Lesson 14: Bacterial Genetics Flashcards
is the science of heredity
genetics
it includes the study of genes and information it carries
genetics
is the genetic information that a cell carry that includes chromosomes and plasmid
genome
are containing DNA that carry hereditary information
chromosomes
carry the genes
chromosomes
are segments of DNA that code for functional products
Genes
is a macromolecule composed of repeating units called ____________.
DNA or deoxyribonucleic acid
Nucleotides
What is genetics?
✓ science of heredity
✓ study of genes and information it carries
genetic information that a cell carry that includes?
chromosomes and plasmid
are segments of DNA that code for functional products except?
RNA viruses
what are the nitrogenous base?
adenine, thymine, cytosine, guanine
deoxyribose
pentose sugar
each nucleotide consist of what?
nitrogenous base, deoxyribose, phosphate group
the cell DNA exist as long strands of nucleotides twisted together in pairs to form a?
double helix
base pair of thymine
adenine
base pair of cytosine
guanine
these strands have two designated ends called?
5’ and 3’ (5 prime end and 3 prime end
which joins a phosphate group that attaches to another nucleotide
5’ or 5 prime end
it is important during replication the new nucleotide is added to this end
3’ or 3 prime end
genetic makeup of an organism that codes for all its characteristics. It is the collection of genes.
Genotype
is the actual expressed properties of an organism or the MANIFESTATION OF A GENOTYPE
phenotype
Due to this advancement in microbiology that some important diseases like ___________ were investigated and tracked around the world
west nile virus
the flow of genetic information from one generation to the next is made possible through the?
DNA replication, or mRNA transcription
the two strands uncoil and permanently separate from each other
DNA replication
The base sequence of parent or old strand directs the base sequence of new or daughter strand
- If there is Adenine in the parent or old strand, complementary thymine will be added to the new strand.
- If there is Cytosine in the parent or old strand, complementary Guanine will be copied into the new daughter strand
before the DNA synthesis begins, both the parental strands must unwind due to an enzyme called?
topoisomerase or gyrase
short sequences of RNA, around 10 nucleotides in length
Primers
synthesizes the primers
primase
New nucleotides are added one by one to the end of growing strand by an enzyme called?
DNA polymerase
the strand, which is synthesized in the same direction as the replication fork is known as the?
leading strand
the strand being synthesized in the other direction
lagging strand
the polymerase has to synthesise one fragment of DNA thus creating many fragments as it moves towards the replication form. these fragments are known as?
Okazaki fragments
Okazaki fragments named after the scientist, who discovered them
Reiji Okazaki
used to make proteins that controls cell activities
information in a DNA
wherein genetic information in DNA is copied or transcribed into a complimentary base sequence of RNA
Transcription
The encoded information is then used by cell to synthesize protein
translation
synthesis of a complimentary strand of RNA from a DNA template
Transcription
what are the three types of RNA in a bacterial cell?
✓ messenger RNA
✓ ribosomal RNA
✓ transfer RNA
carries the coded information for making specific proteins from DNA to ribosomes, where proteins are synthesized.
Messenger RNA (mRNA)
RNA synthesis starts at a site in the strand called ___________ until it reaches a site on the DNA called __________.
promoter
terminator
proteins synthesis is called?
translation
it decodes and translates the genetic codes (codons) made during transcription into specific proteins which consists of a series of amino acids.
translation
codes into a particular amino acid
sense codons
signal the ends of protein synthesis thus it is called stop codons
nonsense codons
site of translation
ribosomes
is a regulatory mechanism that inhibits gene expression and decreases synthesis of enzymes.
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 mutation
✓ base mutation
✓ missense mutation
✓ frame-shift mutation
(point mutation) a single base in one point of a DNA is replaced with another base.
base mutation
happens when as a result of base mutation, an incorrect amino acid is inserted into the synthesized protein
missense mutation
when one or a few nucleotide pairs are inserted or deleted in the DNA
frame-shift mutation
are environmental agents that directly or indirectly cause mutations
mutagens
Chemical Mutagens Examples;
✓ nitrous acid
✓ nucleoside analog
✓ aflatoxin
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
also have altered base-pairing property
nucleoside analog
a frame-shift mutagen and also a potent carsinogen
aflatoxin
Radiation Examples
✓ x-rays and gamma rays
✓ ultraviolet (uv) light
are potent mutagens due to their ability to ionize atoms and molecules
X-rays and Gamma rays
is harmful (at 260 nm wavelength) due to its ability to form covalent bonds between bases.
ultraviolet (uv) light
due to UV light can be repaired by photolyases or light repair enzymes by destroying covalent bonds to return its original sequence
Ultraviolet (UV) light
is the exchange of genes between two DNA molecules to form new combinations of genes on 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). parent to daughter
vertical gene transfer
occurs in a bacteria in several ways. The transfer involves a donor cell that gives a portion of its DNA to a recipient cell
Horizontal gene transfer
the recipient cell that incorporates donor DNA to its own DNA
recombinant
Genetic recombination results from the three types of gene transfer; what are these?
- Transformation
- Conjugation
- Transduction
is tha transfer of genes from one bacterium to another as “naked” DNA in a solution.
Transformation
mechanism by which genetic material is transferred by a plasmid. It 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 chromosome.
plasmid
is a genetic transfer wherein bacteria DNA is transferred from a donor cell to recipient cell inside a virus that infects bacteria called BACTERIOPHAGE, OR PHAGE.
transduction
is an extra chromosomal genetic element that is capable of autonomous replication in the cytoplasm of a bacterial cell
Plasmid
plasmids integrated with host chromosome are known as?
episomes
Plasmid are present in both;
gram-positive and gram-negative bacteria
transfer antibiotic resistant genes to some organism
R plasmids
Many plasmids control medically important properties of pathogenic bacteria. These include;
a. resistance to one or several antibiotics
b. production of toxins
c. synthesis of cell surface structures required for adherence or colonization
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
contains the genetic information, essential for controlling mating process of the bacteria during conjugation.
F factor
F factor genes determine;
a. expression of pili
b. synthesis and transfer of DNA during mating
c. interference with the ability of F bacteria to serve as recipients
d. other example. Ex. F (fertility) plasmid of E. coli
R factor consists of two components:
✓ the resistance transfer factor (RTF)
✓ resistant determinant (r)
is responsible for conjugational transfer
(RTF) Resistance transfer factor
carries resistance for one of the several antibiotics
r determinant
resembles the F factor in promoting conjugation, leading to self-transfer and also at times transfer of segments of chromosomes
col factor
encodes for production of colicins, which are antibiotics-like substances that are specifically and selectively lethal to other enteric bacteria
col factor
col factor also encode for production of;
✓ diphthericin and pyocyanin produced by Corynebacterium diphtheriae and pseudomonas pyocyanea
