Mice homozygous for a null allele of dhh exhibit defective spermatogenesis

TLS Online TPP Program

#Id: 7769

#Unit 2. Cellular Organization

Nuclear envelope

Double-membrane structure; the outer membrane is continuous with the endoplasmic reticulum and the two membranes are perforated by nuclear pore complexes

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#Id: 739

#Unit 3. Fundamental Processes

DNA strand synthesis requires the four deoxynucleoside triphosphates—dGTP, dCTP, dATP, and dTTP in equal in vivo concentration

TLS Online TPP Program

#Id: 9785

#Unit 6. System Physiology – Plant

R gene Mi-1 confers resistance to aphids and whiteflies

Rice R gene Bph14 confers resistance to the brown plant hopper

Melon R gene Vat confers resistance to the cotton aphid. 

All of these R genes encode NBS–LRR receptors.

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#Id: 7819

#Unit 10. Ecological Principles

Many organisms minimize heat loss to the environment via countercurrent heat exchange

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#Id: 10067

#Unit 4. Cell Communication and Cell Signaling

Ca2+ ions bind to sites near each hinge and prevent it

from flexing, so that the whole string of cadherin domains behaves as a rigid and slightly curved rod to generate cell–cell adhesion