Stem Structure
Stem Structure - Related Videos
15:13
Structure-function Studies in Mouse Embryonic Stem Cells Using Recombinase-mediated Cassette Exchange
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Cited by 6 •
2017
Proteins often contain multiple domains that can exert different cellular functions. Gene knock-outs (KO) do not consider this functional diversity. Here, we report a recombination-mediated cassette exchange (RMCE)-based structure-function approach in KO embryonic stem cells that allows for the molecular dissection of various functional domains or variants of a protein.
22:06
Derivation of Hematopoietic Stem Cells from Murine Embryonic Stem Cells
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Cited by 8 •
2007
This protocol details the derivation of transplantable hematopoietic stem cells from mouse embryonic stem cells (ESC) and their subsequent injection into lethally irradiated recipient mice. Briefly, ESC are differentiated as embryoid bodies, which are then infected with retroviral HoxB4 and co-cultured with OP9 stromal cells and hematopoietic cytokines.
01:10
Antibody Structure
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2019
Overview Antibodies, also known as immunoglobulins (Ig), are essential players of the adaptive immune system. These antigen-binding proteins are produced by B cells and make up 20 percent of the total blood plasma by weight. In mammals, antibodies fall into five different classes, which each elicits a different biological response upon antigen binding. The Y-Shaped Structure of Antibodies Consists of Four Polypeptide Chains Antibodies consist of four polypeptide chains: two identical heavy...
08:56
Fate Mapping of Human Embryonic Stem Cells by Teratoma Formation
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Cited by 26 •
2010
Directed differentiation of hESCs into specific cells has generated much interest in regenerative medicine. We provide a concise, step-by-step protocol for determining the in vivo fate of selected hESCs that provides a valuable tool for characterizing tissue-specific reagents for cell-based therapy.
01:33
Adult Stem Cells
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2019
Stem cells are undifferentiated cells that divide and produce more stem cells or progenitor cells that differentiate into mature, specialized cell types. All the cells in the body are generated from stem cells in the early embryo, but small populations of stem cells are also present in many adult tissues including the bone marrow, brain, skin, and gut. These adult stem cells typically produce the various cell types found in that tissue—to replace cells that are damaged or to continuously renew...
FAQs
In woody plants, the vascular cambium produces secondary xylem and secondary phloem. Because these tissues are added within the stem, the stem increases in thickness rather than only extending in length. This distinction helps explain why woody stems become progressively thicker and provides a structural basis for comparing secondary growth with the lengthening driven by the apical meristem.
Nodes and internodes create a repeating structural pattern along the stem. Nodes position leaves, while internodes separate those attachment regions and contribute to the spacing of leaves along the axis. Examining this arrangement helps relate stem organization to leaf placement and provides structural context for understanding how stems support branching and aboveground growth.
Xylem and phloem support different transport directions and materials within the stem. Xylem carries water and minerals upward, whereas phloem distributes sugars produced by photosynthesis. Their complementary functions connect roots, leaves, and growing regions, so interpreting vascular tissues is essential for explaining how stem structure supports both resource delivery and distribution of photosynthetic products.
The apical meristem drives primary growth, meaning the stem extends through activity at its growing tip. This process differs from the thickening produced by the vascular cambium in woody plants. Considering both regions clarifies how a plant can increase stem length and, in a separate growth process, increase stem diameter as development proceeds.
A useful examination focuses on the epidermis, ground tissue, vascular bundles, nodes, internodes, and growing tip. These regions reveal how protective and supportive tissues surround transport tissues, how leaves are positioned, and where primary growth occurs. In a woody specimen, identifying the vascular cambium adds evidence for interpreting increases in stem thickness.
The key comparison is whether the stem organization reflects only primary growth or also secondary growth. Herbaceous and woody species can be interpreted through their tissues and growth regions, while woody stems additionally contain cambium-produced secondary xylem and phloem. This comparison helps explain differences in thickness and supports analysis of structural adaptations across plant types.
Stem structure provides a framework for interpreting plant support, water and mineral transport, sugar distribution, leaf positioning, branching, and growth. Linking each process to features such as vascular tissues, nodes, internodes, or meristematic regions turns anatomical observations into functional explanations. It also helps researchers interpret how herbaceous and woody plants differ in their structural adaptations.