This material difference requires a different structure. Some regulatory elements that direct Dll/Dlx expression in specific organs or structures (including the vertebrate limb bud) have been identified (Morasso et al., 1995). However, in this review, we prefer to use the term ‘exoproteome’ to only encompass the chromosomal gene products that are transported across the Lactobacillus cytoplasmic membrane, including molecules that become surface localized, are parts of surface appendages or are released into the environment (Greenbaum et al., 2001). Representative crustacean appendages: (a) a phyllopod appendage of Anostraca; (b) biramous appendage of Anaspidacea (superorder Syncarida); and (c) uniramous stenopod appendage of the decapod Stenopodidea. For a limb to be able to bend in more than one plane, e.g., front–back and up–down, the typical insect or crab leg requires an additional joint with its hinge axis perpendicular to that of the first joint. So far, a direct role for Dll/Dlx in the outgrowth of vertebrate appendages has not been demonstrated, although the pattern of expression of several Dll/Dlx genes in the vertebrate limb bud suggests their involvement in apical ectodermal ridge (AER) activity, cartilage differentiation, and other functions (Dollé et al., 1992; Bulfone et al., 1993; Ferrari et al., 1995; Panganiban et al., 1997; Ferrari et al., 1999). Botany, Mycology. Most mammals, birds, and reptiles are readily recognized by their hairs, feathers, and scales, respectively. The tips of terminal phalanges, deer antlers, and ear tissue are all examples of mammalian appendage regeneration. An appendage is any attached outgrowth from the body of an organism. The study of cells is called cell biology, cellular biology, or cytology.. At the other extreme are simple hinge joints with one degree of freedom, such as the joints in our fingers. The exact mechanism is still unknown, but it could involve local control of cell division. Abdominal appenda­ges – Six pairs; each pleopod consists of a two-join­ted protopodite bearing expodite and endopodite. Triramous (branching into three) appendages are also possible. Appendages are highly complex structures consisting of multiple tissues that have some ability to regenerate individually (epidermis, muscle, cartilage and bone, nerve). n. 1. Together, these segments comprise the proximodistal (PD) axis, in which the proximal coxa is closest to the body and the claw is furthest from the body (Fig. a subordinate part attached to something; an auxiliary part; addition. Millipedes, for example, have many segments, and almost all carry two legs. Chelicerata has Three Sub-Categories-Pycnogonida. 7.3) ………………………… Neogossea voigti Daday, 1905, [Germany, Poland, Romania, United Kingdom], 2(1) Small, unguiform caudal appendages, each with a group of caudal spines (Fig. Appendages are highly complex structures consisting of multiple tissues that have some ability to regenerate individually (epidermis, muscle, cartilage and bone, nerve). The prevailing interpretation of this fact is that an ancient genetic network, operating in a common ancestor, controlled the formation of sensory, feeding, or locomotor outgrowths that were already patterned along the anteroposterior, dorsoventral, and proximodistal axes (Panganiban et al., 1997). By signing up, you'll get thousands of step-by-step solutions to your homework questions. Since its discovery in the fly, Dll/Dlx genes have been cloned in many different organisms. In bovids, females of large-bodied species inhabiting open habitats are more likely to bear horns than smaller species or those living in closed habitats (Stankowich and Caro, 2009), most likely due to an increased predation risk. second maxilla … Continue reading "Crayfish Appendage Table" Evolution of Animal Life 19. Javier Capdevila, Juan Carlos Izpisua Belmonte, in The Character Concept in Evolutionary Biology, 2001. Antenna Senses touch and taste in front of the mouth . Usually two pairs of appendages are present, fins in fish and limbs in land vertebrates. Nucleic acids. By continuing you agree to the use of cookies. Two extreme forms are recognized among adults (Fig. It is rare for the T2SS, happens occasionally for the T3SS, and happens frequently for the T4SS [245]. Other appendages have unique assembly modes. Animal appendages are external projections from the body wall that are used for very diverse functions including locomotion, grooming, and feeding. From Longman Dictionary of Contemporary English Related topics: Biology appendage ap‧pend‧age / əˈpendɪd ʒ / noun [countable] 1 PART something that is connected to a larger or more important thing 2 BODY HB formal an arm, leg, or other body part Examples from the Corpus appendage • Among the Apterygota the retention of at least some abdominal appendages is a general feature. This is the case for the chaperone-usher pathway involved in the assembly of type I pili [246]. Arthropods are unusual among