Microbial Genetic

Front 1

Define genetics

Back 1

The study of biological properties of heredity of living things. Genetics explores

1. the transmission of biological properties (Traits) from parent to offspring

2. the expression and variation of those traits

3. the structure and function of the genetic material

4. how this material changes

Front 2

Define genome

Back 2

total DNA of a cell, chromosomal & extrachromosomal

Front 3

What is a chromosome

Back 3

discrete cellular structure of a neatly packaged single DNA molecule

Front 4

what is DNA

Back 4

Genetic material, that codes for proteins and other products in a cell

Front 5

Describe the Eukaryotic chromosome structure

Back 5

- Dna is tightly wound around histone proteins

- located in the nucleus

- Few- 100s chromosomes

- Linear

- Haploid or diploid

Front 6

Describe the Prokaryotic chromosome structure

Back 6

-DNA condensed into "packet by histone-like proteins'

-No nucleus

-Single, circular chromosome (usually) or dsDNA

- only haploid

Front 7

What is meant the antiparallelarrangement within DNAmolecules?

Back 7

One helix strand that runs from the 5' to 3' direction and the other strand runs from the 3' to 5' direction.

Front 8

What are the purines, thepyrimidines and how do they pair?

Back 8

Purines: Adenine and Guanine

Pyrimidines: Cytosine, Thymine (DNA), Uracil (RNA)

Front 9

Describe the structure of purines

Back 9

• Two fused rings structures

• Larger

Front 10

Describe the structure of pyrimidines

Back 10

• One rings structures

• Smaller

Front 11

Chargaff’s Rules For DNA

Back 11

%G = %C

%A = %T

Will total to 100%

Front 12

What functional group is found at the 5’ end of a DNA molecule?

Back 12

A phosphate group

Front 13

What functional group is found at the 3’ end?

Back 13

An OH group

Front 14

Where are the functional groups found on a DNA molecule? What are they attached to?

Back 14

The functional groups are found on the 5th and 3rd carbons, which are attached to the pentose sugar.

Front 15

Define haploid

Back 15

one copy of every gene

Front 16

define diploid

Back 16

two copies of every gene

Front 17

sexual reproduction produces what kind of cells?

Back 17

diploid cells

Front 18

How many hydrogen bonds hold together A-T?

Back 18

2

Front 19

How many hydrogen bonds hold together G-C

Back 19

3

Front 20

The origin of replication is going to have a lot of what pair?

Back 20

A-T because it has fewer hydrogen bonds making it easier to break apart the strands.

Front 21

In Semiconservative Replication each strand acts as a what?

Back 21

Template

Front 22

In what direction does DNA AND RNA replication go in?

Back 22

Synthesized for 5' end to the 3' end

Front 23

How are theenzymesHelicase,Primase, DNAPolymerase III,DNA PolymeraseI and Ligase usedin DNAreplication?

Front 24

What enzyme uncoils DNA for replication?

Back 24

Topoisomerase

Front 25

What enzyme separates/unzips the two strands of DNA?

Back 25

Helicase

Front 26

Because DNA Polymerase III can't initiate a strand what happens prior to the addition of nucleotides?

Back 26

An RNA primer is needed which is added onto by Primase, adding short RNA sequences called RNA primers

Front 27

What does DNA Polymerase III do

Back 27

elongates the nucleotide strand and proofreads the chain for mistakes

Front 28

After the strand has been elongated what happens?

Back 28

DNA Polymerase I, removes the RNA primers on the lagging strand changing the RNA nucleotides to DNA nucleotides, closes the gaps and repairs mismatches

Front 29

After the rNA nucleotides have been change and the strand has been proofread what happens?

Back 29

Ligase attaches the fragments

Front 30

What is anOkazakifragment?

Back 30

Short, newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication. They are complementary to the lagging template strand, together forming short double-stranded DNA sections.

Front 31

Why does Okazaki fragments form?

Back 31

Because helicase unwinds DNA in a particular direction. The leading strand is being synthesized in the same direction that helicase is unwinding DNA, therefore it can move continuously. The lagging strand is being synthesized in the opposite direction of the unwinding DNA and therefore can only do so in fragments until more of the DNA is unwound and available for an RNA primer to be put on and then for DNA Pol to bind and synthesize another fragment.

Front 32

What process involves thefollowing: mRNA, tRNA,ribosomes, codons and anticodons?

Back 32

Protein synthesis

Front 33

Replication is from what to what?

Back 33

DNA to DNA

Front 34

Transcription is from what to what?

Back 34

RNA to DNA

Front 35

Reverse Transcriptase is from what to what?

Back 35

RNA to cDNA

Front 36

Translation occurs where?

Back 36

In the ribosomes

Front 37

Translation goes from what to what?

Back 37

RNA to proteins

Front 38

Describe the process of protein

Back 38

Involves the transcription of DNA into mRNA and translation of mRNA, which is read in codons, by ribosomes.Complementary anticodonscarried on tRNA bring correctamino acids to ribosome forpolypeptide assembly.

