27. Enlarged leaves of the Eventually, over many generations, humans have oreate

Question

27. Enlarged leaves of the Eventually, over many generations, humans have oreated a new species were artificially selected for by humans that makes leaves that A Garden Pea B. Mustard Plant C. Red Oak D. Corn Plant 28. True (A) or False (B). Evolution explains how the first cell on Earth originated. 29. In the last 20 years, research has been building that demonstrates that lifestyle (diet exercise, smoking, etc) can cause molecular changes to the introns of DNA that can turn on and turn off certain genes. These molecular changes can get passed on to the next generation The study of this process is called A. genetics B. nucleogenetics C. epigenetics D. agenetics What type of enzyme is used to cut DNA at a particular sequence for the 30. recombination? purpose of DNA A. DNA ligase B. DNA polymerase C. DNA helicase D. a restriction enzyme 31. When, during the cell cycle, does gene expression occur? A. Interphase B. S subphase C. Mitotic phase D. Cytokinesis 32. There has been scientific interest in using embryonic stem cells for research. Stem cells are cells A. plasmid B. tumor free C. engineered D. undifferentiated 33. How are artificial selection and natural selection similar? A. They both rely on human intervention. B. They both work toward a predetermined goal. C. They both select for specific traits within a population. D. They are processes that only affect animals.

Explanation / Answer

27. Kale is cultivar of cabbage derived from wild mustard. So, the correct choice is B) Mustard plant.

28. True. First cells arose 4 billion years ago (bya) according to evolutionary time scale and earth was formed 4.5 bya.

29. Option C) Epigenetics. It is the study of heritable changes in organisms gene expression without changing the DNA sequence.

30. A restriction enzyme acts as molecular scissor and can cut at specific locations within DNA or RNA molecule. So, option D) is the correct choice.

DNA ligase acts as glue and seals the fragments generated by restriction enzyme. DNA polymerase synthesizes / elongates the nucleotide sequence and DNA helicase unwinds the two strands of DNA.

31. Gene expression occurs in G2 phase of cell cycle. The correct choice is A) Interphase.

32. Stem cells are undifferentiated cells i.e. they have not accquired a particular shape, size or function. Thus they are totipotent in nature and can differentiate into any type of tissue/organ.

33. Both the selection select for specific traits within a population.

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