DevBio Test 1

Proteoglycans

Large extracellular matrix molecules consisting of core protein with covalently attached plycosaminoglycan polysaccharide side chain

Laminin

a crucial, cross-shaped protein that acts as both the structural "glue" and the GPS system for cells in a developing embryo.

Caderins

They are calcium-dependent adhesion molecules. adhesion molecules

Induction

One cell population influences the development of neighboring cells through close-range interaction. The inducer

organizer

specialized cluster of cells in an early-stage embryo that directs the development and patterning of surrounding tissues

competence

Ability of cells to respond to a specific inductive signal and thus adopt a specific fate- a responder

instructions interaction

mode of inductive interaction in which a signal from inducing cell is necessary for initiating new gene expression in responding cell

permissive interaction

Inductive interaction in which the responding tissue has already been specified, and needs only an environment that allows the expression of these traits.

cytonemes

Specialized filopodial projections that extend out from a cell (sometimes more than 100 μm) to make contact with another cell producing a paracrine factor. ADD TO PARACRINE

Intrcrine (autocrine) cell signaling

targets the same cell

Juxtacrine cell signaling

-direct cell-to-cell contact, communication between adjacent cells

Paracrine cell signaling

targets nearby cells- in the same immediate region

Endocrine cell signaling

inside or within the same system, done systematically

Ligands- cell signaling

molecule that binds to a specific target protein called a receptor on or inside a cell to dictate cell behavior and fate.

Receptors- cell signaling

act as the primary molecular switches that receive extracellular signals and direct cell fate, patterning, and morphogenesis during embryonic development

Catenins

Anchor for cadherins, bind to actin cytoskeleton, forms adherens junction( dynamic protein complexes that physically link neighboring cells and drive tissue shaping during embryonic development)

relationship between adhesion properties with P-cadherin and E- cadherin

calcium-dependent cell adhesion proteins that form separate, distinct molecular complexes to drive tissue sorting and architecture during development

Basal Lamina

a thin, gel-like layer of extracellular matrix that sits directly beneath epithelial and endothelial cells, anchoring them to the underlying connective tissue

FGF example (JAK-STAT pathway)

Ligand → receptor → JAK → STAT → STAT dimerization → transcription Lab Researchers Just Started Doubling Transcripts

TGF- signaling process

done through serine/threonine receptors that can activate several downstream signaling cascades like the SMAD pathway

What are the four major families of paracrine signaling macros that act as morphogens

Fibroblast growth factor (FGF). TGF-beta superfamily, Hedgehog family, Wnt family.

Describe how cell adhesion properties help sort cell types from

one another.

allow developing cells to recognize, segregate, and organize into distinct tissues and organs

Understand how the extracellular matrix can help cells interact

with each other.

acting as a physical anchor, a signaling highway, and a mechanical bridge that coordinates cellular behavior during development

morphogenesis process and behavior

Process describes the transformation from a zygote to a fully formed embryo- causes a cell, tissue, or organism to develop its shape and structure. Cell migration. cell division and cell shape change.

Explain major juxtacrine signaling pathways and their importance.

Notch Pathway, Ephrin/Eph Receptor System, Cadherins and Adhesion Molecules, Gap Junctions MORE

What is development?

Progressive and continuous change that that generates a complex multicellular organisms from a single cell

Order of development

Fertilization → cleavage → gastrulation → organogenesis → metamorphosis (sometimes) → aging → senescence → death — Find Clever Gamers Online, Making Adults Seem Dumb

Lineage tracing function and process

sTrack fates of individual cells, led to first fate maps when using cytoplasmic markers. involves labeling and tracing cell maturation from zygote to adult to create a 'map' of cell fates

Evolutionary biology

connect the decent of multicellular animals from a common ancestor

Zygote

The initial eukaryotic cell formed when a female gamete (egg) and a male gamete (sperm) fuse during fertilization. Begins from a single cell with “unique” genetic identity

embryo in terms of development

Undergoes cellular divisions and development before birth or hatching

Which scientists first distinguished between ovipary, vivipary, and ovovivipary?

