lecture exam 3 Flashcards
process by which a gene produces its product and the product carries out its function
gene expression
A natural process in which a nucleic acid molecule (usually DNA but can be RNA) is broken and then joined to a different molecule; a result of crossing‐over.
gene recombination
genetic information can be transferred vertically to the next generations of cells
gene replication
in each new DNA double helix, one strand is from the original molecule, and one strand is new
semi-conservative replication
Developed the double helix model of DNA.
Watson and Crick
purines (double ring)
Adenine and Guanine
Guanine and cytosine make ____ H bonds
Adenine and thymine make ____ H bonds
3 / 2
in transcription, the ___ strand contains info to make RNA and is transcribed
master
type of RNA that combines with proteins to form ribosomes
rRNA
An RNA molecule that carries amino acid to the ribosome in translation
tRNA
An RNA molecule that helps decode an mRNA sequence into a protein
tRNA
A type of RNA, synthesized from DNA, that attaches to ribosomes in the cytoplasm and carries message to translate protein
mRNA
- rRNA
- mRNA
- tRNA
types of RNA that is made in transcription
the ribosome demands ____ and _____
rRNA / protein
A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid
Codon
group of three bases on a tRNA molecule that is complementary to an mRNA codon
Anticodon
There are only codons in _______
mRNA
start codon
Methianine
specific region of a gene where RNA polymerase can bind and begin transcription
Promoter
the enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template
RNA polymerase / transcriptase
A Y-shaped region on a replicating DNA molecule where new strands are growing.
replication fork
change in the DNA base sequence
Mutations
genetic composition of an organism
Genotype
physical / expressed characteristics of an organism
Phenotype
random changes that occur naturally in DNA that occur during cell division
spontaneous mutations
refers to those mutations in the DNA induced by a chemical or physical agent
induced mutations
A mutation that changes a single nucleotide and genotype, but does not change the amino acid created or phenotype.
MOST COMMON TYPE
silent mutation
A base-pair substitution that results in a codon that codes for a different amino acid.
missense mutation
A mutation that changes an amino acid codon to one of the three stop codons, resulting in a shorter and usually nonfunctional protein.
nonsense mutation
protein cannot be made because it cuts the mRNA short
why is a nonsense mutation lethal?
the mutation that shifts the “reading” frame of the genetic message by removing or adding a base
frameshift mutation
the genes code for enzymes that catalyze reactions that result in characteristics
Genetics and metabolism are tied together by the fact that :
A person has brown eyes because:
enzymes catalyze reactions that produce products that are brown
radiation-x-rays, UV light
examples of physical mutagens
- adjacent thymines cross link and create a thymine dimer
- endonuclease cuts the dimer and exonuclease removes the dimer
- DNA polymerase fills in the gap from the removed dimer
- DNA ligase seals the remaining gap
what happens when UV light hits a gene?
pesticides, natural plant alkaloids, tobacco smoke, pollutants
examples of chemical mutagens
Marijuana is not a big ____ cancer contributor
lung
what is the greatest fear that teenage girls have about smoking?
wrinkles
what is the greatest fear that teenage boys have about smoking?
erectile dysfunction
A ___ ___ in specific genes in a single cell will initiate cancer
double mutation (DM)
a mutation that happens because it has more target to mutate from than a single mutation
double mutation
Lung cancer takes _____ to develop
20-30 years
When one is suffering from secondhand smoke, they still take in ____ and ____
inducers / promoters
the transfer of genetic material in bacteria that occurs in one direction
one way gene transfer
transformation
conjugation
transduction
types of one way gene transfer in bacteria
one organism must die and release DNA to the environment and DNA is taken up by a cell that is competent and expresses new characteristics
Transformation
an experiment carried out by Griffith using the heat-killed bacteria in mice to discover that a factor in heat-killed, disease-causing bacteria can “transform” harmless bacteria into ones that can cause disease
Griffith’s experiment
In genetic transformation in bacteria, the donor cell has to be ____ and recipient cell has to be _____
dead / alive
what bacteria does not perform genetic transformation?
