History of endoplasmic reticulum

From rags to riches — The history of the endoplasmic reticulu

The Endoplasmic Reticulum, also known as the ER, is an organelle found in cells. It functions to create and distribute certain substances depending on the location of the endoplasmic reticulum, and perform metabolism. The ER is shaped like a long interwoven network of tubules which are called cisternae However prokaryotes don't use organelles to organise their intracellular space. Evolutionarily, there is evidence that mitochondria and chloroplasts are ancestors of symbiotic prokaryotes. This theory is called the endosymbiotic theory. I've tried to find an evolutionary story that explains other organelles, specifically the endoplasmic reticulum

The rough endoplasmic reticulum is named so because of its appearance. It is a series of connected flattened sacs having several ribosomes on its outer surface, hence the name. It synthesizes and secretes proteins in the liver, hormones and other substances in the glands The Endoplasmic Reticulum All eucaryotic cells have an endoplasmic reticulum(ER). Its membranetypically constitutes more than half of the total membrane of an average animal cell (see Table 12-2). The ER is organized into a netlike labyrinth of branching tubules and flattened sacs extending throughout the cytosol(Figure 12-35) In the late 1940s and early 1950s, Porter and colleagues Helen P. Thompson and Frances Kallman introduced the term endoplasmic reticulum to describe the organelle. Porter later worked with Romanian-born American cell biologist George E. Palade to elucidate key characteristics of the ER Discovery of Endoplasmic Reticulum (ER): It was discovered independently by Porter (1945) and Thompson (1945). The name was given by Porter in 1953. Endoplasmic reticulum is a 3-dimensional, complicated and inter­connected syncrri of membrane-lined channels that run through the cytoplasm The endoplasmic reticulum is a network of tubules and flattened sacs that serve a variety of functions in plant and animal cells. The two regions of the ER differ in both structure and function. Rough ER has ribosomes attached to the cytoplasmic side of the membrane

Endoplasmic Reticulum. Endoplasmic reticulum (ER) is a series of membrane-bound chambers within a cell which play an important part in the synthesis of lipids and proteins which are destined to be inserted into the cell membrane. There are two types of ER: smooth and rough Smooth Endoplasmic Reticulum (SER) SER appear smooth as ribosomes are not attached to their walls. It occurs in cells involved in the metabolism of lipids and glycogen. Muscle cells have numerous SER and are known as sarcoplasmic reticulum

In keeping with its name, the endoplasmic reticulum (ER) is a large, continuous organelle that extends throughout the whole cell. The ER not only is the cradle of most lipids and of membrane and.. Endoplasmic Reticulum: Occurrence, Morphology, Types, Modifications, Role and Origins! Endoplasmic reticulum was first of all observed in 1945 by Porter, Claude and Fullam. They noted the presence of a network or reticulum of strands associated with vesicle-like bodies in the cytoplasm of the cultural fibroblast or thinly-spread tissue culture cells endoplasmic reticulum started 10 years ago, in 1945, when Porter, Claude, and Fullam (1), noted the presence of a lace-like reticulum in the ground sub- stance of ceils grown in tissue culture and examined in toto in the electro Type 2 diabetes develops when beta cells are not able to fulfill insulin needs. The role of the endoplasmic reticulum-mitochondria junction in coordinating the functions of these two organelles throughout the natural history of type 2 diabetes is determinant and may explain the alterations of insulin biosynthesis

Endoplasmic Reticulum - Introductio

  1. Endoplasmic Reticulum (Rough) =. Endoplasmic reticulum is a network of membranes inside a cell through which proteins and other molecules move. Proteins are assembled at organelles called ribosomes. When proteins are destined to be part of the cell membrane or exported from the cell, the ribosomes assembling them attach to the endoplasmic.
  2. The lacy membranes of the endoplasmic reticulum were first seen in 1945 using electron microscopy
  3. History and why it matters. The dynamics of the endoplasmic reticulum (ER) are complex and occur over a range of scales. The most commonly described form of ER movement is the gross structural remodelling first identified by Ridge et al, with the development of live-cell fluorescence imaging techniques
  4. Competing theories of the mechanism underlying Kv2.1 clustering have included static tethering to being corralled by an actin fence. Now, recent work has demonstrated channel clustering is due to formation of endoplasmic reticulum/plasma membrane (ER/PM) junctions through interaction with ER-resident VAMP-associated proteins (VAPs)
  5. In biology endoplasmic reticulum is a continuous membrane system that forms a series of flattened sacs within the cytoplasm of eukaryotic cells and serves multiple functions, being important particularly in the synthesis, folding, modification, and transport of proteins
  6. The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding.It is a type of organelle made up of two subunits - rough endoplasmic reticulum (RER), and smooth endoplasmic reticulum (SER).The endoplasmic reticulum is found in most eukaryotic cells and forms an interconnected network of flattened.
  7. Endoplasmic reticulum is a network of membranes inside a cell through which proteins and other molecules move. Proteins are assembled at organelles called ribosomes. When proteins are destined to be part of the cell membrane or exported from the cell, the ribosomes assembling them attach to the endoplasmic reticulum, giving it a rough appearance

