(Bo) Chapter 15: Molecular Genetics

Front 1

Central Dogma of Molecular Genetics

Back 1

The DNA self replicates and directs the production of proteins

Front 2

Three parts of the nucleotide

Back 2

Deoxyribose Sugar, Nitrogen BASE , and phosphate group.

Front 3

What forms the core of the nucelotide.

Back 3

The deoxyribose sugar.

Front 4

Two categories of Nitrogen bases

Back 4

Purines = Double RInged
Pyrimidines = Single Rined

Front 5

Purines

Back 5

Adenine and Guanine

Front 6

Pyrimidines

Back 6

Cytosine and Thymine

Front 7

Why does the ribose sugar have the name 'deoxy' on it?

Back 7

Because on the 2' position, it has an H rather than and OH.

Front 8

The sugar side chain is bound by what kind of bonds?

Back 8

Hydrogen Bonds

Front 9

Inner and outer structure of the DNA molecule.

Back 9

The inner part is the NITROGEN BASE while the outer part is the RIBOSE SUGAR which forms the backbone of the DNA molecule

Front 10

G-C Bonds

Back 10

G-C bonds are the strongest bonds that exists in the DNA molecule

Front 11

Bonding between bases in the DNA molecule.

Back 11

Purines will bond with Pyrimidines and vice versa. Also, for each type of base there is, there will be an equal amount of the other base

Front 12

Anti Parallel

Back 12

The fact that one DNA strand will exhibit 3→5 polarity while the other will exhibit 5→3 polaity. This is important because enzymes can only move in the 5→3 direction.

Front 13

DNA Base Pairing

Back 13

Adenine - Thymine
Guanine - Cytosine

Front 14

Semiconservative Replication

Back 14

The method of DNA replication in which each new DNA molecule is composed on one parent strand and one strand that has been newly synthesized.

Front 15

How can you tell the new strand from the old one?

Back 15

The new strands have not undergone methlyation and will not show methyl group while the older ones will.

Front 16

Origin of Replication

Back 16

The point on the DNA molecule where the DNA starts replicating. There need to be a number of origins of replication in order for the DNA to replicate at a sustainable pace.

Front 17

Replication Fork

Back 17

The split between the two DNA strands during the replication process.

Front 18

Helicase

Back 18

Unwinds the two strands of DNA

Front 19

The bonds between the two strands of DNA.

Back 19

Hydrogen Bonds

Front 20

This protein makes sure that the single strand of DNA does not rebind to other strand during the replication process. They accomplish this by stabilizing the single strand of the DNA

Back 20

Single Strand Binding Proteins

Front 21

This molecule relieves the strain on the single strand of the molecule as a result of the POSITIVE SUPERCOILING by introducing NEGATIVE SUPERCOILING to compensate

Back 21

DNA Gyrase

Front 22

Coiling

Back 22

A feature of the DNA in which the DNA literally wraps into a coil. Negative and postive refer the the direction of the coil.

Front 23

DNA Polymerase

Back 23

Adds nucleotides to the single strand of DNA.

Front 24

RNA Primer

Back 24

DNA Polymerase can only work if it knows where to go. RNA primer is a segment of RNA that guides DNA Polymerse to where it needs to be.

Front 25

Pimase

Back 25

An RNA polymer enzyme that creates the RNA primers

Front 26

DNA Ligase

Back 26

Will fill in the points between the okazaki fragments with the missing nucleotides.

Front 27

Which strand is more likely to find errors?

Back 27

The lagging strand since the DNA molecules need to add and remove from the strand more ofter leading to a higher liklihood of error.

Front 28

Leading Strand - Lagging Strand

Back 28

The enzyme that place neucleotides on the parent strand of the DNA can only do so in the 5 → 3 direction. This is fine for the leading strand becayse the DNA polymerase can move inward in the 5 →3 as the helicase opens th DNA strand. The other strand cannot do this. The DNA polymerase can only move in a 5 → 3 direction if it's moving outward. This is the lagging strand. As such the strand can only take nucelotides in a step by step manner; constantly moving back as the helicase opens the DNA

Front 29

Okazaki Fragments

Back 29

The sections of DNA that are added to the lagging strand of the DNA.

Front 30

Where is RNA found?

Back 30

Cytoplasm and the nucleus

Front 31

Base pairing of the RNA.

