MCB 252 Study Guide - Midterm Guide: Thymosin, Phalloidin, Wild Type

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cyanwoodchuck45

5 Aug 2020

School

University of Illinois

Department

Molecular and Cell Biology

Course

MCB 252

Professor

D Rivier

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Document Summary

Name:_____________________________ __________ network id:__________________ Section:__________________________ ta:_____________________________ This exam consists of 60 questions for a total of 175 points. Choose the best answer from the available choices. Questions 1- 10 are worth 2 points each. Which step in actin filament formation is regulated by acta: nucleation, elongation, capping, treadmilling, disassembly. Page 3 of 21: the ancestors of some of the humans that migrated out of africa interbred with. Some neanderthal genes are still retained in the human descendants of those interbreeding events. Page 5 of 21: the figure below was discussed in lecture. Refer to the diagram below for the next two questions. Both reactions diagrammed below are for reactions involving the polymerization of actin filaments in an experiment discussed in lecture. Page 8 of 21: as described in lecture both actin filaments and actin monomers have plus and minus ends. You add tubulin, an excess of. Gtp, and any other proteins needed for efficient polymerization of microtubules.

Related Questions

QUESTION 30

The function of centrosome is:

	1.	Microtubule initiation and organization in animal cells
	2.	Organization of thin filaments
	3.	Depolymerization of microtubules
	4.	Organization of intermediate filaments

2.5 points

QUESTION 31

The destinations of proteins synthesized on "free" ribomsomes include:

	1.	Endoplasmic reticulum
	2.	Nucleus
	3.	Mitochondria
	4.	Lysosomes

2.5 points

QUESTION 32

Microtubules can be assembled and disassembled quickly in response to the cellular changes is because:

	1.	Cells synthesize tubulin proteins very fast.
	2.	Cells can turn other cytoskeletal filaments into microtubules
	3.	Microtubules have an instable plus end and microtubules are probably organized by weak non-covalent interactions
	4.	The motor proteins of microtubules can organize the microtubules in response to the cellular changes

2.5 points

QUESTION 33

Both signal recognition particle and a translocon in rough endoplasmic reticulum membrane can recognize and bind to the signal sequence of a secretory protein, so they play the exact same role during protein co-translational translocation.

True

False

2.5 points

QUESTION 34

Rough endoplasmic reticulum is so named is because:

	1.	It has many proteins associated with its surface.
	2.	It has ribosomes associated with its cytosolic surface.
	3.	It is associated with nuclear membrane.
	4.	It has vesicles budding off its surface.

2.5 points

QUESTION 35

The membrane vesicles that transport materials between membrane compartments have a protein coat. The protein coat has similar functions in different vesicles. These functions include:

	1.	Help the enclosed material fold correctly.
	2.	Help degrade the protein in the vesicles
	3.	Maintain the internal pH of the vesicles
	4.	Function as mechanical device to form a vesicle and select the components to be carried by a vesicle.

2.5 points

QUESTION 36

Lysosomes are important for:

	1.	Receptor-mediated endocytosis.
	2.	Breaking down foreign particles brought into the cells by endosomes
	3.	Regulating the process of organelle turnover.
	4.	Protein trafficking between membrane compartments

2.5 points

QUESTION 37

Which of the following is correct about membrane biosynthesis?

	1.	Membranes are synthesized in Golgi Complex.
	2.	Membranes arise from preexisting endoplasmic reticulum membranes.
	3.	Membranes are synthesized on ribosomes.
	4.	Membranes of all organelles have the same composition of proteins and lipids, since they all originate from endoplasmic reticulum.

2.5 points

QUESTION 38

During skeletal muscle contractions, the shortening of the muscle fibers is because of:

		The shortening of the thin and thick myofilaments.
		The shortening of the cytoskeletal filaments.
		The kinesin proteins moving over microtubules.
		The actin and myosin filaments sliding over each other.