Endoplasmic reticulum (ER) consists of interconnected network of membrane vesicles. ER is the only organelle that has direct physical connection with nucleus, the nuclear membrane. History: The first one to observe ER was Porter in electron micrographs of liver cells and he coined the term Endoplasmic reticulum 2. History of the Study of the Endoplasmic Reticulum The endoplasmic reticulum (ER) was first observed in fibroblast-like cells by electron microscopy in 1945 [16] and was named the ER by Porter in 1954, a name still used to date [17]. It is one of the most organized eukaryotic organelles. It is a network of mem

Origin of Endoplasmic Reticulum (312 Words) Biolog

  1. Endoplasmic reticulum is a collection of tubes that make, package, and transport proteins and fats. Rough endoplasmic reticulum has protein-making ribosomes on its surface, so it helps make and.
  2. ant and may explain the alterations of insulin biosynthesis. Our goal was to study endoplasmic reticulum and mitochondrial interactions in.
  3. The endoplasmic reticulum. The endoplasmic reticulum (ER) is a system of membranous cisternae (flattened sacs) extending throughout the cytoplasm.Often it constitutes more than half of the total membrane in the cell. This structure was first noted in the late 19th century, when studies of stained cells indicated the presence of some type of extensive cytoplasmic structure, then termed the.

In keeping with its name, the endoplasmic reticulum (ER) is a large, continuous organelle that extends throughout the whole cell. The ER not only is the cradle of most lipids and of membrane and. Definition. Endoplasmic Reticulum (or ER) is an interconnected network of membranes, which is used to make proteins, steroids, and lipids located near the nucleus. In biology endoplasmic reticulum is a continuous membrane system that forms a series of flattened sacs within the cytoplasm of eukaryotic cells and serves multiple functions, being.

Endoplasmic reticulum - CreationWiki, the encyclopedia of

  1. Rough endoplasmic reticulum (RER), so called because it is studded with ribosomes, and secretes proteins into the cytoplasm. Smooth endoplasmic reticulum (SER). Among its functions is the production of proteins and steroids, the maintenance of plasma membranes, and a pathway for molecules to move along
  2. The endoplasmic reticulum (ER) stress response is regarded as an important process in the aetiology of Alzheimer's disease (AD). The accumulation of pathogenic misfolded proteins and the disruption of intracellular calcium (Ca 2+) signalling are considered to be fundamental mechanisms that underlie the induction of ER stress, leading to neuronal cell death
  3. The endoplasmic reticulum, or ER, may not be the first place you'd look to find a culprit in conditions ranging from diabetes and heart failure to Alzheimer's and chronic hepatitis C. But the ER — a mazelike organelle within every human cell — could offer a powerful therapeutic target in the search for new therapies to curb many conditions
  4. The endoplasmic reticulum (ER) has a remarkably complex structure, composed of a single bilayer that forms the nuclear envelope, along with a network of sheets and dynamic tubules. Our understanding of the biological significance of the complex architecture of the ER has improved dramatically in the last few years. The identification of proteins and forces required for maintaining ER shape, as.

