Pertainingtocells的简单介绍
pertaining
由于你没能满足我们的要求，请写另外一份有关该给定论题（的材料），并把它寄来供评估用。祝好运！Edmund-l
（pertain 变pertaining =有关，关于;适合...)
pertaining to与 be appropriate for的区别
pertaining to ?与...有关的，关于；属于
例句：
I?would?much?rather?that?you?asked?Mrs?Mei any?questionspertaining?to?herself.
我宁愿你问梅夫人的是与她本人相关的问题。
Requests and updates pertaining to the service and business related information are issued directly against the repositories.
根据资源库直接发布与服务和企业的相关信息有关的请求和更新。
The supplier must meet the minimum laws and requirements pertaining to working conditions and the working environment.
供应商必须符合与工作条件和工作环境有关的最低法定要求。
Two important concepts pertaining to a principal are keys and tickets.
与主体有关的两个重要概念是：密钥和票据。
We own the house and the land pertaining to it.
我们拥有这所房子和附属的土地。
be appropriate for ?对…适合；适用于...
例句：
This guideline might also be appropriate for other types of products.
本指南可能也适用于其他一些类型的产品。
It would not be appropriate for either interaction to be a part of the other one.
让其中的一个交互成为另一个交互的一部分并不合适。
The consistency of foods should be appropriate for the child's age.
食品的粘稠度应适合儿童年龄。
Consider whether this would be appropriate for your users before you assume that process dialogs are the correct solution.
不过在运用这种进度对话框之前，还是需要考虑它是否适合于你的用户。
Be sure to mention you still have to wear socks and dress must be appropriate for business.
务必要提到你们还是要穿袜子，而且服装是要适合上班场合穿的。
望采纳
pertain to与pertaining to什么区别
都是适合，关于，属于的意思，没有区别具体用哪个要看在句子中的成分。
求英语论文~~生物细胞有关的 150~200字
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of an organism that is classified as a living thing, and is often called the building block of life.[1] Some organisms, such as most bacteria, are unicellular (consist of a single cell). Other organisms, such as humans, are multicellular. (Humans have an estimated 100 trillion or 1014 cells; a typical cell size is 10 μm; a typical cell mass is 1 nanogram.) The largest known cell is an unfertilized ostrich egg cell.[2]
In 1835 before the final cell theory was developed, Jan Evangelista Purkyně observed small "granules" while looking at the plant tissue through a microscope. The cell theory, first developed in 1839 by Matthias Jakob Schleiden and Theodor Schwann, states that all organisms are composed of one or more cells, that all cells come from preexisting cells, that vital functions of an organism occur within cells, and that all cells contain the hereditary information necessary for regulating cell functions and for transmitting information to the next generation of cells.[3]
The word cell comes from the Latin cellula, meaning, a small room. The descriptive term for the smallest living biological structure was coined by Robert Hooke in a book he published in 1665 when he compared the cork cells he saw through his microscope to the small rooms monks lived in.[4]
[edit] General principles
Mouse cells grown in a culture dish. These cells grow in large clumps, but each individual cell is about 10 micrometres acrossEach cell is at least somewhat self-contained and self-maintaining: it can take in nutrients, convert these nutrients into energy, carry out specialized functions, and reproduce as necessary. Each cell stores its own set of instructions for carrying out each of these activities.
All cells have several different abilities:[5]
Reproduction by cell division: (binary fission/mitosis or meiosis).
Use of enzymes and other proteins coded for by DNA genes and made via messenger RNA intermediates and ribosomes.
Metabolism, including taking in raw materials, building cell components, converting energy, molecules and releasing by-products. The functioning of a cell depends upon its ability to extract and use chemical energy stored in organic molecules. This energy is released and then used in metabolic pathways.
Response to external and internal stimuli such as changes in temperature, pH or levels of nutrients.
Cell contents are contained within a cell surface membrane that is made from a lipid bilayer with proteins embedded in it.
Some prokaryotic cells contain important internal membrane-bound compartments,[6] but eukaryotic cells have a specialized set of internal membrane compartments.
[edit] Anatomy of cells
There are two types of cells: eukaryotic and prokaryotic. Prokaryotic cells are usually independent, while eukaryotic cells are often found in multicellular organisms.
[edit] Prokaryotic cells
Main article: Prokaryote
Diagram of a typical prokaryotic cellThe prokaryote cell is simpler than a eukaryote cell, lacking a nucleus and most of the other organelles of eukaryotes. There are two kinds of prokaryotes: bacteria and archaea; these share a similar overall structure.
