College Biology Chapter 20 Smartbook

What explains the profound morphological and physiological differences that are observed in different cells in the same organism?

Different genes are turned on and off in certain cells during development.

The homeotic genes in mammals are known as the _______ genes

Hox

What are possible fates for a daughter cell of a dividing stem cell?

It can become a specialized cell. It can remain a stem cell.

Which of the following are features that all stem cells have?

Their daughter cells can differentiate into one or more cell types. They can divide

How do homeotic proteins promote developmental changes in an animal?

They activate transcription of genes.

How do maternal morphogens in the fruit fly participate in the establishment of the main body axes?

They are asymmetrically distributed in the oocyte prior to fertilization.

Why are homeotic genes important in animals?

They influence the development of segment characteristics.

How do homeotic gene products act on a molecular level?

They interact with DNA and can stimulate or repress the expression of certain genes.

Which of the following is an example of a multipotent stem cell?

a hematopoietic stem cell

The first cellular division of the fertilized oocyte in Arabidopsis is asymmetric and produces two cells of unequal size: a smaller _____ cell and a larger _____ cell

apical, basal

In Drosophila development, maternal morphogens in the oocyte are distributed ______, thus promoting the formation of the ______ axis.

asymmetrically; anteroposterior

The four generalized phases in the development of an animal are: (i) organization of the body along ___________, (ii) organization of the body into several smaller ___________, (iii) organization of cells in ways that produce body parts and (iv) cell _________, where cells change morphologies and become specialized.

axes, regions, differentiation

The first cell division in Arabidopsis produces two cells of unequal size. The ______ cell gives rise to the root and the suspensor, and the ______ cell develops into the shoot of the plant.

basal ; apical

Order the different structures in the flower of Arabidopsis starting at the center of the flower.

carpels, stamens, petals, sepals

In the fruit fly, segmentation genes are genes that:

control the segmentation pattern

The process that gives rise to the structures and functions of living organisms is called

development

in biology, the term _______ refers to a series of changes in the state of a cell, tissue, organ, or organism

development

In mammals, stem cells are categorized according to their ______ stage and their ability to ______.

developmental; differentiate

All stem cells have two common characteristics: they have the capacity to ______ and their daughter cells can _____ into one or more specialized cell types.

divide, differentiate

After it divides the zygote becomes a multicellular:

embryo

The pluripotent stem cells found in the blastocyst of a mammalian embryo are called ______ stem cells

embryonic

Stem cells in the embryo that will later give rise to sperm or egg cells are called _____ (EG) cells.

embryonic germ

The pluripotent stem cells in the blastocyst of the mammalian embryo are called:

embryonic stem cells

True or false: Animals develop by pattern formation, while plants do not.

false

True or false: In sharp contrast to animals, plants do not have homeotic genes.

false

The ultimate morphological features that a cell or a group of cells will adopt is referred to as its/their:

fate

Match each type of cell with the correct description.

fertilized egg --> totipotent embryonic stem cell --> pluripotent bone marrow cell ->multipotent skin cell ->unipotent

Order the stages in the development of an Arabidopsis plant from early to late.

fertilized oocyte two-cell stage eight-cell stage heart stage seedling adult plant

Which of the following are produced by the shoot meristem of a plant?

flowers, stems, leaves

Different cells in the same organism can have profound morphological and physiological differences that arise due to regulation of the expression of

genes

examples of multipotent stem cells are the ________ stem cells which are found in the bone marrow and which gives rise to multiple blood cell types

hematopoietic

Homeotic genes contain a 180-bp coding sequence known as the________; this DNA sequence encodes a protein domain called the homeodomain.

homeobox

One difference between homeotic genes in plants and animals is that plant homeotic genes do not contain a sequence similar to the ______ found in animals

homeobox

The homeobox encodes a region of the homeotic protein called the ________, which can bind to DNA.

homeodomain

What part of a plant produces offshoots of proliferating and differentiating cells?

meristem

Plant development depends on the presence and function of:

meristems

The development of plants is strongly dependent on the presence of organized groups of actively dividing stem cells called

meristems

Developmental biologists study developmental genetics in ______ organisms so that they can understand scientific principles that apply broadly to many species.

model

In the following list, identify mechanisms that convey positional information to cells.

morphogen molecules, cell adhesion

a ______ stem cell can differentiate into several cell types but not as many as an embryonic stem cell.

multiponent

A _____ stem cell can differentiate into several cell types but not as many as an embryonic stem cell.

multipotent

Which of the following are key differences between plant and animal development?

no cell migration during plant development no morphogen deposition in plant oocytes totipotent somatic cells in plants

A unipotent stem cell produces daughter cells that can differentiate into:

one cell type

When a stem cells divides:

one of the daughter cells remains a stem cell, while the other differentiates the two daughter cells can have different fates

both animals and plants develop by _______ formation

pattern

Embryonic germ (EG) cells can differentiate into every or nearly every cell type of the body. That is why they are said to be

pluripotent

Embryonic germ cells are:

pluripotent

Stem cells that can differentiate into every or nearly every cell type of the body are called ______ cells. An example would be embryonic stem cells.

pluripotent

During development, cells receive ______ information which provides them with cues regarding their location relative to other cells in the body.

