exam 5 Flashcards
how can you tell if a pedigree is sex linked?
if males and females aren’t affected equally
x linked dom - more females
x linked rec - more males
y linked - every male, every generation
What is Sutton’s Chromosomal Theory of Inheritance?
mendelian genes have specific loci on chromosomes
chromosomes undergo segregation and independent assortment
What is genetic linkage?
genes located near each other on the same chromosome that tend to be inherited together - less than 50% recombination frequency
What is homologous recombination (crossing over)?
In meiosis I homologous chromosomes swap chunks resulting in new combinations in offspring - the closer genes are, the less likely they are to cross over, so they’re more likely to be inherited together
What is nondisjunction and how can it lead to disorders in chromosome number?
Failure of chromosomes to separate from each other - leads to aneuploidy (incorrect number of chromosomes)
What are the disorders that aneuploidy causes?
monosomy (2n-1)
trisomy (2n+1)
What are some of the errors in chromosome structure?
deletion - removing a chromosome segment
duplication - repeats a segment
inversions - reverses orientation of a segment within a chromosome
translocation - moves a segment from one chromosome to another
What are Chargaff’s rules?
base pairing (A+C=G+T)
What is the main structure of DNA?
antiparallel, phosphate and deoxyribose sugar backbone, double stranded
What is polymerase chain reaction (PCR)?
method to replicate a specific target sequence in DNA, uses heat, includes DNA pol, primers and nucleotides
What are the main differences between eukaryotic and prokaryotic DNA?
eukaryotic is linear
Prokaryotic is circular
How does the structure of DNA reveal its replication process?
It is semiconservative - two strands come apart and act as a template for the synthesis of a new complementary strand - leading and lagging strand
What is the process of DNA replication in prokaryotes?
Replication fork, origin of replication, leading and lagging strands, Okazaki fragments
What are the 7 different proteins that help with DNA replication?
Topoisomerase - stress reducer
helicase - unzipping
Single Stranded Binding Protein (SSBP) - stress reducer
Primase - RNA primer
DNA Pol III - synthesize new DNA
DNA Pol I - remove RNA primer and adds DNA
ligase - glues the fragments together
What are the roles of telomerase in DNA replication?
it lengthens the telomeres (buffer zone)
What are the different types of mutations in DNA?
point - silent, missense (wrong amino acid), nonsense (premature stop)
frameshift - insertion + deletion, alters the reading frame
What are some DNA repair mechanisms?
Proofreading - DNA polymerase finds and corrects errors during replication
mismatch repair - one base pair is wrong - fixed by protein
nucleotide excision repair - repairs thymine dimer (nuclease removes, DNA pol synthesizes new DNA, DNA ligase seals it in)
What is the central dogma of protein synthesis?
DNA to transcription to mRNA to translation to protein
How to nucleotides prescribe the amino acid and proteins?
Codons on the mRNA code for specific acids that create polypeptide chains that make proteins
What are the steps of transcription?
Initiation - DNA unwinds, RNA pol attaches to promoter
Elongation - RNA pol aided by transcription factors; RNA made; DNA rewound
Termination - RNA reaches poly a signal or terminator sequence and falls off
What is the role of RNA polymerases?
makes a complimentary mRNA copy from DNA template strands and add to 3’ end
What is the significance of transcription factors?
They help create mRNA
What are the steps in RNA processing?
5’ cap and 3’ poly A tail
What is RNA splicing?
Cutting out introns (noncoding regions) and keeps the introns (coding regions)
What are the different steps in protein synthesis?
Initiation - small subunit and met tRNA bind to mRNA, large subunit attaches, process takes energy
Elongation - A site, peptide bond, move to P site, empty tRNA exists at E site
Termination - mRNA translate a stop codon, release factor are proteins that bind the stop codon (not tRNA and not an amino acid)
What are the roles of ribosomes in protein synthesis?
A site, P site, E site,
