时间:2019-01-08 作者:英语课 分类:Scientific American(五)月


英语课

This is Scientific American's Sixty-Second Science. I'm Christopher Intagliata. Got the minute?


A couple million years ago, mammoths migrated north from Africa to colonize 2 Eurasia. Sometime around then a massive ice age kicked in—and it was stay warm or die. So their tails and heat-shedding ears shrunk, and they grew thick coats of oily fur. 


But if you're out in the cold all day you also need some biochemical adjustments. Hemoglobin is the protein in red blood cells that delivers oxygen to your tissues. And it doesn't off-load oxygen well at low temperatures; it just clings to it more tightly. So mammoths solved that problem by evolving hemoglobin that releases oxygen more easily in the cold. That’s according to a study published in the journal Nature Genetics. 


Researchers got the DNA 3 that codes for hemoglobin from a 43,000-year-old mammoth 1 specimen 4. They then used E. coli bacteria to produce actual mammoth hemoglobin. Then they compared mammoth hemoglobin to that of their living cousins, Asian elephants, at 37, 25 and 10 degrees Celsius 5. Due to just a few key structural 6 changes, mammoth hemoglobin can release oxygen more readily at cold temperatures which was just the thing to help mammoths keep their cool.


Thanks for your minutes for Scientific American Sixty Second Science. I'm Christopher Intagliata.

 



n.长毛象;adj.长毛象似的,巨大的
  • You can only undertake mammoth changes if the finances are there.资金到位的情况下方可进行重大变革。
  • Building the new railroad will be a mammoth job.修建那条新铁路将是一项巨大工程。
v.建立殖民地,拓殖;定居,居于
  • Around 700 Arabs began to colonize East Africa.公元700年阿拉伯人开始把东非变为殖民地。
  • Japan used to colonize many countries in Asia.日本曾经殖民过许多亚洲国家。
(缩)deoxyribonucleic acid 脱氧核糖核酸
  • DNA is stored in the nucleus of a cell.脱氧核糖核酸储存于细胞的细胞核里。
  • Gene mutations are alterations in the DNA code.基因突变是指DNA密码的改变。
n.样本,标本
  • You'll need tweezers to hold up the specimen.你要用镊子来夹这标本。
  • This specimen is richly variegated in colour.这件标本上有很多颜色。
adj.摄氏温度计的,摄氏的
  • The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
  • The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。
adj.构造的,组织的,建筑(用)的
  • The storm caused no structural damage.风暴没有造成建筑结构方面的破坏。
  • The North American continent is made up of three great structural entities.北美大陆是由三个构造单元组成的。
标签: SSS oxygen
学英语单词
acceleration vector of center of mass
accelerator cross shaft
ammoniacal odo(u)r
anduzes
antigonadotrophic
automatic phase regulation
babying
Batignano
Bol'shoye Leprindo, Ozero
British Standard Fine Thread
capital verification
central-server model
Chiquimulilla
class rate
clovepink
color subtraction
Confucian
crushing down test
current-instruction register
depth encoder
desorption control
double-exposure
earlier
eccentric-strap oil pocket
eigenchannel
El Maraňón
emerald spodumene
fablan
fibromedullary cancer
fixtures and furnitures
fling off cooling
Fridenberg test card
gravity drop hammer
grease someone's fist
hgoes
hiromi
homocamfin
hydrochlorinate
impact-stress
impecunious
in-line flexographic press
ink-jet printers
iridectropium
irregularized
IT distributor
john pierpont morgans
Kengyilia thoroldiana
Klee
lightheavyweights
log arithmic diode
M-protein
main carriageway
make ... market
mechanical orienting tool
megadrought
minor principal stress
mournful-like
nanovoltmeters
nectosac
online working
other instrumentation and measurement systems
paywall
peak pressure meter
Planet X
pole slipping
polymyositis haemorrhagica
poudreuses
release of distress
revolving axle
rhodesdale
rich content
rounded numeric data
salvage department
santyl
scratch crew
season colour
secondary test
self-denier
shiue
sliding vane
station boundary mark
statisticizing
swerve
the great mother
this is your life
Thrinax parviflora
thunder god vine
time-sharing group
traverse error of closure
uniform boundedness principle
unzoned lens
upthurst fault-scarp
urbanitis
uterine rupture
Valafell
vecuronium
verona serge
voltage transducer
Warren-girder
wheel diameter
who'd've
zero-voc