Micro Chapter 9: Microbial Genetics

Front 1

Genetics

Back 1

the study of the inheritance (heredity) of living things

Front 2

The Levels of Structure and Function of the Genome

Back 2

Genome
Chromosome
Gene

Front 3

Genome

Back 3

All genetic material in the cell

Front 4

Chromosome

Back 4

A discrete cellular structure composed of a neatly packed DNA molecule

Front 5

Eukaryotic chromosomes

Back 5

DNA molecule tightly wound around histone proteins

Appear linear

Front 6

Bacterial chromosomes

Back 6

Condensed and secured by means of histone like proteins

Single, circular chromosome

Front 7

Gene

Back 7

A segment of DNA that does something

Front 8

Structural genes

Back 8

code for proteins
code for RNA

Front 9

Regulatory genes

Back 9

control gene exression

Front 10

Genotype

Back 10

what the genes look like; reading sequence

Front 11

Phenotype

Back 11

how the genes are physically expressed

Front 12

What is the basic unit of DNA?

Back 12

nucleotide

Front 13

What makes up a nucleotide?

Back 13

Phosphate
Deoxyribose sugar
Nitrogenous base

Front 14

How many nitrogenous bases?

Back 14

2: purines and pyrimidines

Front 15

What does adenine always pair with?

Back 15

thymine

Front 16

What does guanine always pair with?

Back 16

cytosine

Front 17

What does helicase do?

Back 17

unzips DNA

Front 18

What is the goal of DNA replication?

Back 18

synthesis of DNA

Front 19

Overall replication process of DNA

Back 19

Separate the strands
Copy its template
Produce two daughter molecules

Front 20

Overall sequence of events for DNA replication:

Back 20

DNA Replication: DNA to DNA
Transcription: DNA to mRNA
Translation: mRNA to protein

Front 21

T/F: Transcription and translation are occur at the same time in prokaryotes

Back 21

True

Front 22

Semiconservative

Back 22

Each new DNA strand is made of 1 parent and 1 daughter strand
(1/2 of strand was conserved, 1/2 was used)

Front 23

Primase

Back 23

synthesizing an RNA primer

Front 24

DNA polymerase III

Back 24

Adding bases tot he new DNA chain; proofreading the chain for mistakes

Can only add a new base to an existing 3’ OH

Front 25

DNA polymerase I

Back 25

Removing primer, closing gaps, repairing mismatches

Front 26

Ligase

Back 26

Final binding of nicks in DNA during synthesis and repair

Front 27

Gyrase

Back 27

Supercoiling

Front 28

What is the origin of replication?

Back 28

Enzymes
Denotes the of DNA synthesis
Rich in A and T

Front 29

Helicases bind to what at the origin?

Back 29

DNA

Front 30

Exonuclease activity:

Back 30

(DNA Polymerase III)
Error check
Can “back up” and correct mistakes made during replication
Greatly reduces mutation rate

Front 31

RNA Primase

Back 31

Lays down primer. They don't need a 3' group. Allows DNA polymerase III to start replicating.

Front 32

DNA polymerase I removes ___ ______ and replaces them with ____.

Back 32

RNA primers
DNA

Front 33

What does DNA ligase do to the strand?

Back 33

It seals the strand and moves along any lagging parts.

Front 34

Central dogma of DNA code:

Back 34

DNA to RNA to Protein

Front 35

The major participants in Transcription and Translation:

Back 35

mRNA
RNA Polymerase
regulatory RNAs

Front 36

mRNA

Back 36

made in DNA, sent to ribosomes

Front 37

RNA Polymerase

Back 37

codes DNA into RNA

Front 38

What is different about the assembly line in RNA vs DNA?

Back 38

Single stranded molecule
The sugar is ribose

Front 39

What does a promoter do?

Back 39

starts transcription with the process of making RNA

Front 40

The triplet code and the relationship to proteins:

Back 40

DNA (triplets) to
RNA (codons) to
Proteins (amino acids)

Front 41

Redundancy

Back 41

a particular amino acid can be coded for by more than a single codon

Front 42

Wobble

Back 42

in many cases, only the first two nucleotides are required to encode the correct amino acid

Front 43

Anticodons are complement to what?