E. coli
In bacteria, the direct transfer of DNA between two cells that are temporarily joined.
Conjugation
used for conjugation and randomly touches cells and pulls them into contact to create a mating bridge between the bacterial cells
sex pilus
F+ cell is the “___” cell
F- cell is the “___” cell
male (has pilus)
female (does not have pilus)
gram-positive conjugation was identified in _____
gram-positive conjugation has no ____ ____
gram-positive conjugation uses sex _____
Streptococci
sex pilus
pheromones
chemical signals released by an animal that influence the sexual behavior or physiological state of other individuals of the same species
sex pheromones
sex pheromones are expelled in ____
sweat
DNA is transferred from a donor cell to a recipient via a bacteriophage
Transduction in bacteria
technology that combines genes from different sources into a single DNA molecule
Recombinant DNA technology
enzyme that chemically links DNA fragments together
DNA ligase
physical control
chemical control
antimicrobial control
3 ways to control microorganisms
the killing or removal of all microorganisms from a given area
Sterilization
- heat
- filtration
- desiccation
- radiation
- osmotic pressure
- low temperature
examples of physical methods of control
most practical and efficient physical methods of control
heat
- autoclave
- dry heat
- incineration
- boiling water
- pasteurization
different heating methods of control
121ºC, 15 psi, 15 minutes
Autoclave conditions
how do you perform dry heat method?
oven
Pasteurization is a combination of _____ ____ and ____
high temperature/time
freeze drying; preservation
Lyophilization
- autoclave
- dry heat (oven)
- incineration
- filtration
- ionizing radiation
physical methods of sterilization
The process of burning solid waste materials to reduce volume and mass, sometimes to generate electricity or heat
Incineration
A process that separates materials based on the size of their particles.
Filtration
enough energy to dislodge electrons from atoms, forming ions; capable of causing cancer (gamma, X-rays, UV)
ionizing radiation
- antiseptic
- disinfectant
- sanitizer
chemical methods of control
chemical used topically to inhibit or destroy microorganisms
antiseptic
a chemical used on non-living objects to inhibit or destroy microorganisms
disinfectant
a chemical used to reduce bacterial numbers to a safe level according to public health requirements
Sanitizer
-stasis / -static
means static - ___
-cide / -cidal
means: ___
inhibition; killing
- cell membranes
- cellular proteins
Major targets of the Mechanism of Disinfectant Action
ethanol is most effective at ____
70%
the more concentrated chemical control agent, the ___ effective it is at controlling bacterial growth
more
active ingredient in lysol
Cresol
surfactants that physically flush organisms away
soaps and detergents
An air pollutant that is a colorless chemical used to manufacture building materials and many household products that causes cancer
Formaldehyde
- autoclave
- dry heat (oven)
- incineration
- filtration
- ionizing radiation
- ethylene oxide (carboxide)
methods of sterilization
to destroy disease organisms without destroying the host
chemotherapy
by products of metabolism used in chemotherapy
antibiotics
Chemically-synthesized chemotherapeutic agents
not a true antibiotic but has the same effect (sulfonamides)
Criteria for usefulness for antimicrobial control:
- _____ toxicity to host while destroying/inhibiting the disease organism
- host should not become _____
- disease organism should not become _____
low
allergic
resistance
Major Action Modes of Antimicrobial Drugs:
1. Inhibition of cell ___ synthesis
2. Inhibition of ____ synthesis
3. Inhibition of ____ ___ replication and transcription
4. Injury to ___ ___
5. Inhibition of ____ ____ synthesis
wall
protein
nucleic acid
plasma membrane
essential metabolite
antimicrobial that interferes with cell wall synthesis
Penicillin
antimicrobial that interferes with with protein synthesis
Erythromycin
antimicrobial that interferes with intact cell membrane
Polymyxin B
antimicrobial that interferes with the metabolic synthesis
- not a true antibiotic bc it is chemically synthesized
Sulfanilamide
antimicrobial that interferes with the nucleic acid synthesis
- Fluoroquinolone: drug of choice to treat anthrax
