Chapter 20: Developmental Genetics

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.

What are the correct descriptions of stem cells?

- Multipotent - Unipotent - Totipotent - Pluripotent

What are key differences between plant and animal development?

- No morphogen deposition in plant oocytes - Totipotent somatic cells in plants - No cell migration during plant development

What are the features that all stem cells have?

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

What criteria are used to categorize mammalian stem cells?

- Their developmental stage - Their ability to differentiate

When a stem cell divides,

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

When a stem cell divides, ______.

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

What is a homeobox?

A sequence within a homeotic gene that encodes the DNA-binding portion of a transcription factor

Why are stem cells important in human medicine?

Because they can be used to produce cells which can replace cells that have died due to disease or injury

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

Homeotic proteins typically contain two domains that are important for their function: a ______-binding domain and a ______-activation domain.

DNA; transcription

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.

What is larva in Drosophila?

Free-living organism that is morphologically different from the adult

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

______ provide positional information by acting in a concentration-dependent manner.

Morphogens

What is embryo in Drosophila?

Multicellular; first stage with a visibly segmented body pattern

What is fertilized oocyte in Drosophila?

Single cell that contains positional information

What is the main reason for controversy in the ongoing public debate about using stem cells for research and treatment?

The source of the stem cells

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.

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

They are sequentially activated.

What are features of pluripotent cells?

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

What are the features of pluripotent cells?

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

Why are homeotic genes important in animals?

They influence the development of segment characteristics.

How do developmental biologists study developmental genetics?

They use various model organisms.

What type of cell that can differentiate into the greatest variety of cell types?

Totipotent

What is pupa in Drosophila?

Transitional stage between larva and adult

What type of cell that can differentiate into the least variety of cell types?

Unipotent

What's the fifth step in the development of a fruit fly?

adult

A totipotent cell is one that can give rise to ______ in the adult organism.

all cell types

Totipotent can produce

all specialized cells and give rise to an entire organism

Pluripotent can produce

all specialized cells but not an entire organism

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: (1) organization of the body along _____, (2) organization of the body into several smaller _____, (3) organization of cells in ways that produce body parts, and (4) 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

What is the fourth step in the development of an animal?

cell differentiation

In the fruit fly, segmentation genes _____.

control the segmentation pattern

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

development

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

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

In animals and flowering plants, the zygote divides to produce a multicellular _____ and eventually an adult organism.

embryo

What's the second step in the development of a fruit fly?

embryo

In developmental genetics, the ultimate morphological features that a cell or a group of cells will adopt is referred to as its/their _____.

fate

The term ______ is used to describe the ultimate morphological features that a cell or a group of cells will adopt.

fate

What's the first step in the development of a fruit fly?

fertilized oocyte

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

genes

Homeotic genes contain a 180-bp DNA sequence which encodes a protein domain called the homeodomain. This DNA sequence is known as the _____.

homeobox

The homeobox encodes a DNA-binding region of the homeotic protein called the _____.

homeodomain

Animals and plants bot have _____ genes.

homeotic

In Drosophila, the genes that specify the fate of a particular segment or region of the body are termed _____ genes.

homeotic

In the fruit fly, ______ control the development of a particular segment or group of segments.

homeotic genes

What's the third step in the development of a fruit fly?

larva

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

model

Chemical molecules that impart positional information through their concentration gradient are called _____.

morphogens

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

multipotent

Bone marrow cell

multipotent

The daughter cells produced by a unipotent cell can differentiate into ______.

one cell type

Unipotent can produce

one type of specialized cell

What is the first step in the development of an animal?

organization along axes

What is the third step in the development of an animal?

organization of cells into body parts

What is the second step in the development of an animal?

organization of the body into smaller regions

The main controversy in stem cell research relates to how people feel about the _____ of stem cells.

origin

Both animals and plants develop by _____ formation.

pattern

Embryonic stem cell is

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

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 _____ information.

positional

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

positional information

What's the fourth step in the development of a fruit fly?

pupa

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 ______ of specialized cells.

several types

Multipotent can produce

several types of specialized cells but not all

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 that do not give rise to gametes. These are called _____ cells.

somatic

To treat diseases and injuries that involve cell and tissue death, embryonic _____ cells can be used.

stem

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

stem

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

totipotent

Fertilized egg is

totipotent

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

undifferentiated

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

undifferentiated

A stem cell that produces daughter cells that can differentiate into one cell type is called _____.

unipotent

Skin cell is

unipotent