Aristotle

Ovipary

egg laying

Ovovivipary

What type of animal birth involves eggs hatching inside the mother, followed by live birth?

Vivipary

live birth

Which developmental stage involves the formation of the three primary germ layers

Gastrulatation

Gastrulation

A process involving movement of the blastomeres of the embryo relative to one another resulting in the formation of the three germ layers of the embryo. blastopore forms which leads to three germ layers

3 germ layers

ectoderm, mesoderm and endoderm

What makes a good model organism?

Size, generation time, embryo accessibility, how relevant it is for people and ease of experimental manipulation, availability of tools.

Embryology

Study of animal development from fertilization to birth or hatching

Which scientist is known for the idea that all multicellular life comes from the egg (ex ovo omnia)

William Harvey

Differentiation

The process by which an unspecialized cell becomes specialized into one of the many cell types that make up the body.

ectoderm meaning and examples

interacts with external environment- Integument System, Nervous system

mesoderm examples

you hope it never interacts with external environment- Skeletal system, Muscular System, Cardiovascular System

endoderm and def examples

helps the external environment interact with the internal one. Digestive System and Respiratory System

Triploblastic in terms of germ layer

Have all three- Ectoderm, mesoderm, and endoderm

What is purpose of “find it, lose it, move it”?

To see the function and importance of specific cells

How do you observe the sufficiency of cells in developmental processes?

cell transplantation

Epigenesis process

Organs form de novo from germ layers- Epigenesis in developmental biology is the process by which an organism develops from an undifferentiated, uniform cell (like a zygote or egg) into a complex, multicellular structure with specialized organs and tissues through a gradual sequence of steps

What germ layers do Diploblasic animals have?

Ectoderm and endoderm

What are epithelial Cell? What’s their role?

cells that are tightly linked together in sheets or tubes Role is to help cells adhere to the basal lamina

von Baer’s Law

The law of vertebrate embryology that states that less general characters develop from more general ones. evolutionary change is based on changes in development

Fate mapping and techniques for it

find and track cells and the tissues they give rise to gene expression analysis, cell dyeing, physical dissection of tissue

Specification

the first phase of commitment in cell differentiation. Cell or tissue capable of autonomous differentiation in neutral developmental environment reversibility outside a neutral environment. Cell can still reverse its differentiation a new environment.

Determination

2nd stage of commitment stage where a cell's fate is fixed and cannot be reversed, even in a non-neutral environment. Irreversible.

Autonomous specification description and characteristics - what creates asymmetry

Fixed fates regardless of context. Cells differentiate based on the localization of internal cytoplasmic factors and asymmetry is from the uneven distribution of cytoplasmic determinants.

Types of specification

Autonomous, conditional, syncytial

Conditional specification

ability of cells to achieve their respective fates by interactions with other cells- neighbor and environmental influence is key

Edwin Conklin “yellow crescent” fate map experiment observation, what did he use?

Fate map and lineage tracing. A region of the embryo giving rise to muscle cells

Syncytial Specification

Localization of cytoplasmic factors in a multinucleated cytoplasm- most closely related to the environment in early development where multiple nuclei share a common cytoplasm. combines elements of both autonomous and conditional specification

Commitment

a cell's developmental fate becoming restricted without yet showing overt changes in biochemistry and function. two phases are specification and determination

Wilhelm Roux experiment

challenged the notion of autonomous specification using the hot needle technique

Driersch’s experiments with sea urchins, what was the result of separating the cells at various early stages What were the major conclusions of his findings

Complete larvae developed, cell fates are influenced by environmental condition. cell fates were altered to suit the conditions

Drosophila(fruit flies) what is the primary mechanism that helps maintain proper nuclear spacing during interphase?

Cytoskeletal elements like microtubules

cytoplasmic determinants

Factors within the egg cytoplasm that determine cell fate; these are molecules, often transcription factors, that regulate gene expression

What is the role of cytoplasmic determinants like Bicoid and Caudal in Drosophila development?

to from a gradient for spatial organization

How does single-cell RNA sequencing contribute to understanding cell identity?

analyzes the transcriptome of individual cells

What does computational modeling in developmental biology help achieve?

grouping cells by gene expression

Differential gene expression

every somatic cell in an organism contains the entire genome but expresses different proteins.

