Chapter 18 Flashcards
cells don’t replicate themselves, ____ replicates itself
DNA
Transforming principle: (by _____ and ___) rough and smooth strains in mice
Oswald Avery and Fredrick Griffith
chemists to solve mouse case: _____ and ____
____enters cells, not protein, so proved that DNA codes for _____, not proteins
Hershey and Chase
DNA
genes
what makes up a single nucleotide?
1 deoxyribose sugar, phosphate, base (ACTG)
What are the 4 nitrogenous bases?
A-adenine
T- thymine
C- cytosine
G- guanine
What is Chargaff’s rule of base pairing (example)
A=T and C=G
so if 17% T then also 17% A
What did Rosalind Franklin do?
took pics of DNA with x-rays
figured out double helix shape, and that bases are on the inside with phosphate and sugar on the outside
RNA is different from DNA in what ways?
- leaves the nucleus
- sugar backbone is ribose (not deoxyribose so it has all its O2)
- single stranded, not double helix
- can be tRNA, mRNA, or rRNA
- 3 bases code for an amino acid (codon- triplet coding)
If you have 2 codons, how many amino acids do you have? How many bases?
2 codons = 2 amino acids = 6 nitrogenous bases
What did Watson and Crick do?
produced a structural model of DNA with double helix and complimentary base pairs (took everyone else’s ideas)
____ makes up all of the DNA in the cell (all genes in body)
genome
Steps of DNA replication
- Initiation
- elongation
- termination
What are helicases and what do they do?
enzymes that cut/ unwind the DNA (in the first step of DNA replication- initiation), forming a replication bubble… if bubble keeps expanding = replication fork
What holds the unzipped DNA apart and serves as a template for new bases? (in initiation)
SSB- single strand binding proteins
____ makes up primer, which serves as a starting point, constructed by ____ _______
RNA, primase enzyme
what splices the okazaki fragments ?
DNA ligase
Transcription
splitting DNA and making a copy of RNA
Translation
proteins are made by bringing amino acids as described by the mRNA
in which of the 2 major steps in making proteins does the RNA messenger leave the nucleus?
translation
cancer causing gene
oncogenes
What is a teratogen + example
something that causes a mutation (changes dna)
ex. x-rays, smoking, etc
2 types of mutagens (causes of mutations) with examples
- physical (x-rays, gamma rays, UV radiation, etc)
2. chemical or carcinogens ( smoke, gas fumes, nitrites)
2 types of mutations with definitions
- point mutation: substitution of one nucleotide for another
- frameshift mutation: nucelotide insertions or deletions (sliding)
silent mutation
no apparent affect on polypeptide produced
mis-sense mutation
produces an altered or different protein (eg sickle cell)
non-sense mutation
does not produce a functional polypeptide (always make a stop- incomplete protein)
somatic mutations are in ____ cells, and germ-line mutations are in ____ cells
body cells
sex cells
recombinant DNA
DNA molecules formed by laboratory methods of genetic recombination (such as molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome.
gene splicing/ engineering
genetic info from 1 organism is spliced into the chromosome of the other
- 2 organisms that would never exchange genetic info are joined
eg of recombinant DNA: insulin production. explain the 4 steps
- cut out donor gene for insulin with restriction enzyme(specific cuts leaving sticky ends)
- cut bacterial plasmid with same enzymes
- use ligase enzyme to fuse donor gene into the plasmid (join sticky ends)
- the transgenic bacteria produce insulin and we harvest it
DNA is/ is not a protein
is not! it is a source for RNA production which then can produce protein
what is the role of polymerase in DNA replication?
adds nucelotides to growing strands
nucelic acids are/ are not a major grouping of proteins in cells
are not
Purine bases are ____ (2ring/ 1 ring) and includes bases __ and ___
2 ring (big) A and G
pyrimidine bases are ___( 1 or 2 ring) and includes bases __, ___, and ___
1 ring (small) C, T, and U
C and G have how many H-bonds between them?
3 H bond
A and T have how many H bonds between them?
2 h bond
catabolic = cutting or adding?
cutting
anabolic= adding
what is the last step in transcribing DNA to mRNA?
the mRNA carries the message to the ribosome
mRNA has ____ and tRNA has ________
codons/ anti-codons
codons, anti-codons
mRNA is synthesized in ___
transcription
tRNA brings amino acids to the ___
ribosome
a polypeptide is a sequence of _____
amino acids
tRNA transfers amino acids in _____
translation
ribsomes are the site where ___ takes place
translation
explain the steps of genetic engineering (restriction and ligase enzymes)
restriction enzymes are added to a gene of intrest to cut them, exposing sticky ends. Different DNA is introduced, and cut with the same restriction enzymes (same stick ends). DNA ligase attaches them (with the corresponding sticky ends) and then you have recombinant DNA!
DNA has a slightly ___ charge
negative
