Final Exam Flashcards
Things from Unit 4
nucleic acids
a polymer of nucleotides
DNA
- deoxyribonucleic acid (DNA)
- Has an H sugar group
- double helix structure
- stores RNA and protein encoding info transfers into next generation of a cell
RNA
- ribonucleic acid (RNA)
- has an OH sugar group
- single stranded
- carries protein encoding info, helps to make proteins
nucleotide
- monomer of nucleic acid
contain - one phosphate group
- one sugar group
- one nitrogenous base
how are nucleic acids formed and broken down?
formed through dehydration synthesis
broken down through hydrolysis
nitrogenous bases
adenine (A), thymine (T), cytosine (C), guanine (G), uracil (U)
U ~ RNA only
T ~ DNA only
gregor mendel (1822 - 1884)
- patterns of inheritance experiments
- Law of segregation
- Law of independent assortment
law of segregation
2 separated factors (separated during development of gametes) recombine into one during fertilization
law of independent assortment
factors separate randomly when sperm and eggs form
knowledge about genetic material (during Gregor Mendel time, 1822-1884)
or rather, what are the requirements of genetic material?
1) Had to store info related to structure and function of cells
2) stable enough to replicate repeatedly
3) able to have small changes that don’t hurt organism but maintain variability in population (mutations)
chromosome theory (1902 /1908)
Walter Sutton and Theodor Boveri independently conclude that chromosomes are involved in matter of genetics through staining cells undergoing meiosis and mitosis
Avery et al (1944)
comparing disease causing vs non disease causing bacteria
- Evidence for DNA
1) DNA not proteins from S strain cause R strain bacteria to be “transformed” and become virulent
2) DNase (enzyme that breaks down DNA) stops R strain from becoming virulent
3) addition of enzymes to degrade proteins or addition of RNase did not stop R strain from becoming virulent
Hershey-Chase Experiment (1952)
- T bacteriophage composed of radioactively labeled DNA or capsid proteins
- radioactive tracers on DNA were transmitted to bacterial cells but not radioactive proteins
DNA studies determined…
Accumulatively determined that DNA was the inherited material, carrying traits of organisms
purines
adenine (2 bond) and guanine (3 bond)
2 ring!
pyrimidines
thymine (2 bond) and cytosine (3 bond)
1 ring!
Chargaff’s experiment
- % of each nucleotide differs from species to species
- % is same for A & T
- % is the same for C & G
Rosalind Franklin and Maurice Wilkins
X-Ray diffraction experiment
- provided mathematical measurement of spacing between base pairs
Watson and Crick Model
- nucleotides in DNA are arranged in a double helix
- strands are antiparallel, and oriented in opposite directions
Semiconservative replication
half of the DNA is replicated, half is conserved
DNA helicase
unwinding DNA
unzipping
DNA primase
attaches RNA primer
DNA polymerase
complementary base pairing
DNA ligase
joining base pairs
gluing
starting DNA replication
- DNA pol only binds in 5’ to 3’ direction
- ## needs a primer to start complementary base pairing
replication fork
site of DNA rep on a chromosome
leading strand
side of DNA that allows synthesis in 5’ to 3’ direction continuously
lagging strand
opposite side of DNA, requires synthesis in segments which are eventually connected by DNA ligase
–> segments known as okazaki fragments
okazaki fragments
segments of DNA formed from lagging strand
prokaryotes and DNA replication
division can occur in two directions at once because DNA is circular
eukaryotes and DNA replication
replication occurs at numerous “bubbles” creating forks. The forks move away until they eventually meet
SSB
single stranded binding proteins - keep single stranded DNA stable
transcription
- DNA –> RNA
- uses mRNA
- occurs in nucleus
- writing actual recipe (the template)
translation
- RNA –> protein
- uses mRNA, tRNA, and rRNA
- occurs in cytoplasm by ribosomes
- reading recipe to make baked good (product)
- involves a set of rules that cells use to assemble correct sequences of amino acids
mRNA
messenger RNA, used during transcription and translation as middle man for genetic code between DNA and protein, encodes amino acid sequence
tRNA
transfer RNA, used in translation, transfers amino acids to ribosome for protein formation, physically links message in mRNA to an amino acid with an anticodon, carries amino acid to correct placement on mRNA
- ACCEPTOR END - that holds animo acid (aminoacyl-tRNA synthases are responsible for attachment of aa to tRNA)
- ANTICODON END - 3 bases that are complementary and antiparallel to a specific mRNA codon (at least one for each of the 20 aa’s)
rRNA
ribosomal RNA, used in translation, site of protein assembly composed of protein and RNA
transcription - initiation
RNA pol attaches promoter sequence to indicate start of transcription