Portal for selective export of mrna out of the nucleus | Homework Help
1. What is the portal for selective export of mRNA out of the nucleus?
D) Nuclear Matrix
E) Nuclear Pore Complex
2. When microtubules grow out of a centrosome, which end is oriented away from the centrosome?
A) the plus end
B) the minus end
C) the N-terminal end
D) the C-terminal end
E) the 5′- end
3. When a microtubule is growing, the plus end is present as an open sheet to which GTP-dimers are aIDed. A cap of GTP-dimers can often form on the growing microtubules during rapid growth periods. How does this cap form?
A) Tubulin dimers are aIDed to the microtubule slower than the GTP is hydrolyzed.
B) Tubulin dimers are aIDed to the microtubule faster than the GTP is hydrolyzed.
C) Tubulin dimers are aIDed to the microtubule at the same rate as GTP is hydrolyzed.
D) Dimers circularize during rapid assembly periods.
E) Dimers are hardened during rapid assembly periods.
4. The presence of what ion appears to be necessary for connecting the ciliary (axonemal) dynein arms to the A microtubules of the axoneme?
5. Which organelle below is not found in both plants and animals?
A) cell membrane
6. The position of a gene on a chromosome is referred to as a(n) ________.
7. What is the process by which complementary RNAs are synthesized from a DNA template?
C) protein synthesis
8. Which of the following is normally associated with the cilia of organisms from protists to mammals?
A) a 9 + 1 pattern
B) a 9 + 3 pattern
C) a 9 + 4 pattern
E) None of these are correct.
9. What protein component do all MTOCs share?
10. Which of the following regulate intracellular levels of Ca2+ ions?
A) Golgi apparatus
C) endoplasmic reticulum
E) both endoplasmic reticulum and mitochondria
11. What is defined as a domain of the inner mitochondrial membrane that is present within the interior of the mitochondrion as a series of invaginated membranous sheets?
A) inner boundary membrane
B) outer boundary membrane
12. What was the original strain of fruit flies called?
A) wild ones
C) wild type
D) normal type
E) dominant type
13. In what form are proteins and neurotransmitters usually transported down the axon of a nerve cell?
A) individually by diffusion
B) in groups of ten
C) inside transport vesicles
D) inside the Golgi complex
E) tied individually to microtubules
14. An unusual type of phospholipid is found in the myelin sheath that insulates brain axons; abnormalities in the synthesis of this phospholipid can lead to severe neurological dysfunction. What are these phospholipids called?
15. The macromolecular complex that associates with each intron and splices it is called a(n)
E) splicing vesicle
16. What phenomenon below seems to accompany closure of the microtubule?
A) ATP hydrolysis
B) hydrolysis of GTP bound to dimers
C) hydrolysis of GDP bound to dimers
D) hydrolysis of GTP bound to trimers
E) phosphorylation of GDP bound to dimmers
Section III_Extended Multiple Choice; clearly circle the letter corresponding to the best answer and explain your rationale. Answer six of the following questions.
1. What causes the appearance of large chromosomes in the salivary glands of Drosophila
A) The cells divide at a faster rate.
B) The cells grow and synthesize DNA, but fail to divide.
C) The cells swell osmotically.
D) The cells take up extra DNA from the extracellular milieu.
E) The chromosomes take in water and swell.
2. Which organelle below is not found in both plants and animals?
A) cell membrane
3. In cell biology and with respect to microtubules and microfilaments, the word “dynamic” means ________.
4. Elevated temperatures at which temperature-sensitive mutants do not work are called ________ temperatures.
5. Which of the following is not a normal property of eukaryotic mRNAs?
A)They contain a continuous nucleotide sequence encoding a specific polypeptide.
B) They are found in the cytoplasm and inside the Golgi complex.
C) They are attached to ribosomes when they are translated.
D) Most have a significant noncoding segment that does not direct assembly of amino acids.
E) Eukaryotic mRNAs have special modifications at their 5′ and 3′ termini.
6. Where are misfolded secretory proteins eventually destroyed?
A) in the RER
B) in the SER
C) in the Golgi complex
D) in the cytosol (cytoplasm)
E) in the nucleus