1. Introduction to Biology

2. Chemistry

3. Water

4. Biomolecules

5. Cell Components

6. The Membrane

7. Energy and Metabolism

8. Respiration

9. Photosynthesis

10. Cell Signaling

11. Cell Division

12. Meiosis

13. Mendelian Genetics

14. DNA Synthesis

15. Gene Expression

16. Regulation of Expression

17. Viruses

18. Biotechnology

19. Genomics

20. Development

21. Evolution by Natural Selection

22. Evolution of Populations

23. Speciation

24. History of Life on Earth

25. Phylogeny

26. Prokaryotes

27. Protists

28. Plants

29. Fungi

30. Overview of Animals

31. Invertebrates

32. Vertebrates

33. Plant Anatomy

34. Vascular Plant Transport

35. Soil

36. Plant Reproduction

37. Plant Sensation and Response

38. Animal Form and Function

39. Digestive System

40. Circulatory System

41. Immune System

42. Osmoregulation and Excretion

43. Endocrine System

44. Animal Reproduction

45. Nervous System

46. Sensory Systems

47. Muscle Systems

48. Ecology

49. Animal Behavior

50. Population Ecology

51. Community Ecology

52. Ecosystems

53. Conservation Biology

[BOOK BIO] CLUTCH

Eukaryotic RNA Processing and Splicing

mRNA splicing

Types of RNA: (mRNA, tRNA, rRNA)

mRNA, rRNA and tRNA

Overview of mRNA Processing in Eukaryotes

2) RNA Splicing Creates Mature mRNA

Animation: A Spliceosome

A cap is added to the 5′ end of the mRNA.

Adenine nucleotides are added to the 5' end of the mRNA.

RNA polymerase requires tRNA to elongate the molecule.

Which of the following processes occurs in eukaryotic gene expression?

Biologists have investigated how fast pre-mRNA splicing occurs by treating cells with a toxin that blocks the production of new pre-mRNAs, then following the rate of splicing of the pre-mRNAs that were transcribed before adding the toxin. Why is addition of a toxin important in this study?

Animation: Adding the 5' Cap and Poly-A Tail

Eukaryotic RNA processing and modifications - Transcription

Both introns and exons are transcribed, but neither type of transcribed region leaves the nucleus.

Both introns and exons are transcribed, but the RNA transcribed from introns does not leave the nucleus.

Consider the meaning of the "ex" in exon and the "in" in intron.

Which accurately describes the usual process of eukaryotic transcription?

Splicing begins:
a. as transcription occurs.
b. after transcription is complete.
c. as translation occurs.
d. after translation is complete.

Alternative Splicing / Alternative Processing (Eukaryotes)

No. DNA packaging makes genes more or less available for transcription.

No. These modifiers act before transcription, not after.

Construction of a transcription initiation complex

No. The transcription initiation complex forms before transcription, not after.

What is the product of transcription?

In eukaryotes, which mechanism operates after transcription, but before translation of mRNA into protein?

Which of the following is true of RNA processing? 
(A) Exons are cut out before mRNA leaves the nucleus. 
(B) Nucleotides are added at both ends of the RNA. 
(C) Ribozymes may function in the addition of a 5′ cap. 
(D) RNA splicing adds a poly-A tail to the mRNA.

Compared with mRNAs that have a cap and tail, predict what will be observed if a eukaryotic mRNA lacked a cap and poly(A) tail.
a. The primary transcript would not be processed properly.
b. Translation would occur inefficiently.
c. Enzymes on the ribosome would add a cap and poly(A) tail.
d. tRNAs would become more resistant to degradation.

HHMI BioInteractive: Somatic Cell Nuclear Transfer

The regions in DNA &amp; RNA that encode actual gene products are known as:

BioFlix: RNA Processing

What are RNA, mRNA and tRNA?

RNases and proteases are enzymes that destroy RNAs and proteins, respectively. Which of the following enzymes, if added to a spliceosome, would be predicted to prevent recognition of pre-mRNA regions critical for splicing?
a. an RNase specific for tRNAs
b. an RNase specific for snRNAs
c. a protease specific for initiation factors
d. a protease specific for a release factor

1) RNA Processing

Animation: Post-Transcriptional Control Mechanisms

5 Prime Capping of mRNA | Eukaryotic mRNA Processing

Which of the following is not true of RNA processing?
a. Exons are cut out before mRNA leaves the nucleus.
b. Nucleotides may be added at both ends of the RNA.
c. Ribozymes may function in RNA splicing.
d. RNA splicing can be catalyzed by spliceosomes.

Different systems of DNA unpacking could result in two different mRNAs.

No. DNA packing does not affect the nucleotide sequence.

A point mutation might have altered the gene.

No. Though a point mutation may affect the protein product, it will not result in the production of two different mRNAs from the same DNA sequence.

Different transcription factors were involved in the transcription of the two mRNAs.

No. mRNAs do not change as a function of the transcription factors used to drive their expression.

Exons from the same gene could be spliced in different ways to make different mRNAs.

Think about what happens during processing of mRNA.

Two different proteins with mostly different structures are translated from two different mRNAs. These mRNAs, however, were transcribed from the same gene. Which mechanism could best account for this?

Would the coupling of the processes shown in Figure 17.24 be found in a eukaryotic cell? Explain why or why not.

RNA: mRNA & tRNA - Biology

5 Types of RNA: mRNA, tRNA, rRNA, HnRNA, and SnRNA

In prokaryotes, proteins are assembled directly from DNA.

No. Neither prokaryotes nor eukaryotes assemble proteins directly from DNA.

RNA polymerases are involved only in initiation of transcription in eukaryotes.

No. RNA polymerases are involved in initiation of transcription in both types of cells.

In eukaryotic cells, transcribed RNA sequences function as termination signals.

In prokaryotic cells, the RNA transcript is immediately available as mRNA without processing.

Think about differences and similarities between prokaryotic and eukaryotic cells.

What is a key difference between eukaryotic and prokaryotic gene expression?

RNA Processing

DNA Transcription Processing | Exons, Introns, Splicing, 5' Cap, and 3' Poly A Tail

mRNA, tRNA, and rRNA function | Types of RNA

Exons are cut out of the primary transcript, and the introns are spliced together.

No. Introns are cut out of the primary transcript, not exons.

Introns are cut out of the primary transcript and spliced together at the end of the transcript.

Exons are cut out of the primary transcript and transported to the endoplasmic reticulum.

No. Exons are spliced together and exported to the cytoplasm.

Introns are cut out of the primary transcript, and the resulting exons are spliced together.

Keep introns and exons straight.

Which statement correctly describes mRNA processing?

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