Genetics Part III Flashcards
definition of a MUTATION
MUTATION:
- permanent change within the NUCLEOTIDE SEQUENCE of the GENOME of an ORGANISM
RESULTS:
- begin to see GENETIC VARIABILITY–impacts VIABILITY, FUNCTION, and PATHOGENICITY
- essential to NATURAL SELECTION
(not all mutations are bad–lets EVOLUTION occur)
- occurs at RANDOM in NATURE
describe ANTIBIOTIC RESISTANCE
an example of MUTATIONS that begin to INCREASE BACTERIA and the MICROBE’s RESISTANCE towards ANTIBIOTICS
- reason for why we need to continue ANTIBIOTIC TREATMENT–allows to kill the FULL RANGE OF BACTERIA (despite their RESISTANCE LEVELS)
what are the CHROMOSOMAL MUTATIONS?
- DELETION
- DUPLICATION
- INVERSION
- TRANSLOCATION
Down’s Syndrome
DUPLICATION MUTATION (TRISOMY)–CHROMOSOME 21:
- results in a WIDE RANGE of DEVELOPMENTAL DELAYS and PHYSICAL DISABILITIES
- around approx. HALF of PEOPLE with condition have a CONGENITAL HEART DEFECT
- DUPLICATION of around 500-800 GENES
- specific PHENOTYPE; mainly due to VARIABLE EXPRESSION of SUBSET of GENES
CRI DU CHAT SYNDROME
DELETION IN CHROMOSOME 5:
- have MICROCEPHALY (weaker development of brain)
- WEAK MUSCLE TONE
- DELAYED DEVELOPMENT
WOLF-HIRSCHHORN SYNDROME
DELETION IN CHROMOSOME 4:
- DELAYED DEVELOPMENT and INTELLECTUAL DISABILITY
- SEIZURES
- change within FACIAL CHARACTERISITICS
JACOBSEN SYNDROME
DELETION in CHROMOSOME 11:
- has a VARIETY of SYMPTOMS
- has LEARNING DIFFICULTIES and COGNITIVE IMPAIRMENT
- has DISTINCTIVE FACIAL FEATURES
definition of POINT and what are its TYPES?
change within a SINGLE BASE PAIR–BASE SUBSTITUTION
- can HAPPEN NATURALLY during replication of result of DNA DAMAGE and IMPROPER REPIAR
TYPES:
- MISENSE
- NONSENSE
types of FRAMESHIFTS
- DELETIONS
- INSERTIONS
does POINT MUTATIONS ALWAYS lead to changes within our PHENOTYPE? what are SILENT MUTATIONS? what are MISSENSE MUTATIONS?
NO!
- our GENETIC CODE is REDUNDANT
- not EVERY CHANGED NUCLEOTIDE necessarily will change the actual AMINO ACID SEQUENCE of the PROTEIN–this is considered a SILENT MUTATION
- if there is CHANGE in the SEQUENCE and results in a CHANGE within the AMINO ACID SEQUENCE–this is considered a MISSENSE MUTATION; and EVEN THEN!! they don’t always translate to phenotypic or functional changes
what is a NEURAL MUTATION?
type of MISSENSE MUTATION that ALTERS the AMINO ACID SEQUENCE of the PROTEIN
- but DOES NOT CHANGE FUNCTION
- typicaly when the ONE AMINO ACID REPLACED by a CHEMICALLY SIMILAR ONE or just has LITTLE INFLUENCE on PROTEIN FUNCTION
sickle cell anemia
single change within the GLOBIN GENE
definition of a NONSENSE MUTATION
CHANGE in the SEQUENCE that introduces a STOP CODON–STOPS TRANSLATION
definition of FRAME SHIFT MUTATIONS
mutations that occur when NUCLEOTIDES are EITHER INSERTED or DELETED from the DNA SEQUENCE
- have PRETTY SEVERE EFFECTS–can begin to EFFECT ALL AMINO ACIDS DOWNSTREAM of the INSERTION
- can result in INTRODUCTION of STOP CODON and EARLY STOP of TRANSLATION
- PROTEINS cannot be PROPERLY SYNTHESIZED and have PROPER FUNCTION
define MUTAGENS + describe NUCLEOTIDE ANALOGS
CHEMICAL MUTAGENS:
- causes a SPECIFIC BASE CHANGE
NUCLEOTIDE ANALOGS:
- similar to the NITROGENOUS BASES but with SLIGHTLY DIFFERENT BASE PAIRING
- if present during growth = can cause MISTAKES during REPLICATION
- can cause SMALL DELETIONS and INSERTIONS–making FRAME-SHIFT MUTATIONS
what are our types of MUTAGENS (2)?
