Molecular Biology Overview

The process of translating mRNA into a sequence of amino acids to create proteins.

A network of interconnected membranes in the cytoplasm. It's involved in the production and transportation of proteins and lipids.

A type of ER that contains ribosomes. Its main function is to synthesize and modify proteins.

A type of ER that lacks ribosomes. It is involved in the synthesis and modification of lipids and steroids.

A stack of membrane-bound sacs in the cytoplasm. It modifies, packages, and sorts proteins for transport.

Small, membrane-bound organelles found in the cytoplasm. They contain enzymes responsible for breaking down waste materials and harmful substances.

Small, membrane-bound organelles found in the cytoplasm. They break down harmful molecules like hydrogen peroxide.

Organelles typically found in plant and fungal cells, as well as in some protozoa. They store water and waste products, regulate pH, and help maintain internal pressure.

The study of genes and their inheritance, focusing on how traits are passed from parents to offspring.

The branch of biology that studies the molecular mechanisms of cellular processes.

Observable characteristics of an organism, such as eye color or height.

The first person to develop a mathematical model of heredity, using pea plants.

Units of heredity, responsible for passing traits from parents to offspring.

The process by which organisms evolve over time, driven by natural selection.

The process by which organisms produce offspring.

A characteristic that can be inherited from parents to offspring.

The study of a cell's composition and how it functions, providing the foundation for understanding complex organisms.

They are not considered living because they cannot interact with their surroundings independently, relying on host cells for survival.

A physical system able to partially replicate itself, potentially emerging under specific conditions with sufficient energy.

Applying the simplest explanation to a phenomenon, choosing the most straightforward interpretation.

A physical system that is not in a state of balance, requiring constant energy input to maintain its organization.

A physical entity is considered living if it can be born, grow, interact with its environment, repair itself evolve, reproduce, and eventually die.

The basic building block of all living beings present on Earth.

They are essential molecules carrying genetic information, enabling replication and passing on traits.

Archaebacteria are single-celled organisms that thrive in extreme environments like hot springs or highly saline lakes. They are believed to be among the earliest life forms on Earth.

Archaea are characterized by having a cell membrane with unique lipids that are more stable in extreme environments, making them different from Bacteria.

Eukaryotic cells are complex cells that possess a nucleus and other membrane-bound organelles, which are specialized compartments within the cytoplasm.

The nucleus is the control center of a eukaryotic cell, containing the genetic material (DNA) in the form of chromosomes.

The cytoskeleton is a network of protein fibers essential for maintaining cell shape, supporting the cell's structure, and facilitating the movement of molecules within the cytoplasm.

Organelles are specialized structures within the cytoplasm of eukaryotic cells, each performing a specific function. Examples include the nucleus, mitochondria, and Golgi apparatus.

Histones are proteins that bind to DNA in the nucleus, helping to regulate DNA structure and control gene expression. They are crucial for processes like replication and transcription.

Lamin proteins are proteins that line the inner nuclear membrane, providing structural support and contributing to nuclear shape and function.

A specific DNA sequence that serves as the starting point for DNA replication in prokaryotes.

A protein that binds to oriC and initiates the unwinding of the DNA double helix, marking the beginning of replication.

A protein that is essential for the unwinding of the DNA double helix, utilizing its helicase activity to separate the two strands.

A protein responsible for stabilizing single-stranded DNA during replication, preventing their premature re-association.

A key enzyme in DNA replication responsible for synthesizing new DNA strands using an existing template strand. It adds nucleotides in the 5' to 3' direction.

A region where DNA replication is initiated and where the two DNA strands separate, creating a bubble.

The process of DNA replication in which each new DNA molecule consists of one original strand and one newly synthesized strand.

The direction of DNA strand elongation occurs from the 5' end to the 3' end.

In eukaryotes, the large ribosomal subunit (60S) is responsible for peptide bond formation. This is accomplished by the 28S rRNA within the 60S subunit, aided by specific ribosomal proteins. This contrasts with prokaryotes where the peptidyl transferase activity resides within the 23S rRNA of the 50S subunit.

Eukaryotic ribosomes do not have an E site (exit site) like prokaryotic ribosomes. This means that "unloaded" tRNAs, after delivering their amino acid, exit the ribosome differently in eukaryotes.

Similar to prokaryotes, eukaryotic ribosomes use the EF-G protein for translocation. Translocation is the movement of the mRNA and tRNA complex along the ribosome after a peptide bond has been formed.

In eukaryotes, translation termination is mediated by the release factors eRF1 and eRF2. eRF1 recognizes stop codons on the mRNA and releases the newly synthesized protein chain, while eRF2 assists in the process. This contrasts with prokaryotes that use release factor RF1 and RF2.

Eukaryotic ribosomes are synthesized in the nucleolus and then transported to the cytoplasm. Once in the cytoplasm, they can either remain free or become associated with the Rough Endoplasmic Reticulum (RER).

In eukaryotes, the initiation of translation starts with the binding of the 40S ribosomal subunit along with other proteins to form the 43S complex. This complex then interacts with the mRNA, forming the 48S complex. This complex scans the mRNA to find the start codon, 'AUG', where translation will begin.

In eukaryotic translation, the first amino acid incorporated into a polypeptide chain is always methionine (Met). This is different from prokaryotes where the first amino acid is formylmethionine (fMet).

Eukaryotes lack the Shine-Dalgarno sequence, a key element in prokaryotic translation for ribosome binding to mRNA. This sequence is replaced by other mechanisms in eukaryotic translation initiation.