Genome equivalency

Provides the same genetic material to all somatic cells, explains that each somatic cell in an organism contains the same complete set of genes

what tool can be used to "find" gene expression by characterizing gene transcripts

RNA sequencing (RNA-seq)

missense mutation what is it and what causes it

a single DNA base change that alters a codon so that a different amino acid is added to a growing protein chain, A base pair substitution resulting in an amino acid change

What is the role of transcriptional regulation in gene expression?

It dictates when and where specific genes are expressed

What is an example of a "Move it" experiment in developmental genetics? what is the def of move it

PAK 6 exp What happens when we transplant/ express the cells some where else in the body? Expressing a gene of interest in a different context.

Why do Tbx5 mutations affect the limbs and heart but not other tissues?

Tbx5 is essential for both limb and heart development

What process was demonstrated by the successful cloning of Dolly the lamb?

Genomic equivalency

What is the purpose of forward genetics in developmental biology? and what is forward genetics

organism is exposed to an agent that causes unbiased, random mutations, and the resulting phenotypes can be screened to identify those that affect development

mutagenesis, screen for phenotypes of interest. used in find it

Which gene expression technique detects RNA molecules in a tissue section?

In situ hybridizaiton

what tool is used in forward genetics to induce random mutations and screen for phenotypes?

EMS (ethyl methanesulfonate)

What is an example of a 'Lose it' experiment in developmental genetics

Reverse genetics - Knocking out or knocking down a specific gene of interest to try and determine its function. Examples are CRISPR-Cas9 and CRE-lox

What did the 1995 Nobel Prize in Physiology or Medicine recognize?

Discoveries concerning the genetic control of early embryonic development

What is the role of transcription factors in gene expression? What are the 2-3 types of domains

They bind to promoter regions to initiate mRNA synthesis. DNA-binding domain: recognize specific sequences. Protein-protein interaction domain: allow for binding in dimers or recruitment of other co-factors. Trans-activation domain: bind to RNA polymerase machinery or histone modification proteins

What distinguishes high CpG promoters (HCPs) in developmental control genes?

They are typically in a 'poised' state and can change direction based on context

What is the main function of RNA polymerase II in transcription?

Synthesize mRNA from a DNA template

What did the cloning of Dolly the lamb in 1997 discover

provided strong proof of genomic equivalence in animals

Enhancer sequences

provides fine-tuned control of gene expression by bridging promoter complexes with permissive DNA sequences using transcription factors

What could be a consequence of a mutation in an enhancer region of a gene, such as Pax6?

Altered gene expression during development

Pioneer transcription factors

binds to heterochromatin (only ones)

Yamanaka factors

Pioneer facts that reprogram a cell back to pluripotent state.

What role do microRNAs (miRNAs) typically play in gene expression?

Bind to mRNA to inhibit translation

What is the function of the DNA-binding domain of a transcription factor?

To recognize and bind specific DNA sequence

alternative splicing

contributes to gene expression by increasing the variability of proteins produced from a single gene

What is the significance of maternal RNAs in early development?

They allow early cell processes to occur without the zygotic genome

Morphogen

Diffusible biochemical molecules that can determine the fate of a cell by their concentrations, in that cells exposed to high levels of a morphogen will activate different genes than those exposed to lower levels. THE GRADIENT

What occurs during the epithelial to mesenchymal transition (EMT)?

Cells lose their adhesion properties and become migratory

What is the significance of morphogen gradients in tissue development?

They provide positional information that influences cell fate based on local concentration.

What cell behaviors allow a set of uniform cells to

become complex?

Directions and number of divisions, Cell migration, Cell shape changes, Cell growth, Cell death, Composition of cell membrane/secretions

Germ layers definition

tissue types that will give rise to specific organs of the body

Mesenchymal cells

cells that are unconnected or lloosely connected and can act as independent migratory units.

What are the two broad categories of cells within the embryo that contribute to morphogenesis

Epithelial cells and Mesenchymal cells