Exam 4 Ch 16-21 DNA Flashcards
Erwin Chargaff Contribution
1) Base composition of DNA varies btw species 2) Number of A and T are equal to number of G and C’s
Maurice Wilkins
Studies molecular structure using X-ray Crystallography
Rosalind Franklin
Produced picture of DNA molecule using X-Rays and Chem of DNA
Watson and Crick
Built models of double helix to conform to X-Rays and Chem of DNA
Three Component parts of nucleotide
Five-carbon sugar covalently bonded to a nitrogenous base and one or more phosphate groups
Base Pairing Rules for DNA
Adenine bonds with Thymine/Cytosine bonds with Guanine
Relationship btw DNA, Chromosomes, genes, and proteins?
DNA creates chromosomes, which make genes, which are all made out of proteins.
5 and 3 as they relate to orientation of of the two strands of the double helix is called what?
Antiparallel
What type of replication process does DNA use?
Semi-conservative
Why does DNA need to be replicated?
Hereditary information is encoded and reproduced in all the cells of your body.
Identify the enzymes involved in DNA Replication-what do they do?
Helicases- untwist double helix; Topoisomerase- relieve strain by breaking, swiveling, and rejoining DNA strands
Primer
RNA Chain
Primase
synthesize RNA chain-add RNA nucleotides one at a time
Mutations
Occur when there is a change of a single nucleotide in the DNA’s template strand
Transcription
synthesis of RNA using info in the DNA-simply “rewritten” information from DNA to RNA (antiparallel)
Where does transcription take place in Eukaryotic cells?
Nucleus separate compartment
mRNA (messenger RNA)
Carries genetic message from DNA to protein (produced by transcription)
RNA Polymerase
pries two strands of DNA apart and joins together RNA nucleotides (uracil instead of thymine)
Translation
synthesis of polypeptide using mRNA info (change in language takes place and amino acids are chained together)
What is the site of translation?
Ribosomes (link amino acids into polypeptide chains)
Codons
mRNA nucleotide triplets (read in 5—>3 direction)
Anticodons
one end of tRNA which base pairs with codon on mRNA
tRNA role in translation
translates mRNA codon into a protein/amino acid
Central Dogma Chain
DNA-RNA-Protein
What is the first stage of Gene expression?
Transcription
Three stages of Transcription?
Initiation, elongation, termination
RNA sugar?
Ribose
DNA sugar?
Deoxyribose
tRNA structure and function (2)
1)each carry a specific amino acid 2) each has an anticodon on the other end
Mutations
changes in genetic material of cell or virus
Why are mutations important?
The change of one nucleotide in DNA can lead to production of abnormal protein
Point Mutations
chemical changes in just one base pair of a gene
Frameshift Mutations
Insertion/deletion of nucleotides can alter reading frame
Gene expression
process by which DNA directs protein synthesis (transcription and translation)
Activator
(positive gene regulation) accelerates transcription
Differential Gene Expression
expression of different genes by cells with same genome
Which is larger? Ribose or Deoxyribose?
Deoxyribose
Which bonds form the DNA ladder?
Hydrogen Bonds
Adenine pairs with?
Thymine
Guanine pairs with?
Cytosine
What is replaced in mRNA polymerase?
Thymine with Urasil
Epidemic
Illness of a large group (evola virus)
Pandemic
Illness breakout worldwide
Prion
slow-acting, infectious proteins-cause brain diseases in mammals
Bacteriophages (phages)
viruses that infect bacteria
Genomics
study of genomes and their evolution
Viroids
small, circular RNA molecules-infect plants, disrupt growth
Virus
small infectious particle consists of nucleic acid enclosed in protein coat (NOT CELLS)
Capsid
protein shell that encloses viral genome
Retrovirus
use reverse transcriptase to copy RNA genome into DNA
Transformation
change in genotype and phenotype due to assimilation of external DNA cell
Somatic Cell
any cell in multicellular organism except sperm or egg
Ribosome
subunit assembled in nucleolus (site of protein synthesis)
Polymerase Chain Reaction (PCR)
technique for amplifying DNA in vitro-incubating it with specific primers/nucleotides
Chromosome
cellular structure carrying genetic material
Allele
any alternate versions of a gene that may produce phenotype effects
Nucleotides
Building blocks of twisted DNA ladder
Major Genetic Discoveries
Diagnosis/treatment, DNA Identification, Pharmaceutical Products
Role of Restriction Enzymes
cut DNA molecules down to specific sequences
Transgenic
animals-pharmaceutical factories of large amts of rare substances for med use
Creating a Transgenic Organism
introduce genes from one species into genome of another animal
Hazards/Benefits DNA Technology
Concern is genetically modified animals used as food, creation of super weed, could cause allergic reactions