Cells - Cell specialization

What is fertilization?

The process when the sperm cell and egg cell fuse to form a zygote.

What is the embryonic stage?

The period from fertilization until about 10 weeks of pregnancy.

What happens to the zygote after fertilization?

It undergoes mitosis to multiply.

What are unspecialized cells in early embryonic development?

Cells that have not yet differentiated into specific cell types.

When does cell specialization begin in embryonic development?

When the morula becomes a blastocyst, around 4-5 days after fertilization.

What is cell differentiation?

The process where cells become specialized for specific functions.

What role do morphogens play in cell differentiation?

They create a chemical gradient that impacts gene expression.

How many distinctly specialized cell types do humans have?

220 specialized cell types.

What are stem cells?

Undifferentiated or partially differentiated cells that can divide infinitely.

What happens to stem cells once they differentiate?

They are no longer considered stem cells.

What are totipotent stem cells?

Stem cells that can differentiate into any type of cell, including placental tissue.

What are pluripotent stem cells?

Stem cells that can differentiate into any cells in the three germ layers of the embryo.

What are multipotent stem cells?

Adult/somatic stem cells that can differentiate into multiple related cell types.

What is a stem cell niche?

The area within a tissue where stem cells are located and maintained.

What is the significance of the size and shape of a cell?

They are adaptations that allow the cell to perform specific functions.

How do red blood cells adapt in shape?

They are flattened to increase surface area-to-volume ratio.

What are microvilli?

Protrusions that maximize entry of information into cells.

What are invaginations?

Depressions that maximize exit of substances from cells.

What ethical debates surround stem cell research?

Concerns about the use of embryonic stem cells and their therapeutic applications.

What are stem cell lines?

Groups of identical cells that replicate indefinitely for research purposes.

Metabolism occurs in the cytoplasm and requires what?

absorbtion of reactants and removal of waste products

The rate at which particles move in and out of the cell depends on what?

the surface area

the rate at which it can move around the cytoplasm on what?

the volume of the cell

Microville/protrusions do what?

maximise entry info

inviginations/depressions do what?

maximize exit of the proximal convoluted tubal cells

What are the two types of cells needed to perform gas exchange?

(pneumocytes) Type I - where diffusion happens, wide but thin, diffusion is passive so not many extra organelles. Type II - make up 90% of the cells but occupy less than 5% of the surface area of alveoli, many contain secretory vesicles to produce a phospholipid/protien lyer called surfactant that reduces surface tension

Three adaptations of muscle cells for contraction

1. muscle cells are long multinucleated cells formed from the fusion of individual cells

2. Contain contractile myofibrils (actin and myosin)

3. Branched vs. unbranched

Adaptations of the sperm and egg cells

1. each contain only half the genetic material

2. one very large egg adapted for support and nourishment of potential offspring

3. many small sperm adapted for movement