DNA, RNA, and Proteins Flashcards
What did this experiment show?
Genetic material can be transferred from one bacteria to another
(Transformation)
What experiments lead to our understanding of DNA? What happened in Frederik Griffith’s experiment with pneumonia and mice?
Smooth coated pneumonia bacteria kills mice
Rough coated pneumonia bacteria- mice live
Heat killed smooth pneumonia bacteria- mice live
heat killed smooth plus harmless rough bacteria together mice die
What happened in Oswald Avery’s experiment?
Same as Griffith except he added enzymes to destroy different molecules
If RNA, PROTEINS, CARBS, LIPIDS are destroyed transformation still happens.
If DNA is destroyed- no transformation
What did this experiment show?
DNA is the genetic material
What happened in Alfred Hershey and Martha Chase’s blender experiment?
Radioactively labeled proteins and Dna in bacteriophages (viruses that infect bacteria) and loked to see what passed into the cell
What role did Rosalind Franklin and James Watson and Francis Crick play in our understanding of DNA’s structure?
Her X-ray images were used by Watson and Crick to figure out the double helix structure
What is a bacteriophage?
Virus that infects bacteria
What is transformation?
change in a bacteria caused by picking up foreign DNA
What molecule is involved in transformation?
DNA
What are the building blocks of DNA?
nucleotides
What are the building blocks of proteins?
amino acids
What is a purine?
Nitrogen base composed of 2 rings
What is a pyrimidine?
nitrogen base composed of 1 ring
What is the structure of a DNA molecule?
double helix- twisted ladder
What forms the backbone of the DNA molecule?
Sugars and phosphates
What forms the “steps of the ladder”
nitrogen bases (A, T, C, G)
What does it mean when we say a DNA strand is “anti-parallel”
the two strands in the DNA mollecule run in opposite directions
What does it mean when we say a DNA strand is “anti-parallel”
the two strands in the DNA molecule run in opposite directions
HOw does DNA fold into a chromosome?
DNa wraps around histone proteins to form nucleosomes
nucleosomes coil further to make chromosomes
What is a nucleosome?
Beadlike structure formed when DNa wraps around histones
What are histones?
proteins DNA wraps around to make a nucleosome
What is the difference between chromatin and chromosomes?
CHromatin- in non-dividing cells
Chromosomes- in dividing cells
What is replication?
making a DNA copy (DNA DNA)
Transcription
Copying an RNA message from DNA (DNA RNA)
Translation
making a protein from an RNA message (RNA proteins)
What is the Central Dogma of molecular biology that shows how information is passed in cells?
DNA RNA PROTEINS
How is DNA copied?
DNA strand separates and uses old strand as a template to make a new strand; DNA polymerase adds in nucleotides and spell checks as it goes
What enzye plays a role in this process?
DNA poLYMERAse
What are the 3 kinds of RNA?
messenger, transfer, ribosomal
Messenger
carries the message from nucleus to cytoplasm
Ribosomal
joins with proteins to make ribosomes
Transfer
has anticodon to math m-RNA codon and brings in amino acid to form protein chain
What enzyme is involved in transcription?
RNA polymerase attaches to start ttranscription
What is a promoter?
Region where DNA polymerase attaches to start transcription
What are introns?
pieces of the message that are cut out
What are exons?
Pieces of the message that are expressed in the final message
What is noncoding or “junk” DNA?
Sequences of DNA that do not code for proteins
What is a transposon?
DNA sequence that can move and change position to another chromosomes
What is a codon?
Group of 3 nitrogen bases on a m-RNA that are read together
What is an anticodon
group of 3 nitrogwen bases on a t-RNA that match the m-RNA codon
What happens in translation?
protein syntesis= making proteins from RNA message
How are genes regulated in prokaryotes and eukaryotes?
Prokaryores have opereons
Eukaryotes- morew complex; TATA boxes; enhancers; non operons
What is an operon?
Group of genes that work together in a pathway that are controlled by same operator
What is an operator?
Region where repressor attaches to turn off the genes
What is a repressor?
MOlecule that can attach to the operator site to turn off genes
if repressor is not attached gene is turned on
How is the lac operon in E. Coli turned on and off?
When lactose is NOT present, repressor attaches to operator to turn genes off
What is a TATA box?
Region in front of eukaryotic gee that helps position RNA polymerase to bein transcription
What is an enhancer region?
Regions in front of eukaryotic genes where regulatory proteins can bind to speed up gene transcription
What are hox genes?
Genes that control the growth, development, and location of body parts in developing embryos
What role do they play in differentiation and growth and development of embryos?
When embryonic cells are differentiating, hox genes help tell where and when body organs should grow
WHat is a mutation?
Change in DNA code
How are gene mutations different from chromosomal mutations?
gene mutations- change code in just one gene
Chromosomal mutations- change structure of sequence in whole chromosome
How are point mutations different from frameshift mutations?
Point mutations- change in one nucleotide 9Can be a deletion, insertion, substitution)
Frameshift mutations- change in code that causes a change in the reading frame in a gene
Why are frameshift mutations at the beginning of a gene more damaging than at the end?
Everything after the mutation is changed so change t beginning causes more damage
deletion
loss base from DNA code
duplication
addition of extra copies of a section in DNA code
insertion
addition of bases into DNA code
translocation
movement of piece of DNA to a non-homologous chromosome
inversion
chromosome rearrangement in which a segment of a chromosome breaks and reattaches in reversed order
WHat is polyploidy?
cell with 3 or more sets of chromosomes
What kind of organisms can it be seen in?
polyploidy is seen in plants/rrare in animals