evolution - How did the endoplasmic reticulum come to be

Endoplasmic-reticulum-associated protein degradation (ERAD) designates a cellular pathway which targets misfolded proteins of the endoplasmic reticulum for ubiquitination and subsequent degradation by a protein-degrading complex, called the proteasome Mechanism. The process of ERAD can be divided into three steps:. Werstuck, GH, et al. Homocysteine-induced endoplasmic reticulum stress causes dysregulation of the cholesterol and triglyceride biosynthetic pathways. J Clin Invest 2001. 107:1221-1222. Mudd, SH, et al. The natural history of homocystinuria due to cystathionine beta-synthase deficiency. Am J Hum Genet 1985. 37:1-31 The ubiquitin-proteasome system regulates the abundance of many cellular proteins by mediating their targeted degradation. We previously developed a method—differential proteomics-based identification of ubiquitylation substrates (DiPIUS)—for the comprehensive identification of substrates for a given F-box protein subunit of SCF-type ubiquitin ligases endoplasmic reticulum lumen Ontology cellular_component Synonyms ER cisterna, ER lumen, cisternal lumen, endoplasmic reticulum cisterna Alternate IDs GO:0016022 Comment None History See term history for GO:0005788 at QuickGO Subset None Related Link to all genes and gene products annotated to endoplasmic reticulum lumen

Abstract. Original Findings on Cultured MateriaL--The relatively short history of the endoplasmic reticulum started 10 years ago, in 1945, when Porter, Claude, and Fullam (1), noted the presence of a lace-like reticulum in the ground substance of ceils grown in tissue culture and examined in toto in the electron microscope Hotamisligil GS. Endoplasmic reticulum stress and the inflammatory basis of metabolic disease. Cell. 2010;140:900-17. CAS Article Google Scholar 36. Inceoglu B, Bettaieb A, da Silva CAT, Lee KSS, Haj FG, Hammock BD. Endoplasmic reticulum stress in the peripheral nervous system is a significant driver of neuropathic pain

Endoplasmic Reticulum - Structure and its Function

  1. Identification of agents that promote endoplasmic reticulum stress using an assay that monitors luciferase secretion. Doudican NA(1), Wen SY, Mazumder A, Orlow SJ. Author information: (1)1The Ronald O. Perelman Department of Dermatology, New York University School of Medicine, New York, NY, USA
  2. Media in category Endoplasmic reticulum The following 181 files are in this category, out of 181 total. 0313 Endoplasmic Reticulum a en.png 604 × 362; 230 K
  3. Endoplasmic reticulum definition, a network of tubular membranes within the cytoplasm of the cell, occurring either with a smooth surface (smooth endoplasmic reticulum ) or studded with ribosomes (rough endoplasmic reticulum ), involved in the transport of materials. See more
  4. Endoplasmic Reticulum: Endoplasmic reticulum refers to a structure having a network appearance and resides within eukaryotic cells. They contribute to protein and fat production
  5. endoplasmic reticulum - WordReference English dictionary, questions, discussion and forums. All Free
  6. ant, showing rumen, reticulum - endoplasmic reticulum stock illustration
  7. GO ID GO:0072599 Aspect Biological Process Description The directed movement of a protein to a specific location in the endoplasmic reticulum. Synonym

Selective export of transmembrane proteins from the endoplasmic reticulum (ER) relies on recognition of cytosolic-domain-localized transport signals by the Sec24 subunit of the COPII vesicle coat. Human cells express four Sec24 isoforms, termed Sec24A, Sec24B, Sec24C and Sec24D that are differentially required for selective, signal-mediated ER. History See term history for GO:0005790 at QuickGO Subset None Related Link to all genes and gene products annotated to smooth endoplasmic reticulum. Link to all direct and indirect annotations to smooth endoplasmic reticulum. Link to all direct and indirect annotations download (limited to first 10,000) for smooth endoplasmic reticulum

The Endoplasmic Reticulum - Molecular Biology of the Cell

endoplasmic reticulum Definition, Function, & Location

The endoplasmic reticulum is a multifunctional organelle responsible for storage and release of calcium in the oocyte, which contributes to fertilization. Additionally, complexes of endoplasmic reticulum and associated mitochondria are essential for energy accumulation, protein synthesis and assembly, lipid synthesis, and production of. The main difference between these two terminologies is that the Smooth Endoplasmic Reticulum is known for stocking the lipids and proteins. It is not bounded by ribosomes. Whereas, the Rough Endoplasmic Reticulum is bounded by the ribosomes and also stores proteins. Learn the difference between smooth endoplasmic reticulum and rough endoplasmic reticulum Crystal structure of sarcoplasmic reticulum Ca (2+)-ATPase (SERCA) from bovine muscle. The SERCA pump, a membrane protein of about 110kDa, transports two Ca (2+) ions per ATP hydrolyzed from the cytoplasm to the lumen of the sarcoplasmic reticulum. In muscle cells, its ability to remove Ca (2+) from the cytosol induces relaxation

