No, chromosomal diseases are random mistakes in the genome, they are accidents that occur during meiosis.
Chromosomal Diseases
-Arise from huge errors in the DNA that result from having extra chromosomes, large missiing sequence or other error
-Usually cause by a random physical error during reproduction.
DNA
It is amolecule made up of nucleic acids, which are the principal informational molecule of a cell
-DNA is a polymer of nucleotides, which consist of purine and pyrimidine bases linked to phosphorylated sugars
Nucleotide
Consists of sugar+base+phosphate
Nucleoside
Base and sugar
___________are proteins that associate with DNA and provide first order of structure of chromatin
Histones
List the 5 histones types
1. H1
2. H2A
3. H2B
4. H3
5.H4
Nucleosome
composed of DNA wrapped arround a histone
Chromatosome
A nucleosome bound by a linker histone
Euchromatin
Relatively decondensed and distributed throughout the nucleus, genes are transcribed and DNA is replicated in preparation for cell division.
Heterochromatin
Very highly condensed state that resemble that chromatin of cell underdoind mitosis: transcriptionally inactive
Constitutive heterochromatin
It is always condensed
Facultative heterochromatin
It is not always condensed; depends on the cell and phase of cell cycle
Levels of chromatin structure
1. Beads on a string
2. looped form (mediated by scaffolding proteins)
3. euchromatinf or solenoid form
4. heterochromatin or looped solenoid form
Telomeres
Rich in G C
a chromosome end contains variable number of telomeric repeats (non coding DNA sequences)
-3' end of DNA at each telomere is sligthly linger than the 5' end with which it is paired
The normal end of the chromosome has a unique structure called the __________ that serves as protection from degradative enzymes and clearly distinguished it from the and ends of the broken DNA molecules that the cell rapidly repairs.
by telomere repeating factors TRF1 and TRF2
A non functional telomerase can promote cancer and other proliferative diseases?
No
Transcription is ______dependent-_______synthesis
DNA dependent-RNA synthesis
RNA polymerase binds to a DNA promoter sequence in the ____stage
Binding
The first step in forming a transcription complex for mRNA transcription in eukaryotes is binding of _______ to the TATA box
TFIID
In what stage does RNA polymerase starts the synthesis of a RNA chain
initiation
RNA polymerase does not require a____to initiate RNA synthesis
Primer
DNA Transcription requires_____strand of DNA
one
Where does transcription occur
the nucleus
unwinding of the double helix occurs in the _____stage
elongation
It is the type of transcription factor that bind to DNA sequences for control gene expression
specific
This specific transcription factor serves as a bridge to RNA polymerase II
TFIIB
It is used in initiation as it begins de novo synthesis of RNA joining two free NTPs
RNA polymerase II
IN the termination sequence, the symmetrical inverted repeat if a ___rich sequence is followed by four or more A residues. Results in the formation of stable stem-loop structure.
GC-
During elongation, no more______factors are involved
transcription
The end of transcription in eukaryotes is signaled by an RNA polymerase transcribing a _____sequence
Termination
The DNA strand or blueprint that is to be read by the RNA polymerase for transcription is called the _____strand
template
the _______area is the area of the DNA molecule that is to be transcribed. It is located past or below the start site, towards the 3' end of the template (positive numbers)
Downstream
The non-transcribed region og the DNA template is known as the __ area. It is located past or below the start site, towards the 5' end of the template(negative numbers)
upstream
The new RNA transcript is also known as the ____ strand
Coding
Compared to DNA synthesis, RNA makes hundreds of copies during its synthesis. Because of that, RNA synthesis does not possess 3' -5'________proofreading activity
exonuclease
During the binding stage, the______dictated which if the two DNA strands will serve as the template
promoter
chaperones are responsible for
Assist in the proper folding of a protein
Why are chemical bonds important
They help to understand how molecules and structures fold due to their hydrophobic and hydrophilic interactions
A lipid is both hydrophibic and hydrophilic
Yes
Protein
Its a complex molecule that can be simplified into molecular chains, can turn on and off, myoglobin in muscle cells and porin are examples of proteins
All aminoacids have
Amino and a carboxyl group
Intermolecular force in dipole molecules is a
vander waals force
Examples of amphipathic molecules
fatty acids, detergents, cholesterol
The primary structure of a protein is written from
Amino to carboxyl end
Which aminoacids from below are more likely to be found on the exterior of globular proteins
A-G
F-Y
R-I
E-V
A
F
I
V
Polar covalent bond
Type of bonf that occurs when atoms of a molecule differ in electronegativity and geometry
T or F: BOth polar and non-polar covalent bonds share electrons equally between atoms of a molecule
false
Whuch helix contains mainly hydrophilic aminoacids on one side of the helix and hydrophobic aminoacids on the other side of the helix
Alpha helix
An alpha helix makes a turn every
3.6 residues
which amino acid is used to initiate protein synthesis
methionine
an alpha helix
forms H bonds with the CO group of one pepride with the NH group of another peptide
What regulates G1 checkpoint? and what does it check for?
G1 checkpoint is regulated by p53 and it checks for cell size, nutrients, growth factors, and DNA damage before going into the S phase (DNA synthesis phase).
WHat regulates g2 check point? what is cheked for at this point?
G2 check point is regulated by Chk1 and CHK2; it checks for cell size , DNA replication and DNA damage defore going to M phase
What dies the sprindle assembly checkpoint check for?
Sprindle assembly checkpoint checks for chromosome attachment to sprindle and chromosome alignment
