Cell Structure Chapter 20

Both multicellular plants and animals have:
A) Cells capable of locomotion
B) cells with cell walls
C) a cytoskeleton composed of actin filaments, microtubules, and intermediate filaments.
D) tissues composed of multiple different cell types.

A is incorrect because plants are not capable of locomotion
.B is incorrect because animal cells do not have cell walls.
C is incorrect because plant cells do not have intermediate filaments.
D is correct

A major distinction between the connective tissues in an animal and other main tissue types such as epithelium, nervous tissue or muscle is the:
A) ability of connective-tissue cells such as fibroblasts to change shape
B) amount of extracellular matrix in

A is incorrect because cells in nonconnective tissues can change shape (for example, muscle cells when they contract),
B is correct
C is incorrect because cells in nonconnective tissues can withstand mechanical stress (for example, cells of the epidermi

Indicate whether the following are found in plants, animals, or both:
A) intermediate filaments
B) cell walls
C) microtubules
D) cellulose
E) collagen

A) animals
B) plants
C) both
D) plants
E) animals

A is columnarB is squamousC is cuboidalThe yellow layer is the basal laminaThese tissues all appear simple - one layer. If they had many layers, they would be stratified.

The plasmodesmata in plants are functionally most similar to which animal cell junction?
A) tight junction
B) Adherens junction
C) gap junction
D) desmosome

C - gap junction

When a terminally differentiated cell in an adult body dies, it can typically be replaced in the body by a stock of..
A) proliferating precursor cells
B) cells more apically located than the terminally differentiated cells
C) Wnt proteins
D) induced pluri

Proliferating precursor cells already within the tissue are typically used to replace terminally differentiated cells. Induced pluripotent cells are produced in the laboratory and are not typically used to replace adult terminally differentiated cells w

Which of the following statements about stem cell niches is false?
A) The paneth cell serves as a stem cell niche for the stem cells of the mammalian intestine
B) Wnt signaling is required for a functional stem cell niche in the mammalian intestine
C) Dr.

D is incorrect because Paneth cells serve as the stem cell niche and are therefore required to maintain stem cells in the intestine.

Induced pluripotent stem (iPS) cells:
A) can be created by the expression of a set of key genes in most somatic cells types, including cells derived from adult tissues
B) require a supply of donor egg cells, as in the case of embryonic stem cells
C) can d

B is incorrect because iPS cells do not require donor egg cells and are made from adult (and not embryonic) cells.
C is incorrect because embryonic stem cells can differentiate into all tissue and cell types
.D is incorrect because iPS cells (in additio

A malignant tumor is more dangerous than a benign tumor because
A) its cells are proliferating faster
B) it causes neighboring cells to mutate
C) its cells attack and phagocytose neighboring normal tissue cells
D) its cells invade other tissues


Ras is a GTP-binding protein that is often defective in cancer cells. A common mutation found in cancer cells causes Ras to behave as though it were bound to GTP all the time, which will cause cells to divide inappropriately. From this description, the no

The normal Ras gene is a proto-oncogene. Only the mutated form of Ras is an oncogene and a gain-of-function mutation.