Chapter 9 Microbio Review
Genetic material used to be stored in
RNA
A nucleotide consists of-
- a nitrogen base
- 5 carbon sugar
- phosphate group
What are the 5 nitrogen bases
adenine, guanine, cytosine, thymine, uracil ( in RNA)
Which nitrogen bases are purines
adenine and guanine
which nitrogen bases are pyrimidines
thymine, cytosine, uracil
a gene is
a piece of DNA that codes for a PROTEIN
Bacterial DNA appears
circular, when it is unwound it is up to 1000x its length
E.coli has about how many genes
4000
The average human has about how many genes
28000
a eukaryotic cell stores its DNA by
enclosing nucleic acids in nuclear membrane
a prokaryotic cell stores its DNA by
DNA is spread out through the cell
What is the purpose for inserting human DNA into a plasmid of bacteria
it can be replicated and commercialized
What does a restriction enzyme do?
cleaves DNA sequences at sequence specific sites, which produces DNA fragments with a known sequence at the end
What is the purpose of ligase
ligase catalyzes the formation of covalent phosphodiester linkages, which join nucleotides together.
What is Translation
The process of converting a sequence of mRNA into a sequence of amino acids during protein synthesis
What is transcription
process by which genetic information from DNA is written into mRNA by RNA polymerase
How many nitrogenous bases make a codon
three
How many amino acids are there?
20
Define a ribosome
an organelle made of rRNA and a protein
-rRNA is used for identification
How many Americans die from highly resistant staphylococcus infections?
50,000
What is a shotgun?
a tool used to insert DNA into bacteria
How many enzymes participate in the replication of DNA
30
DNA is semi-conservative, which means
each strand in the DNA double helix will act as a template for the synthesis of a new complementary strand
tRNA is
in protein synthesis in ribosomes
comes from transcription
has about 75-80 nitrogen bases
are loaded with one amino acid
TAKES AMINO ACIDS TO THE RIBOSOME FOR TRANSLATION IN THE A SITE
How many combinations of nitrogen bases are there?
64 combinations
- many codons can code for the same amino acid
AUG is a
start codon
UAG, UAA, UGA are all
stop codons
The genetic code is
- the universal language of life
- first discovered in bacteria
-found in bacteria and humans
Which are NOT stop codons in PARAMECIUM?
UAA and UAG, they code for glutamine instead
a bond between two amino acids is called
a peptide bond
The first step of protein synthesis is
mRNA comes from transcription, and binds to the codon on the A site
Second step of protein synthesis
tRNA brings the complementary bases to the A site
Final step of protein synthesis
the A site products go to the P site, when the P site is full it releases through the E site.
How many amino acids are in bacteria
400
at 37 degrees celcius, about how many amino acids are added to a chain per second?
12-17 amino acids
in bacteria, transcription occurs in the
cytoplasm
in eukaryotes, transcription occurs in the
nucleus
DNA IN BACTERIA IS
CLEAN
IN EUKARYOTIC CELLS, DNA HAS
SECTIONS THAT CANNOT PRODUCE mRNA
- they get "cleaned" by spliceosome- molecule of riboenzyme (made of RNA)
an exon is
clean mRNA; a region in the genome that ends up within an mRNA molecule
intron
junk, segment of DNA or RNA that does not code for proteins
what percentage of human DNA is "junk"
97%
What is a product of the electron transport chain
water
the three parts of an enzyme are
-active site
-cofactor
-apoenzyme
silent/missense mutation
mutation that does not affect the protein
nonsense mutation
mutation that changes an amino acid producing codon into a STOP CODON, leading to premature termination
Frameshift mutation/ insertion or deletion
mutation which changes the codon reading fram from the point of mutation to the final codon
-almost ALWAYS leads to a non functional protein
- spontaneous or chemically induced
alkylating agents are
methyl group to guanine, cause it to pair with thymine instead of cytosine
- acvidine derivative
- distorts helix
- partial unwinding of DNA
- from x-rays, UV light, gamma rays
Deinococcus radiodurans
bacteria that survives radiation due to its fast repair system
Genetic recombination methods are
conjugation, transformation, transduction
conjugation is
when bacteria transfer genes through th epillus form the plasmid (a DNA accessory)
- good for gentic engineering
-does not occur often
transformation is
a piece of DNA that enters a live bacteria
Transduction is
when a cell accepts a virus having bacterial DNA instead of viral DNA
Transposons are
jumping genes
A palindrome is
sequences of nitrogenous bases expressed in reverse
Barbara McClintock
discovered why different corn kernels express different colors
(transposons)
a holoenzyme has
all the three parts that make an enzyme
an enzyme has two site
active site and allosteric site
Fredrick Griffith
experiment with mice that concluded that bacteria are capable of transferring genetic information through transformation