A prokaryotic cell has three architectural regions:
on the outside, flagella and pili project from the cell's surface. These are structures (not present in all prokaryotes) made of proteins that facilitate movement and communication between cells;
enclosing the cell is the cell envelope – generally consisting of a cell wall covering a plasma membrane though some bacteria also have a further covering layer called a capsule. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, serving as a protective filter. Though most prokaryotes have a cell wall, there are exceptions such as Mycoplasma (bacteria) and Thermoplasma (archaea)). The cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and finally bursting (cytolysis) from osmotic pressure against a hypotonic environment. Some eukaryote cells (plant cells and fungi cells) also have a cell wall;
inside the cell is the cytoplasmic region that contains the cell genome (DNA) and ribosomes and various sorts of inclusions. A prokaryotic chromosome is usually a circular molecule (an exception is that of the bacterium Borrelia burgdorferi, which causes Lyme disease). Though not forming a nucleus, the DNA is condensed in a nucleoid. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular. Plasmids enable additional functions, such as antibiotic resistance.
[edit] Eukaryotic cells
Main article: Eukaryote
Diagram of a typical animal (eukaryotic) cell, showing subcellular components.
Organelles:
(1) nucleolus
(2) nucleus
(3) ribosome
(4) vesicle
(5) rough endoplasmic reticulum (ER)
(6) Golgi apparatus
(7) Cytoskeleton
(8) smooth endoplasmic reticulum
(9) mitochondria
(10) vacuole
(11) cytoplasm
(12) lysosome
(13) centrioles within centrosomeEukaryotic cells are about 15 times the size of a typical prokaryote and can be as much as 1000 times greater in volume. The major difference between prokaryotes and eukaryotes is that eukaryotic cells contain membrane-bound compartments in which specific metabolic activities take place. Most important among these is the presence of a cell nucleus, a membrane-delineated compartment that houses the eukaryotic cell's DNA. It is this nucleus that gives the eukaryote its name, which means "true nucleus." Other differences include:
The plasma membrane resembles that of prokaryotes in function, with minor differences in the setup. Cell walls may or may not be present.
The eukaryotic DNA is organized in one or more linear molecules, called chromosomes, which are associated with histone proteins. All chromosomal DNA is stored in the cell nucleus, separated from the cytoplasm by a membrane. Some eukaryotic organelles such as mitochondria also contain some DNA.
Many eukaryotic cells are ciliated with primary cilia. Primary cilia play important roles in chemosensation, mechanosensation, and thermosensation. Cilia may thus be "viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation."[7]
Eukaryotes can move using motile cilia or flagella. The flagella are more complex than those of prokaryotes.
Table 1: Comparison of features of prokaryotic and eukaryotic cells Prokaryotes Eukaryotes
Typical organisms bacteria, archaea protists, fungi, plants, animals
Typical size ~ 1–10 μm ~ 10–100 μm (sperm cells, apart from the tail, are smaller)
Type of nucleus nucleoid region; no real nucleus real nucleus with double membrane
DNA circular (usually) linear molecules (chromosomes) with histone proteins
RNA-/protein-synthesis coupled in cytoplasm RNA-synthesis inside the nucleus
protein synthesis in cytoplasm
Ribosomes 50S+30S 60S+40S
Cytoplasmatic structure very few structures highly structured by endomembranes and a cytoskeleton
Cell movement flagella made of flagellin flagella and cilia containing microtubules; lamellipodia and filopodia containing actin
Mitochondria none one to several thousand (though some lack mitochondria)
Chloroplasts none in algae and plants
Organization usually single cells single cells, colonies, higher multicellular organisms with specialized cells
Cell division Binary fission (simple division) Mitosis (fission or budding)
Meiosis
Table 2: Comparison of structures between animal and plant cells Typical animal cell Typical plant cell
Organelles Nucleus
Nucleolus (within nucleus)
Rough endoplasmic reticulum (ER)
Smooth ER
Ribosomes
Cytoskeleton
Golgi apparatus
Cytoplasm
Mitochondria
Vesicles
Lysosomes
Centrosome
Centrioles
Vacuoles
Nucleus
Nucleolus (within nucleus)
Rough ER
Smooth ER
Ribosomes
Cytoskeleton
Golgi apparatus (dictiosomes)
Cytoplasm
Mitochondria
[edit] Subcellular components
The cells of eukaryotes (left) and prokaryotes (right)All cells, whether prokaryotic or eukaryotic, have a membrane that envelops the cell, separates its interior from its environment, regulates what moves in and out (selectively permeable), and maintains the electric potential of the cell. Inside the membrane, a salty cytoplasm takes up most of the cell volume. All cells possess DNA, the hereditary material of genes, and RNA, containing the information necessary to build various proteins such as enzymes, the cell's primary machinery. There are also other kinds of biomolecules in cells. This article will list these primary components of the cell, then briefly describe their function.
