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How Does Cryptobiosis work — Reading Comprehension

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MS-LS1-3
RI.6.3
RI.7.3
RI.8.8

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This passage explains cryptobiosis, the process where organisms like tardigrades pause their metabolism to survive extreme dehydration, heat, and radiation. Covers cellular adaptations (TDP proteins), revival cases, and aligns with NGSS MS-LS1-3 on energy use in organisms.

CONTENT PREVIEW

What Exactly is Cryptobiosis?

Cryptobiosis is an extraordinary biological state where an organism completely pauses all visible signs of life to survive impossible conditions. Think of it like a computer going into hibernation mode - but far more extreme. In this suspended state:

● The organism appears completely dead (no movement, breathing, or metabolic activity)

● All biological processes are put on hold

● Cells enter a protective "time capsule" state

● The organism can withstand what would normally be instant death

The Step-by-Step Science of Cryptobiosis

When conditions turn deadly, here's exactly what happens inside the organism's cells:

Phase 1: Water Emergency Protocol
As dehydration begins:

Cells activate special genes that produce protectant molecules (like trehalose in brine shrimp or TDPs in tardigrades)
These molecules gradually replace water inside cells, forming a thick, syrup-like glass
This biological "antifreeze" coats delicate cellular structures like a protective shell

Phase 2: Metabolic Shutdown
Once protected:

The heart/brain (if present) stops completely
Energy production drops to near-zero (only 1/10,000th of normal activity remains)
Cells disconnect from each other gently to prevent damage

Phase 3: Structural Lockdown
To prevent collapse:

DNA coils into ultra-tight protective bundles
Cell membranes change structure to become flexible yet strong
All repair enzymes position themselves for instant action upon revival

Phase 4: The Waiting Game
The organism remains in this state until:

● Water returns

● Temperatures normalize

● Radiation levels decrease

Documented cases of cryptobiotic survival include these remarkable examples. While revival success decreases over time, verified cases include:

● Tardigrades:

○ 30 years in dried moss (Japan, 2016)

○ 10 days in open space (2007 ESA mission)

● Nematode Worms:

○ 39 years in Arctic permafrost (Siberia, 2018)

● Bacteria:

○ 250 million years in salt crystals (controversial 2000 study)

Revival Process:
When conditions improve:

Water re-enters cells within minutes (like a dried sponge soaking up water)
Protective molecules gradually dissolve
Cellular "machinery" reboots over 24-48 hours
The organism goes about its business as if nothing happened!

Fun Fact: In 2021, scientists revived 24,000-year-old microscopic rotifers from Siberian permafrost - organisms that were frozen when woolly mammoths still roamed Earth!

What is the primary purpose of cryptobiosis?

Speed up reproductionSurvive temporary extreme conditionsEnhance photosynthesisHelp organisms grow larger

Which molecule do tardigrades use to replace water in their cells?

HemoglobinTardigrade Disordered Proteins (TDPs)CollagenChlorophyll

3. During cryptobiosis, metabolic activity drops to approximately:

50% of normal10% of normal1% of normal0.01% of normal

What happens FIRST when an organism enters cryptobiosis?

DNA repairs itselfWater-replacement molecules activateThe heart stops beatingCells divide rapidly

5. The term "cryptobiosis" literally means:

"Hidden life""Cold sleep""Death mimicry""Waterless state"

In this context, "trehalose" refers to:

A protective sugar moleculeA type of radiationAn enzyme that digests foodA reproductive cell