2.5 points

QUESTION 39

The assembly and disassembly of microtubules is regulated by rate of growth and shrinkage of the plus end.

True

False

2.5 points

QUESTION 40

The functions of Golgi complex include:

	1.	O-linked oligosaccharides and most of a cellâs complex polysaccharides are assembled in Golgi complex
	2.	Cis Golgi complex sorts proteins
	3.	Trans Golgi complex segregates proteins in different types of vesicles for dilevery.
	4.	N-linked oligosaccharides are further processed in Golgi complex

ochrecoyote721

__________ are fairly small organelles that provide a safe place within the cell to carry out certain biochemical reactions that generate harmful, highly reactive oxygen species. These chemicals are both generated and broken down in the same location.

Lysosomes

Endosomes

Peroxisomes

Nucleosomes

Biologists cannot possibly study all living species. Instead, they try to understand cell behavior by studying a select subset of them. Which of the following characteristics are useful in an organism chosen for use as a model in laboratory studies?

rapid rate of reproduction

all of the above

ability to grow under controlled conditions

amenability to genetic manipulation

By definition, prokaryotic cells do not possess __________.

ribosomes.

a nucleus.

membrane bilayers.

replication machinery.

Cell biologists employ targeted fluorescent dyes or modified fluorescent proteins in both standard fluorescence microscopy and confocal microscopy to observe specific details in the cell. Even though fluorescence permits better visualization, the resolving power is essentially the same as that of a standard light microscope because the resolving power of a microscope is limited by the __________ of light.

intensity

absorption

wavelength

filtering

Choose the phrase that best completes this sentence: Microtubules ____________ and are required to pull duplicated chromosomes to opposite poles of dividing cells.

generate contractile forces

can rapidly reorganize

are found in especially large numbers in muscle cells

are intermediate in thickness

Despite the differences between eukaryotic and prokaryotic cells, prokaryotes have proteins that are distantly related to eukaryotic actin filaments and microtubules. What is likely to be the most ancient function of the cytoskeleton?

cell division

cell motility

vesicle transport

membrane support

DNA and RNA are different types of nucleic acid polymer. Which of the following is true of DNA but not true of RNA?

It contains thymine.

It has 5'-to-3' directionality.

It is single-stranded.

It contains uracil.

Double covalent bonds are both shorter and stronger than single covalent bonds, but they also limit the geometry of the molecule because they ____________________.

prevent additional bonds from being formed with the bonded atoms.

limit the rotation of the bonded atoms.

create a new arrangement of electron shells.

change the reactivity of the bonded atoms.

Drosophila melanogaster is a/an __________. This type of animal is the most abundant of all animal species, making it an appropriate choice as an experimental model.

mammal

amphibian

bird

insect

10.

If the isotope 32S has 16 protons and 16 neutrons, how many protons, neutrons, and electrons will the isotope 35S have, respectively?

16, 19, 17

16, 19, 15

16, 19, 16

16, 20, 15

11.

Living systems are incredibly diverse in size, shape, environment, and behavior. It is estimated that there are between 10 million and 100 million different species. Despite this wide variety of organisms, it remains difficult to define what it means to say something is alive. Which of the following can be described as the smallest living unit?

cell

organelle

protein

DNA

12.

Macromolecules in the cell can often interact transiently as a result of noncovalent interactions. These weak interactions also produce stable, highly specific interactions between molecules. Which of the factors below is the most significant in determining whether the interaction will be transient or stable?

the concentration of each molecule

the size of each molecule

surface complementarity between molecules

the rate of synthesis

13.

Many of the mechanisms that cells use for maintenance and reproduction were first studied at the molecular level in bacteria. Which bacterial species had a central role in advancing the field of molecular biology?

E. coli

S. pombe

C. elegans

D. melanogaster

14.

Many types of cells have stores of lipids in their cytoplasm, usually seen as fat droplets. What is the lipid most commonly found in these droplets?

cholesterol

isoprene

triacylglycerol

palmitic acid

15.

