B2.3 Cell Specialization Flashcards
State that a zygote is an unspecialized cell produced from fertilization.
A zygote is an unspecialized cell produced from fertilization
Outline the impact of chemical gradients on gene expression within an early-stage embryo.
Chemical gradients determine which genes are expressed thus the type of specialized cell
Outline two properties of stem cells.
Unlimited capacity to divide
Can differentiate into specialized cells
Define stem cell niche.
Locations in the body where stem cells can be maintained or promoted to proliferate and differentiate
Outline the location and function of two types of multipotent stem cells in an adult human body.
Hematopoietic stem cells : found in bone marrow and can differentiate to all types of blood cells
Epithelial located in hair follicles can self-renew, differentiate, regulate hairgrowth, maintain skin homeostatis
Define totipotent, multipotent and pluripotent.
Totipotent : stem cells can differentiate into all types of cells or develop to an embryo
Pluripotent : stem cells can differentiate into all cells but not develop into an embryo
Multipotent : stem cells can differentiate into a limited range of cells. Adult stem cells are multipotent
List an example of a totipotent, multipotent and pluripotent stem cell.
Totipotent : zygote
Pluripotent : Inner mass cells
Multipotent : Immune system
Explain why pluripotent stem cells are most prevalent in the early embryonic development of a multicellular organism.
Because they have the potential to differentiate into any cell type
Relate the relative cell size to the specialized function of sperm, egg, red blood cell, white blood cell, neuron and striated muscle fibers.
Sperm length 50 to 70 µm width 2 to 3 µm adapted to reduce resistance
Ova diameter 100 µm store all the materials and nutritional reserves
Neurons width 4-100µm and up to 1m in length small diameter to densely pack information
Red blood cells diameter 6-8 µm allows them to move through cappilaries
White blood cells range from 6 to 20 µm increase in size during infection
Striated muscle fibers lenght 4mm -3cm diameter 10-100 µm greater length of contraction
Outline the activities occurring in the volume and at the surface of the cell.
Volume: Metabolic processes, protein synthesis, intracellular transport, cellular respiration.
Surface: Cell signaling, receptor-ligand interactions, nutrient uptake, waste elimination, cell adhesion, communication with neighboring cells.
Calculate the surface area, volume and SA:V ratio of a cube.
surface area 6a *a^2
Volume a^3
SA/V = 6/a
Explain the benefits and limitations of using cubes to model the surface area and volume of a cell.
Benefits
Simplicity
Proportional Scaling
Limitations
Irregular shape of Cells
Organelles and membrane folding
Functional considerations
Describe the relationship between cell size and the SA:V ratio of the cell.
The bigger the cell the lower the Surface Area to volume ratio.
Explain why cells are often limited in size by the SA:V ratio.
Because if cells are too big their metabolism increases faster than it’s ability to transfer materials in and out of the cell
List two examples of cells that are specialized for exchange of materials and have adaptations to increase the SA:V ratio.
Ethrocytes
Proximal convoluted tubule