[edit] Cell membrane: A cell's defining boundary
Main article: Cell membrane
The cytoplasm of a cell is surrounded by a cell membrane or plasma membrane. The plasma membrane in plants and prokaryotes is usually covered by a cell wall. This membrane serves to separate and protect a cell from its surrounding environment and is made mostly from a double layer of lipids (hydrophobic fat-like molecules) and hydrophilic phosphorus molecules. Hence, the layer is called a phospholipid bilayer. It may also be called a fluid mosaic membrane. Embedded within this membrane is a variety of protein molecules that act as channels and pumps that move different molecules into and out of the cell. The membrane is said to be 'semi-permeable', in that it can either let a substance (molecule or ion) pass through freely, pass through to a limited extent or not pass through at all. Cell surface membranes also contain receptor proteins that allow cells to detect external signaling molecules such as hormones.
[edit] Cytoskeleton: A cell's scaffold
Main article: Cytoskeleton
Bovine Pulmonary Artery Endothelial cell: nuclei stained blue, mitochondria stained red, and F-actin, an important component in microfilaments, stained green. Cell imaged on a fluorescent microscope.The cytoskeleton acts to organize and maintain the cell's shape; anchors organelles in place; helps during endocytosis, the uptake of external materials by a cell, and cytokinesis, the separation of daughter cells after cell division; and moves parts of the cell in processes of growth and mobility. The eukaryotic cytoskeleton is composed of microfilaments, intermediate filaments and microtubules. There is a great number of proteins associated with them, each controlling a cell's structure by directing, bundling, and aligning filaments. The prokaryotic cytoskeleton is less well-studied but is involved in the maintenance of cell shape, polarity and cytokinesis.[8]
[edit] Genetic material
Two different kinds of genetic material exist: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Most organisms use DNA for their long-term information storage, but some viruses (e.g., retroviruses) have RNA as their genetic material. The biological information contained in an organism is encoded in its DNA or RNA sequence. RNA is also used for information transport (e.g., mRNA) and enzymatic functions (e.g., ribosomal RNA) in organisms that use DNA for the genetic code itself. Transfer RNA (tRNA) molecules are used to add specific amino acids during the process of protein translation.
Prokaryotic genetic material is organized in a simple circular DNA molecule (the bacterial chromosome) in the nucleoid region of the cytoplasm. Eukaryotic genetic material is divided into different, linear molecules called chromosomes inside a discrete nucleus, usually with additional genetic material in some organelles like mitochondria and chloroplasts (see endosymbiotic theory).
A human cell has genetic material in the nucleus (the nuclear genome) and in the mitochondria (the mitochondrial genome). In humans the nuclear genome is divided into 23 pairs of linear DNA molecules called chromosomes. The mitochondrial genome is a circular DNA molecule distinct from the nuclear DNA. Although the mitochondrial DNA is very small compared to nuclear chromosomes, it codes for 13 proteins involved in mitochondrial energy production as well as specific tRNAs.
Foreign genetic material (most commonly DNA) can also be artificially introduced into the cell by a process called transfection. This can be transient, if the DNA is not inserted into the cell's genome, or stable, if it is. Certain viruses also insert their genetic material into the genome.
[edit] Organelles
Main article: Organelle
The human body contains many different organs, such as the heart, lung, and kidney, with each organ performing a different function. Cells also have a set of "little organs," called organelles, that are adapted and/or specialized for carrying out one or more vital functions.
There are several types of organelles within an animal cell. Some (such as the nucleus and golgi apparatus) are typically solitary, while others (such as mitochondria, peroxisomes and lysosomes) can be numerous (hundreds to thousands). The cytosol is the gelatinous fluid that fills the cell and surrounds the organelles.
