LESSON 14: BACTERIAL GENETICS Flashcards
- is the science of heredity; study of genes and
information it carries.
GENETICS
are containing DNA that carry hereditary information; the chromosomes carry the genes.
CHROMOSOMES
-is the genetic information that a cell carry that includes
chromosomes and plasmid.
GENOME
are segments of DNA (except in RNA viruses) that code for functional products.
GENES
The cells DNA exist as long strands of nucleotides twisted together in pairs to f
DOUBLE HELIX
DNA or Deoxyribonucleic acid is a macromolecule composed of repeating units called?
NUCLEOTIDES
Nucleotide consist of :
NITROGENOUS BASE
DEOXYRIBOSE
PHOSPHATE GROUP
The two strands are held by________ between base pairs.
HYDROGEN BONDS
These strands have two designation called:
5 prime end & 3 prime end
5 & 3 represent the?
represent the 5th and 3rd carbon atom of the
sugar ring.
is the end, which joins a phosphate group that attaches to
another nucleotide
5th end
is the end important as during replication the new nucleotide is added to the end.
3rd end
is the genetic makeup of an organism that codes for all its
characteristics
GENOTYPE
actual expressed properties of an organism or the manifestation of a genotype
PHENOTYPE
the two strands uncoil and permanently
separate from each other.
DNA REPLICATION
both the parental strands must unwind due to an enzyme called?
Topoisomerase or gyrase
separate permanently into single stranded state made
possible by this enzyme?
HELICASE
are short Sequences of RNA, around 10 nucleotide in length
PRIMERS
it synthesizes the primers the?
PRIMASE
New nucleotides are added one by one to the end of
growing strand by an enzyme called ?
DNA POLYMERASE
The strandwhich is synthesized in the same direction as the replication fork, is known as? 5’-3’
LEADING STRAND
the strand being synthesized in the other direction, which is known as 3’-5’?
LAGGING STRAND
in lagging strand polymerase has to synthesized this _______ as it moves to replication fork.
FRAGMENTS or OKAZAKI FRAGMENTS
When DNA polymerase is adding nucleotides to the lagging strand and creating Okazaki fragments, it at times leaves a gap or two between the fragments. These gaps are filled with?
LIGASE
This process wherein genetic information in DNA is
copied or transcribed into a complimentary base sequence of RNA ?
TRANSCRIPTION
carries the coded information for making specific proteins from DNA to ribosomes, where proteins are
synthesized
messenger RNA
RNA synthesis starts at a site in the strand called
PROMOTER
until RNA synthesis reaches a site on the DNA called??
TERMINATOR
protein synthesis is called_____ because it decodes and translates the genetic codes (codons) made during transcription into specific proteins which
consists of a series of amino acids
TRANSLATION
while the nonsense codons signal the ends of protein synthesis thus called??
STOP CODONS
site of translation is in the ??
RIBOSOMES
Two genetic control mechanism:
REPRESSION & INDUCTION
-is a regulatory mechanism that inhibits gene expression and decreases synthesis of enzymes, usually in response to overabundance of an end-product.
REPRESSION
is the process that turns on the transcription of a gene.
INDUCTION
is a change in the base sequence of a DNA which sometimes cause a change in the end-product (protein)
MUTATION
Types of mutations :
- BASE MUTATION
- MESSENSE MUTATION
- FRAME-SHIFT MUTATIONS
are environmental agents that directly or indirectly cause mutation
MUTAGENS
a type of mutations with a single base in one point of a DNA is replaced with another base.
BASE MUTATION
a type of mutation where somthing happens when as a result of base mutation, an incorrect amino acid is inserted into the synthesized protein.
MISSENSE MUTATIONS
a type of mutations when one or a few nucleotide pairs are inserted or deleted in the DNA
FRAME-SHIFT MUTATIONS
chemical mutagens examples:
- NITROUS ACID
- NUCLEOSIDE ANALOG
- AFLATOXIN
a frame-shift mutagen and also a potent carcinogen
AFLATOXIN
type of chemical mutagens, also have altered base-pairing property.
