Exam

Question 1

Write a good definition of a gene.

Answer 1

• They code for different proteins which do work for the cell/they are information passed down from a parent.

Question 2

Name THREE types of mRNA processing after transcription.

Answer 2

• Poly (A)

• 5’ cap

• Alternative Splicing

Question 3

What are the TWO conditions within a region of the cell that could lead to catastrophic microtubule collapse?

Answer 3

• Low Tubulin

• Low GTP

Question 4

Describe TWO molecular mechanisms that control gene expression.

Answer 4

• HETEROCHROMATIN - turns off gene expression/suppress/methylation

• EUCHROMATIN - turns on gene expression/not suppress/phosphorylation & acetylation

Question 5

The genomes of any two cells in your body are identical. Given this fact, how can you have cells with radically different cell function, such as muscle cells and neurons?

Answer 5

• Genes are expressed differently depending on the location in the body. It can turn on/off a gene to code different proteins.

Question 6

1. Topiomerase - ?
2. Helicase - ?
3. Ligase - ?
4. Polymerase - ?

Answer 6

1. Topiomerase - Release TENSION
2. Helicase - UNWINDS DNA at the middle
3. Ligase - SEAL gaps
4. Polymerase - COPIES DNA

Question 7

_____ releases tension

Answer 7

• Topiomerase

Question 8

_____ unwinds at the middle

Answer 8

• Helicase

Question 9

_____ Seals gaps

Answer 9

• Ligase

Question 10

______ Copies DNA

Answer 10

• Polymerase

Question 11

In order for a neuron to secrete neurotransmitters, what process need to take place?

A) movement of vesicles from golgi to membrane
B) translation in the rough ER
C) transcription
D) all of these
E) exocytosis

Answer 11

D) ALL OF THESE

Question 12

For Na+ transport, you find 150mM outside of the cell and 50mM inside the cell. You also measure a Vm of -20mV. Which way will the ion move and why?

A) out of the cell because of both concentration and charge
B) into the cell because of both concentration and charge
C) out of the cell due to charge
D) into the cell due to charge
E) into the cell due to concentration

Answer 12

B) INTO THE CELL BECAUSE OF BOTH CONCENTRATION AND CHARGE

Question 13

For Cl- transport, you find 40mM outside of the cell and 150mM inside the cell. You also measure a Vm of -15mV. Which way will the ion move and why?

A) out of the cell because of both concentration and charge
B) into the cell because of both concentration and charge
C) out of the cell due to charge
D) into the cell due to charge
E) into the cell due to concentration

Answer 13

A) OUT OF THE CELL BECAUSE OF BOTH CONCENTRATION AND CHARGE

Question 14

Which junction + cytoskeleton association is correct?

A) gap junctions and actin
B) desmosomes and intermediate filaments
C) hemidesmosomes and microtubules
D) adherens junction and intermediate filaments
E) tight junctions and actin

Answer 14

B) DESMOSOMES AND INTERMEDIATE FILAMENTS

Question 15

Which junction is required for cell polarity?

A) gap junctions
B) desmosomes
C) hemidesmosomes
D) adherens junctions
E) tight junctions

Answer 15

E) TIGHT JUNCTIONS

(polariTy = Tight)

Question 16

Which type of DNA element controls gene-specific transcription?

A) core promoter
B) upstream promoter
C) terminator
D) transcription factor
E) repressor

Answer 16

B) UPSTREAM PROMOTER

Question 17

Which motor protein is required for vesicle movement around the cell?

A) dynein
B) myosin
C) non-muscle myosin
D) clatherin
E) helicase

Answer 17

A) DYNEIN

(D = Drive)

Question 18

You are studying a eukaryotic gene whose initial transcript is 1500 nucleotides in length. The mature mRNA derived from the gene is 1200 nucleotides in length. What is the most probable reason for the discrepancy?

A) a mutation that results in a shorter product
B) removal of introns
C) removal of exons
D) mRNA breakage
E) a mutation that result in a shorter product of mRNA breakage could have occurred

Answer 18

B) REMOVAL OF INTRONS

Question 19

The 5’ cap of an mRNA regulates:

A) mRNA translation
B) mRNA length
C) mRNA splicing
D) mRNA location
E) all of the above

Answer 19

A) mRNA TRANSLATION

Question 20

The nuclear envelope functions as a:

A) means of separating nuclear and cytoplasmic proteins
B) means of localizing of the chromosomes within the cell
C) selective barrier, allowing certain proteins in or out
D) means of sequestering many of the mRNA processing activities from the cytosol
E) all of the above

Answer 20

E) ALL OF THE ABOVE

Question 21

Moving material against a charge or concentration gradient requires?

