Page 53 - How It Works - Book of Amazing Answers To Curious Questions, 12

---- Environment Q�
_______________

What is the musc mntron cycl

Physique
Muscle power is common to all these creatures, so here's an explanation of
how muscles provide the power that in turn provides the speed

1. Attachment
Firstly a myosin head
(akin to an organic
hook) attaches itself to
an exposed binding site
on the muscle
filaments, gripping it in
a cross bridge.
2. Power stroke
The myosin head then
pulls the filament by
pivoting backwards and
dragging it into a Actin filament
compressed position. is pulled

3. Detachment
A molecule of ATP
(adenosine triphosphate)
then binds to the myosin,
Cross bridge
detaches releasing its grip of the
filament so that the cross
bridge detaches.
4. Energy release
Finally. the ATP releases
energy to convert the
myosin head from its bent.
low·energy position back to Energised myosin
its initial high·energy head
configuration ready for the
next cycle.

---------------------- �� -----------------------

Usain Bolt The fastest anima�1L'D
on Earth are
The fastest human alive, Usain Bolt ...
recently broke the world 100-metre Here's a list of the most
record with a staggeringly quick super-fast critters on the planet
time of 9.58 seconds
FASTEST FISH
0 ne of the most successful species of animal on the Sailfish 68mph (uokph) Peregrine falcon
planet, Homo sapiens have evolved over the last Marlin 50mph (8okph) Spine-tailed swift
120,000 years into creatures with formidable Wahoo 48mph (78kph) Frigatebird
physical abilities. Currently, the fastest human is Usa in Tunny 46mph (74kph) Spur-winged goose
Bluefish tuna 44mph (7okph) Red-breasted
Bolt, a jamaican-born sprinter who has won the world 100 merganser 8omph (129l<ph)
and zoo-metre gold medals. FASTEST LAND INSECTS�--'
Bolt epitomises the ideal human anatomy needed to Tiger beetle 5.6mph (8.4kph) FASTEST MAMMALS
produce such high speeds: a tall height (1.95m), balanced Cockroach 3.4mph (5.4kph) Cheetah 71mph (114kph)
Pronghorn antelope
57mph (95kph)
weight (93·9kg) and long, powerful muscles with an FASTEST REPTILES Springbok 5omph (8okph)
excellent metabolism- muscles cannot utilise energy-rich Spiny-tailed iguana 21mph (34kph) Blue wildebeest 5omph (8okph)
'fuels' such as glucose, instead they must convert it into Black mamba 12mph (2okph) Lion 45mph (72kph)
ATP (adenosine triphosphate) with the amount of ATP a
Sources:Americanjourna/o!Zoology_ UniversityofMichigan,SeattleZoo,Americanjournalof
muscle produces directly correlating to thea mount of Physiology, National Geographic, US Fish and Wildlife Service, Forest Preserveof/1/inois
power it can generate.

WorldMags.net
WorldMags.net How It T%rks 53