Front 39

What are the steps of RNA Transcription

Back 39

Initiation. The DNA molecule unwinds and separates to form a small open complex. RNA polymerase binds to the promoter of the template strand.Elongation. RNA polymerase moves along the template strand, synthesising an mRNA molecule. In prokaryotes RNA polymerase is a holoenzyme consisting of a number of subunits, including a sigma factor (transcription factor) that recognises the promoter. In eukaryotes there are three RNA polymerases: I, II and III. The process includes a proofreading mechanism.Termination. In prokaryotes there are two ways in which transcription is terminated. In Rho-dependent termination, a protein factor called "Rho" is responsible for disrupting the complex involving the template strand, RNA polymerase and RNA molecule. In Rho-independent termination, a loop forms at the end of the RNA molecule, causing it to detach itself. Termination in eukaryotes is more complicated, involving the addition of additional adenine nucleotides at the 3' of the RNA transcript (a process referred to as polyadenylation).Processing. After transcription the RNA molecule is processed in a number of ways: introns are removed and the exons are spliced together to form a mature mRNA molecule consisting of a single protein-coding sequence. RNA synthesis involves the normal base pairing rules, but the base thymine is replaced with the base uracil.

Front 40

Explain the process of Translation

Back 40

tRNA in at A site,accepts polypeptidechain from tRNA atP site. P site tRNAnow empty somoves to E site andexits ribosome.tRNA holding thepolypeptide chainmoves to P site anda new tRNA entersA site. The processrepeats until a stopcodon is reached.

Front 41

Each codon is translatedfrom nuecleic acidlanguage to...

Back 41

the amino acid language

Front 42

tRNA have what?

Back 42

anticoons

Front 43

What are anticodons

Back 43

the three-base segments in transfer RNA or tRNA.

Front 44

How many possible mRNA codons are they?

Back 44

64

Front 45

How many codons specify amino acids?

Back 45

61

Front 46

How many codons are stop codons?

Back 46

3

Front 47

How many anticodons are they?

Back 47

61 to complement amino acid codons

Front 48

Exons code for?

Back 48

Proteins

Front 49

Introns code for?

Back 49

do not code for protein

Front 50

How are introns removed during transcription?

Back 50

They are removed by splicing into the nucleus by spliceosomes

Front 51

After introns are removed in the mRNA transcript what happens?

Back 51

the mRNA is moved to cytoplasm for translation

Front 52

A eukaryotic gene putdirectly into a prokaryotichost’s chromosome willnot function. Why not?

Back 52

Prokaryotic goes do not have introns, the introns must be removed first

Front 53

What are operons?

Back 53

Groups of coordinately expressedand regulated genes

Front 54

What is the start codon?

Back 54

AUG

also encodes for Methionine

Front 55

Can transcription be turned on or off?

Back 55

Yes

Front 56

What are the 3 important features of lactose operon?

Back 56

1. the regulator, composed of the gene that codes for a protein capable of repressing the operon (the repressor)

2. the control locus composed of two areas, the promoter (recognized by RNA polymerase) and the operator, a sequence that acts as an on/off switch for transcriptase

3. the structural locus , made up of three genes, each coding for a different enzyme needed to catabolize lactose

Front 57

what is an operon?

Back 57

a unit made up of linked genes that is thought to regulate other genes responsible for protein synthesis.

an organized collection of genes

described as either repressible or inducible

Front 58

What is the ole of RNA Polymerase in transcription?

Back 58

Transcription begins when an enzyme called RNA polymerase attaches to the DNA template strand and begins assembling a new chain of nucleotides to produce a complementary RNA strand.

Front 59

what are mutations?

Back 59

• Mistakes during replication or damage to DNA • Wrong bases incorporated

– Transition (nitrogenous base type does notchange) A<>G or C<>T

– Transversion (nitrogenous base type does change)A!"(C or T) or G!"(C or T)

• Insertion or deletion of bases

Front 60

What is a mutant?

Back 60

An organism carrying a mutation

Front 61

What is a mutagen?

Back 61

Agent causing a mutation

Front 62

How many reading frames in the forward direction?

Back 62

3

Front 63

What are the 3 point mutations?

Back 63

Silent mutation

Missense mutation

Nonsense mutation

Front 64

What are point mutations?

Back 64

A single base is altered in the sequence

Front 65

Define silent mutations

Back 65

TAT to TAC >> Tyr to Tyr

– Codon changes but amino acid does not

Front 66

Define missense mutation

Back 66

TAT to TTT >> Tyr to Phe

– Codon and amino acid change

Front 67

What is a nonsense mutation?

Back 67

TAT to TAA >> Tyr to stop

– Protein truncated, rendered non-functional

Front 68

If the wild type DNA sequence reads THE CAT ATE THE BIGRAT, what type of mutation would change the sequence to THECAT ATA ETH EBI GRA T? Would this type of mutation likely befatal? Why or why not?

Back 68

An indel, specifically the insertion of the E fatal mutation because indel mutations of 1 or 2 bases are always fatal. This is because they nearly always result in a nonfunctional protein which is important for basic functions at the cellular level

Front 69

What are the three types of horizontal gene transfer in bacteria?

Back 69

Conjugation, Transformation, and Transduction

Front 70

Which type(s) of horizontal gene transfer is direct?

Back 70

Conjugation

Front 71

Which type(s) of horizontal gene transfer is indirect?

Back 71

Transformation and Transduction

Front 72

What is conjugation?

Back 72

Plasmid-directed transfer requires cell contact

Front 73

What does high-freuqency transfer involve?

Back 73

It in voles the transmission of chromosonmal genes from a donor cell to a recipient cell The plasmid jumps into the chromosome and when the chromosome is duplicated the plasmid and part of the chromosome are transmitted to a new cell through conjugation. This plasmid/chromosome hybrid then incorporates into the the recipient chromosome.

Front 74

How does Transformation work?

Back 74

Transformation involves uptake of short fragments of naked DNA by naturally transformable bacteria. Requires a live competent recipient cell.

Front 75

What is competence?

Back 75

This is the ability to take up exogenous DNA