Micro Exam 2

Define Genetics

The study of how traits are passed from one generation to the next

Define trait

A measurable of defineable characteristics of an induvidual

Where do the traits for singer celled organisms come from

The expression of the genetics instructions in the cells of the chromosomes

Define genome

All of the genetic instructions contained within a cell or virus

Define Genes

individual instructions that make up chromosomes and other genetic material

what do the bases form inside of DNA

Hydrogen bonds

Each DNA strand is a one chain of smaller molecules called….

Nucleotides

What is the backbone of a nucleotide consisted of?

5 Carbon Sugar

Phosphate group

Define complementarity

When the base Pairs math white their opposite

Define the Central dogma

The process by which DNA becomes protein is governed by a set of rules called the central dogma

What is the process of the central dogma?

Genetic sequence is stored, information is processed into RNA, Ribosomes use that to make a protein

DNA must be copied first into a….

RNA molecule

Define Transcription

When DNA is is separated by breaking hydrogen bonds, the genetic sequence is read from beginning to end and copied using the rules of base pairing

Define RNA Polymerase

The enzyme in the cell that slide along the DNA molecule reads it and makes an almost exact copy of the opposite strand

Define the template strand

The strand that is read by RNA polymerase

Define the coding strand

The strand that will be copied by RNA polymerase

RNA polymerase does not use T it uses

Uracil

Define DNA

Uses Deoxyribose as sugar

Uses Thymine

Double stranded

Define RNA

Uses Ribose as sugar

Uses Uracil

Single stranded

Define mRNA

The RNA molecules made by transcribing genes

What type of enzyme makes mRNA

RNA polymerase

Where does transcription happen in prokaryotic microbes?

Cytoplasm

Where does transcription happen in eukaryotic cells?

Nucleus and then the mRNA is transported to the cytoplasm

What grabs mRNA and makes it into a protein?

Ribosome

Proteins are long chains of….

Amino acids

What are the 3 letter codes that RNA is organized in?

Codons

How does the Ribosome read RNA?

It slides along it by reading codons and it creates a new protein chain

Define tRNA

It forms base pairs with the mRNA that allows it to carry the correct amino acid into the ribosome

Define mutations

Permanent changes to the genetic sequences in a genome

What do mutations change?

The Sequence of mRNA which ultimately changes the protein

Define Binding

All proteins need to attach to other molecules to work properly

Define Ligand

The molecule or atom that a protein binds to(must be very close)

Define Antibodies

Proteins that bind to molecules and tag them for destruction by the immune system

Mutations to microbial proteins can….

Change the shape of the proteins and make antibodies unable to bind to them

Mutations can…

Make existing treatments ineffective

Make microbs more severe

Make it harder for the immune system to recognize the pathogen

Define a Deletion Mutation

One or more nucleotides are permanently removed from the sequence(Becomes shorter)

Define a insertion mutation

One or more nucleotides in the genetic sequence are added(the gene sequence becomes longer then normal)

Define a substitution mutation

One nucleotide base is swapped out(the gene sequence stays the same length)

Define Silent Substitution mutations

When a substitution does not result in a change in the proteins sequence

Define Missense Subsitituion mutations

When a substitution changes one amino acid to another in the proteins sequence(or when stop codon becomes a amino acid)

Define Nonsense substitution Mutation

When a substitution changes one amino acid to a stop codon

Define a Frame shift

When insertions or deletions move the reading frame over

Define a reading frame

The grouping of all codons in an mRNA

Define Spontaneous mutations

Occur naturally and randomly and they usually happen when the cells genome divides

Define Induced mutations

Caused by external factors(radiation or chemicals)

Define a mutagen

Something that caused a mutation

Before replicating DNA the cell must….

Unwind the 2 DNA strands of its chromosomes

Define Topoisomerase

A protein that undoes the supercoiling of DNA

Define Gyrase

A protein that separates the 2 strands of the double helix

When DNA is unwound and separated is called the..

Replication fork, this is where DNA is actively being copied

Define DNA polymerase

An enzyme that actually does the copying of DNA

After the entire chromosome is copied and there are 2 complete copies the 2 proteins Gyrase and topoisomerase….

Will wind both copies until they are supercoiled again

Why do DNA mutations occur during replication?