In human and mouse hepatocytes palmitic acid at a lipotoxic concentration triggered early activation of endoplasmic reticulum (ER) stress-related kinases, induced the apoptotic transcription factor CHOP, activated caspase 3 and increased the percentage of apoptotic cells. These effects concurred with decreased IR/IRS1/Akt insulin pathway MANF is an endoplasmic reticulum resident protein that plays a crucial role in attenuating ER stress responses. Although MANF is indispensable for the survival and function of mouse beta cells, its precise role in human beta cell development and function is unknown. Herein, we show that lack of MANF in humans results in diabetes due to increased ER stress leading to impaired beta cell function.

Endoplasmic Reticulum (ER): Discovery, Types and Function

The mechanism of poisoning may be associated with endoplasmic reticulum stress, oxidative stress damage and organ/tissue inflammation. Recent studies have reported that human amnion-derived mesenchymal stem cells (hAMSCs) secrete a variety of cytokines, and that hAMSC-conditioned medium (CM) has anti-inflammatory and immunomodulatory effects Smooth endoplasmic reticulum (SER) is a type of endoplasmic reticulum consisting of tubular vesicles that lack ribosomes on the outer surface and is involved in the synthesis and storage of lipids. Rough ER has ribosomes on the outer surface Answer: 2 question Which structures are in the cytoplasm? Check all that apply. cell membrane chloroplasts endoplasmic reticulum lysosomes cell wall nucleus vacuoles - the answers to estudyassistant.co

The Structure and Function of the Endoplasmic Reticulu

Answer: 1 on a question Which of these organelles is NOT in animal cells? Ribosome Endoplasmic Reticulum Cell Wall - the answers to answer-helper.co Request PDF | Involvement of Kisspeptin in androgen-induced hypothalamic endoplasmic reticulum stress and its rescuing effect in PCOS rats | Endoplasmic reticulum (ER) stress, with adaptive. Endoplasmic Reticulum Diagram. Endoplasmic Reticulum (ER) is the tubular membrane inside the cytoplasm of the cell. Also, ribosomes cover their surface. Besides, the ER has both smooth and rough surface. In addition, they help in the transportation process. Transportation of food material, water and minerals in the body of a living organism Being a major factory for protein synthesis, assembly, and export, the endoplasmic reticulum (ER) has a precise and robust ER quality control (ERQC) system monitoring its product line. However, when organisms are subjected to environmental stress, whether biotic or abiotic, the levels of misfolded proteins may overwhelm the ERQC system, tilting the balance between the capacity of and demand. GAT-1(P361T) mutant protein was retained inside the endoplasmic reticulum. We have previously identified that mutant GABA A receptor subunits are more likely to be retained inside the endoplasmic reticulum (ER) due to misfolding and glycosylation arrest [25, 26]

Let's Build: An Animal Cell Anchor Chart by A House Called

Endoplasmic Reticulu

Entamoeba histolytica, the cause of amebiasis, is believed to have no continuous endoplasmic reticulum (ER), with ER functions occurring in vesicles. Here, using an ER-targeted green fluorescent protein fusion protein and fluorescence loss in photobleaching, we have unambiguously demonstrated the presence of a continuous ER compartment in living E. histolytica trophozoites Endoplasmic reticulum exit sites (ERES) are present on the high curvature tubular ER membranes. 63 Altered distribution of tubular ER would affect the number of ERES on the ER membrane and eventually result in delayed protein transport out of the ER Shiga toxin (Stx) follows a complex intracellular pathway in order to kill susceptible cells. After binding to cell surface glycolipids, the toxin is internalized and trafficked in retrograde fashion to the endoplasmic reticulum (ER). From the ER lumen, the toxin must gain access to the cytoplasm, where it enzymatically inactivates the 28S rRNA, inhibiting protein synthesis. The host molecules. the interior of an eukaryotic cell. this is the most common generic type of cell and it's present in all mammals. - endoplasmic reticulum stock illustration

