Chapter8a:MicrobialGenetics 1

Genome

The sum total of all the genetic material of an organism.

What are genomes of prokaryotes and eukaryotes cells composed of?

Entirely of DNA

What are genomes of viruses made of

Either DNA or RNA

In prokaryotes and eukaryotes where do most genomes exist

Chromosomes

Chromosome

Cellular structures composed of a packaged DNA molecule wound around proteins.

What are two genomic material that also exists

Plasmids in bacteria and some fungi, or in organelles of eukaryotes (mitochondria,chloroplast)

Chromosomes (Prokaryotes)

Circular and float freely in the cytoplasm.

Chromosomes (Eukaryotes)

Linear and found in the nucleus.

Virus genomes

Genetic material found in the capsid, can contain either DNA or RNA.

DNA and have does it serve as

Deoxyribonucleic acid, a molecule that stores biological information and is the instruction manual from which microbes are build

Blueprint of life

Another term for DNA, as it is also the hereditary molecule of life establishing uniqueness of microbes

Do all life forms have DNA, and what do they use it for

yes, use DNA to store biological information and transmit it to the offspring

Nucleotide

The basic unit of DNA structure, consisting of a sugar(deoxyribose), phosphate group, and nitrogenous base.

What are most DNA molecules in microbes made up of

Two strands of nucleotide subunits linked together in long chains

Double helix

The spiral shape formed by two strands of linked nucleotides paired up and twisted around each other

Sugar phosphate backbone

The outer structure of a DNA molecule, formed by alternating sugar and phosphate groups.

Nitrogenous bases

Point towards its center forming internal “rungs” like steps on twisting ladder

What are rungs and what do they do

Are the the DNA ladder made up of the nitrogenous bases, are what make microbes diffrent

How are the bases in strands associated with bases from the other strand, and why is it important

The bases are associated with the other through hydrogen bonds, which hold the DNA double helix together

Hydrogen bonds

Weak bonds that hold the nitrogenous bases together in a DNA strand.

Adenine (A)

One of the four nitrogenous bases in DNA pairs with thymine

Thymine (T)

One of the four nitrogenous bases in DNA, pairs with adenine.

Cytosine (C)

One of the four nitrogenous bases in DNA, pairs with guanine.

Guanine (G)

One of the four nitrogenous bases in DNA, pairs with cytosine.

Base pairing rules

Adenine pairs with thymine, and cytosine pairs with guanine.

What do the four nucleotides do in a DNA single strand

Repeat over and over millions of times in different orders along DNA strand

What does the phosphate group do in a DNA single strand

Bind to sugar of the next nucleotides called a DNA strand

What is the polar covalent bond

Phosphodiester bond

What charge does the phosphate group change to

Negative

How are DNA double strands formed

Nucleotides in DNA pair up in consistent pattern to form DNA double strand

In DNA double strand formation what does A Pair with and, how many hydrogen bonds

Pairs with T via two hydrogen bonds

In DNA double strand formation what does G pair with and, how many hydrogen bonds

Pairs with C via three hydrogen bonds

Complementary strands

Two strands of DNA that fit together perfectly according to base pairing rules.

Why do complementary bases pair so well

They are the right shape to form stable hydrogen bonds with each other

Why is the order of nucleotide bases in DNA important

Is a key form of genetic information in cells it provides the instructions for making proteins

Sequence

The order the for bases that make up a DNA molecule (ex, GATCGG)

What does DNA sequence determine

The information available for building and maintaining an organism

Gene

A section of DNA with instructions for building proteins.

What are the two groups DNA can be classified into and how is the difference determined

Coding DNA and Non coding DNA depending on the what instructions are stored in its sequence

What are prokaryotes genes

Uninterrupted set of nucleotides coding for a protein

What do eukaryote genes contain

Introns and exons

Intron

Non-coding portions of a gene that are removed during RNA processing.

Exon

Coding portions of a gene that are expressed as proteins.

Coding DNA or genes

Are sections of DNA with sequences that provide instructions for building and assembling proteins responsible for all enzymes in microbes

Structural genes

Code for protein

Type of gene that code RNA for what?

To be used in protein production

Regulatory genes

Control gene expression

Genotype

Sum of all gene types and organisms distinct genetic makeup

Phenotype

Expression of certain traits(structures of function)

What are Non coding DNA

Sections of DNA with sequences that do not provide instructions for building and assembling proteins once thought to be “ junk”

Non coding DNA function

Some of its integral to the function of the cells particularly the control of gene activity

DNA replication

The process by which DNA makes a copy of itself before cell division.

Why must DNA be relocated

Each cell comes from division of pre existing cells, the DNA of the parent is copied so they is one for each daughter cell

Semiconservative replication

The model of DNA replication where each new DNA molecule consists of one old strand and one new strand.

Semi conservative replication step 1

Careful orchestration of the actions of many different enzymes

Semi conservative replication step 2

Enzymes separate the strands of the existing DNA molecule, coping one strand and producing two complete daughter molecules

Semi conservative replication step 3

Each daughter molecule is identical to the parent in composition

Semi conservative replication step 4

Neither is completely new, one strand that serves as template is an original parent of the DNA strand

Complementary strand

During DNA replication each strand of DNA severs as template for creation of this new strand which is called?

DNA replication step 1

Topoisomerases unwind the double helix to initiate DNA replication

DNA replication step 2

An enzyme called helicase separates the helix and the two stands “ unzip” from each other

DNA replication step 3

Enzyme DNA polymerases builds a new strand of DNA along unzipped stand after the enzymes primates has added RNA primer in Uniate DNA synthesis

DNA replication step 5

Free nucleotides floating inside the cells nucleus are added to each new strand in a sequence that is complementary to the nucleotide sequence on the original template stand, A pairing with T and C with G

The new strand will contain

Will have bases complementary to the original strand following base pairing rules (A-T)

DNA polymerase 1

Removing primer,closing gaps , repairing mismatches

DNA polymerases lll

Adding bases to the new DNA chain proofreading the chain for mistakes

Helicase

An enzyme that unzips and separates the DNA helix strands during replication.

Primase

An enzyme that synthesizes an RNA primer to initiate DNA replication.

Ligase

An enzyme that complete the final binding nicks in DNA during synthesis and repair

Topoisomerase l and ll

Supercoiling and untangling

DNA based microbial identification

Identify microbes by molecular means DNA collected from microbial cells by cell lysis, DNA replication provides useful applications for identification

Polymerase chain reaction (PCR)

A method used to amplify specific genes of microbial DNA that can be used for identification

Amplification

The process of increasing the number of copies of a specific DNA segment.

Cell lysis

The process of breaking down a cell to extract its DNA.

RNA primer

A short strand of RNA that provides a starting point for DNA polymerases to bind to start replication

PCR step 1

To small samples of DNA scientists add nucleotide, DNA polymerases, primers(bind to 16s or 18s gene)

PCR step 2

The DNA is first heated to separate the strands and then cooled to allow the primers to associating DNA and new nucleotides to be added by DNA polymerases

PCR step 3

From starting sample of just a few DNA molecules, PCR can make billions of copies of a specific region of the DNA in less than a few hours

Base sequence

The order of nucleotide bases in a DNA strand, determining genetic information.

Structural genes

Genes that code for proteins.

DNA sequencing

The process of determining the exact sequence of nucleotides in a DNA molecule.