时间:2019-01-02 作者:英语课 分类:60秒科学


英语课

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.


—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。
学英语单词
abreuvoir
acetylacetic acid
afterbody drag
air-cushion sign
air-tube clutch
ammonia converter
amortization of organization expenses
arma
artificial neural nets
auto shows
auxiliary loop
avenacea
Bakewell
barometries
black pot
Blu-ray Discs
blunt leading edges
cable earth capacitance
calyptopogon albitarsis
centropyge bicolor
close leg jump
clothes pole,clothespole
codebreakers
cold wall vacuum furnace
competent teaching
constant-current filter
crablikest
credit in business
cruciform structure
diffraction camern
disposted
dragline excavator
dry-dock launching
e-metrics project
external lateral velar bar
fissium
foeto-
gagosa (amerindian)
genus Junco
getton
glycocolls
great grandmaster
Greco-Buddhism
griffithii
hard service cord
Hardinsburg
headmaster
hemipteroids
horizontal miller
hyperrealities
image phase-change coefficient
in jest
in the same manner
inconvertibility
interpersonal messaaging protocol (p2 protocol)
interrupt logging
intravehicular
introvertere
investigatorial
isopicropodophyllotoxin
Jabuticabal
jet axis dynamical pressure
John-a-stiles
kyger
labor disturbances
Leopoldo de Bulhões
limit visibility
liquidborne noise
local an (a) esthesia
marillions
mountain lover
nonpenal
Nulsa
oes'
outer circling vacuum evaporator
phonak
quick close stop
relative surplus
remote optical sensing
rusty-brown
scalloped selvedge
serjeants-at-arms
sexual orientations
side slope of cut
sign optional
soda can
spheric explosion
stiff shafting
subroutine re-entry
tectonic forces
terrain effect
Trilobine
Trumpler star
uics
umbraquult
unofearned
unsurprisings
urotropin(e)
vagines
VVC
won't've
zrenjanin (petrovgrad)