Disturbance in the normal functions of the endoplasmic reticulum (ER) induces a signaling cascade that integrates adaptive and apoptotic responses. There are accumulating reports which demonstrate that prolonged ER stress results in the development and progression of metabolic diseases, including diabetes, obesity, fatty liver diseases, as well as many other diseases like neurodegenerative. The endoplasmic reticulum (ER) in most cell types is an interconnected membrane network of flattened sheet-like cisternae and narrow-diameter tubules dispersed throughout the cell cytoplasm ( Baumann and Walz, 2001 ). The network is continuous with the outer nuclear envelope and extends outward toward the cell periphery Endoplasmic reticulum is a network of membranes or tubes in a cell through which materials move. As an organelle in a eukaryotic cell (complex cells having nuclei and other organelles), it is involved with the production of new proteins as well as with the movement of materials throughout the cell The endoplasmic reticulum is the cell's highway and is responsible for the production of the protein and lipid components of most of the cell's organelles. There are two types of ER- rough, which synthesizes proteins to be exported and is covered with ribosomes, and smooth, which organizes the synthesis of lipids and other biosynthetic activities

The endoplasmic reticulum (ER) is an essential intracellular organelle with multiple roles, including the synthesis of nascent proteins, Ca 2+ storage, glycosylation, and the trafficking of newly-synthesized membrane and secretory proteins. Perturbations of these processes have been demonstrated to interfere with the proper functioning of ER. Background The endoplasmic reticulum plays an important role in many cellular processes, which includes protein synthesis, folding and post-translational processing of newly synthesized proteins. It is also the site for quality control of misfolded proteins and entry point of extracellular proteins to the secretory pathway. Hence at any given point of time, endoplasmic reticulum contains two. endoplasmic reticulum (plural endoplasmic reticula) ( cytology ) A network of membranes within the cytoplasm of cells , where proteins and lipids are synthesized . Translations [ edit What is endoplasmic reticulum answer in one sentence? Endoplasmic reticulum (ER), in biology, a continuous membrane system that forms a series of flattened sacs within the cytoplasm of eukaryotic cells and serves multiple functions, being important particularly in the synthesis, folding, modification, and transport of proteins History See term history for GO:0036490 at QuickGO Subset None Related Link to all genes and gene products annotated to regulation of translation in response to endoplasmic reticulum stress. Link to all direct and indirect annotations to regulation of translation in response to endoplasmic reticulum stress

Here we show that blocking protein translocation into mitochondria results in the accumulation of mitochondrial membrane proteins at the endoplasmic reticulum, thereby triggering the unfolded protein response (UPR ER). Moreover, we find that mitochondrial membrane proteins are also routed to the ER under physiological conditions Gan PP, Zhou YY, Zhong MZ, Peng Y, Li L, Li JH. Endoplasmic reticulum stress promotes autophagy and Apoptosis and reduces chemotherapy resistance in mutant p53 lung Cancer cells. Cell Physiol Biochem. 2017;44:133-51. PubMed Google Scholar 17. Rabinowitz JD, White E. Autophagy and metabolism. Science. 2010;330:1344-8 Smooth Endoplasmic Reticulum Definition. The smooth endoplasmic reticulum (smooth ER) is a membranous organelle found in most eukaryotic cells. It is a subset of the endomembrane system of the endoplasmic reticulum. Its main functions are the synthesis of lipids, steroid hormones, the detoxification of harmful metabolic byproducts and the storage and metabolism of calcium ions within the cell A new study led by Ying Maggie Chen, MD, PhD, Division of Nephrology, found a new class of drugs that shows great promise in the treatment of nephrotic syndrome (NS) resulting from podocyte endoplasmic reticulum (ER) dysfunction.. NS is a leading cause of chronic kidney disease affecting over 500 million people worldwide. Damage to podocytes, the highly specialized epithelial cells that cover.