Back 31

Adenine - Uracil
Guanine - Cytosine

Front 32

Four types of RNA

Back 32

mRNA, tRNA, rRNA, hnRNA

Front 33

Major Function of cytoplasmic RNA

Back 33

Transcription and Translation

Front 34

mRNA

Back 34

Carries genetic message from the nucelus to the cytoplsm so that it can be tranlated into a PROTEIN

Front 35

Monocistronic - Polycistronic

Back 35

The former means that the RNA can only be used to make one product while the latter means that one RNA molecule can be used to make many products. The latter are generally found in prokaryotes

Front 36

What received the RNA to make proteins

Back 36

The ribsome

Front 37

tRNA

Back 37

Links RNA together to form a polypeptide chain

Front 38

Codon

Back 38

Selects for different amino acids

Front 39

rRNA

Back 39

Ribosomal RNA. Made in the NUCLEOLOUS and forms an integral part of the ribsome

Front 40

hnRNA

Back 40

Heterogeneous Nuclear RNA. A precursor to mRNA

Front 41

Antisense strand

Back 41

During RNA synthesis, only one strand is used which is known as the antisense strand

Front 42

Transcription

Back 42

The encoding of mRNA

Front 43

RNA Polymerase

Back 43

Synthesizes the production of RNA from the DNA template

Front 44

Promoters

Back 44

Signel to the RNA polmerase where to begin transcription.

Front 45

Termination Sequences

Back 45

Sequences on the DNA that signal to the RNA Polymerase to stop transcription

Front 46

Three steps that hnRNA undergoes to become mRNA

Back 46

- 5-Guanosyl is added to cap one end in order to stabilize molecule
- Poly Adenine cap is added to 3' of molecule
-Removal of INTRONS which are the NON CODING PARTS of te hnRNA

Front 47

In the genetic language________are the letters and_______are the words.

Back 47

Letters: A,C,T/U, G
Words: All 20 Amino Acids

Front 48

Degeneracy/Redundancy

Back 48

The fact that the genetic code, give the number of permutations that it has, will have a segment of the code that is redundant

Front 49

The forming of proteins from mRNA and Amino Acids

Back 49

Translation

Front 50

During the translation process, what molecule a) recognizes the codon and b) the amino acid that the codon specifies?

Back 50

tRNA has one region that recognizes the codon and another region that will bind the correct Amino acid specified by the codon.

Front 51

The region of the tRNA that recognizes the codon.

Back 51

Anticodon region

Front 52

Sequence on the tRNA that will bind the Amino Acid

Back 52

CCA

Front 53

tRNA Synthetase

Back 53

Binds the correct amino acid to the tRNA forming an AMINOACYL-tRNA COMPLEX.

THIS PROCESS USES GTP NOT ATP!!!!!

Front 54

Structure of Ribosome

Back 54

The ribsome has two units that come together during translation

Front 55

Ribosomal Binding Sites

Back 55

One site is for the mRNA. Another site is called the A SITE which holds the aminoacyl tRNA complex. The other is the P SITE which binds to the tRNA attached to the growing polypeptide chain.

Front 56

Three Stages of Protein Synthesis

Back 56

Initiation, Elongation, and Termination

Front 57

Codon Convention

Back 57

When the codon attached to the anti codon, it does so in a reverse order and always 5 → 3. If you have an 5- AUG- 3 codon, the anticodon wil be 5 - CAU -3

Front 58

Start Codon

Back 58

Start Codons are always AUG. They will also result in the synthesis of methionine.

Front 59

Methionine tRNA

Back 59

This tRNA has the anticodone sequence of 5 - CAU - 3 which will bind to the start codon of AUG.

Front 60

Peptdyl Transferas

Back 60

This enzyme will catalyze the formation of peptide bonds between the amino acids as the ribosome move along the mRNA

Front 61

Translocation

Back 61

As the ribosome moves along the mRNA, a peptide bond is formed between the two amino acids. When this bond is formed, the unchared tRNA molecule that was in the P SITE is not ejected to make room for the new tRNA molecule to elongate the chain.

Front 62

Termination Codon.

Back 62

This is a UAG codon which will stop the process totally. When the ribosome meets the stop codon it signal a release factor which will bind to the termination codon causing a water molecule to add to the polypeptide chain

Front 63

Polyribosome

Back 63

A ribosome that can translater a number of mRNA molecules at the same time

Front 64

What is the difference between transcription and Translation?

Back 64

Transcription uses the same language which means that it is something that will go from DNA to RNA. Translation goes from one language to the ther which means RNA can be translated into proteins.