DNA Polymerase sometimes makes mistakes(can sometimes be fixed by proteins called dna repair proteins) but they are not always caught

Define Mutation rate

The frequency in which cells make replication errors

Viruses are….

Much more error prone than all other cells

Mutations are only passed on when….

The organism reproduces itself which is why viruses have more genetic change

Bacteria can mutate…

Every time they go through cell division which can happen every 30-2 hours which is why they can develop antibiotic resistance very quickly

Define genetic variation

Naturally occurring differences in genetic sequences between individuals of a species

Genetic variation is necessary….

For organisms to adapt to changing environments

Eukaryotic microbes all use….

Sexual reproduction

Define a gamete

Produced by meiosis and they have ½ of the number of chromosomes as the parent

Define fertilization of gametes

When gametes of 2 different mating types fuse together and then the combination of their genes are different from the parent

In plasmodium Fertilization happens…

When the mosquito takes them from the intermediate host and it happens In the gut

Adult Tapeworms produce what in their prologtids?

Sperm and Eggs( they are self fertilized)

What is the infective from of the tape worm

The eggs produced in the progglotids

Bacteria reproduce by…

Binary fission

Define Horizontal gene transfer

The transfer of genetic material between individuals rather than instead of offspring(Much of genetic variation of bacteria comes from this)

Horizontal gene transfer depends upon the cells ability to perform…

Homologus recombination

Define Homologus recombination

Transferred DNA is incorporated into the cells chromosomes using matching sequences between the transferred dna and the chromosome

Define the Transformation mechanism of HGT

Fragments of bacterial DNA are recombined into the chromosome after being absorbed from the environment

Define the Transduction mechanism of HGT

Fragments of bacterial DNA are recombined into the chromosome after being transferred to the cytoplasm by a virus

Define the conjugation mechanism of HGT

Plasmid or chromosomal DNA is directly transferred from one cell to another

Transformation occurs when….

A cell incorporates DNA absorbed from the environment

Define a Competent cell

A cell that can be transformed by a DNA environment

Define Natural Competence

Bacteria that have systems that can absorb environmental DNA

Define Artificial competence

Done in a lab and makes the cell permeable to DNA

Vibrio Cholerae uses….

Homologus recombination

Define a Virulent Phage

It rapidly replicates in bacterial cells and destroys them

Define Temperate phages

They insert their genome into the cells chromosome(Can become dormant and later become virulent phages)

Transducing particles

They are the particles that phages sometimes randomly pick up, they cannot cause infection but they can transfer bacterial DNA from one cell to another

When the transducing particle attempts to infect another cell it…

releases bacterial DNA into the cell its trying to infect that can be incorporated by homologous recombination

Define a Plasmid

A small piece of Dna that a donor cell carries

Define the conjugation Pilus

The thing that forms the bridge between the 2 cells that allows the transfer of the plasmid

Define the R plasmids

plasmids that carries genes for antibiotic resistance which helps for the rapid spread of that resistance

In micro Growth means….

The growth in the # of cells within an organism

Define Asexual Reproduction

The production of genetically identical offspring by a single cell(Done by cell division)

Asexuall Reproduction can be performed by all microbes except…..

Helminths

Define the DNA replication phase of Asexual reproduction

The entire genome of the microbe is copied and the single parent cell will have 2 complete copies of the genome

Define the Cell division phase of asexual reproduction

The cell creates new proteins and cell structures until it is large enough to split into 2 cells they are then partitioned into the 2 parts of the cell

Define the cell separation phase of asexual reproduction

The plasma membrane splits the cell in Half creating 2 new offspring cells and the result is 2 genetically identical cells

Define Binary fission

The process of asexual reproduction in prokaryotes

Define Cytokinesis

When the plasma membrane splits the internal parts in half in binary fission

Define cell wall synthesis

When the cell wall splits the external parts of the cell in half in binary fission

Define Mitosis

The process of asexual reproduction in eukaryotes

What is different about the cell division step in mitosis??

It is in a series of defined phases

Define sexual reproduction

The production of genetically distinct offspring by combining 2 haploid cells

In eukaryotic cells each cell naturally has…..

2 complete copies of the cells genome

Define gametes

Procuced by meiosis they are special reproductive cells

In meiosis cell division is done….

2 times in a row and it produces 4 gametes that eat have ½ pf normal # of chromosomes

Define Haploid

A cell with half the number of chromosomes