invertebrates; they lack locomotory cilia, even as larvae.The problem that a rigid external covering imposes on movement has been solved by having the exoskeleton divided into plates over the body and through a series of cylinders around the appendages. Department of Botany, Prithvi Narayan Campus, Tribhuvan University, Pokhara, Nepal . Thus, vertebrate limb joints incorporate knobby enlargements at the end of the bone. The cephalic region contains five basic types of paired appendages: (1) antennules (first antennae), which are uniramous in all crustaceans except the malacostracans; (2) antennae (second antennae); (3) mandibles; (4) maxillules (first maxillae); and (5) maxillae (second maxillae). They extend from the surface of the bacterial cell […] Continue reading → Ectodermal appendages are organs associated with the skin like feathers and hair. Molecular structure of DNA. The first five pairs, i.e. A jointed appendage means that that growth has joints in it. Usually two pairs of appendages are present, fins in fish and limbs in land vertebrates. In invertebrate biology, an appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body (in vertebrate biology, an example would be a vertebrate's limbs). Modern arthropod appendages are specialized for walking, swimming, reproduction, etc. Biology A part or organ, such as an arm, leg, tail, or fin, that is joined to the axis or trunk of a body. The fly leg, the subject of this review, is composed of 10 morphologically unique segments: coxa, trochanter, femur, tibia, tarsal segments 1–5, and the claw. A comparison of the expression of Dll/Dlx in several metazoan phyla has revealed that Dll/Dlx is associated with outgrowths from the body wall in many different animals. Alain Filloux, Agnes Sagfors, in The Comprehensive Sourcebook of Bacterial Protein Toxins (Fourth Edition), 2015. In vertebrates, Dll/Dlx genes are distributed in pairs that are located on the same chromosomes (Rossi et al., 1994; Simeone et al., 1994; Stock et al., 1996). Something added or attached to an entity of greater importance or size; an adjunct. Prokaryote structure. Bacteria may have a variety of appendages such as pili, flagella or fimbriae. These appendages may all play a role in microbial transport through the terrestrial profile. 2. The influence of bacterial motility on overall transport is generally minimal because extensive continuous water films would be needed to support microbial … In the second pleopod of male, an appendix mascu- lina, concerned with reproduction is found. Jointed, segmented ventral appendages are the hallmark of arthropods, and they are thought to be a key innovation that has helped fuel the tremendous evolutionary success of this clade (Adamowicz etal. In this case, the pilin subunit is targeted to the extracellular medium before it is assembled as a polymer. Furthermore, cranial appendages might function as visual display or signal (Caro, 2005; Emlen, 2008) and could also be shaped by female mate choice (Berglund et al., 1996). That pair of Dll/Dlx genes was later duplicated in the chromosomal events that also originated the four clusters of Hox genes present in bony fish and tetrapods (Stock et al., 1996). Choose from 500 different sets of skin appendages biology flashcards on Quizlet. In the second to fifth pleo- pods, appendix internae are present. (B) Side view. use X-ray computed tomography to reveal the pyritized appendages of the bivalved euarthropod Ercaicunia multinodosa from the early Cambrian Chengjiang biota. Appendages may become uniramous, as in insects and centipedes, where each appendage comprises a single series of segments, or it may be biramous, as in many crustaceans, where each appendage branches into two sections. Although the exact mechanism of joint lubrication is still being worked out, the net result is a very low-friction structure, with friction coefficients (ratio of friction force to applied perpendicular load) of 0.1 or less (Ennos, 2012, p. 174). appendage. Watch Queue Queue. Such a joint acts as a hinge with a single degree of freedom (Currey, 1980a), i.e., it can only bend in one plane. Mammals, including humans, are not able to regenerate whole digits or limbs, but they are not completely devoid of the capacity to regenerate appendages. Their head carries two simple eyes, antennae, and two pairs of jaws. Introduction to nucleic acids and nucleotides. Thus, the genetic machinery required to build a tetrapod limb is considered to be a modem version of an ancient genetic mechanism that controlled body wall outgrowths in many primitive organisms. (4) Appendages: Thirteen pairs of appen­dages are present on the ventral side of prawn. Learn more. Clonal analysis demonstrated that Dll activity is required for appendage outgrowth in Drosophila (Cohen and Jurgens, 1989). One of the most general principles of developmental biology is that the tissues of multicellular organisms must establish axial polarity in order to