Front 65

Things that can occur to the polypeptide chain after sythesis.

Back 65

-Phosphorylation
-Carboxylation
-Methylation
-Sugar Added
-Cleavage into smaller parts or active form

Front 66

Three type of genetic mutation

Back 66

Base Pair Mutaions, Insertions, Deletions

Front 67

Point Mutation

Back 67

Base Pair Mutation

Front 68

Frameshift Mutation

Back 68

Insertions and Deletions

Front 69

Silent Mutation

Back 69

Mutations that occur in non coding regions or regions where it will have no effect

Front 70

Missense Mutation

Back 70

A mutation in which one amino acid is replaced with another

Front 71

Transposons

Back 71

Elements that can insert and remove themselves from the genome.

Front 72

How do viruses violate a key tenet of Cell Theory

Back 72

Cell theory states that all living things reproduce. Viruses do not reproduce on their own but need a host to do so.

Front 73

Capsid and cell invasion

Back 73

A virus can only invade a cell is the protein coat of the virus can recognize a given cell and infect it.

Front 74

RNA Replicase

Back 74

In the case of a virus that has an RNA based genome, when it infects a cell it will bring with an enzyme known as RNA replicase which will replicate RNA. A normal cell cannot replicate RNA

Front 75

Retroviuses

Back 75

These viruses create DNA from RNA using REVERSE TRANSCRIPTASE. The virus will use this enzyme to turn its RNA genome into DNA which it will then integrate into the host genome.

Front 76

Virions

Back 76

Virus particle. When the DNA of the virus is transcribed by the hosts enzymes, it will create VIRAL PROTEINS. There viral proteins or virus particles are known as virions.

Front 77

Two ways in which viral progeny can be release

Back 77

One process is EXTRUSION in which the virus particles will bind with the host's cell membrane. A virus that does this is said to be in its PRODUCTIVE CYCLE. The other method is that the virus will create so many virus particles that it will simply lyse the cell.

Front 78

Bacteriophages

Back 78

Viruses that specifically target bacteria

Front 79

Lytic Cycle

Back 79

When a bacteriophage infects a cell and replicates to such an extent that it causes cell lysis

Front 80

Lysogenic Cycle

Back 80

When the bacteriophage integrates into the host DNA, the viral DNA is known as a provirus. As the cell replicates so will the bacteriophage DNA. Given certain environmental factors, the provirus will enter the lytic cycle, remove itself from the host DNA, and lyse the cell.

Front 81

Plasmids

Back 81

Extracellular DNA in Bacteria

Front 82

Episomes

Back 82

Plasmids that capable of integrating into the DNA.

Front 83

Polycistronic Character of Bacterial Proteins

Back 83

In bacteria, transcription and translation occur simultaneously. As such bacterial mRNA may have more than one function and can have varying effect on the cells

Front 84

Replication Origin in Bacteria

Back 84

Since their DNA is less extensive than human DNA, bacteria only need on origin of replication.

Front 85

Three methods of increasing genetic diversity in bacteria

Back 85

Transformation, Conjugation, and Transduction

Front 86

Transformation

Back 86

Results from the integration of foreign chromosome fragments into the DNA of the cell which confers a unique genetic identity

Front 87

Conjugation

Back 87

Occurs when a CYTOPLASMIC BRIDGE forms between DONE MALE and RECIPIENT FEMALE in which genetic material is passed from one to the other.

Front 88

What is the cytplasmic bridge formed from?

Back 88

Sex Pilus that are found on the Donor Males

Front 89

How do the males forms the sex pilus?

Back 89

The males need plasmids called SEX FACTORS in order to create the sex pilus.

Front 90

Term used to designate cells that have undergone conjugation?

Back 90

Hfr Recombinants

Front 91

Operons

Back 91

Proteins that regulate the RNA Polymerase's access to the genome.

Front 92

Three parts of the operon

Back 92

Structural Genes, Operator Genes, Promoter Genes

Front 93

Structural Gene

Back 93

Codes for the protein of interest

Front 94

Operator Site

Back 94

Capable of binding a repressor protein.

Front 95

Promoter

Back 95

Region where the RNA polymerase binds

Front 96

Repressor

Back 96

Serves as a roadblock to the RNA polymerase in the case where the protein could be transcribed

Front 97

Inducible - Repressible Systems

Back 97

An inducible system requires the presence of an INDUCER for the system to initiate transcription. A repressible system is one that is constantly transcribing unless a COREPERSSOR is present.