Exam 1 Flashcards
Nucleotides
have 5 carbon carbohydrate, phosphate group, nitrogen containing base
DNA
permanent form: AGCT, antiparallel, in DNA replication/transcription
RNA
temporary info storage, AGCU, transcription/translation
DNA double helix
sugar-phosphate backbone coild around outside of helix: nitrogenous bases point inwards (AT: 2 hydrogen bonds, GC: 3 H bonds)
Eukaryotes
DNA wraps around histones, packed into coil, linear chromosomes, mitosis
Prokaryotes
no histones, circular chromosomes, single cell division
Energy for DNA synthesis
comes from breaking of phosphate bonds
Helicase
unwinds DNA in DNA replication
Topoisomerase
nicks DNA as is untwisted (relieves twisting forces, will be repaired) in DNA replication
Single-stranded DNA binding proteins
prevents two strands from snapping shut in DNA replication
Primase
makes RNA primer
which will be eventually degraded) in DNA replication (DNA needs base
DNA Polymerase
synthesizes DNA, works in 5’ –> 3 ‘ direction ONLY
Okazaki fragments
segments of RNA made on lagging strand in DNA replication
Telomeres/Telomerase
caps overhanging DNA strands/catalyzes additions of lost sequence
Haploid
1 copy of every set of chromosomes (Gametes in humans)
Diploid
2 copies of every set of chromosomes (most human cells are diploid; 23 pairs)
Polypoid
3 or more copies of every set of chromosomes
Genes
segments of DNA that provide instructions for proteins/RNA molecules: rest of “non-coding” segments = key role in expression
Exons
segments of gene that get expressed to make final product
Introns
intervening segments that are spliced out in pre-mRNA phase
Allele
each copy of the 2 copies of every gene on autosome (not sex chromosome)
Homozygous Allele
two alleles are identical (AA)
Heterozygous Allele
any extent of difference (Aa)
Genotype
genetic make-up
Phenotype
physical expression of genetic make-up
Transcription
DNA –> RNA single stranded
mRNA
Messenger RNA used in transcription
tRNA
Transfer RNA used in translation, Amino Acid Attachment + AntiCodon, used in RNA polymerase
rRNA
Ribosomal RNA used to make ribosomes: structure
Translation
RNA polymerase unwinds DNA, creates amino acid chain through tRNA/codons, U replaces T
Mature RNA
Leaves nuclei, goes into cytoplasm/ribosomes after being processed TRANSLATION
Vertical Transmission
Bacteria pass down DNA to following generation
Horizontal Tansmission
Bacteria obtain DNA from other bacteria: phage (virus), physical bridge, cell breaks
Rifampicin
antibiotic that inhibits RNA polymerase, can’t do transcription
Point Mutation
small mutation affecting 1- a few nucleotides
Missense Point Mutation
change which amino acids are coded(UCA –> UUA)
Nonsense Point Mutation
changes to STOP codon: shorter protein
Silent Point Mutation
change in mRNA but no change in final product
DNA replication
DNA polymerase: right nucleotides at right locations, error rate: proofreading/editing mechanisms that correct mistakes
Alzheimer’s Disease
aggregates of misfolded proteins (plaques)
AMLYOID protein: cut by enzymes: different sizes, more likely for proteins to fold
TAU protein (helps with structure of microtubules) –> when misfolded microtubules fall apart
Transmissible Spongiform Encephalopathies
“Spongy” brain appearance, Prion hypothesis
Prion Hypothesis
chain reaction of misfolded proteins: tangled/nonfunctional protein aggregates: Prion proteins can change/convert proteins into abnormal/aggregate types
Amino Acid Structure
Amino Group + Carboxyl Group + Side Chain (R Group), codons
Primary Protein Structure
linear sequence of amino acids
Secondary Protein Structure
localized regions of folding: specific regions that adopt specific conformations: ALPHA HELIX/BETA PLEATED SHEET
Tertiary Protein Structure
folding of entire protein, hydrogen bonds: Cysteine: participates in DISULFIDE BONDS (b/ 2 sulfur atoms found in R-group of Cys)
Quaternary Protein Structure
Interacts with other proteins
Chaperons Proteins
proteins that assist in folding/unfloding/assembly/disassembly of macromolecular structure
Ubiquitin-proteasome system (UPS)
control system that tags misfolded proteins for refolding/degradation
Ubiquitin
chemical tag for degredation
“Gene is fully expressed”
mature/active product is function in location
Plaques
extracellular deposits of amyloid protein
Neurofibrillary Tangles
Tangles are aggregates of tau protein (taupathy) microtubules in neurons break down: Cytoskeletal changes