to form mature transcript (codons) from pre-transcript (no premature! just pre and mature) |
|
|
Term
| start codon vs. stop codon vs. anticodon |
|
Definition
| AUG initiates protein synthesis vs. stop codons end it vs. thingy on bottom of tRNA structure that grabs opposite of it which is the amino acid (so anticodon is the opposite letters of the amino acid!) |
|
|
Term
| translation (what happens, and waht is tRNA) |
|
Definition
-mRNA transcript travels to ribosomes in cytoplasm and tRNAs deliver amino acids to ribosomes to form polypeptide chains
-tRNA is a single strand of RNA that contains an anticodon which is complementary to the mRNA codon, and also carries amino acid which corresponds to codon on mRNA |
|
|
Term
| Aminoacyl-tRNA Synthetase |
|
Definition
-joins aa to tRNA by catalyzing covelant attachment of aa to tRNA
-20 different synthetases for 20 amino acids
-needs ATP |
|
|
Term
|
Definition
1. AUG "start" codon on mRNA initiations translation at ribosomes
2. initiation factors bring subinits mRNA and tRNA together at p-site
3. GTP is used to form initiation complex |
|
|
Term
| translation elongation (4 things) |
|
Definition
-rRNA and proteins make up ribosome (2 part thingy that comes and clamps down on mRNA)
-amino acids bind together wiht PEPTIDE bond
-tRNA anticodon pairs with mRNA codon to bring corresponding amino acid
-A site (left): holds tRNA carrying next to aa
P site (middle): holds tRNA carrynig growing pp chain (all the action here!)
E site (exit): where discharged tRNA's exit ribosome and go find new amino acids |
|
|
Term
| translation termination (3 things) |
|
Definition
-stop castop codon (UGA, UAA, UGA) in mRNA reaches A-site of ribosome
-release factor: binds to stop codon on A-site that causes hydrolysis of polypeptide from P-site = released!
-then, all components of assembly dissociate |
|
|
Term
|
Definition
| transcription is easy and RNA is sent to cytoplasm, then in translation |
|
|
Term
| polyribosomes / post-translational modifications |
|
Definition
several strings of ribosomes translating mRNA simulataneously: enables a cell to make many copies of a pp quickly
/
attach sugars, lipids, and phosphate groups, remove aas from end of pp chain, cleave pp chain, combine two pp chains |
|
|
Term
| point mutation vs. frameshift mutation |
|
Definition
| change in just one base pair (substitution that won't cause frameshift, insertion, deletion) vs. may be caused by point mutations (insertion or deletion that causes shifting in codons, resulting in completely different amino acids |
|
|
Term
|
Definition
silent mutations: no effect on protein because of redundancy
missense mutations: altered codon does for aa that makes sense but not right
nonsense mutations: replaces aa with a stop codon so translocation is terminated prematurely creating a short pp chain (usually nonfunction proteins..like PKU?) |
|
|
Term
| significance of mutations |
|
Definition
-many are neutral (no effect)
-some are spontaneous
-those that cause dramatic changes in protein structure are harmful
-source of genetic variability can be beneficial |
|
|