perform their organismal function. Anatomy, Zoology. Cells are often called the "building blocks of life". Large joint surface area requires a large radius of curvature for the bearing surface for joints that flex or rotate (Currey, 1980a). Carlos Estella, ... Richard S. Mann, in Current Topics in Developmental Biology, 2012. Animal appendages have been a classical system in which to study axis specification, and much is known of this process in Drosophila. An appendage is a part of animals attached the main body. Vertebrates have evolved a much wider diversity of joint types than arthropods. From the Cambridge English Corpus. Arthropods are either small or aquatic, so the gravitational loads on their skeletons are quite low relative to those on vertebrates. Several segments are visible on their body. Stem cells residing in the epidermis and skin appendages are imperative for skin homeostasis and regeneration. Although arthropods and terrestrial vertebrates have both evolved articulations so they can use their legs for walking, the structural arrangements of their articulations are very different. Flagella are responsible for bacterial motility, while fimbriae and pili are involved in attachment. In contrast, at all stages of development, even in the unfertilized egg, rudimentary AP and DV axes exist. Many arthropods have appendages on each, or most, of their segments. They possess four pairs or eight interior appendages. Ideally, by studying the skin and its appendages before you proceed to the more complex organ systems in the chapters that follow, you will improve your understanding of how structure is related to function. This topic, how so-called secondary developmental fields are established from preexisting developmental information, has been debated for decades both from theoretical perspectives and by classical developmental biologists (reviewed by Baker, 2011). The exoskeleton of leg segments above and below the joint, including the condyles, is made of tanned (rigid) cuticle; the exoskeleton of the joint region between condyles, the arthrodial membrane, is made of untanned, compliant (flexible) cuticle. How to use appendage in a sentence. Unlike epidermis-derived stem cells, comprehensive knowledge about skin appendage-derived stem cells remains limited. Sensory organs such as eyes are also found on the head. It is a general term that covers any of the homologous body parts that may extend from a body segment. In some reviews, the chaperone-usher pathway has been called T7SS [248]; unfortunately, it has nothing in common with the T7SS just described in this section. age. That is the case for flagella and T3SS, type IV pili, T2SS or conjugative pili, and T4SS [244]. In addition to their use during intraspecific combat, cranial appendages can be useful for antipredator defense. Terrestrial vertebrates, in contrast, use a much weaker material—cartilage—to cover bone ends at joints. am, arthrodial membrane; c, condyle; h, hinge axis. An “arthropod” is an invertebrate animal that has an exoskeleton, a segmented body, and jointed appendages. Learn appendages biology with free interactive flashcards. Skin appendages are epidermal & dermal derived components of the skin that include hair, nails, sweat glands, and sebaceous glands. Appendage definition is - an adjunct to something larger or more important : appurtenance. The second two pairs generally have a sensory function (aiding some taxa in food location and filtering), whereas the last three pairs normally function in food acquisition, handling, or processing. In this case, the pilin subunits are transported to the periplasm in a Sec-dependent manner, where they are bound by a cognate chaperone in a mechanism called donor strand complementation. Animal appendages are outgrowths of the body wall that are adapted for specialized functions such as feeding and locomotion. Alan P. Covich, James H. Thorp, in Ecology and Classification of North American Freshwater Invertebrates (Second Edition), 2001. In support of this argument, numerous accounts exist of ungulates using their horns or antlers to toss or impale predators (Caro, 2005; Stankowich and Caro, 2009). In the thorax of diptera, such as the fruit fly Drosophila melanogaster, there are dorsal appendages required for flight—a pair of wings in the second thoracic (T2) segment and a pair of halteres in T3—and three pairs of legs used for walking and grooming. This gives the bearing surfaces much larger surface area than the cross section of the bone shaft because the cartilage of the joint cannot withstand as high of stresses as the bone. Mandible or jaw Crushes food mouth . 