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1.1 The study of life Read Online
Viewed from space, Earth offers no clues about the diversity of life forms that reside there. The first forms of life on Earth are thought to have been microorganisms that existed for billions of years in the ocean before plants and animals appeared. The mammals, birds, and flowers so familiar to us are all relatively recent, originating 130 to 200 million years ago. Humans have inhabited this planet for only the last 2.5 million years, and only in the last 200,000 years have humans started looking like we do today.
Chapter 15: Genes and Proteins MCQ Multiple Choices Questions Quiz Test Bank
15.1 The Genetic Code
15.2 Prokaryotic Transcription
15.3 Eukaryotic Transcription
15.4 RNA Processing in Eukaryotes
15.5 Ribosomes and Protein Synthesis
Question: What transcripts will be most affected by low levels of a-amanitin?
Choices:
18S and 28S rRNAs
pre-mRNAs
5S rRNAs and tRNAs
other small nuclear RNAs
Question: How many nucleotides are in 12 mRNA codons?
Choices:
12
24
36
48
Question: The RNA components of ribosomes are synthesized in the ________.
Choices:
cytoplasm
nucleus
nucleolus
endoplasmic reticulum
Question: The AUC and AUA codons in mRNA both specify isoleucine. What feature of the genetic code explains this?
Choices:
complementarity
nonsense codons
universality
degeneracy
Question: Which pre-mRNA processing step is important for initiating translation?
Choices:
poly-A tail
RNA editing
splicing
7-methylguanosine cap
Question: The -10 and -35 regions of prokaryotic promoters are called consensus sequences because ________.
Choices:
they are identical in all bacterial species
they are similar in all bacterial species
they exist in all organisms
they have the same function in all organisms
Question: Which subunit of the E. coli polymerase confers specificity to transcription?
Choices:
a
ß
ß'
s
Question: What processing step enhances the stability of pre-tRNAs and pre-rRNAs?
Choices:
methylation
nucleotide modification
cleavage
splicing
Question: In any given species, there are at least how many types of aminoacyl tRNA synthetases?
Choices:
20
40
100
200
Question: Which feature of promoters can be found in both prokaryotes and eukaryotes?
Choices:
GC box
TATA box
octamer box
-10 and -35 sequences