A) a channel protein
B) passive transport
C) active transport
D) all of these
E) cell junctions

Answer 21

C) ACTIVE TRANSPORT

(Active = against/energy)

Question 22

Heterochromatin differs from euchromatin in that it:

A) is modified with methylation sites
B) contains genes whose expression is suppressed
C) is tightly packed and condensed chromatin
D) contains low levels of histone acetylation
E) all of these statements are true

Answer 22

C) IS TIGHTLY PACKED AND CONDENSED CHROMATIN

Question 23

Telomeres are thought to play a role in preventing rapid aging because:

A) telomeres play a role in cell division
B) telomeres protect against chromosome degradation during DNA replication
C) telomeres suppress metabolism
D) telomeres are highly repetitive and do not contain genes
E) telomeres attach to microtubule ends and ensure high fidelity chromosome segregation

Answer 23

B) TELOMERES PROTECT AGAINST CHROMOSOME DEGRADATION DURING DNA REPLICATION

Question 24

A gene is:

A) a chromosome
B) RNA
C) a codon
D) a monomer
E) DNA that codes for some functional unit in the cell

Answer 24

E) DNA THAT CODES FOR SOME FUNCTIONAL UNIT IN THE CELL

Question 25

Which of the following junctions is abundant in tissues such as skin and is required to resist significant mechanical stress?

A) gap junctions
B) gap junctions
C) focal adhesions
D) tight junction
E) desmosomes

Answer 25

E) DESMOSOMES

Question 26

Kinesin motor proteins move vesicles along which type of cytoskeletal filament?

A) actin
B) septins
C) microtubules
D) intermediate filaments
E) gap junctions

Answer 26

C) MICROTUBULES

Question 27

The cytoskeletal motor protein is a major component of muscle fibers.

A) actin
B) tubulin
C) integrin
D) intermediate filaments
E) myosin

Answer 27

E) MYOSIN

(Muscle = Myosin)

Question 28

What type of pyruvate metabolism take place in the mitochondria:

A) synthetic
B) anaerobic
C) fermentation
D) anabolic
E) aerobic

Answer 28

E) AEROBIC

Question 29

A temporary oxygen deficit during strenuous exercise cause a muscle to:

A) synthesize muscle proteins in response to steroid hormone stimulation
B) synthesis glycogen
C) ferment pyruvate to lactate
D) switch to aerobic glycolysis
E) synthesize more NAD+

Answer 29

C) FERMENT PYRUVATE TO LACTATE

(No O2 = Fermentation)

Question 30

Glycolysis cleavage to pyruvate takes place in the:

A) cytoplasm
B) mitochondria
C) endoplasmic reticulum
D) nucleus
E) all of the above

Answer 30

A) CYTOPLASM

Question 31

Transmembrane proteins called channels allow for:

A) active transport
B) facilitated transport
C) endomembrane transport
D) protein folding
E) ER trafficking

Answer 31

B) FACILITATED TRANSPORT

Question 32

Water moves across the plasma membrane into or out of a cell by osmosis when:

A) water can not move across the plasma membrane
B) water diffuses through a semipermeable membrane toward a lower solute concentration
C) ATP hydrolysis drives aquaporin transport
D) water diffuses through a semipermeable membrane toward a higher solute concentration
E) there is an equal solute concentration on both sides of the membrane

Answer 32

D) WATER DIFFUSES THROUGH A SEMIPERMEABLE MEMBRANE TOWARD A HIGHER SOLUTE CONCENTRATION

(Water follows solute)

Question 33

A positive membrane potential (Vm) could describe:

A) an excess of negatively charged solute molecules outside the cell
B) an excess of water outside the cell
C) the inability of a cell to change shape
D) the ability of a cell to migrate
E) an excess of positive charged solute molecules outside the cell

Answer 33

A) AN EXCESS OF NEGATIVELY CHRGED SOLUTE MOLECULES OUTSIDE THE CELL

Question 34

Match GTPases with its major biological function

A) tubulin
B) ran
C) rho
D) rab
E) rac

1) nuclear transport
2) lamellipodia
3) actin stress fibers
4) vesicle fusion
5) microtubule stability

Answer 34

A) TUBULIN —— microtubule stability
B) RAN —— nuclear transport
C) RHO —— actin stress fibers
D) RAB —— vesicle fusion
E) RAC —— lamellipodia

Question 35

Match the cell junction with its major protein constituent.

A) tight junction
B) adherens junction
C) desmosomes
D) gap junction
E) hemidesmosomes

1) cadherin
2) connexin
3) integrin
4) claudin
5) desmosomal cadherin

Answer 35

A) TIGHT JUNCTION —— claudin
B) ADHERENS JUNCTION —— cadherin
C) DESMOSOMES —— desmosomal cadherin
D) GAP JUNCTION —— connexin
E) HEMIDESMOSOMES —— integrin