Cell Bio Exam 4 Flashcards
Based on cell activities readily visible in the light microscope, there are two major cell cycle
phases, ________ and __________.
M phase, interphase
The first gap in the cell cycle (G1) corresponds to
Normal growth and cell function
Cells that have stopped dividing and are arrested in a stage preceding the initiation of DNA synthesis are said to be in a ___ stage
G0
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?
Cyclin
What multiprotein complex has recently been shown to play a significant role in chromosome compaction
Condensin
At the outer surface of the centromere of each chromatid is a proteinaceous, buttonlike structure called
the kinetochore
Which stage of mitosis starts as sister chromatids split apart and begin to move towards opposite poles
Anaphase
The mitotic spindle is a microtubular structure that is involved in
Separation of sister chromatids
Metaphase is characterized by
aligning of chromosomes on the equator
Movement of the chromosomes during anaphase would be most affected by a drug that prevents
Shortening of microtubules
The beginning of anaphase is indicated by which of the following
Cohesin is cleaved enzymatically
During which phase of mitosis do the chromatids become chromosomes
Anaphase
The drug cytochalasin B block the function of actin. Which of the following aspects of the cell cycle would be disrupted by cytochalasin?
Cleavage furrow formation and cytokinesis
Crossing- over is important for
ensuring proper chromosome segregation and introducing additional genetic variation into the population; 1 and 3
After telophase I of meiosis, the chromosomal makeup of each daughter cell is
Haploid and the chromosomes are composed of two chromatids
Sister chromatids separate from each other during
Mitosis and Meiosis II
No matter how the signal initiated by the binding of a ligand is transmitted, what is the outcome of that signal
A protein at the top of an intracellular signal pathway is activated
Which amino acids are known to be phosphorylated by protein kinases
Serine, threonine, and tyrosine
How do cells in the body of multicellular organism usually communicate with each other
Extracellular messenger molecules
The overall process in which info is carried by extracellular messenger molecules is translated into change that occurs inside the cell
Signal Transduction
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
3; the cell has decreased sensitivity to subsequent stimuli
The process that blocks active receptors from turning on additional G proteins
Desensitization
Which of the following features would be a requirement for a receptor that exhibits ligand-mediated dimerization
the ligand has two binding sites for receptors
What phosphorylates the tyrosine residues found on docking proteins
A receptor protein-tyrosine kinase
What event is usually responsible for terminating signal transduction by RTKs
Receptor internalization
The activation of a common effector by signals from a variety of unrelated receptors, each of which binds to its own ligand
Convergence
The ___ pathway of apoptosis is one in which external stimuli activates apoptosis
Extrinsic
What do all the environmental agents that can cause cancer have in common
The can all alter the genome
What is the most important property of a cancer cell, whether it is in the body or culture dish?
Its loss of growth control
Cancer results from the uncontrolled proliferation of a single wayward cell and is therefore considered to be
Monoclonal
Sometimes an enzyme is activated by a receptor and brings about the cellular response by generating a second messenger. Such an enzyme is called
Effector
Describe the basic properties of cancer cells (from the cellular level and genetic level)
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
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
- Synapsis and crossing over
- Homologous pairs at the metaphase plate
- Separation of homolog
Cells communicate with each other using extracellular messenger molecules. What are the features of each?
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
Receptor protein tyrosine kinases can interact with different signaling proteins. List the names
adaptor proteins
docking proteins
transcription factor
signaling enzymes
Describe what apoptosis and necrosis is and compare similarities and differences between the two
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