Mitochondria contain their own genome, are able to duplicate, and actually divide on a different time line from the rest of the cell. Nevertheless, mitochondria cannot function for long when isolated from the cell because they are __________________.

anaerobes.

viruses.

parasites.

endosymbionts.

16.

Mitochondria perform cellular respiration, a process that uses oxygen, generates carbon dioxide, and produces chemical energy for the cell. Which answer below indicates a correct pairing of material âburnedâ and the form of energy produced during cellular respiration?

17.

Polar covalent bonds are formed when the electrons in the bond are not shared equally between the two nuclei. Which one of these molecules contains polar bonds?

1. You have the following prokaryotic DNA sequence: 5â²-GGACTAGACAATAGGGACCTAGAGATTCCGAAA-3â² 3â²-CCTGATCTGTTATCCCTGGATCTCTAAGGCTTT-5â² If the top strand is the template strand which sequence below is the correct mRNA transcript? A. 5â²-GGACUAGACAAUAGGGACCUAGAGAUUCCGAAAâ3â² B. 5'-UUUCGGAAUCUCUAGGUCCCUAUUGUCUAGUCC-3' C. 5'-CCUGAUCUGUUAUCCCUGGAUCUCUAAGGCUUU-3' D. None of the above are correct

2.Starting in the cytoplasm with a fully mature mRNA explain the process of translation initiation and then elongation and termination to me.

3.Prior to export from the nucleus, pre-mRNA must be processed. What specifically does this entail?

4.The biosynthetic pathway for the two amino acids E and H is shown schematically in the figure. You are able to show experimentally that E inhibits enzyme V, and H inhibits enzyme X. The most logical hypothesis regarding the regulation of Enzyme T would be that it is most likely subject to feedback inhibition by E alone. True or False?

5. A. kinase B. ligase C. polymerase D. oxido-reductase E. Phosphatase F. protease G. nuclease H. ATPase 1. Removes a phosphate group from a molecule 2. Hydrolyzes ATP 3. Hydrolyzes bonds between nucleotides 4. Adds phosphate groups to molecules 5. Catalyzes reactions in which one molecule is oxidized and another is reduced 6. Hydrolyzes peptide bonds 7. Joins two ends of DNA together 8. Catalyzes the synthesis of polymers such as RNA and DNA

6. Looking at the figure showing the change in reaction rate for two different enzymes that both utilize the same substrate, answer the following questions. a. What is the approximate Vmax for enzyme B ? b. What is the approximate Vmax for enzyme A ? c. What is the approximate Km for the enzyme which has a higher affinity for the substrate uM.

7. Answer the following question either yes or no (spell out the word, do not abbreviate as y or n). Looking at the following coupled reaction: Luciferase luciferin + O 2 ==========> oxyluciferin + light âG = + + Mg2+ ATP <=> AMP + PPi âG = - - - a. Based on your knowledge of free energy change and reactions would this coupled reaction occur ? b. Would changing the second step from ATP<=> AMP + PPi âG = - - - to ATP <=> ADP + Pi âG = - change your answer

7.Spontaneous reactions by definition will happen instantaneously. Why false?

8. Each of the following questions apply to the image of the channel protein. The purple sphere is a charged ion. Type your response to each question in the blank provided. a. Based you on what you know about cells and ions, what does the tri-lobed red and white molecule represent (although there aren't anywhere near enough of them shown) ? b. Since the question stated the purple sphere was a charged particle, using what you know about the tri-lobed red and white molecule what is the charge of the purples sphere c. On the extracellular space, on the right side of the purple sphere, there are two tri-lobed red and white molecules in close proximity to one another. The red of one appears to be attracted to the white of the other. What type of bond is this ? d. Based on your knowledge of proteins that interact with the membrane and the properties of the membrane, to what family of amino acids would the amino acid marked by A. most likely belong? ?

MCB 252 Study Guide - Midterm Guide: Thymosin, Phalloidin, Wild Type

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