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
a great deal of
aeronautical mobile-satellite service
Alabama claims
alpamayo
amtifertilizin
annual ring breadth
apodicticity
Aristotle
axis of channel
balancing condenser
belewe
bevered
blastophorum truncatum
capr-
carrier frequency shift
comptonia peregrinas
continuation of solutions
counter current eletrophoresis
design H-point
dim down
dissimilar redundancy
distributed information processing
DIVC
drop out of sight
dull as ditchwater
eagle boat
eating it up
electromagnetic compatability
equivalent noise method
ex-role behavior
face and fill
floating gate
floating pump assembling unit
forum leader
Franz Schubert
galeopithecids
grace period for the payment of fees
grandifolius
gurly
gyropraph
Haebang
healing time
hickups
ideker
impulse-withstand test
interfrontal bristle
issuing authority note
jellium
jointweeds
kooky, kookie
L-cells
Lepidosigillaria
Lolipid
loss of faculty
malthinus (malthinus) notsui
mat type
matsucythere reticulata
metacarprophalangeal
metaemotions
metallized aluminum
mini-Winchester disk drive
national capitalism
net processor
non-ischemic
nonmonitored
nucleolonema (estable & sotelo 1950)
obstropolos
oha
oubliette
percentage indicator
pitous
PSNC
Reitano
Rhododendron huguangense
rubble filling
sagittata
scathophaga mellipes
separate channel signaling
shifting wrench
slot diffuser
social-ism
solvated H-ion
space-loop direction-finder
special constable
spectral-shift reactor
square turret
sroka
statelier
stock clearing account
stress cracking resistance
sugarplums
suntanned
superior cubitoradial articulation
tabular actual
thruple
trinketed
two single ended siding
unit record equipment
urodele
veurne (furnes)
Wigtown
wrongtook