Mircobiology- Bacterial Genetics (Chapters 13-16)

What molecules are involved in genetics?

DNA and RNA

What enzyme causes the packaging of bacterial DNA?

DNA gyrase

What is the genome of a human cell composed of?

DNA

What type of gene is also called housekeeping genes?

Constitutive Genes

What is the replication  process of the plasmid called?

Rolling circle replication

What enzyme places RNA primer at the origin of replication during replicon model?

DNA primase

Why is one of the newly made plasmids left linear at the end of rolling circle?

Continuously elongated from a nicked circular DNA template. The replication can stop before this strand is circularized, leaving it as a linear piece until further processing occurs

Name a gram positive species that can do conjugation.

Bacillus, Streptococcus, Staphylococcus, and Enterococcus

What horizontal gene transfer involves the bacteriophage and its normal replication cycle?

Transduction, this process bacteriophages can transfer genetic material from one bacterium to another during infection

What scientists discovered transformation? And what species did he work with?

Frederick Griffith, worked with Streptococcus pneumoniae

Replicon model

Understand replicon model from PowerPoint (this picture is a general overview)

Rolling circle

Use PowerPoint to understand rolling circle replication (this is a general picture)

Conjugation

Use PowerPoint to understand conjugation (this picture is a general idea)

Transduction

This picture is general idea for transduction use the PowerPoint to understand in depth

DNA replication

The transmission of biological properties (traits) from parent to offspring

Protein synthesis

The expression and variation of the those traits

What molecules are involved in genetics

DNA, RNA and proteins

What do DNA and RNA do in genetics?

Carry information

What do proteins do in genetics?

Proteins carry out most cellular functions and are built using info from DNA and RNA

Genome

Sum total of genetic material of a cell

Cell are _____ stranded DNA

double

Viruses=

DNA and RNA

DNA makes up __________

Chromosomes (with proteins)

________ are divided into genes

Chromosomes

Packing of chromosomes are done with ______

Gyrase

Who are the three scientists involved with the discovery of DNA structure?

Rosalind Frankin, James Watson, Francis Crick

Rosalind Franklin provided…

Vital information about DNA structure. Double helix

Who received the Nobel Prize?

James Watson and Francis Crick

DNA replication is crucial for…

cell division, growth, and repair. Transfer genetic material for next generation)

Protein synthesis allows…

Cells to create proteins budling blocks of cells

Regulation of gene expression

Occurs by controlling the process of transcription and translation

Old proteins

Wear out and are tagged with Ubiquitin

Proteins that are made incorrectly (misfolded) and those that are “old” are made for degradation by the addition of a molecule called?

Ubiqutin

After being labeled with ubiquitin the protein is sent through a huge, cylindrical complex called?

Proteasome

Proteasome are found in…

eukaryotic cells and some bacteria

The ubiquitin tagged protein is fed into the proteasome like traabranched into a wood chipped being broken down into?

Smaller peptides

Constitutive (housekeeping) genes

genes that are always expressed and that are necessary for basic function of the cell

Nonconstitutive (induced) genes

Genes that are expressed due to environmental signals. These genes are only expressed when needed to save energy and resources for the cell, expression is regulated

Lactose operon was discovered by

Monod and Jacob

Lactose operon is ______ to synthesize enzyme when lactose is not present?

Wasteful

Regulator genes makes ______ protein

Repressor

Control locus- Promotor

RNA polymerase binds

Control locus- Operator

On/Off switch for transcription

Structural locus- Gene 1

β-Galactosidase- Breaks lactose down into glucose and galactose

Structural locus- Gene 2

Lactose permease- A protein responsible for lactose uptake

Structural locus- Gene 3

Enzyme unknown- Makes an enzyme but its function uncertain

Operon normally off (lactose not present):

Repressor protein binds to operator to prevent RNA polymerase from transcribing 3 genes