Mitochondria and Chloroplasts – the power generators
Mitochondria are self-replicating organelles that occur in various numbers, shapes, and sizes in the cytoplasm of all eukaryotic cells. Mitochondria play a critical role in generating energy in the eukaryotic cell. Mitochondria generate the cell's energy by the process of oxidative phosphorylation, utilizing oxygen to release energy stored in cellular nutrients (typically pertaining to glucose) to generate ATP. Mitochondria multiply by splitting in two.
Organelles that are modified chloroplasts are broadly called plastids, and are involved in energy storage through the process of photosynthesis, which utilizes solar energy to generate carbohydrates and oxygen from carbon dioxide and water.[citation needed]
Mitochondria and chloroplasts each contain their own genome, which is separate and distinct from the nuclear genome of a cell. Both of these organelles contain this DNA in circular plasmids, much like prokaryotic cells, strongly supporting the evolutionary theory of endosymbiosis; since these organelles contain their own genomes and have other similarities to prokaryotes, they are thought to have developed through a symbiotic relationship after being engulfed by a primitive cell.[citation needed]
Ribosomes
The ribosome is a large complex of RNA and protein molecules. They each consist of two subunits, and act as an assembly line where mRNA from the nucleus is used to synthesise proteins from amino acids. Ribosomes can be found either floating freely or bound to a membrane (the rough endoplasmatic reticulum in eukaryotes, or the cell membrane in prokaryotes).[9]
Cell nucleus – a cell's information center
The cell nucleus is the most conspicuous organelle found in a eukaryotic cell. It houses the cell's chromosomes, and is the place where almost all DNA replication and RNA synthesis (transcription) occur. The nucleus is spherical in shape and separated from the cytoplasm by a double membrane called the nuclear envelope. The nuclear envelope isolates and protects a cell's DNA from various molecules that could accidentally damage its structure or interfere with its processing. During processing, DNA is transcribed, or copied into a special RNA, called mRNA. This mRNA is then transported out of the nucleus, where it is translated into a specific protein molecule. The nucleolus is a specialized region within the nucleus where ribosome subunits are assembled. In prokaryotes, DNA processing takes place in the cytoplasm.
Diagram of a cell nucleus
Endoplasmic reticulum – eukaryotes only
The endoplasmic reticulum (ER) is the transport network for molecules targeted for certain modifications and specific destinations, as compared to molecules that will float freely in the cytoplasm. The ER has two forms: the rough ER, which has ribosomes on its surface and secretes proteins into the cytoplasm, and the smooth ER, which lacks them. Smooth ER plays a role in calcium sequestration and release.
Golgi apparatus – eukaryotes only
The primary function of the Golgi apparatus is to process and package the macromolecules such as proteins and lipids that are synthesized by the cell. It is particularly important in the processing of proteins for secretion. The Golgi apparatus forms a part of the endomembrane system of eukaryotic cells. Vesicles that enter the Golgi apparatus are processed in a cis to trans direction, meaning they coalesce on the cis side of the apparatus and after processing pinch off on the opposite (trans) side to form a new vesicle in the animal cell.[citation needed]
Diagram of an endomembrane system
Lysosomes and Peroxisomes – eukaryotes only
Lysosomes contain digestive enzymes (acid hydrolases). They digest excess or worn-out organelles, food particles, and engulfed viruses or bacteria. Peroxisomes have enzymes that rid the cell of toxic peroxides. The cell could not house these destructive enzymes if they were not contained in a membrane-bound system. These organelles are often called a "suicide bag" because of their ability to detonate and destroy the cell.[citation needed]
Centrosome – the cytoskeleton organiser
The centrosome produces the microtubules of a cell – a key component of the cytoskeleton. It directs the transport through the ER and the Golgi apparatus. Centrosomes are composed of two centrioles, which separate during cell division and help in the formation of the mitotic spindle. A single centrosome is present in the animal cells. They are also found in some fungi and algae cells.[citation needed]
Vacuoles
Vacuoles store food and waste. Some vacuoles store extra water. They are often described as liquid filled space and are surrounded by a membrane. Some cells, most notably Amoeba, have contractile vacuoles, which are able to pump water out of the cell if there is too much water.
