B2.3 Cell Specialization

Question 1

Define Zygote.

Answer 1

Multicellular organisms begin life as a single cell—a zygote: a fertilized egg that results from the union of female gamete (egg or ovum) with a male gamete (sperm).

Question 2

Define Morphogens.

Answer 2

During the early-stage of embryonic development, patterns of genes determine the way cells differentiate and take on specific roles.

The specific signaling molecules that are involved in gene expression for cell differentiation are called morphogens.
* Morphogens occur in gradients in different regions of the early embryo
* The gradient of the signaling molecule results in different genes being expressed in different parts of the embryo

Question 3

Define Stem Cells.

Answer 3

Populations of cells within organisms that retain the ability to divide and differentiate into various cell types.

Question 4

What is Potency?

Answer 4

The ability of a stem cell to give rise to different cell types.

Question 5

Define a Stem Cell Niche.

Answer 5

An area of a tissue that provides a specific environment where stem cells exist in an undifferentiated and self-renewable state. Here, they receive stimuli to determine their behavior (maintain a dormant state, cause to self-renew, or commit to a more differentiated state).

Question 6

Define Totipotent.

Answer 6

Totipotent cells are capable of giving rise to any cell type in an organism, including making more totipotent cells and making the cells that become the placenta.

Question 7

Define Pluripotent.

Answer 7

Pluripotent cells are able to develop into many different cell types, except for becoming placental cells or totipotent stem cells.

Question 8

Define Multipotent.

Answer 8

Multipotent cells can create, maintain and repair the cells of one particular organ or tissue.

Question 9

Stem Cells are Unspecialized IF:

Answer 9

• They can divide repeatedly to make large numbers of new cells.
• They can differentiate into multiple types of cells.
• They have a large nucleus relative to the volume of the cytoplasm.

Question 10

Define Embryonic Stem Cells.

Answer 10

The inner cells of the blastocyst are known as embryonic stem cells. They can divide indefinitely and can differentiate along different pathways.

Question 11

Female Gamete (Egg Cell)

Answer 11

• Human egg cell is approximately 100 um.
• It’s larger body allows it to store nutrients for the early development of the fertilized egg.

Question 12

Male Gamete (Sperm Cell)

Answer 12

• Human sperm cell is approximately 55 nm.
• It’s cell body only needs to hold the nucleus, for delivery to the egg, so can be much smaller.

Question 13

Red blood carry oxygen through the organisms and have several adaptation

Red Blood Cells:

Question 14

Neurons:

Question 15

Striated Muscle Fibres: