In humans, albinism (unpigmented skin, hair, and eyes) is due to an enzymatic deficiency, and it is an autosomal recessive trait. Suppose that in a small country of one million people (“Generation 1”), there are 500 aa albinos and 9000 Aa heterozygous carriers. Has the frequency of allele a changed between Generations 1 and 2? 

#Question id: 10752

#Unit 10. Ecological Principles

Which of the following is an example of Batesian mimicry?

A) a butterfly that resembles a leaf

B) a nonvenomous larva of a moth that moves like a venomous snake

C) a fawn with fur coloring that camouflages it in the forest environment

D) a snapping turtle that uses its tongue to mimic a worm, thus attracting fish

#Question id: 10765

#Unit 8. Inheritance Biology

#Question id: 380

#Unit 1. Molecules and their Interaction Relevant to Biology

The Henderson-Hasselbalch equation:

#Question id: 5002

#Unit 11. Evolution and Behavior

All animals with eyes or eyespots that have been studied so far share a gene in common. When mutated, the gene Pax-6 causes lack of eyes in fruit flies, tiny eyes in mice, and missing irises (and other eye parts) in humans. The sequence of Pax-6 in humans and mice is identical. There are so few sequence differences with fruit fly Pax-6 that the human/mouse version can cause eye formation in eyeless fruit flies, even though vertebrates and invertebrates last shared a common ancestor more than 500 million years ago.

The appearance of Pax-6 in all animals with eyes can be explained in multiple ways. Based on the information above, which explanation is most likely?

#Question id: 1253

#Unit 4. Cell Communication and Cell Signaling

Following statements are regarding to the wnt signalling.

A. Wnt proteins interact with several cell-surface proteins and activate multiple downstream signal transduction pathways. The principal signaling receptor for Wnt proteins is Frizzled (Fz), which contains seven transmembrane α helices.

B. The palmitate attached to the Wnt protein binds to a specific site on the Fz intracellular domain and stabilizes the Wnt-Fz complex.

C. “canonical” Wnt signaling pathway uses a second transmembrane protein, LRP, that associates with Frizzled in a Wnt signal– dependent manner.

D. In the resting state, two kinases in the complex, casein kinase 1 (CK1) and GSK3, sequentially phosphorylate β-catenin on multiple tyrosine residues.

Which of the following statements are correct?