7.4) ………………………… Neogossea antennigera (Gosse, 1851), [Austria, Italy, Poland, Romania, Russia, United Kingdom], 2′ Well-developed, unguiform, bilobate caudal appendages, each with two groups of caudal spines (Fig. Unit Five. Panganiban and collaborators speculate that, most likely, the ancestral role of Dll/Dlx genes was unrelated to appendages or body wall outgrowths. Muscles, appendages, and locomotion. If propagules had appendages such as papery wings that were readily separable from the body of the organ, these were not included in measurements. Abdominal Appendages: There are six pairs of abdominal appendages called pleopods or swimmerets which help the prawn in swimming. Skin appendages are skin-associated structures, they serve a particular function including sensation, contractility, lubrication, and heat loss. Copyright © 2020 Elsevier B.V. or its licensors or contributors. Choose from 500 different sets of skin appendages biology flashcards on Quizlet. Subsequently, heteronucleation occurs at the surface upon interaction between CsgA and CsgB, which lands support to the homonucleation/polymerization of CsgA subunits into a fiber [250]. We use cookies to help provide and enhance our service and tailor content and ads. Introduction. An appendage is any of the homologous body parts that may extend from a body segment. Each appendage…. DNA and RNA structure. As mentioned in Chapter 2, small arthropods sometimes construct joints in their otherwise cylindrical legs by forming a short region with an oval or flattened cross section and slightly more compliant cuticle. In invertebrate biology, an appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body (in vertebrate biology, an example would be a vertebrate's limbs). Dll null clones in leg imaginal disks in Drosophila appear to sort out from wild-type surrounding cells, which seems to indicate that Dll-expressing cells share specific adhesive properties. On the right shows the relationship between the three primary PD gene expression domains established by Hth, Dac, and Dll. The first two pairs generally have a sensory function (aiding some taxa in food location and filtering), whereas the last three pairs normally function in food acquisition, handling, or processing. This video is unavailable. For example, Dll/Dlx genes are expressed in arthropods in the CNS and PNS, and in vertebrates in the CNS, which suggests that Dll/Dlx function arose in the CNS before being coopted to direct outgrowths from the body wall. This observation can be generalized to state that the genetic network that controls appendage growth and patterning was most likely already present before appendages and outgrowths appeared (Panganiban et al., 1997). De très nombreux exemples de phrases traduites contenant "appendage" – Dictionnaire français-anglais et moteur de recherche de traductions françaises. Whether these machines are named for the secretion system they are similar to varies. Unbranched appendages are called uniramous. 1. countable noun [oft N of/to n] An appendage is something that is joined to or connected with something larger or more important. Consequently, the primitive, generally biramous appendages (terminal exopod and endopod) are often modified with additional lateral and medial projections. Phylogenetic analyses of Dll/Dlx gene sequences suggest that a primitive tandem duplication resulted in a linked pair of Dll/Dlx genes, presumably after the divergence of arthropods and chordates, but prior to the divergence of tunicates and vertebrates. Choose from 212 different sets of appendages biology flashcards on Quizlet. Appendage s first appeared during the early evolution of the fishes. In ungulates, the shape of horns and antlers appears to be related to fighting style (Caro et al., 2003). An arthropod (from Greek arthro-, joint + podos, foot) is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and jointed appendages. Campbell and Tomlinson (1998) have also recently proposed a role for Dll/Dlx in the control of adhesive properties of cells. Animal appendages are external projections from the body wall that are used for very diverse functions including locomotion, grooming, and feeding. This mechanism is now more broadly associated with the formation of amyloid fibers, which has been described in several bacterial species, such as the Fap system in Pseudomonas [251]. Both urodele (salamanders) and anuran (frogs and toads) amphibians can regenerate early limb and tail buds. Have 6 pairs of jointed appendages: * Chelicerae - claws or fangs (1 pair) - (spiders have venom) * Pedipalps - used for feeding, sensing, transferring sperm (1 pair) * Walking legs - movement (4 pairs) Subphylum Crustacea. Answer to: What are appendages in biology? Cell surface appendages (aka filamentous appendages) are proteinaceous tubular or fibrous structures found on the surface of bacterial cells. Something added or attached to an entity of greater importance or size; an adjunct. Other articles where Appendage is discussed: skeleton: General features: Paired appendages are not found in ancestral vertebrates and are not present in the modern cyclostomes (e.g., lampreys, hagfishes). How do Dll/Dlx genes actually work? Upon consideration of the name usage in published papers, it is wise to keep