[edit] Structures outside the cell wall
[edit] Capsule
A gelatinous capsule is present in some bacteria outside the cell wall. The capsule may be polysaccharide as in pneumococci, meningococci or polypeptide as bacillus anthracis or hyaluronic acid as in streptococci.[citation needed] Capsules not marked by ordinary stain and can detected by special stain. The capsule is antigenic. The capsule has antiphagocytic function so it determines the virulence of many bacteria. It also plays a role in attachment of the organism to mucous membranes.[citation needed]
有关英语问题－克隆人与克隆羊
Use of Cloning Technology to Clone a Human Being
As a consequence of scientific and biotechnological progress during the past decades, new biological therapies involving somatic cells and genetic material are being investigated. The Food and Drug Administration (FDA) described existing legal authorities governing a new class of human somatic cell therapy products and gene therapy products in an October 14, 1993 Federal Register Notice.
On February 23, 1997, the public learned that Ian Wilmut, a Scottish scientist, and his colleagues at the Roslin Institute successfully used a technique called somatic cell nuclear transfer (SCNT) to create a clone of a sheep; the cloned sheep was named Dolly. SCNT involves transferring the nucleus of an adult sheep somatic cell, into a sheep egg from which the nucleus had been removed. After nearly 300 attempts, the cloned sheep known as Dolly was born to a surrogate sheep mother.
SCNT is not reproduction since a sperm cannot be used with the technique, but rather it is an extension of technology used not only in research but also used to produce medically relevant cellular products such as cartilage cells for knees, as well as gene therapy products. On February 28, 1997, FDA announced a comprehensive plan for the regulation of cell and tissue based therapies that incorporated the legal authorities described in FDA's 1993 guidance Proposed Approach to Regulation of Cellular and Tissue-Based Products
On March 7, 1997 then President Clinton issued a memorandum that stated: "Recent accounts of advances in cloning technology, including the first successful cloning of an adult sheep, raise important questions. They potentially represent enormous scientific breakthroughs that could offer benefits in such areas as medicine and agriculture. But the new technology also raises profound ethical issues, particularly with respect to its possible use to clone humans." (Prohibitions on Federal Funding for Cloning of Human Beings)
The memorandum explicitly prohibited Federal Funding for cloning of a human being, and also directed the National Bioethics Advisory Commission (NBAC) to thoroughly review the legal and ethical issues associated with the use of cloning technology to create a human being.
"NBAC found that concerns relating to the potential psychological harms to children and effects on the moral, religious, and cultural values of society merited further reflection and deliberation." The report, Ethical Issues in Human Stem Cell Research, September 1999, describes 5 recommendations.
Somatic cell nuclear transfer holds great potential to someday create medically useful therapeutic products. FDA believes, however, that there are major unresolved questions pertaining to the use of cloning technology to clone a human being which must be seriously considered and resolved before the Agency would permit such investigation to proceed. The Agency sent a "Dear Colleague" letter which stated that creating a human being using cloning technology is subject to FDA regulation under the Public Health Service Act and the Food Drug and Cosmetic Act. This letter notified researchers that clinical research using SCNT to create a human being could precede only when an investigational new drug application (IND) is in effect. Sponsors are required to submit to FDA
Recently, FDA sent letters to remind the research community that FDA jurisdiction over clinical research using cloning technology to create a human being, and to advise that FDA regulatory process is required in order to initial these investigations. (March 2001 letter - PDF, Text)
On March 28, 2001, Dr. Kathryn C. Zoon, Director, Center for Biologics Evaluation and Research gave testimony before the Subcommittee on Oversight and Investigations Committee on Energy and Commerce, United States House of Representatives. Her statement described FDA's role in regulating the use of cloning technology to clone a human being and further described current significant scientific concerns in this area.
参考
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Clone (genetics)
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In genetics, a clone is a replica of all or part of a macromolecule (eg. DNA). Cloning a gene means to extract a gene from one organism (for example by PCR) and insert it into a second organism (usually via a vector), where it can be used and studied.
Cloning a gene sometimes can refer to success in identifying a gene associated with some phenotype. For example, when biologists say that the gene for disease X has been cloned, they mean that the gene's location and DNA sequence has been identified, although the ability to specifically copy the physical DNA is a side-effect of its identification. A related technique called subcloning refers to transferring a gene from one plasmid into another for further study.
pertaining to一般是在修饰语前还是后
pertaining to，适合，合宜；与…有关
Any beast that comes from the sea therefore must have to do with something pertaining to the unknown.
任何的野兽都是来自海洋，因此肯定有 一些附属的不为人知的事情。
现在分词短语作定语，放在修饰词后面，比如上式中修饰something。