34 Questions
What is the correct order of organization in multicellular organisms?
Cells → Tissues → Organs → Organ Systems → Body
What is the main component of animal connective tissues?
Extracellular matrix
What is the main function of collagen in animal connective tissues?
Providing tensile strength
What type of modification occurs to collagen during its synthesis?
Glycosylation and acetylation
What is the precursor to collagen?
Procollagen
Why doesn't procollagen proteinase cleave procollagen inside the fibroblast?
Because the unstructured ends of procollagen prevent proteinase activity
What happens to epithelial cells when apical bundles of actin filaments contract?
They narrow at their apex
What is the fate of a vesicle in a developing animal?
Its fate depends on the orientation of contraction of the epithelial sheet
What type of proteins binds to the dense plaque of intracellular linker proteins on the cytoplasmic side of the plasma membrane?
Cadherin proteins
What is the function of hemidesmosomes in an epithelial cell?
To anchor the intermediate filaments to the basal lamina
Why are integrins used in hemidesmosomes instead of cadherins?
Because integrins are specific to the basal lamina
What is the earliest tube that forms in a developing embryo?
Neural tube
How do integrins inform the cell that it is anchored to the extracellular matrix?
By undergoing a conformational change
What triggers the switch to an active conformation in integrins?
Binding to fibronectin or intracellular adaptor proteins
What do polysaccharides and proteins in tissues do, according to the text?
Fill spaces and resist compression
What is the role of glycosaminoglycans (GAGs) in tissues?
Fulfilling the role of resisting compression
What characterizes Hyaluronan as a glycosaminoglycan?
Consists of a single long chain with up to 25,000 repeated disaccharide units
Why are the negative charges on glycosaminoglycans (GAGs) important to their function?
Affect the interaction with other extracellular matrix components
What is a characteristic of oncogenes?
They act in a dominant manner.
What happens to the function of tumor suppressor genes in cancer cells?
It is lost.
What is a common feature of the key regulatory pathways perturbed in human cancers?
They regulate cell growth and proliferation.
What type of mutations can convert a proto-oncogene into an oncogene?
Gain-of-function mutations.
What is a characteristic of tumor suppressor genes?
They generally act in a recessive manner.
What is the result of a loss-of-function mutation in a tumor suppressor gene?
The function of the gene is lost.
What do gap junctions provide neighboring cells with?
Direct channel of intercytosolic communication
Which protein assemblies penetrate the apposed membranes of adjacent cells in gap junctions?
Connexons
What do stem cells have the ability to do in terms of lineage production?
Renew themselves and produce terminally differentiated lineages
Where does renewal occur continuously in the mammalian intestine?
In the epithelial lining
What type of cells are primarily renewed from stem cells in the epidermis?
Keratinocyte stem cells
Which type of stem cells are found in red bone marrow and give rise to various blood cell types?
Hemopoietic stem cells
What maintains the proliferation of stem cells in the precursor cells of the intestinal crypts?
Wnt signaling pathway
What protein interacts with the GPCR frizzled in the Wnt signaling pathway?
Dishevelled
Which cell types increase in production during an infection due to hemopoietic stem cells?
White blood cells (leukocytes)
What allows stem cells of different types to be maintained in culture?
Culturing techniques
Test your knowledge on tissues, stem cells, and cancer based on the reference text Essential Cell Biology, 5th ed. by Alberts et al., 2019. This quiz covers the concepts of how cells form tissues, the role of stem cells, and the connection between tissues and cancer.
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