Chapter 1 : Nature and organisation of the genetic information Flashcards
(164 cards)
1
Q
Who discovered the hereditary factor ?
A
G. Mendel
2
Q
Who’s the father of modern genetic ?
A
G Mendel
3
Q
Who isolated the DNA ?
A
F. Miescher
4
Q
What did F. Miescher ?
A
he isolated DNA
5
Q
Who used the word “gene” for the first time ?
A
Johannson
6
Q
What did Johannson ?
A
He used the word “gene” for the first time ?
7
Q
Who showed that the chromosomes contains DNA ?
A
R. Feulgen
8
Q
What did R.Feulgen discovered ?
A
That chromosomes contains DNA?
9
Q
Who discovered the transforming factor ?
A
Griffith in 1928
10
Q
What did Griffith ?
A
Made an experiment to show that there is a transforming factor in DNA and that it was the support of the genetic information
11
Q
Who discovered the double helix structure of DNA?
A
Watson and Crick
12
Q
What did Watson and Crick ?
A
They discovered the double helix structure of DNA
13
Q
Who invented the DNA sequencing ?
A
Maxon and Gilbert
14
Q
What did Maxon and Gilbert ?
A
They invented the DNA sequencing
15
Q
What did Karry Muliss ?
A
He invented PCR
16
Q
Who invented PCR ?
A
K. Muliss
17
Q
What does the PCR ?
A
It emplifies some piece of DNA
18
Q
What did Craig Venter ?
A
A massive sequencing of the human genome
19
Q
Who had the idea to make the massive sequencing of the human genome ?
A
Craig Venter
20
Q
What is DNA ?
A
The support of the genetic information
21
Q
How the DNA was showed to be the support of genetic information ?
A
Thanks to the experiment of Griffith in 1928 and the demonstration of Avery in 1944
22
Q
Explain the experiment of Griffith in a few words
A
same specy, 2 types of bacteria : smooth looking ones (capsid) = S = virulent rough looking bacteria = R = harmless Dead S (heat)+alive R = Dead mice bc of a TRANSFORMING FACTOR Used enzyme to know from where it was: DNAase (=alive mice, it's harmless again) and protease (=dead mice)
=> transforming principle in DNA
23
Q
Explain the Chase and Hershey experiment in a few words
A
Some normal cell that stop growing at a certain point in a petri dish bc of contact inhibition, but some are modified = they keep growing
centrifugation and purification of the nucleus of modified cells, there are : prots, RNA and DNA that are added to normal cell, only the one with the DNA of modified cells became modified cells again
=> transforming principle in DNA
24
Q
How to explain the transforming principle of DNA ?
A
S bacteria = G protein (=capsid) that S bacteria don’t have
When lysed, S bacteria released part of their DNA (one with the G protein gene), and R bacteria exchange their R gene with the S gene and can by then create a capsid too.
Only a few of them achieve this, but it’s enough to kill
25
What's different between the horizontal gene exhange and the transfroming principle of DNA ?
transforming principle = same specy
| horizontal transfer = different species
26
Define what's a gene
It's a nucleotide sequence used to program the synthesis of RNA and necessary to one function, i can also produce a protein but not always the case
27
How's define the phenotype ?
By your DNA and your environment
28
What's the DNA made of ?
Polymer of polynuclotides of 4 monomers (deoxynuleotides: A,C,G,T)=carbohydrates skeleton
29
What are the groupe attached to the extremity of the DNA molecule ?
```
5' = phosphate
3' = OH
```
30
How are bond nucleotides to each other ?
```
The phosphate (5') binds to the OH group (3')
=phosphodiester bond
```
31
What are the 6 essential things to know about the DNA strand ?
- double strand
- helix structure
- complementary strands
- anti-parallel strands
- phosphodiester bonds btw nuclotides of a strand
- hydrogen bonds btw the nucleotides of the two strands
32
What happens when you put DNA at a high temperature ?
denaturation = the two strands separate themselves
33
What material is needed for DNA synthesis ?
- Template (single strand DNA)
- Primer (doube stranded RNA)
- Nucleotides
- DNA polymerase
34
What's the template ?
A single strand DNA molecule which will be complementary to the newly synthetized one
35
What kind of bonds DNA Polymerase creates ?
Phosphodiester bonds
36
How hydrogenous bonds are created ?