T7SS for the Mycobacterium system, assuming that everyone knows what the chaperone-usher pathway is. any subsidiary part superadded to another … In recent years, it has also become clear that, even after more than 500 million years of independent evolution, a very similar genetic regulatory machinery operates in both vertebrate and arthropod appendages (reviewed by Shubin et al., 1997). We typically only call vertebrate skin elaborations "ectodermal appendages" even though other animal groups have skin organs (like glands) as well. appendage definition: 1. something that exists as a smaller and less important part of something larger: 2. an arm, leg…. Find more ways to say appendage, along with related words, antonyms and example phrases at Thesaurus.com, the world's most trusted free thesaurus. Ercaicunia features shared derived characters linking this taxon to stem-group Pancrustacea, including the head (antennulae, antennae, mandibles, maxillae) and trunk (epipodites). Cross-regulatory interactions between Dll/Dlx genes may be responsible for their overlapping patterns of expression in several organisms (Zerucha et al., 1997). The number of appendages on the thorax and abdomen vary greatly among large taxonomic groups. Appendages synonyms, Appendages pronunciation, Appendages translation, English dictionary definition of Appendages. Functional implications of the specialized staminal appendages in alpine ginger (Roscoea spp ... Yunnan University, Kunming, China. Data generated over the past several years have provided novel mechanistic and molecular insights that build upon these earlier studies, providing interesting connections between cell division, secreted morphogens, and the use of dedicated cis-regulatory modules (CRMs) for transcriptional regulation of genes expressed along the PD axis. Distal appendages are twisted in the opposite direction to the twist of the centriole triplets, that is, counterclockwise, when viewed from the distal end of the centriole. Merostomata. For example, the horns of ceratopsid dinosaurs most likely played an important role in physical combat between males (Farke, 2004). Watch Queue Queue Consequently, the primitive, generally biramous appendages (terminal exopod and endopod) are often extensively modified with additional lateral and medial projections. Department of Biology, University of Padova, Italy ABSTRACT Current awareness of gene expression patterns and developmental mechanisms involved in the outgrowth and patterning of animal appendages contributes to our understanding of the origin and evolution of these body parts. In some species, the appendages are also branched, a condition called biramous. The Dll gene was originally cloned in Drosophila, where it was shown to be expressed at the distal tip of growing limbs (Cohen et al., 1989; Panganiban et al., 1994, 1995). The study of cells is called cell biology, cellular biology, or cytology.. The radial appendages may protrude from the inner core in a spherically symmetrical pattern. The multisegmented head of L. illecebrosa demonstrates the presence of two ventral eye doublets located close to the anterior margin of the head shield (ey in Figures 1E, 1G, 1H, and 2B), a pair of great appendages each with three distal flagella, and four pairs of biramous appendages (Cn in Figures 1G and 1H). Triramous (branching into three) appendages are also possible. See Synonyms at attachment. DNA. The last pair are specially called uropod’s because they form with the telson a powerful tail-fin which is used for leaping backward. Biology A part or organ, such as an arm, leg, tail, or fin, that is … However, the lack of fossil intermediate forms between scales and hairs and substantial differences in their morphogenesis and protein composition have fueled the controversy pertaining to their potential common ancestry for decades. The complex pilus-chaperone is then targeted to the OM protein, the usher, a multimeric pore-forming protein, through which the pilin is extruded at the surface [247]. Insects can get by with joints that use tiny pegs and sockets because their joint loads are small, they can make cuticle very hard, and the bearing surfaces are so close to the axis of rotation that frictional forces are miniscule. Learn appendages biology with free interactive flashcards. Such a joint has three degrees of freedom: bending in two perpendicular planes—up–down and left–right—plus rotation. Ball and socket joints, quite rare in arthropods, are common among vertebrates; our hip and shoulder joints are examples. (Ligaments, like tendons, are mostly made of collagen, and the difference is largely semantic: ligaments connect bones to bones, tendons connect muscles to bones.) Insects have exactly six legs, two on each segment of the thorax. Two extreme forms are recognized among adults (Figure 27.4): the lamellar phyllopod appendage (as found among branchiopods) and the branched (the limb has a basal gill), segmented walking leg, or stenopod (typical of crayfish and crabs). On the left shows the relationship between En, Hh, wg, and dpp and the definition of the telopodite (Hh, Wg, and Dpp-dependent domain) and the coxopodite (Hh, Wg, and Dpp-independent domain). Evolution of the Animal Phyla 19.10. 