NUCLEOSIDE ANALOG
is a type of chemical mutagens that is exposure of bacteria to nitrous acid can convert the base adenine (A) to a form no longer unpairable with thymine at a random location.
NITROUS ACID
radiation example of mutagens:
- X RAYS
- GAMMA RAYS
- ULTRAVIOLET
are potent mutagens due to their ability to ionize
atoms and molecules.
X RAYS & GAMMA RAYS
is harmful (at 260 nm wavelength) due to its ability to
form covalent bonds between bases.
UV LIGHT
Cell damage due to UV light can be repaired by this __________ by destroying covalent bonds to return its
original sequence.
photolyases or light repair enzymes
is the exchange of genes between two DNA
molecules to form new combinations of genes on a chromosome that results to a genetic diversity in a population.
GENETIC RECOMBINATION
occurs when genes are passed from an organism to
its offspring (plants and animals).
VERTICAL GENE TRANSFER
occurs in bacteria in several ways. In principle, the
transfer involves a donor cell that gives a portion of its DNA to a recipient cell.
HORIZONTAL GENE TRANSFER
recipient cell that incorporates donor DNA to its own DNA is called??
RECOMBINANT
genetic recombination results from these three types of
gene transfer:
- TRANSFORMATION
- CONJUGATION
- TRANSDUCTION
n is the transfer of genes from one bacterium to another as “naked” DNA in a solution
TRANSFORMATION
in bacteria is a mechanism by which genetic material is
transferred by a plasmid, requires cell to cell contact, only donor cell must carry the plasmid.
CONJUGATION
Is a circular piece of DNA that replicates independently from the cells chromosomes.
PLASMID
Is a genetic transfer wherein bacterial DNA is transferred
from a donor cell to recipient cell inside a virus that infects bacteria called bacteriophage, or phage
TRANSDUCTION
is an extrachromosomal genetic element that is capable of autonomous replication in the cytoplasm of a bacterial cell
PLASMID
The plasmids can also be present as integrated with bacterial chromosomes, and plasmids integrated with host chromosome are know as
EPISOMES
this plasmid transfer antibiotic resistant genes to some
organism.
R PLASMID
2 categories of plasmid:
- TRANSMISSIBILITY
- NATURE OF PLASMID
cell to cell genetic transfer through conjugation, Responsible for synthesis of the sex pilus and for the synthesis of enzymes required for their transfer.
TRANSMISSIBLE
empty of genes, thus unable to transfer
NON-TRANSMISSIBLE
efers to a hair-like appendage found on the surface of some bacterial cells, particularly those of Gram-negative bacteria, These pili are involved in a process called conjugation
SEX PILI, or sex pilus
3 factor of NATURE OF PLASMID;
- F FACTOR
- R FACTOR
- COL FACTOR or Colicinogenic factor
contains the genetic information, essential for controlling mating process of the bacteria during cojugatipn.
F FACTOR
large plasmid molecular weight ? that contains R
factor and are conjugated
mol. wt. 60 million
it contains (mol. wt. 10 million) , “r” factor and non-conjugation.
SMALL PLASMID
R factor consists of two components:
- resistance transfer factor
- r determinants
is responsible for conjugational transfer
RESISTANCE TRANSFER FACTOR
carries resistance for one of the several
antibiotics
r determinants
esembles the F factor in promoting conjugation, leading to self-transfer and also at times transfer of segments of
chromosomes.
COL FACTORS
The Col factor encodes for production of_____ ehich is lethal to other enteric bacteria.
Colicins
Col factors also encode FOR PRODUCTION OF?
diphthericin and pyocyanin
DIPTHERICIN is produce by?
Corynebacterium diphteriae
PYOCYANIN- is produced by ?
Pseudomona pyocyanea
