在线观看亚洲精品专区-在线观看亚洲免费-在线观看亚洲免费视频-在线观看亚洲欧美-欧美freexxx-欧美free嫩交video

食品伙伴網(wǎng)服務(wù)號
 
 
當(dāng)前位置: 首頁 » 專業(yè)英語 » 專業(yè)知識 » 正文

微生物學(xué)教案 Chapter 5 Nurtution of Microbes(微生物的營養(yǎng))

放大字體  縮小字體 發(fā)布日期:2005-06-01  來源:華南師大

Chapter5 Nurtution of Microbes

第5章 微生物的營養(yǎng)

CHEMICAL REQUIREMENTS         

1.     Microorganisms require a carbon source; chemoheterotrophs use an organic molecule, and autotrophs typcally use carbon dioxide.

2.     Nitrogen is needed for protein and nucleic acid synthesis. Nitrogen can be obtained from decomposition of proteins or from NH4+ or NO3-; a few bacteria are able to fix N2.

3.     Water is also necessary to the growth of all microorganisms.

4.     Other chemicals required for microbial growth include iroganic salt(sulfur, phosphorus, and some trace elements), and, for some microorganisms, organic growth factors.

MOVEMENT OF MATERIALS ACROSS MEMBRANES

1.      1Movement across the membrane may be by passive processes, in which materials move from higher to lower concentration and no energy is expended by the cell.

2.      In simple diffusion, molecules and ions move until equilibrium is reached.

3.      In facilitated diffusion, substances are transported by permeases across membranes from high to low concentration.

4.      Osmosis is the movement of water from high to low concentration across a selectively semipermeable membrane until equilibrium is reached.

5.      In active transport, materials move from low to high concentrations by permeases, and the cell must expend energy.

6.      In group translocation, energy is expended to modify chemicals and transport them across the membrane.

Culture Media

1.      A culture medium is any material prepared for the growth of bacteria in a laboratory.

2.      Microbes that grow and multiply in or on a culture medium are known as a culture.

3.      Agar is a common solidifying agent for a culture medium.

CHEMICALLY DEFINED MEDIA

A chemically defined medium is one in which the exact chemical composition is known.

COMPLEX MEDIA

1. A complex medium is one in which the exact chemical composition is not known.

ANAEROBIC GROWTH MEDIA AND METHODS

1.    Reducing media chemically remove molecular oxygen

2.    Petri plates can be incubated in an anaerobic jar or an­aerobic glove box.

SPECIAL CULTURE TECHNIQUES

1.      Some parasitic and fastidious bacteria must be cultured in living animals or in cell cultures.

1.      CO2 incubators or candle jars are used to grow bacteria requiring an increased CO2 concentration.

SELECTIVE AND DIFFERENTIAL MEDIA

1.    By inhibiting unwanted organisms with salts, dyes, orother chemicals, selective media allow growth of only the desired microbe.

2.          Differential media are used to distinguish between different organisms.

ENRICHMENT CULTURE              

An enrichment culture is used to encourage the growth of a particular microorganism in a mixed culture.

Trace Elements

Microbes require very small amounts of other mineral elements, such as iron, copper, molybdenum, and zinc; these are referred to as trace elements. Most are essential for activity of certain enzymes, usually as co-factors. Although these components are sometimes added to a laboratory medium, they are usually as­sumed to be naturally present in tap water and other components of media. Even most distilled waters con­tain adequate amounts, but tap water is sometimes specified to ensure that these trace minerals will be present in culture media.

 

 ●What advantages do solid media offer for the culture of microorganisms?

●What is the enrichment culture technique and why was it a useful new method in microbiology?

 

 

更多翻譯詳細信息請點擊:http://www.trans1.cn
 
[ 網(wǎng)刊訂閱 ]  [ 專業(yè)英語搜索 ]  [ ]  [ 告訴好友 ]  [ 打印本文 ]  [ 關(guān)閉窗口 ] [ 返回頂部 ]
分享:

 

 
推薦圖文
推薦專業(yè)英語
點擊排行
 
 
Processed in 0.136 second(s), 17 queries, Memory 0.92 M
主站蜘蛛池模板: 国内免费视频成人精品 | videofreeones性欧美另类 | 狠狠狠狠狠狠狠狠 | 999久久久免费精品国产牛牛 | 欧洲成品大片在线播放 | 国模吧在线视频 | 性视频一区 | 欧美福利网 | 黄色片日本网站 | 18性夜影院午夜寂寞影院免费 | 草草影院私人免费入口 | 白丝丝袜高跟国产在线视频 | 色宅男看片午夜大片免费看 | 爱爱永久免费视频网站 | 123综合网在线| 亚洲黄色天堂 | 激情综合丝袜美女一区二区 | 日本护士撒尿 | 校园 春色 欧美 另类 小说 | 男人午夜免费视频 | 色综合综合色综合色综合 | 性色在线观看 | 在线免费视频手机版 | 视频在线一区 | 久久免费视频精品 | 亚洲国产成人久久77 | 手机看片1024久久 | 免费黄色一级 | 成人在色线视频在线观看免费大全 | 女人18毛片水多 | 美女张开大腿让男人捅 | 亚洲va中文字幕 | 在线视频人人视频www | 在线欧美三级 | 香蕉视频在线观看国产 | 四虎影院在线视频 | 全黄h全肉边做边吃奶在线观看 | 五月天激情综合网 | 天堂成人 | 久久99热久久精品99 | 男人j进人女人j 的视频 |