Lactose is brownen down by ___________________ into glucose and galactose

β-Galactosidase

DNA is always (living cells or viruses) copied in a ________ fashion

Complementary

In DNA replication the parent strand separated and is used to make

new halves

Bacterial Genome

Chromosome copied during binary fission by replicon model. Plasmid copied during conjugation by rolling circle

Replicon Model occurs on

both strands simultaneously

Replication process creates

complementary stands

The bacterail chromose is a single ____ beccause

Replicon, because it’s replicated from a single origin of replication

Helicase

Breaks hydrogen bonds holding two strands of DNA together, promotes primase activity, involved in primrose assembly

DNA Gyrase

Relieves supercoiling at DNA ahead of helicase; separates daughter molecules in final stages of replication

Primase

Synthesis of RNA primer, component of primosome

DNA Polymerase III

Catalyzes most the DNA synthesis during replication has

3’—>5’ exonuclease (proofreading) activity

DNA Polymerase I

Removed RNA primers and fills the resulting gaps in DNA

DNA ligase

Synthesizes phosphodiester bonds to join Okazaki fragments

Plasmid replication

Rolling circle

Plasmid replication: Rolling circle is the replication of a _____ during _______

plasmid, conjugation

In plasmid replication, the outer strand is ____ and the end is _____

Nicked, extended

Inner strand (uncut strand) is copied while ______ the outer strand

Displacing

The displaced outer strand is then _____

Copied

Spontaneous mutations

Random change in the DNA due to errors in replication that occur without known cause

Induced mutations

The result from exposure to known mutagens, physical (primarily radiation) or chemical agents that cause changes int the DNA

Beneficial mutaiton

Creates an advantage for microbe (retained by population)

Neutral mutation

No significant change

Harmful mutation

Creates a disadvantage for microbe

Lethal mutation

kills the microbe

Genetic recombination

Occurs when an organism acquires and expresses genes that organized in another organism

Horizontal gene transfers (within the same generation )

Conjugation, transformation, transduction, transposons

Conjugation

the ability of some gram-negative bacteria to grow a pilus and share a plasmid with another species (requires the F plasmid)

In conjugation, some gram-positive species have been Pilusobserved doing conjugation without ______

Pilus

Bacillus, streptococcus, staphylococcus, and enterococcus

Transformation

Chromosome fragments from a lysed cell are accepted by a recipient cell, and the genetic code of the DNA fragment is acquired by the recipient

Transformation generally occur in

Gram postive species

Transformation: Classic experiment by

Fredrick Griffith

Griffith worked with

Streptococcus, pneumoniae

R strain

Rough colonies, no capsule, not pathogenic

S strain

Smooth colonies, capsule, pathogenic

Transuction

Involves a virus pricking (in the process of replication) a bacterial donors DNA and transferring it to a recipient bacteria

Transduction: Virus=

Bacteriophage (type of virus that only infects bacteria)

Transposons

Special DNA segments that have the capability of moving from one location in the genome to another- “ jumping genes”

Transposons caused ___________ of the genetic material

Rearragement

Transposons can move

one chromosome site to another, from a chromosome to a plasmid to a chromosome

Transposons may be

Beneficial or harmful

Who discovered transposons

Barbara McClintock

What is the role of lactose permease produced by the Lactose Operon?

It causes the cell to bring in lactose to the cell

A mutation the causes an advantage for the microbe and is retained by offspring is called:

Beneficial mutation

Where does the RNA polymerase bind in the Lactose Operon to start transcription?

promoter

A mutation that creates no change in the protein produced from the DNA is called:

Neutral mutation

Genetic changes that happen within the same generation of microbes are called:

Horizontal gene transer

A change in the nitrogenous base sequence of the DNA that changes the protein made from it, is called:

Mutation

Genetic changes that are passed from the parent cell to the daughter cell are called:

Vertical gene transfer

Which of the following is NOT one of the two very important events that are always talked about in biology courses in association with the DNA and its importance.

Plasmid exchange

The F plasmid is involved in which of the following processes?

Conjugation

How does the virus pick up bacterial DNA during transduction?

The process breaks up bacterial DNA and the virus a picks it up