LESSON 2: NUCLEIC ACIDS & PROTEINS Flashcards
transfer of genetic
information from DNA to RNA through transcription, and then
from RNA to protein through translation.
THE CENTRAL DOGMA
The genetic material that
carries hereditary information in cells.
DNA (Deoxyribonucleic Acid)
The single-stranded nucleic acid
molecule that serves as a messenger carrying genetic
information from DNA to the site of protein synthesis.
RNA (Ribonucleic Acid)
The end product of the central dogma,
synthesized through translation. Proteins play crucial roles
in the structure and function of cells, tissues, and
organisms.
Protein
NUCLEOSIDE - composition and is held by
Nitrogenous base +
Pentose SUGAR
It is held together by:
N-glycoSidic bond
NUCLEOTIDE - composition and is held by
NucleoSIDE + PhosphaTe
It is held together by:
EsTer bond
these are your Purines and
Pyrimidines
Nitrogenous bases
Your phosphate groups are held together by
ANHYDRIDE BONDS
T or F: RNA has its HYDROXYL GROUP (OH)
T
T or F: DNA has hydroxyl group
F
Building blocks of nucleic acids
NUCLEOTIDES
In ____, there was a group of scientists (they still didn’t know
what the structure of DNA looked like). They were trying to
figure out what thing in the body contained the info that we
pass on to the next generations.
1920
Erwin Chargaff’s experimental finding:
Chargaff’s
rule
T or F: A-T pair has 3 hydrogen bonds (weaker);
T or F: G-C pair has 2 hydrogen bonds (stronger)
F and F
Who obtained X-ray crystallography
images of DNA
Rosalind Franklin
created the two-strand, double-helix model
James Watson and Francis Crick
Striuctures and properties od DNA
Made up of nucleotides held together by ___
3’ to 5’ phosphodiester bonds
T or F: 10.5 base pairs per turn (usually)
T
- ____ - backbones are closer together
- ____ - backbones are far from each other
1.Minor grooves
2.Major grooves
The bases will cluster inside since
they are hydrophobic in nature
Hydrophobic interactions
These forces help maintain the
structural integrity of the DNA
double helix by stabilizing the
close packing of the bases along
the helical axis.
van der Waals forces
number of BP per turn of A-DNA*, B-DNA, Z-DNA**
11,10,12
morphology of A-DNA*, B-DNA, Z-DNA**
Broad &Short, Long & Thin, Long & Thin
screw sense of A-DNA*, B-DNA, Z-DNA**
Right handed, Right handed, Left-handed
Features of A-DNA*, B-DNA, Z-DNA**
A-DNA*-In low humidity & high salt conditions
B-DNA-Most common form
Z-DNA**-In 5’ end of chromosomes
LEVELS OF DNA ORGANIZATION
Will eventually loop around a histone octamer
1
- Histone + DNA wrapped around it =
- Made of nucleosomes separated by ___
- NA wrapped ___x over a histone octamer
(left-handed)
1.NUCLEOSOME
2.LINKER DNA
3.1.75
LEVELS OF DNA ORGANIZATION
When many nucleosome group together in a 30 nm chromatin fibril it is now called a ___
What level and what’s it called?
3
Solenoid
LEVELS OF DNA ORGANIZATION
Condensation of DNA during PROPHASE of mitosis
5
● Condensed, darker on EM
● Sterically inaccessible
● Transcriptionally INACTIVE
HETEROCHROMATIN
● Less condensed, lighter in EM
● Sterically accessible
● Transcriptionally ACTIVE
EUCHROMATIN
- In ____, if you have more methyl groups it mutes your DNA; nagiging inactive
- In ____, if you have more acetyl groups it
activates your DNA; nagiging active
1.Methylation
2.acetylation
Most heterogeneous RNA (5% of total RNA) and template for PROTEIN SYNTHESIS
Messenger RNA (mRNA)
Most abundant RNA (80% of total RNA)
Ribosomal RNA (rRNA)
Smallest RNA (15% of total RNA)
Transfer RNA (tRNA)
● Functions in mRNA processing and
rRNA processing
● Splice together the EXONS to form the
mature mRNA
Small Nuclear RNA (snRNA)
● Acts as an interference
● Interact with the 3’ untranslated region of
mRNA to induce mRNA
DEGRADATION and TRANSLATIONAL
REPRESSION
Micro-RNA (miRNA)
Non-coding transcripts of >200 nt
● Involved in regulation of cell
differentiation & development, and
maintenance of telomere length
Long Non-Coding RNA (lncRNA)
● Double-stranded RNA (20-24 bp)
● Induces mRNA degradation
Silencing RNA (siRNA)
Sugar moiety of DNA and RNA
Deoxyribose
Ribose
Purines ofDNA and RNA
Adenine & Guanine in DNA ONLY
Pyrimidinesof DNA and RNA
Cytosine &Thymine - DNA
Cytosine & Uracil - RNA
DNA is more stable because it lacks ____;
withstands the ____by alkalis
1.hydroxyl group
2.hydroxylation
Most abundant and functionally diverse
molecules in living systems
PROTEINS
basic side chains
● Lysine
● Arginine
● Histidine
acidic side chains
● Glutamate
● Aspartate
uncharged polar side chians
● Asparagine
● Glutamine
● Serine
● Threonine
● Tyrosine
Between 100-1000 AAs in length
○ Longest protein is ____(25,000 AA)
TITIN
➔ Regulate metabolism
➔ Facilitate muscle contraction
➔ Provide structural framework
PROTEIN FUNCTIONS
PRIMARY STRUCTURE
- Determined by the AA sequence
- Has an _____and a _____ terminus
Has an N (NH3) and a C (COOH) terminus
SECONDARY STRUCTURE
● Stabilized by _____
● _____ - supersecondary structures produced by packing of side chains from adjacent secondary
structural elements
HYDROGEN BONDS
MOTIFS
what is the ost common secondary structure?
_____ AAs per turn?
ALPHA HELIX
~3.6
● AA residues form zigzags or a pleated pattern
● R groups of adjacent residues project in
OPPOSITE directions
BETA SHEET
Most proteins fold to a __ ?
single stable conformation
2 or more polypeptide chains forming one
macromolecule
QUATERNARY STRUCTURE
Due to a point mutation (missense) in both genes
coding for the β-chain
CLINICAL CORRELATE: SICKLE CELL DISEASE
Low affinity for oxygen; Abundant HbS
than HbA
Anemia
Less to no oxygen delivered in the tissues
Tissue anoxia
treatment on SICKLE CELL DISEASE
○ Reduce oxidative stress
○ Reduce the damage
L-glutamine
treatment on SICKLE CELL DISEASE
Counteracts the low affinity of your HbS to
O2 by increasing the production of HbF
(Fetal Hemoglobin) which has higher
affinity to oxygen
Hydroxyurea
Because of those occluded vessels
Painful crises
Treatment for the pain
Analgesics
Monoclonal bodies
Inhibits p-selectin
Crizalizumab
Changes affinity of Hbs to O2 to increase its affinity
Voxcelator