"Naturally"
37
What are the different abreviation for nucleotides ?
The different dNTPS are :
- dATP
- dTTP
- dCTP
- dGTP
38
How does DNA polymerase reads and synthetizes it ?
It reads the template from 3' to 5'
| and synthetizes the new strand from 5' to 3'
39
What's the semi conservative replication model ?
one parental strand, one new strand for each two daughter molecule
40
What's the conservative replication model ?
one of the daughter molecule have the two parental strand, and the other daughter molecule have two new strand
41
What's the dispersive replication model ?
the two strands of each daughter molecule have some parts of parental DNA and parts of newly synthetized DNA
42
What kind of replication model applies to DNA ?
The semi-conservative model
43
Explain in a few word how Caesium Chloride gradient works
Some DNA put in an environment with 15N (heavy nitrogen) => they only have 15N
then they're put aside in an environment with 14N (light nitrogen
The 15N DNA is the parental one and the 14N DNA is the new one
The obtained DNA are put in the CsCl gradient and they migrate according to their density. As 15N is more dense, it goes down the gradient, and 14N less dense, it quite stays up. When it's hydride DNA, it goes btw the two levels.
44
How do you call DNA with 14N ?
light DNA
45
How do you call DNA with 15N ?
heavy DNA
46
Where does the replication of DNA starts from ?
from the origin of replication (ORI)
47
The DNA replication is a uni or bidirectional mechanism ?
bidirectional (2 opposite directions)
48
How many ORi do you find in prokaryotes ?
Only one (one small circular chromosome)
49
How many ORI do you find in eukaryotes ?
many
| 1 chromosome = at least 1 ORI
50
How does the replication starts ?
By denaturating DNA = opening the heliw structure
51
What does the opened DNA structure form when replicating ?
```
Replication bubbles (looking like bubbles)
with replication fork on each side of it
```
52
What's the leading strand ?
The strand that needs only one RNA primer and synthetize DNA continuously
53
What's the lagging strand ?
The strand that needs many RNA primers to synthetize a new strand
54
What are Okasakis fragments ?
They are on the lagging strand, each Okasaki fragment is made of one primer and the DNA synthetized after it, until the next primer
55
What's the length of an Okasaki fragment in prokaryotes ?
~1000 bases (much longer than eukaryotes ones)
56
What's the length of an Okasaki fragment in humans cell ?
~200 bases (much shorter than prokaryotes ones)
57
What's the function of helicase ?
it's an enzyme that opens the double helix structure
58
What's the function of RNA polymerase in DNA replication ?
It's an enzyme also called primase that synthetize RNA primers
59
What's the double function of DNA Polymerase ?
- synthetize DNA from the primer
| - rempace the RNA of the primer by DNA (degrade RNA=RNAase)
60
What's the function of ligase ?
It binde the Okasaki's fragments together to form a whole strand
61
Comment on the speed of replication in eukaryotes and prokaryotes
very fast in prokaryotes = 1500bp/sec
| a bit slower in eukaryotes = 10 à 100 bp/sec (à cause processus de vérification)
62
The reading and synthesis of DNA is uni or bidirectional ?
Unidirectional
63
What happen to replication bubbles during DNA replication ?
they grow larger and larger until they meet themselves
64
What's the function of SSBP enzyme ?
It avoid the two strands to reconnect themselves
65
What's the difference btw synthetization of DNA in vitro and in vivo ?
in vivo = primases (=RNApol) that makes double stranded RNA primer for the synthetization to starts
66
What are the two functions of primers ?
- fixation of DNA polymeras
| - synthetization of DNA
67
How many chromosome in the prokaryotes, and where is it situated ?
prokaryotes = 1 mb and it has no organelles so chromosome is directly in the cytoplasm
68
What do the prokaryotes' genes code ?
- 90% are coding for proteins
- <1% non coding RNAs
+ regulatory regions
69
What do have prokaryotes that eukaryotes do not have ?
plasmids
70
What can you say about plasmid ?
- surnumerary
- selective advantage
- double strand DNA molecule
- self replicating
- multicopy
- daughter c has the same as its mother c
71
What does it mean when we say that plasmid is "self replicating" ?
it replicates at the same time as the bacteria genome
72
What does it mean when we say that plasmid is "multicopy" ?
there are many copies of the same plasmid in the cell
73
Are the plasmid under natural selection ?
yes obviously, cells only keep the one that are useful to it
74
What differenciates prokaryotes and eukaryotes when talking about the structure of the genome only ?
