Cellular Communication
What is an example of long distance endocrine signaling?
A. Neurotransmitters being secreted across a synapse to stimulate a muscle cell
B. Sweating
C. Pancreas releasing insulin into the blood
D. A cell secreting growth hormone to itself
C. Pancreas releasing insulin into the blood
Which of the following statements best explains the mechanism for DNA replication?
a. DNA replication is reductive, because half the total DNA present is copied.
b. DNA replication is semi-conservative, because each DNA strand serves as a template during replication.
c. DNA replication is dispersive, because the two resulting DNA molecules are mixtures of parent and daughter DNA.
d. DNA replication is conservative, because one resulting molecule is identical to the original and the other consists of two new strands.
b. DNA replication is semi-conservative, because each DNA strand serves as a template during replication.
A bacterial sample was collected & the next day there were colonies. Bacterial cells are able to replicate through which reproductive process?
A. Mitosis
B. Meiosis
C. Binary Fission
D. Horizontal Gene transfer
C. Binary Fission
What type of cells are produced in Meiosis?
A. Somatic cells
B. Gametes
C. Cancer cells
D. Zygotes
B. Gametes
TRUE or FALSE. Homologous chromosomes contain the same genes but are inherited from different parents.
True.
Epinephrine will bind to GPCR which in turn activates the G protein. The G protein will activate the adenylyl cyclase which converts ATP to cAMP. cAMP will initiate the signal transduction phase by activating the first kinase in the phosphorylation/dephosphorylation series. In this example, epinephrine is the _____ messenger and cAMP is the _____ messenger.
a. first; first
b. first; second
c. second; first
d. second; second
b. first; second
In DNA replication, DNA "unwinds" to form two template strands: the leading strand and the lagging strand. Which of the following statements about these strands is true?
a. Okazaki fragments are used to synthesize the leading strand of DNA.
b. The leading strand of DNA is synthesized continuously.
c. DNA polymerase can only synthesize DNA on the leading strand.
d. The lagging strand can only be synthesized once the leading strand has been completed.
b. The leading strand of DNA is synthesized continuously.
Which of the following enzymes control the cell cycle?
a. kinases
b. DNA polymerases
c. phosphatases
d. nuclease
a. kinases
**Cyclin-dependent kinases**
In which phase are the homologous chromosomes separated from each other?
A. Anaphase I
B. Metaphase I
C. Anaphase II
D. Metaphase II
A. Anaphase I
A cell with 10 chromosomes undergoes mitosis. ____ daughter cells are produced, each with ___ chromosomes.
a. 1; 10
b. 1; 20
c. 2; 10
d. 2; 20
c. 2; 10
(In mitosis, each parent cell produces two daughter cells that each have the same number of chromosomes of the parent cell).
During cell communication in the nervous system, chemical messengers called neurotransmitters travel between neurons. As they travel, neurotransmitters send messages from one neuron to another. Which of the following best describes the role of neurotransmitters in cell-to-cell communication?
a. Neurotransmitters are local regulators that allow neurons to communicate over short distances.
b. Neurotransmitters are local regulators that allow neurons to communicate over long distances.
c. Neurotransmitters are long-distance signaling molecules that allow neurons to communicate over short distances.
d. Neurotransmitters are long-distance signaling molecules that allow neurons to communicate over long distances.
a. Neurotransmitters are local regulators that allow neurons to communicate over short distances.
There are several DNA repair mechanisms in place to help detect and correct DNA damage. Which of the following is true regarding these DNA repair mechanisms?
a. DNA damage from chemical reactions cannot be undone.
b. Proofreading from DNA polymerase reduces the error rate in DNA to about 1 in 100 nucleotides.
c. Copying errors not caught by the replication machinery can be corrected by mismatch repair.
d. Non-homologous end joining is less likely to produce mutations than homologous recombination.
c. Copying errors not caught by the replication machinery can be corrected by mismatch repair.
During mitosis, what structure is responsible for moving the chromosomes within the cell, and for separating sister chomatids?
a. nucleolus
b. mitotic spindle
c. metaphase plate
d. cleavage furrow
b. mitotic spindle
Which of the following is true regarding the process of meiosis I?
a. Sister chromatids separate.
b. Sister chromatids in a cell undergoing meiosis are always identical.
c. Tetrads are formed by synapsis of homologous chromosomes.
d. One pair of homologous chromosomes line up at the metaphase plate.
c. Tetrads are formed by synapsis of homologous chromosomes.
Human skin cells divide about once a day. Which of the following conditions could prevent a skin cell from passing the G1 checkpoint?
a. The chromosomes of the cell are not properly attached to spindle fibers.
b. The cell's DNA is damaged.
c. The cell has not completed DNA replication.
d. All of the above.
b. The cell's DNA is damaged.
