Cell Biology Overview - Lecture 2

Proteins that bind sister chromatids together during mitosis, ensuring accurate chromosome separation.

The duplicated 'anchors' for spindle fibers in mitosis, consisting of two centrioles.

Microtubules that extend outward from the centrosomes during mitosis, helping to position the spindle within the cell.

Microtubules that attach to chromosomes at the kinetochore during mitosis, pulling them apart.

Microtubules that overlap in the center of the spindle during mitosis, providing structural integrity.

The stage of mitosis where chromosomes condense and become visible, centrosomes migrate, and the spindle begins to form.

The stage of mitosis where the nuclear envelope breaks down, microtubules attach to kinetochores, and chromosomes align at the metaphase plate.

The stage of mitosis where chromosomes are aligned at the metaphase plate, ensuring even distribution to daughter cells.

The process of DNA replication involves copying the entire genome, ensuring that each new cell receives a complete set of genetic information.

DNA polymerase is the enzyme responsible for synthesizing new DNA strands, adding nucleotides one by one, following the base pairing rules. It builds DNA in the 5' to 3' direction starting from an existing primer.

Short RNA sequences that provide a free 3'-OH group essential for DNA polymerase to start adding nucleotides. They act as starting points for DNA synthesis.

The leading strand is synthesized continuously as DNA polymerase moves along the template in the 5' to 3' direction.

The lagging strand is synthesized in short fragments called Okazaki fragments. This is because DNA polymerase can only build in the 5' to 3' direction. Each fragment requires a new primer.

A special enzyme that adds repetitive sequences (telomeres) to the ends of chromosomes, counteracting the shortening that occurs during DNA replication. It extends the 3' end using an RNA template.

The central dogma describes the flow of genetic information in living organisms: DNA replicates itself, DNA is transcribed into RNA, and RNA translates into proteins.

Proteins are essential for various cellular functions, including structure, transport, and catalysis. They're produced through translation, where the genetic information encoded in mRNA is used to assemble a specific protein.

A DNA sequence where RNA polymerase binds to initiate transcription. It acts like a 'parking spot' for the transcription machinery.

A DNA region that signals the end of transcription, like a 'stop sign' on a road.

Proteins that bind to DNA and regulate gene expression, either by promoting (activators) or blocking (repressors) RNA polymerase binding.

A complex in bacteria that controls the expression of genes needed for lactose metabolism. It is only active when lactose is present and glucose is absent.

The enzyme responsible for transcribing DNA into RNA in eukaryotes. It doesn't directly bind to DNA like in prokaryotes, relying on transcription factors.

Specific DNA sequences that act as binding sites for transcription factors. They recruit the RNA polymerase II complex to initiate transcription.

Distant DNA regions that bind regulatory proteins to control gene expression. They can activate or repress transcription by interacting with the RNA polymerase II machinery via DNA looping.

A complex of proteins that act as a 'communication hub' between enhancers and the RNA polymerase II machinery.

Cellular junctions that prevent diffusion of molecules between cells, like a tight seal between bricks in a wall.

Junctions that allow communication between cells by passing small molecules through channels.

Junctions that connect actin filaments of adjacent cells using cadherin proteins.

Junctions that link intermediate filaments of adjacent cells using cadherin proteins.

Junctions that anchor epithelial cells to the basal lamina, the underlying layer of the tissue.

The structural support network surrounding cells, composed of collagen, laminin, fibronectin, and proteoglycans.

Transmembrane receptors that connect ECM components to the intracellular cytoskeleton, acting as bridges between the cell and its environment.

A gene that specifies the future dorsal side of the embryo in Xenopus laevis. It is initially localized in the cortical cytoplasm and transported to the future dorsal side by microtubule bundles and kinesin.

This region of the Xenopus laevis embryo contains maternal mRNA and proteins that are crucial for development.

A transcription factor that specifies the endoderm autonomously in Xenopus laevis.

A structure discovered by Spemann and Mangold, found in the dorsal lip of the blastopore in amphibian embryos. It has the ability to induce the formation of a second body axis.

A protein that acts as a motor for the transport of Wnt11 along microtubule bundles during cortical rotation in Xenopus laevis.

The process where the cytoplasm of the Xenopus laevis egg rotates, leading to the formation of the gray crescent and the specification of the future dorsal side.

A transcription factor that, along with VegT, plays a role in mesoderm induction in Xenopus laevis.

A model organism for vertebrate developmental studies due to its large eggs, rapid development, and the discovery of the Spemann-Mangold Organizer.

The process that generates organized forms during development. It involves cellular behaviors like movement, adhesion, and shape changes, as well as interactions between specialized cell types.

A type of cell found in tissues that are tightly connected and form sheets or tubes. They have distinct apical and basal surfaces.

Loosely connected cells that can move around and invade other tissues. They are important for processes like migration, cell signaling, and creating new tissue.

A protein family involved in embryonic development. They influence cell fate and pattern formation along the dorsal-ventral axis.

Molecules secreted by the SMO that inhibit the activity of BMP4. They help establish the dorsal-ventral axis by creating a gradient of BMP activity.

The process by which the SMO establishes the dorsal-ventral axis. Chordin and Noggin inhibit BMP4, creating a gradient of BMP activity. High BMP activity leads to ventral structures, while low BMP activity leads to dorsal structures.