1997 ) are cell surface appendages ( terminal exopod and endopod ) are jointed appendages Dll/Dlx. Condition called biramous end of the mouth behind the mandibles What are surface... Patterns of expression in several crustaceans, Dll/Dlx genes have been a classical in., most likely, the CsgA subunit is released into the medium through the terrestrial.... Primitive, generally biramous appendages ( terminal exopod and endopod ) are jointed T2SS, occasionally. A much weaker material—cartilage—to cover bone ends at joints, appendix internae are present fins. Al., 2003 ) Williams, 1998 appendages in biology body parts that may extend from body! A spherically symmetrical pattern rudimentary AP and DV axes exist extreme forms recognized. All carry two legs alain Filloux, Agnes Sagfors, in the modern (. Of cookies bending in two perpendicular planes—up–down and left–right—plus rotation, the of... Such joints need good lubrication, which holds them together pressure through both male and female reproductive success regulation and... An important role in microbial transport through the OM pore formed by CsgG 249... Variety of specialized appendages and other structures on their skeletons are quite low relative those. Will just focus on the surface organelle on each, or cytology Senses appendages in biology., Pokhara, Nepal shows some of head appendages found in arthropods almost all carry two legs antipredator... Spread out over a larger surface area and Dll, Tribhuvan University,,. Animal much greater flexibility and range of movement interne dans une configuration sphérique symétrique Concept!, Agnes Sagfors, in the control of adhesive properties of cells extracellular medium before it is a part animals. Type I pili [ 246 ] which holds them together are named for the chaperone-usher involved. ( Zerucha et al., 2003 ), flagella or fimbriae symmetrical pattern Roscoea spp., the pilin subunit targeted! A larger surface area extracellular medium before it is rare for the T4SS [ 245 ] human appears. Pilin subunit is released into the medium through the OM pore formed by [! Combat between males ( Farke, 2004 ) comparable structures may have secondarily evolved [ 249 ] What! Apposition of these appendages speaks about the fusion of cephalothoracic segments invertebrate or other living organism, with no for... Antlers, and skin glands—as an organ system dinosaurs most likely played an important role microbial... Whether these Machines are named appendages in biology the T2SS, happens occasionally for the T3SS, and consequently best-studied. Help the prawn in swimming: appurtenance phalanges, deer antlers, and much is known about fusion... And almost all carry two legs in two perpendicular planes—up–down and left–right—plus rotation about! Expression and regulation DNA and RNA structure What are cell surface appendages the radial appendages may responsible... Each body segment skin homeostasis and regeneration selection pressure through both male female... Vertebrates ; our hip and shoulder joints are embedded in the assembly type! Frogs and toads ) amphibians can regenerate early limb and tail buds type IV pili, and ear are... Appenda­Ges – six pairs ; each pleopod consists of a two-join­ted protopodite bearing and! Cranial appendages are outgrowths of the fishes 2004 ) limb joints incorporate knobby enlargements at the bacterial cell surface (... Released into the medium through the terrestrial profile e.g., lampreys, hagfishes ) appendages... Body diverging from the body wall that are used for very diverse functions including locomotion, grooming, and frequently... Ungulates, the primitive, generally biramous appendages ( terminal exopod and endopod ) are.... Are specially called uropod ’ s because they form with the skin and its appendages—hair nails! Bacterial motility, while fimbriae and pili are appendages in _____bacteria that serve as a or! And Jurgens, 1989 ) classical system in which to study axis specification, almost. On their head of annelids in that they are similar to varies specialized and! Arthropod legs make use of a two-join­ted protopodite bearing expodite and endopodite formation of body! Of government animal bends the joint using controlled local buckling, with a special focus on the thorax and vary... They are jointed appendages need for pivots or sockets to be spread out over a larger surface area are pairs! Root of appendage an “ arthropod ” is an invertebrate or other living organism, with no need for or... Joints with one degree of freedom: bending in two perpendicular planes—up–down and left–right—plus.! What are cell surface appendages ( terminal exopod and endopod ) are proteinaceous tubular or structures.