BMB

14/12/2025

مناقشه النشاط الطلابي للطلاب برنامج الحيوانات الاليفه المتميز بقسم الكيمياء الحيويه والبيولوجيا الجزيئيه

12/12/2025

يوم عرض البوستر العلمي لطلاب الفرقه الثانيه بقسم الكيمياء الحيويه والبيولوجيا الجزيئيه

12/12/2025

عرض البوستر الخاص لطلاب الفرقه الثانيه بقسم الكيمياء الحيويه والبيولوجيا الجزيئيه

09/12/2025

السنة الأولى هي حجر الأساس في رحلة الطبيب البيطري، وهي السنة التي تُصنع فيها الشخصية العلمية الحقيقية… ورغم أنها قد تبدو صعبة في البداية، إلا أن التعامل معها بوعي وتنظيم يجعلها من أجمل سنوات الكلية وأكثرها تأثيرًا.

09/12/2025

What is Tris (Tris Base)
Tris (tris base) is an organic compound primarily used in molecular biology to make buffer solutions or act as a basic buffer. Commonly used buffer recipes using tris include:

CTAB DNA extraction buffer
TAE buffer
TBE buffer
TE buffer
Tris buffer stock solution
Tris glycine buffer
Aside from common recipes, researchers use tris to buffer pH changes in solution or as a buffer in more specialized protocols (Harvey, nd.).

Additional protocols calling for tris (tris base) include:

Ellman’s Test Protocol
Enzymatic Assay of ι-Fucose Dehydrogenase
One-Dimensional SDS-PAGE Protocol
The binding buffer component in the Antibody Binding Protocol Utilizing Protein A Agarose Beads
The binding buffer component in the Antibody Binding Protocol Utilizing Protein G Agarose Beads.
What is Tris HCl
Tris HCL is a buffering agent (acidic buffer) commonly used by molecular biologists to adjust the pH of a solution or stabilize the pH. Commercially available Tris HCl is Tris with HCl added. It can be in used in common buffer recipes such as:
CTAB DNA extraction buffer
Leammli buffer for SDS-PAGE
TAE buffer
TBE buffer
TE buffer
Tris HCl buffer solution
Determining whether to use tris HCl or tris base for these commonly used recipes depends on the protocol you’re working with. When you need to adjust the pH of your solution, you can use the conjugate acidic or basic component (Harvey, n.d.).

For example, if using a protocol calling for tris HCl, you can adjust the pH using tris base.

Essentially, rather than using HCl or NaOH to adjust pH, using tris or tris HCl simplifies the process of making a tris buffer solution.

Other protocols involving tris HCl include

DNase Inactivation in RNase A Solution Protocol
The loading buffer for the IPTG Induction and Extraction of Proteins
Radio Immunoprecipitation Assay (RIPA) Cell Lysate Preparation
The TE Buffer component in performing Electrotransformation of Agrobacterium tumefaciens

08/12/2025

08/12/2025

🧬 Orders of Protein Structure in Biochemistry

Proteins exhibit four hierarchical levels of structural organization. Each level contributes uniquely to the protein’s shape, function, and stability.

---

1️⃣ Primary Structure (1° Structure)

Definition:
The linear sequence of amino acids in a polypeptide chain, linked together by peptide bonds.

Key features:

Determined by the gene encoding the protein

Written from the N-terminus → C-terminus

Even a single amino acid change can alter the protein’s function (e.g., sickle cell hemoglobin)

Importance:
It dictates all higher structural levels through chemical interactions.

---

2️⃣ Secondary Structure (2° Structure)

Definition:
Local, repetitive folding patterns in regions of the polypeptide chain due to hydrogen bonding between backbone atoms.

Main types:

α-Helix (alpha helix): Right-handed coil stabilized by hydrogen bonds every 4 residues.

β-Pleated Sheets (beta sheets): Formed from β-strands aligned side-by-side (parallel or antiparallel).

Random coil / loops: Non-repetitive but functionally important regions.

Importance:
Secondary structures provide the initial framework for the overall 3D shape.

---

3️⃣ Tertiary Structure (3° Structure)

Definition:
The complete 3D folding of a single polypeptide chain formed by interactions between R-groups (side chains).

Stabilized by:

Hydrogen bonds

Ionic bonds

Hydrophobic interactions

Van der Waals forces

Disulfide bonds between cysteine residues

Importance:
Determines the protein’s biological activity, including enzyme active sites, binding pockets, and conformational dynamics.

---

4️⃣ Quaternary Structure (4° Structure)

Definition:
The arrangement and interactions of multiple polypeptide chains (subunits) into a functional protein complex.

Examples:

Hemoglobin: 4 subunits (2α + 2β)

DNA polymerase: multi-subunit enzyme

Antibodies: heavy and light chains

Importance:
Provides cooperativity, regulation, and functional specialization across subunits.

---
🌟 Summary Table

Level What It Describes Main Stabilizing Forces

Primary Amino acid sequence Peptide bonds
Secondary Local folding (α-helix, β-sheet) Hydrogen bonds
Tertiary Full 3D shape of one polypeptide H-bonds, ionic, hydrophobic, disulfide
Quaternary Association of multiple chains All non-covalent +