Endocrine signals are transmitted more slowly than paracrine signals because . . .
a. the ligands are transported through the bloodstream and travel greater distances
b. the target and signaling cells are close together
c. the ligands are degraded rapidly
d. the ligands don't bind to carrier proteins during transport
a. the ligands are transported through the bloodstream and travel greater distances
Which of the following statements is false?
a. DNA polymerase cannot initiate a strand.
b. DNA polymerase requires a template strand.
c. DNA polymerase adds a nucleotide to a hydroxyl functional group.
d. DNA polymerase catalyze DNA strand elongation in the 3' to 5' direction.
d. DNA polymerase catalyze DNA strand elongation in the 3' to 5' direction.
Duplicated chromosomes that stay together & are identical to each other are called what?
A. Sister chromatids
B. Homologous chromosomes
C. Centromeres
D. Daughter chromosomes
A. Sister chromatids
Which of the following correctly describes how Meiosis I and Meiosis II differ?
a. Meiosis I produces diploid daughter cells, while Meiosis II produces haploid daughter cells.
b. Pairs of homologous chromosomes are separated during Meiosis I, while sister chromatids are separated during Meiosis II.
c. Genetic material is exchanged between homologous chromatids during Meiosis II bit not Meiosis I.
d. Cytokinesis occurs following Meiosis II, but not Meiosis I.
b. Pairs of homologous chromosomes are separated during Meiosis I, while sister chromatids are separated during Meiosis II.
Checkpoints are the cell cycle control system. Which of the following occurs at the M checkpoint? What happens if the cell does not pass the M checkpoint?
a. The M checkpoint checks for proper attachment of sister chromatids. If it fails, then cells may undergo nondisjunction of chromosomes.
b. The M checkpoint checks if the DNA is damaged and promotes its repair. If it fails, then the cell may undergo apoptosis.
c. The M checkpoint ensures the proper duplication of DNA. If it fails, the daughter cells may end up with damaged DNA.
d. The M checkpoint ensures that all the components required for cell division are available. If it fails, the cell cycle will be inhibited.
a. The M checkpoint checks for proper attachment of sister chromatids. If it fails, then cells may undergo nondisjunction of chromosomes.
*b. G1 Checkpoint
*c. G2 Checkpoint
*d. G1 Checkpoint
Which statement best describes the role of first messengers in cellular communication?
a. Function as enzymes responsible for phosphorylation.
b. Extracellular signals that bind to a membrane receptor.
c.Intracellular receptors the receive the initial signal.
d. Intracellular signals that diffuse throughout the cytoplasm in the transduction stage.
b. Extracellular signals that bind to a membrane receptor.
1. _____ opens up the DNA at the replication fork.
2. _____ works at the region ahead of the replication fork to prevent supercoiling.
3. _____ synthesizes RNA primers complementary to the DNA strand.
4. _____ seals the gaps between DNA fragments.
a. Ligase
b. Helicase
c. Topoisomerase
d. Primase
1. b. Helicase
2. c. Topoisomerase
3. d. Primase
4. a. Ligase
Which of the following is incorrectly paired?
a. PROPHASE - DNA is replicated
b. METAPHASE - chromosomes line up along the imaginary plane that is equidistant from the two poles.
c. ANAPHASE - sister chromatids separate and become chromosomes
d. TELOPHASE - chromosomes begin to decondense and the nuclear envelope forms around each set of chromosomes.
a. PROPHASE - DNA is replicated
*DNA replication occurs in the S-phase of the interphase. In prophase, chromosomes begin to condense.
During meiosis I, pairs of homologous chromosomes align randomly along the metaphase plate before being separated. This process helps generate genetic variation in the offspring of sexual reproduction. Which of the following best explains how the random alignment of homologous chromosomes during meiosis helps generate varied offspring?
a. Random alignment results in the formation of gametes that contain different numbers of chromosomes.
b. Random alignment increases the likelihood of crossing over between non-sister chromatids.
c. Random alignment results in the formation of some diploid and some haploid gametes.
d. Random alignment increases the number of possible chromosome combinations in the gametes.
d. Random alignment increases the number of possible chromosome combinations in the gametes.
*When homologous chromosomes align on the metaphase plate, their arrangement is random and independent of one another. This results in different combinations of maternal and paternal chromosomes segregating into different gametes, which increases genetic diversity in the offspring of sexual reproduction.
Gametogenesis occurs when diploid germ cells undergo meiosis. In fruit flies, diploid germ cells contain eight chromosomes. Which of the following correctly describes the number of chromosomes in the daughter cells produced during gametogenesis in fruit flies?
a. The daughter cells each contain four chromosomes after meiosis I and four chromosomes after meiosis II.
b. The daughter cells each contain eight chromosomes after meiosis I and eight chromosomes after meiosis II.
c. The daughter cells each contain four chromosomes after meiosis I and two chromosomes after meiosis II.
d. The daughter cells each contain eight chromosomes after meiosis I and four chromosomes after meiosis II.
a. The daughter cells each contain four chromosomes after meiosis I and four chromosomes after meiosis II.