positional

during development, cells receive ______ information which provides them with cues regarding their location relative to other cells in the body

positional

Various cues that cells receive at appropriate times during development provide them with information regarding their location in the body relative to other cells. This type of information is known as:

positional information

The ______ meristem in plants gives rise to root structure, while the ______ meristem produces all the aerial structures of the plant

root apical, shoot apical

Genes that alter the pattern of segment formation in the fruit fly are called ______ genes

segmentation

genes that alter the pattern of segment formation in the fruit fly are called _______ genes

segmentation

the body of the fruit fly embryo divides into segments due to the sequential activation of ________ genes

segmentation

A multipotent stem cell can usually differentiate into:

several types of specialized cells

In Arabidopsis, the apical cell of the two-cell stage gives rise to the _______ of the plant, while the basal cell gives rise to the ______ of the plant and the suspensor which channels nutrients from the parent plant to the embryo

shoot; root

In contrast to animals, an entirely new plant organism can be regenerated from many types of ______ cells, which are cells that do not give rise to gametes.

somatic

Embryonic germ cells are stem cells in the embryo that will later give rise to ____ or ____ cells

sperm or egg

Which of the following is a totipotent cell?

the fertilized egg

According to the ABC model in Arabidopsis flowers:

three classes of genes (A, B and C) control the formation of the flower parts

A(n) ______ stem cell can produce all of the cell types of an organism and give rise to an entire organism.

totipotent

The fertilized egg is considered to be a(n) _____ stem cell

totipotent

The fertilized egg is considered to be a(n) _______ stem cell

totipotent

Which of the following are correct descriptions of stem cells?

totipotent unipotent pluripotent multipotent

Match each type of stem cell to the type of differentiated cells it can produce.

totipotent - can produce all specialized cells and give rise to an entire organism pluripotent - can produce all specialized cells but not an entire organism multipotent - can produce several types of specialized cells but not all unipotent - produces one type of specialized cell

In both animals and plants, the products of homeotic genes are ______ factors that contain a(n) ______-binding domain.

transcription ; DNA

True or false: Hox genes in the fruit fly and those in the mouse and other mammals are evolutionary related.

true

A typical Arabidopsis embryo goes through several critical stages, the first two being the ______-cell stage and the ______-cell stage.

two ; eight

The stem cells that divide and supply the cells that constitute the body of a plant or animal are:

undifferentiated

The homeodomain of homeotic protein consists of alpha-helices that can bind the protein to:

DNA

Homeotic genes encode products that bind to specific

DNA sequences to promote transcription of specific genes.

In Arabidopsis plants, what characterizes the first cell division after fertilization?

It is an asymmetrical division that produces two cells of unequal size.

Which of the following criteria must be met in order to call a cell totipotent?

It must be able to produce every cell type of the adult organism. It must be able to give rise to an entire organism.

Which of the following is a feature of homeotic genes in animals?

They are homologous.

How do segmentation genes act to promote the formation of segments in the embryo of the fruit fly?

They are sequentially activated.

Why are stem cells important in human medicine?

They can be used to produce cells which can replace cells that have died due to disease or injury.

Which of the following are features of pluripotent cells?

They can produce all types of cells; they cannot produce an entire organism.

How do developmental biologists study developmental genetics?

They use various model organisms

Match each stage of development in Drosophila with the correct description.

fertilized oocyte - single cell that contains positional information embryo - multicellular; first stage with a visibly segmented body pattern larva - free-living organism that is morphologically different from the adult pupa - transitional stage between larva and adult

Place the stages in the development of a fruit fly in order from earlier to later stages.

fertilized oocyte, embryo, larva, pupa, adult

Most _______ genes contain a 180-base pair coding sequence known as the homeobox.

homeotic

Similar to animals, plants have _____ genes, such as the ABC genes in flowers of Arabidopsis

homeotic

The Hox genes found in mammals are evolutionary related to the fruit fly's:

homeotic genes

What group of genes is responsible for the development of particular structures, such as wings and legs, in specific segments of an animal?

homeotic genes

Genes that are evolutionarily derived from the same ancestral gene are called:

homologous genes

Undifferentiated cells that divide and supply the cells that constitute the body of all animals and plants are known as _____ cells

stem

in Drosophila, _________ genes specify the fate of a particular segment or region of the body.

homeotic

in vertebrates, the _________genes are known as Hox genes and are homologous to genes that control development in simpler invertebrate species.

homeotic

similar to animals, plants have _______ genes, such as the ABC genes in flowers of Arabidopsis

homeotic

In the fruit fly, genes that specify the fate of a particular segment are called:

homeotic genes

the two main molecular mechanisms used to convey _______ information to cells are: (1) gradients of __________; and (2) cell adhesion

positional, morphogens

Undifferentiated cells that divide and supply the cells that constitute the body of all animals and plants are known as ______ cells

stem

embryonic _____ cells can be used to treat diseases and injuries that involve cell and tissue death

stem

Arrange the following terms in order, beginning with the type of cell that can differentiate into the greatest variety of cell types at the top.

totipotent, pluripotent, multipotent, unipotent

The primary function of homeotic proteins is to activate the _______ of specific genes, thus promoting developmental changes in an animal.

transcription