- Genome of eukaryotes is fragmented
| - linear chromosomes in eukaryotes (circular in pro)
75
What's the chromatin ?
DNA + proteins attached to it
76
How are called the extremities of chromosomes ?
telomers
77
How many copy of each chromosome do we have in our cell ?
excluding gametes, we have two copies of each chromosome (=diploidy)
78
What are chromosomes associated with, and what does it form ?
proteins, forming chromatin
79
How do you call the position of a gene on a chromosome ?
the locus
80
Is there a correlation btw the complexity of the genome and the complexity of the organism ?
absolutely not, it can have more chromosomes, a way longer genome, these two factors aren't related
81
What are the two main family of DNA ?
Informative and non-informative DNA
82
What is informative DNA ?
DNA sequences that are transcripted as RNA (and then proteins or not)
83
What is non-informative DNA ?
DNA sequences that aren't transcripted (as RNA nor as proteins)
84
What are the two types of informative DNA ?
coding genes and non-coding genes
85
Coding and non-coding genes belong to informative or non-informative DNA
informative DNA
86
What is the fucntion of coding DNA ?
- it codes proteins
| - many exempaires/genome (++proteins)
87
Whats is the function of non-coding DNA ?
- it codes for RNA only !!
| ex: genes for rRNA...
88
How important is informative DNA in the human genome ?
1,4%
89
What's the function of non-informative DNA?
Structural/functional function
90
How's consituted non-informative DNA ?
Of repeated sequences of DNA
91
What are the two types of non-informative DNA ?
- repeated in tandem (side by side)
| - dispersed repetition
92
What percentage of DNA is constitute of non-informative DNA repeated in tandem ?
10%
93
What percentage of DNA is constitute of non-informative DNA have disperserd repetition ?
45%
94
Give an exemple of sequences in tandem
minisatellites
95
How many membrane does the nucleus have ?
2
96
How do you call the two membranes of the nucleus ? What do they form ?
inner layer + outer layer = an envelope
97
How to describe a nucleus that isn't replicating ?
interphasic
98
How many nuclues per cell ?
One par cell (most of the time)
99
How are the chromosome when the nucleus is interphasic ?
they are all mixed together and can't be dissociated from e/o
100
According to what the size and the form of the nucleus does change ?
according to the state of the cell
101
What are the two ultrastructures that the nucleus contains?
- chromatine (dna + prot)
| - nucleolus
102
What is the nucleolus ?
a part of the nucleus that is way more dense
103
How do you call the inside of the nucleus ?
the nucleoplasm
104
How do you call the space between the inner and outer layer of the nucleus ?
perinuclear space
105
The envelope of the nucleus is a barrier btw what and what ?
btw the nucleoplasm and the cytoplaqm
106
What can we found in the nucleoplasm ?
The cellular matrix and the chromatin
107
With what is connected the outer layer of the nucleus ?
with the rough endoplasmic reticulum (in continuity, the lumens are connected)
108
Define the nuclear matrix
it's a complex structure composed of lamina, proteins and RNA
=lamina+prots+RNA
109
what is the lamina ?
made of lamins, attached to the inner membrane
110
What's the function of lamina ?
it maintains the envelope
111
Is the envelope of the nucleus completely waterproof ?
no, there are nuclear pores in the envelope
112
What are the nuclear pores ?
in the interruption of the nuclear envelope, are organized structure of ~50 proteins
(with cytoplasmic filaments and cytoplasmic particles)
113
What's the function of the nuclear pores ?
they regulate cytonuclear exchange
114
What size can be a nuclear pore ?
80 to 100 nm
115
How do you call the proteins that form the nuclear pores ?
the nucleoporines
116
What's NPC acronym for ?
Nuclear Pore Complex
117
How do the nuclear pores regulate the cytonuclear exchange ?
by modifying their diameter = regulation of molecules which enters the nucleus
118
What kind of transport go through the nuclear pores ?
passive AND active transport
119
What are the outputs of the nuclear envelope ?
the molecules made in the nucleus that have a function in the cytoplasm
120
What are the inputs of the nuclear envelope ?
the molecules made in the cytoplasm that have a fucntion in the nucleus
121
What are the two types of chromatin ?
eu chromatin and heterochromatin
122
How do you recognize euchromatin on a microscope image ?
it's less dense so looks less dark
123
How do you recongize heterochromatin on a microscope image ?
it's really dense so it looks very dark
124
How large can the diameter of nuclear pores can increase/decrease ?
