Cell Bio Exam 4

Question 1

Based on cell activities readily visible in the light microscope, there are two major cell cycle
phases, ________ and __________.

Answer 1

M phase, interphase

Question 2

The first gap in the cell cycle (G1) corresponds to

Answer 2

Normal growth and cell function

Question 3

Cells that have stopped dividing and are arrested in a stage preceding the initiation of DNA synthesis are said to be in a ___ stage

Answer 3

G0

Question 4

Which of the following is a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex?

Answer 4

Cyclin

Question 5

What multiprotein complex has recently been shown to play a significant role in chromosome compaction

Answer 5

Condensin

Question 6

At the outer surface of the centromere of each chromatid is a proteinaceous, buttonlike structure called

Answer 6

the kinetochore

Question 7

Which stage of mitosis starts as sister chromatids split apart and begin to move towards opposite poles

Answer 7

Anaphase

Question 8

The mitotic spindle is a microtubular structure that is involved in

Answer 8

Separation of sister chromatids

Question 9

Metaphase is characterized by

Answer 9

aligning of chromosomes on the equator

Question 10

Movement of the chromosomes during anaphase would be most affected by a drug that prevents

Answer 10

Shortening of microtubules

Question 11

The beginning of anaphase is indicated by which of the following

Answer 11

Cohesin is cleaved enzymatically

Question 12

During which phase of mitosis do the chromatids become chromosomes

Answer 12

Anaphase

Question 13

The drug cytochalasin B block the function of actin. Which of the following aspects of the cell cycle would be disrupted by cytochalasin?

Answer 13

Cleavage furrow formation and cytokinesis

Question 14

Crossing- over is important for

Answer 14

ensuring proper chromosome segregation and introducing additional genetic variation into the population; 1 and 3

Question 15

After telophase I of meiosis, the chromosomal makeup of each daughter cell is

Answer 15

Haploid and the chromosomes are composed of two chromatids

Question 16

Sister chromatids separate from each other during

Answer 16

Mitosis and Meiosis II

Question 17

No matter how the signal initiated by the binding of a ligand is transmitted, what is the outcome of that signal

Answer 17

A protein at the top of an intracellular signal pathway is activated

Question 18

Which amino acids are known to be phosphorylated by protein kinases

Answer 18

Serine, threonine, and tyrosine

Question 19

How do cells in the body of multicellular organism usually communicate with each other

Answer 19

Extracellular messenger molecules

Question 20

The overall process in which info is carried by extracellular messenger molecules is translated into change that occurs inside the cell

Answer 20

Signal Transduction

Question 21

If the receptor is degraded along with its ligand afte internalization, what is the effect on the cell’s ability to respond to a hormone

Answer 21

3; the cell has decreased sensitivity to subsequent stimuli

Question 22

The process that blocks active receptors from turning on additional G proteins

Answer 22

Desensitization

Question 23

Which of the following features would be a requirement for a receptor that exhibits ligand-mediated dimerization

Answer 23

the ligand has two binding sites for receptors

Question 24

What phosphorylates the tyrosine residues found on docking proteins

Answer 24

A receptor protein-tyrosine kinase

Question 25

What event is usually responsible for terminating signal transduction by RTKs

Answer 25

Receptor internalization

Question 26

The activation of a common effector by signals from a variety of unrelated receptors, each of which binds to its own ligand

Answer 26

Convergence

Question 27

The ___ pathway of apoptosis is one in which external stimuli activates apoptosis

Answer 27

Extrinsic

Question 28

What do all the environmental agents that can cause cancer have in common

Answer 28

The can all alter the genome

Question 29

What is the most important property of a cancer cell, whether it is in the body or culture dish?

Answer 29

Its loss of growth control

Question 30

Cancer results from the uncontrolled proliferation of a single wayward cell and is therefore considered to be

Answer 30

Monoclonal

Question 31

Sometimes an enzyme is activated by a receptor and brings about the cellular response by generating a second messenger. Such an enzyme is called

Answer 31

Effector

Question 32

Describe the basic properties of cancer cells (from the cellular level and genetic level)

Answer 32

Cellular Level:

• Growth of cancer cells are out of control
• Don’t respond to inhibitory influences from the environment
• Don’t need stimulatory growth signals
• Fail to elicit the apoptotic response

Genetic Level:

• Cancer cells are genetically unstable
• often have highly aberrant chromosome complements

Question 33

There are 3 events that are unique to meiosis, and all three can occur in meiosis I when compare mitosis to meiosis. What are they

Answer 33

• Synapsis and crossing over
• Homologous pairs at the metaphase plate
• Separation of homolog

Question 34

Cells communicate with each other using extracellular messenger molecules. What are the features of each?

Answer 34

Autocrine signaling- cell has receptors on its surface that interacts with messenger

Paracrine signaling- messenger molecules travel short distances through extacellular space and works on neighboring cells

Endocrine signaling- hormones travel through the bloodstream to reach their target cells

Question 35

Receptor protein tyrosine kinases can interact with different signaling proteins. List the names

Answer 35

adaptor proteins
docking proteins
transcription factor
signaling enzymes

Question 36

Describe what apoptosis and necrosis is and compare similarities and differences between the two

Answer 36

Apoptosis- and ordered normal process leading to the cell death in animals; shrinkage in volume of the cell and its nucleus

Necrosis- the process of cell death which follows some type of physical trauma or biochemical insults; swelling of both the cell and its internal membranous organelles