Ciprofloxacin (Cipro)
examines the effect of different chemical agents against a specific bacterium
disk diffusion method
- blocking entry
- inactivation by enzymes
- alteration of the target molecule (most common)
- efflux (throw out) of the antibiotic
4 types of antimicrobial resistance
Measures to minimize antimicrobial resistance:
- avoidance of ____ use
- dose should be ____
- combination of antimicrobial agents
indiscriminate
high
possible complications minimizing antimicrobial resistance
- allergy
- toxic side effects
- destruction of normal flora
microorganisms are present
contamination
pathogenic microorganisms are in or on the body and they are multiplying (may or may not cause harm)
infection
when microorganisms do harm to the host
disease
disease organism is constantly in a certain geographic location (bubonic plague bacterium is always in the San Francisco Bay)
endemic
relatively large number of cases of a disease develops in a community within a short time (flu on a college campus)
epidemic
worldwide epidemic (AIDS / COVID)
Pandemic
the ability of a microorganism to cause disease (very few microorganisms are this)
Pathogenicity
measure of pathogenicity (some flu viruses are deadly and some are mild and just cause discomfort)
Virulence
hospital acquired infection (8th leading cause of death in the USA) - normally 2 million people in the USA contract it and 20,000 die
nosocomial infection
- respiratory tract through nose and mouth
- gastrointestinal tract through the mouth
- skin and mucous membranes
- genitourinary tract
- blood
5 ways pathogens enter and leave the body
- capsules
- fimbriae
- exotoxins and enzymes
3 invasive mechanisms of bacteria
prevent phagocytosis by white blood cells in the immune system
Capsules
this bacteria without a capsule will not cause disease
S. pneumoniae
some bacteria excrete toxins or enzymes that cause damage (killing, dissolving, coagulating) to the host cells
exotoxins and enzymes
____ is NOT considered an invasive mechanism because the invading cell must die first to release ____. If the cell is dead, it cannot invade.
Endotoxin
- portal of entrance
- virulence
- ability to flourish outside of the body
- vector
- number of pathogens
5 factors in the development of disease
The flu virus must get into the ____ tract to cause the flu
respiratory
For inhalation anthrax, the critical number appears to be about _____ endospores. As few as 7 cells of the bacterium that causes _______ are required to cause disease.
20,000 / tularemia (rabbit fever)
DNA directly participates in ____ and ____
replication / transcription
a silent mutation is always a change in ___ ___ and sometimes a change in ____ ___
base sequence / amino acid
product of translation
Polypeptide
What requires a living donor and recipient cells?
conjugation
occurs due to a mistake in packaging of DNA
transduction
endospores have resistance to some levels of ionizing radiation because they are ____
dessicated
membrane filtration does not necessarily remove ____
viruses
cholera is normally transmitted via the ____ tract
Gastrointestinal
the genetic code is made up of bases in ____ and codons that correspond to ___ ___
mRNA / amino acids
key discovery that contributed to the development of genetic engineering
restriction enzymes
genetic engineering very often uses what to move hybrid plasmids into cells
transformation
one of the best disinfectants to use for a biological spill is
bleach
example of mild antiseptic
hydrogen peroxide
presence of non-multiplying bacteria in the blood
Bacteremia
TB and leprosy are examples of
chronic infection
comes on rapidly, with severe but short-lived effects
acute infection
normal sequence of events in living cells is
DNA codes for mRNA codes for protein
anticodons are found in ____
codons are found in ____
tRNA
mRNA
uptake and expression of naked DNA
transformation
mutation that might result in response to UV light
silent mutation
boiling water is not a method of sterilization because it cannot kill ____
endospores
multiplying bacteria in the blood
septicemia
Caffeine my interfere with ___ ___
DNA repair
Pasteurization is designed to kill the organism that causes ____
TB
useful way to sterilize food
ionizing radiation
simplest non-heated method to sterilize a liquid is
filtration