9 to 26 nm
125
How many protein complexes form the nuclear pores ?
8 complexes = nuclear pore
126
Tell some exemples of molecules getting out of the nucleus by the nuclear pores
mRNA, rRNA, tRNA
127
Tell some exemples of molecules getting in the nucleus by the nuclear pores
- proteins (for chromatin and lamina)
- transcription factor
- ribosomal proteins
128
What is the state of the chromosomes in euchromatin ?
decompacted, they are active (bc more accessible to the cell)
129
What's the DNA structure in euchromatin ?
Pearl necklace structure
130
What is the state of the chromosome in heterochromatin ?
well more compacted, they are inactive (bc less accessible to the cell)
131
Where do you mainly find heterochromatin ?
new to the inner membrane
132
Can DNA be a free molecule ?
no, even isolated it keeps its pearl necklace structure
133
What's the DNA structure in heterochromatin ?
solenoid structure (fibers piles)
134
What's the protein used for the structuration of DNA ?
histones
135
what are the 5 different types of histones ?
H1? H2A, H2B, H3, H4
136
Are histones basic or acid ? from what amino acids are they mainly made ?
they are basic
basic aa : lysine and arginine
=binds to acid DNA
137
What is pearl necklace structure made of ?
fibers made of sequences of nucleosomes
138
What is a nucleosome ?
Core particle :
- core of 8 histones
- Fragment of DNA wrapped around
+ DNA linker internucleosomal
139
How many bp are wrapped around the histone core ?
140/200 bp
140
How many bp do we found in DNA linker ?
60 bp
141
What is the histone core of nucleosome made of ?
2xH2A; 2xH2B; 2xH3; 2xH4
142
What's the first level of organisation of DNA ?
the nucleosomes of the pearl neacklace structure in euchromatin
143
From which proteins are solenoids tructures made of ?
histone H1
144
What's the second level of organisation of DNA ?
solenoids structures in heterochromatin
145
What's the third level of organisation of DNA ?
the condensed chromosome during the division of the cell
146
Are chromosome randomly placed in the nucleus ?
no, each of them occupy a specific chromosome territory
147
Are the chromosomes territories the same for all eukaryotes ?
no, it depends on the type of the cell
148
Why do the chromosome territories different btw the different cell of an organism ?
bc it depends on which part of the DNA the cell need to use
149
What is the nucleolus ?
NOT A COMPARTIMENT
| but a specific area in the cell where chromosomes with the rRNA-45S Gene reunites
150
How many nucleolus per cell ?
Usually 1, but sometimes more and sometimes none
151
What can you deduce from the number/size of nucleolus ?
we can deduce the metabolic activity of the cell, the more it has the more active it is
152
What are the two functions of the nucleolus ?
- rRNA synthesis
| - formation of ribosomal subunits (only the subunits, not the whole ribosome)
153
Do ribosomes exist as a free form ?
no bc the two subunits onky assembly themselves when replicating
154
What are the two subunits that constitutes the ribosome ?
the small subunit
| the large subunit
155
With which RNA is the small ribosomal unit made of ?
RNA 18S
156
With which RNAs is the large ribosomal unit made of ?
RNA 28S, 5S and 5.8S
157
Where are produced the RNA28S, 18S and 5.8S ?
in the nucleolus
158
Is RNA5S produced in the nucleolus ?
no, it's only RNA28S,18S and 5.8S
159
Which gene code for RNA 28S, 18S and 5.8S ?
rRNA 45S gene (found in the nucleolus)
160
Is rRNA-45S a coding or non-coding gene ?
non-coding -> no proteins but RNA
161
rRNA-45S gene can be found many times in our genome, are the repetitions in tandem or dispersed ?
the repetitions of rRNA-45S gene are dispersed in the genome
162
What are the different chromosome that has rRNA-45S genes ?
the chromosomes :
- 13,14,15
- 21, 22
163
What is abundantly synthetized in the nucleolus ?
ribosomal RNA
164
Where is rRNA 5S produced ?
in the nucleus but not in the nucleolus so it has to move