RADIATION:
(X RAYS and GAMMA RAYS)
- releases ELECTRIONS and begins to BOMBARD SURROUNDING CELLS and can cause damage to DNA MOLECULES
UV RADIATION:
- causes DNA DAMAGE by causing the FORMATION of COVALENT BOND between 2 ADJACENT THYMINE’S within DNA
what is the RATE of MUTAGENESIS?
MISTAKES:
occurs during REPLICATION with RATE of 1 in 1 BILLION per BASE PAIR
**all depends on HOW BIG A GENE IS
- 1000 bp gene = 1 in a million
- BIGGER GENE, MORE CHANCE OF ERRORS
CHEMICAL MUTAGENS:
- can increase RATE OF MUTAGENSIS by 10-1000x (rate of 1 in 1000)
how can we IDENTIFY MUTATIONS?
can be DETECTED by SELECTING for an ALTERED PHENOTYPE
POSITIVE SELECTION:
- mutation results in a GAIN OF FUNCTION that can be DIRECTLY SELECTED FOR
INDIRECT SELECTION:
- where the MUTATION RESULTS in a LOSS OF FUNCTION–screening COLONIES for DESIRED PHENOTYPE
definition of CARCINOGENS
- many known MUTAGENS can cause CANCER
- can use BACTERIA to determine if something if MUTAGENIC–most likely CARCINOGENIC
- use of the AMES TEST
what are our TYPES of GENETIC TRANSFERS?
VERTICAL:
- parent to child
HORIZONTAL:
- passing GENES between MICROBES
- occuts in less than 1% of POPULATION
what are our TYPES OF HORIZONTAL GENE TRANSFERS?
- TRANSFORMATION
*NATURAL
*CHEMICAL COMPETENCE - CONJUGATION
- TRANSDUCTION
definition of TRANSFORMATION
- derived from experiment; DNA transferred from the DEAD ENCAPSULATED STRAIN to the NON-ENCAPSULATED STRAIN (now BECAME VIRULENT)
- can make the bacteria CHEMICALLY COMPETENT
BACTERIAL SPECIES:
- bacillus
- haemolphilus
- niseeria
- streptococcus
- staphylococcus
definition of CONJUGATION
- MEDIATED by a PLASMID
(PLASMIDS–small independently replicating SMALL CIRCULAR DNA - uses DIRECT CELL-To-CELL CONTACT
- requires DIFFERENT MATING TYPES;
DONOR–carries a SPECIFIC PLASMID with GENES that encode for a SEX PILI - RECIPENT CELLS DO NOT HAVE PLASMID
definition of TRANSDUCTION
the TRANSFER of DNA from DONOR CELL to RECIPENT CELL inside a VIRUS that INFECTS the BACTERIA
- known as BACTERIOPHAGES; viruses that infect bacteria
- can sometimes package and move BACTERIA’S CHROMOSOMAL DNA and make their own PHAGE DNA
definition of PLASMIDS
genetic elements that provide a MECHANISM for MOVING GENETIC MATERIAL between BACTERIA
- small independently REPLICATING SMALL CIRCULAR DNA
- non-essential
TYPES:
- FERTILITY PLASMIDS
- RESISTANCE PLASMIDS
- VIRULENCE PLASMIDS
