Netrin function as (A)_______ at ventral midline of spinal cord. Once the growth cone crosses the midline, (B)_______ will be down regulated and (C)______ will be up regulated. This physiological change prevents growth cone to cross the midline twice.
a. (A) Chemoattractant (B) Robo (C) Netrin receptor
b. (A) Chemoattractant (B) Netrin receptor (C) Robo
c. (A) Chemorepellent (B) Robo (C) Netrin receptor
d. (A) Chemorepellent (B) Netrin receptor (C) Robo
Answer: b. (A) Chemoattractant (B) Netrin receptor (C) Robo
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Which of the following sequences indicates the promoter region of a gene?
a. CAAT b. UAAG c. CTTT d. ACAT e. TAAC
The separation of members of a gene pair into the gametes is called ____________________. Fill in the blank(s) with the appropriate word(s)
Membership in a clade cannot be established by shared ancestral traits alone
_____________________ Indicate whether the statement is true or false.
Which of the following is evidence that the transition to multicellularity did not require the origin of large numbers of novel genes?
a. The multicellular groups, animals and fungi, are unikonts. Some studies based on whether the genes for DHFR and TS are separate or fused indicate the unikonts were the first group of eukaryotes to diverge. b. The cadherin proteins of animals, which are involved in animal cell adherence to each other, contain only one novel domain not found in the cadherin proteins of unicellular choanoflagellates. c. Multicellularity evolved once and may have involved two stages: First, colonies arose as dividing cells remained attached by their shared cell walls; then differentiated cells arose as some cells became specialized for reproduction. d. Genomic studies indicate that multicellular Volvox has few novel genes compared with unicellular Chlamydomonas, and the cadherin proteins of animals, which are involved in animal cell adherence to each other, contain only one novel domain not found in the cadherin proteins of unicellular choanoflagellates. e. Genomic studies indicate that multicellular Volvox has few novel genes compared with unicellular Chlamydomonas.