Isolation of Endoplasmic Reticulum (Theory) : Cell biology

Endoplasmic_reticulum (ER): WeMove Glossary of Terms [home, info] Endoplasmic reticulum: Drug Medical Dictionary [home, info] Science (2 matching dictionaries) Endoplasmic reticulum (ER): Drug Discovery and Development [home, info] endoplasmic reticulum: Natural History Terms [home, info] Slang (1 matching dictionary The endoplasmic reticulum (ER) is an organelle that appears in all eukaryotic cells, usually surrounding the nucleus. The ER is made of a series of membranes that extend throughout the jelly-like. The GET pathway is required for the insertion of tail-anchored (TA) membrane proteins in the endoplasmic reticulum (ER) of yeast and mammals. Some orthologous genes had also been identified in higher plants with the exception of one of the two ER membrane receptors required for membrane insertion. Get2/CAML is required for the pathway's cytosolic chaperone to dock and release its TA protein. Neutrophils amplify inflammation in lupus through the release of neutrophil extracellular traps (NETs). The endoplasmic reticulum stress sensor inositol-requiring enzyme 1 α (IRE1α) has been implicated as a perpetuator of inflammation in various chronic diseases; however, IRE1α has been little studied in relation to neutrophil function or lupus pathogenesis

History. Contributing to Cancer Research. Strategic Planning . Leadership. Director's Page. Principal Deputy Director's Page. Previous NCI Directors. NCI Organization. NCI Frederick. Advisory Boards and Review Groups. Budget & Appropriations. About the Annual Plan & Budget Proposal The decrease in rough endoplasmic reticulum in the small intestine epithelial cells of obese mice indicates that obesity starting in childhood influences various functions of the small intestine, such as protein synthesis, and could impair both the defense mechanism against invasion of pathogenic microbes and nutritional absorption ERP27 is a noncatalytic member of the protein disulfide isomerase (PDI; see 608012) family of endoplasmic reticulum (ER) proteins (Alanen et al., 2006). Cloning and Expression. By searching databases for novel PDI family members, Alanen et al. (2006) identified ERP27. The deduced 273-amino acid protein has an N-terminal signal sequence, an N.

Cell, drawing - Stock Image - C006/3915 - Science Photo

(PDF) The Endoplasmic Reticulum - ResearchGat

Vitamin D-sufficient patients (≥30 ng/ml 25(OH)D) had lower monocyte endoplasmic reticulum (ER) stress, a predominance of M1 over M2 macrophage membrane receptors, and decreased mRNA expression of monocyte adhesion molecules PSGL-1, β 1-integrin, and β 2-integrin compared with patients with 25(OH)D levels of <30 ng/ml. In vitamin D. The endoplasmic reticulum or ER (endoplasmic means within the cytoplasm, reticulum means little net) is an organelle found in all eukaryotic cells.The ER modifies proteins, makes macromolecules, and transfers substances throughout the cell. Prokaryotic organisms do not have organelles and thus do not have an ER. ER's base structure and composition is similar to the plasma membrane, though. The smooth endoplasmic reticulum, or smooth ER, is an organelle found in both animal cells and plant cells.Smooth ER helps the body make and metabolize fats and steroid hormones. Smooth and rough ER. There are two types of endoplasmic reticuli: smooth and rough. Rough ER is studded with ribosomes.Smooth ER is not

Endoplasmic Reticulum: Occurrence, Morphology, Types

Lipid-induced endoplasmic reticulum stress in liver cells results in two distinct outcomes: adaptation with enhanced insulin signaling or insulin resistance. Achard CS, Laybutt DR. Endocrinology, 153(5):2164-2177, 28 Feb 2012 Cited by: 38 articles | PMID: 2237497 Start studying Lecture #6 - BMS 300 - 1/30/2020 - Endoplasmic reticulum. Learn vocabulary, terms, and more with flashcards, games, and other study tools HGNC Approved Gene Symbol: SEC16B. Cytogenetic location: 1q25.2 Genomic coordinates (GRCh38): 1:177,928,787-177,984,283 (from NCBI) TEXT. Description. SEC16B is a mammalian homolog of S. cerevisiae Sec16 that is required for organization of transitional endoplasmic reticulum (ER) sites and protein export (Bhattacharyya and Glick, 2007) The endoplasmic reticulum is the intracellular organelle responsible for many critical functions such as lipid synthesis, calcium storage and protein maturation. The cell experiences ER stress when these functions are disrupted and activates mechanisms to restore homeostasis

Plasma cell, TEM - Stock Image - C012/4995 - Science PhotoStructural Biochemistry/Cell Organelles/Golgi ApparatusPlant Cells, illustration - Stock Image - C027/8490Why Is the Egg Larger Than the Sperm?Smooth ER (TEM) - Stock Image - C030/4818 - Science PhotoLeydig cell - Wikipedia