Chapter 1

Question 1

What is a protozoan?

Answer 1

A microscopic single-called organism

Question 2

What is a metazoan?

Answer 2

A multicellular animal with a body composed of more than one type of cell.

Question 3

What is a nerve net, and what animals are known for having them?

Answer 3

A diffuse network of neurons distributed throughout the body, found in jellyfish and related animals.

Question 4

What is cell differentiation?

Answer 4

The process by which individual cells in an organism become progressively more specialized and different from each other.

Question 5

What is a challenge that comes with cell differentiation? What is the solution?

Answer 5

How to coordinate the specialization of cell types. Metazoans must establish a body plan.

Question 6

What is epigenesis?

Answer 6

The process by which the body changes shape, gaining new structures and becoming more complex.

Question 7

What are cells?

Answer 7

Small, compartment like structures that are the building blocks of life.

Question 8

What is preformationism?

Answer 8

The notion that development consists of simply enlarging the preexisting body plan (initially too small to see).

Question 9

What is an embryo?

Answer 9

The earliest stage of development for a new individual, consisting of a spherical collection of cells.

Question 10

What is ontogeny?

Answer 10

The developmental process by which an individual grows up and grows old.

Question 11

What is a fetus?

Answer 11

A stage of development where all major organs and body parts are in place.

Question 12

How did the modern synthesis of evolution come about?

Answer 12

The fusion of Darwin’s theory of evolution and Mendel’s laws of discrete inheritance.

Question 13

What is a genotype?

Answer 13

The total genetic makeup an individual inherits.

Question 14

What is a phenotype?

Answer 14

The sum total of physical characteristics that an individual displays at a particular time.

Question 15

What are stem cells?

Answer 15

Cells that can grow and divide indefinitely, and can differentiate into all cell types.

Question 16

What are totipotent cells?

Answer 16

Stem cells that can form all adult body cell types, including tissues needed for embryo development.

Question 17

What are pluripotent cells?

Answer 17

Stem cells that can differentiate into a variety of cell types (not those involved in embryo development). Also called embryonic stem cells.

Question 18

What are adult-derived stem cells?

Answer 18

Stem cells that reside in differentiated tissue.

Question 19

What are induced pluripotent stem cells?

Answer 19

Stem cells generated by the over-expression of Yamanka factors in mouse adult fibroblasts. Can be de-differentiated and then differentiated into a new cell type.

Question 20

What is a zygote?

Answer 20

A fertilized egg.

Question 21

What is cell fate?

Answer 21

The particular structure and function a cell adopts.

Question 22

What is the mosaic specification of cell fate?

Answer 22

Each cell has its own given role regardless of what neighboring cells are doing.

Question 23

How does cell fate occur?

Answer 23

Cells are granted different mixes of transcription factors based on where they are in the mother cytoplasm.

Question 24

What is the maternal effect in cells?

Answer 24

The influence the mother has on an offspring is phenotype desperate from the inherited genes.

Question 25

What is the blastula stage of the embryo?

Answer 25

When the embryo is a roughly spherical collection of cells with a fluid-filled hollow space at its center.

Question 26

What is the fluid-filled center of the blastula called?

Answer 26

The blastocoel.

Question 27

When is an embryo called a gastrula?

Answer 27

When the embryo starts forming a primitive gut.

Question 28

What is the process of an embryo becoming a gastrula called?

Answer 28

Gastrulation.

Question 29

What happens during gastrulation?

Answer 29

The embryo forms the three germ layers.

Question 30

What is the outermost germ layer and what does it form?

Answer 30

Ectoderm. Forms epidermal skin cells, CNS neurons, PNS neurons, melanocytes.

Question 31

What is the middle germ layer and what does it form?

Answer 31

Mesoderm. Forms notochord, bone tissue, kidney cells, red blood cells, and muscle cells.

Question 32

What is the inner germ layer called and what does it form?

Answer 32

Endoderm. Forms stomach cells, thyroid cells, and lung cells.

Question 33

What body is present in mammalian gastrulation?

Answer 33

The inner cell mass, which gives rise to all of the body.

Question 34

What is the primitive streak?

Answer 34

A crease formed in the inner cell mass during gastrulation.

Question 35

Where is the node and what does it form?

Answer 35

A pronounced end of the primitive streak where the animal’s brain and head will form.

Question 36

What is the neural plate?

Answer 36

An elongated layer of ectodermal cells where the nervous system begins.

Question 37

What is the neural tube?

Answer 37

A structure formed by the neural groove, which forms from the sides of the neural plate rising up from which the central nervous system arises.

Question 38

What is the notochord?

Answer 38

A rodlike structure formed from the mesodermal tissue of the neural plate that contributes to the production of the spine.

Question 39

What is the neural crest?

Answer 39

A formation of ectodermal cells at the peak of the two sides of the neural crest which gives rise to the peripheral nervous system.

Question 40

From what does the epidermis arise?

Answer 40

The outermost layer of the ectoderm.

Question 41

When the embryo begins to develop a nervous system, what is it called? How does it become this form?

Answer 41

A neurula, formed by neurulation.