Bio Unit 4 Review

what is the expected percent change in the DNA content of a typical eukaryotic cell as it progresses through the cell cycle from the start of the G1 phase to the end of the G2 phase?

+100%

if a cell has 8 chromosomes how many chromosomes will each of its daughter cells have after cytokineses?

8

which of the following statements regarding the movement of molecules across cell membranes is true?

three examples of passive transport are diffusion, facilitated diffusion, and osmosis

which of the following would likely move through the phospholipid bilayer the most easily?

CO2

which of the following is true of mitosis?

it maintains the same chromosome number in the daughter cells as in the parent cell

why is it important for cells of multicellular organisms to undergo mitosis?

mitosis produces cells that are identical to the original dividing cell

which of the following is true of malignant tumors

they can cause tumors in other parts of the body

cancer can result from a variety of different mutational events. which of the following is least likely to result in the initiation of a cancerous tumor?

a defect in a cell cycle checkpoint prevent a cell from entering the S phase

what type of cellular transport requires a cell to use energy?

active transport

the process of keeping the internal environment of the body stable by responding to changes in the external environment is known as homeostasis. which of the following accurately describes a mechanism for maintaining homeostasis at the cellular level?

active transport, where molecules are pumped across the cell membrane against the gradient form low to high concentration

the endocrine system incorporated feedback mechanisms that maintain homeostasis. which of the following demonstrates negative feedback by the endocrine system?

after a meal, blood glucose levels become elevated stimulating beta cells of the pancreas to release insulin into the blood. excess glucose is then converted to glycogen in the liver reducing blood glucose levels.

during which phase of mitosis do sister chromatids separate from each other?

anaphase

while in the womb, the webbed fingers of the embryo undergo programmed cell death, also known as

apoptosis

one difference between a cancer cell and a normal cell is that

cancer cells divide uncontrollably

substances known to produce or promote cancer cells are called

carcinogens

ethylene is an organic compound produced by ripening fruits. in a controlled experiment, researchers found that ethylene gas stimulated the ripening process in newly harvested fruits. which of the following describes the most likely connection between natural ethylene production and fruit ripening?

ethylene gas is a chemical signal through which ripening fruits trigger the ripening process in other fruits

which of the following best describes the role of mitosis in the cell cycle?

exchanging genetic material between homologous chromosomes

most cells that have become transformed into cancer cells have which of the following characteristics when compared to normal healthy cells?

shorter cell cycle

cancer cells behave differently than normal body cells. for example, they ignore signals that tell them to stop dividing. which of the following conditions will most likely cause a normal body cell to become a cancer cell?

the environment contains mutagens that induce mutations that affect cell cycle regulator proteins

which of the following statements best describes how a growth factors stimulates cell division from outside a cell?

the growth factor binds to receptors on the cell surface, initiating a signal transduction pathway that activated specific target genes

researchers studying cell cycle regulation in budding yeast have observed that mutation in the CDC15 gene causes cell cycle arrest in telophase when the yeast cells are incubated at an elevated temperature. which of the following statements best predicts the effect of the cell cycle arrest on proliferating yeast cells?

the yeast cells will replicate their chromosomes but will fail to complete cytokinesis

which of the following best explains the most likely method by which antitumor drug works?

trabectedin interferes with the duplication of DNA during interphase and thus prevents cancer cells from passing the G2 checkpoint

which of the following scientific questions is most relevant to the model represented in the figure?

which molecular substance is actively transported across the plasma membrane

based on figure 1, what percent of the time required to complete a cycle do the cells typically spend in interphase?

95%

which level of organizations forms the fundamental base for all other levels in the hierarchy of life?

cell

which organelle is critical for cell division?

centrioles

a student is examining an onion root tip cell under a microscope. based on her observations the student proposes that the onion root tip cell has completed interphase and is now in the first phase of mitosis. which of the following pieces of evidence would best support the students claim

discrete chromosomes are scattered throughout the cell's nucleus

DNA replication occurs

during the S phase of the cell cycle

the graph shows how cellular DNA content changes over the course of a typical mitotic cell cycle in rapidly proliferating human cells. based on the graph, which of the following statements is correct?

human cells spend the majority of their life in interphase

cortisol is a hormone produced in response to stress, including starvation in humans. which of the following is most likely an immediate effect of a starvation-induced increase in cortisol secretion?

increased mobilization of fatty acids from fat cells