Back 43

codons

Front 44

Where are anticodons found?

Back 44

tRNA

Front 45

Translation:
The Second Stage of Gene Expression

Back 45

All of the elements needed to synthesize a protein are brought together on the RIBOSOMES

Front 46

Transfer RNA: The Key to Translation

Back 46

Also a copy of a specific region of DNA
Cloverleaf shape

Front 47

The prokaryotic (70S) ribosome composed of:

Back 47

tightly packed rRNA and protein

ribosomal RNA aligns mRNA w/ tRNA

Front 48

Initiation of Translation

Back 48

*mRNA molecule leaves DNA transcription site
*Is transported to ribosomes in the cytoplasm

Front 49

What is the fundamental difference between prokaryotic ribosomes and eukaryotic ribosomes?

Back 49

size

Front 50

What is bringing amino acids to the ribosomes?

Back 50

tRNA

Front 51

Modifications to Proteins: Post translational modifications may be necessary

Back 51

Starting animo acid clipped off
Cofactors added
Join with other proteins to form quaternary levels of structure

Front 52

What are operons?

Back 52

*Prokaryotes organize collections of genes called operons.
*They are either inducible or repressible

Front 53

3 important features of lactose (lac) operon:

Back 53

Regulator
Promoter
Operator
fig 9.18

Front 54

Regulator

Back 54

a gene that codes for a protein capable of repressing the operon [a Repressor]

Front 55

Promoter

Back 55

recognized by RNA polymerase

Front 56

Operator

Back 56

a sequence that acts as an on/off switch for transcription

Front 57

2 pathways for lactose operon:

Back 57

Operon off
Operon on

Front 58

Operon off

Back 58

absence of lactose, repressor protein attaches to the operator of the operon. This locks operator and prevents any transcription. No more lactose.

Front 59

Operon on

Back 59

When entering the cell, lactose becomes an inducer by attaching to the repressor, which detaches. RNA polymerase can now bind to promoter and initiate transcription. Lactose made.

Front 60

Mutation

Back 60

when phenotypic changes are due to changes in the genotype

Front 61

Wild type

Back 61

an organism that exhibits a natural, non-mutated characteristic

Front 62

Mutant strain

Back 62

when a microorganism bears a mutation

Front 63

Causes of mutation:

Back 63

spontaneous mutation
induced mutation

Front 64

Spontaneous mutation

Back 64

random change in the DNA arising from errors in replication

Front 65

Induced mutation

Back 65

results from exposure to known mutagens.

Front 66

Chemical mutagenic agents

Back 66

Nitrous acid, bisulfite
Ethidium bromide
Acridine dyes
Nitrogenous base analogs

Front 67

Radiation mutagenic agents

Back 67

Ionizing
Ultraviolet

Front 68

Point mutations

Back 68

involve addition, deletion, or substitution of single bases

Front 69

Missense mutation

Back 69

any change in the code that leads to placement of a different amino acid

Front 70

Nonsense mutation

Back 70

changes a normal codon into a stop codon

Front 71

Silent mutation

Back 71

alters a base but does not change the amino acid and thus has no effect

Front 72

Back-mutation

Back 72

when a gene that has undergone mutation reverses to its original base composition

Front 73

Frameshift mutations

Back 73

mutations that occur when one or more bases are inserted into or deleted from a newly synthesized DNA strand

Front 74

T/F:Most ordinary DNA damage is resolved by enzymatic systems specialized for finding and fixing such defects

Back 74

True

Front 75

Excision repair

Back 75

*Excise mutations by a series of enzymes
*Remove incorrect bases and add correct one

Front 76

What are the three means of genetic recombination in bacteria?

Back 76

Conjugation
Transformation
Transduction

Front 77

Conjugation

Back 77

Direct

Front 78

Transformation

Back 78

Indirect

Living cell taking up "naked" DNA from the environment

Front 79

Transduction

Back 79

indirect

virally mediated transfers