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
Define “alveolar epithelium.”
an example of tissue where more than one cell type is present because multiple adaptations are required for that tissue to function
List three adaptations of cells thatmaximize the SA: volume ratio.
(blood cells) A biconcave shape to increase surface area
(Proximal Convoluted tubule) Microvili to increse the rate of absorption
Folded membranes
Outline the structure and function of type I pneumocytes.
Long and extremely flat to adapt for gas exchange
Outline the structure and function of type II pneumocytes.
Cuboid shaped cells with secretory vesicles to release the surfactant by exocytosis
Describe two functions of the fluid secreted by type II pneumocytes.
reduces surface tension in the alveoli and provides liquid for rapid diffusion of gases
List three types of muscle tissue found in the human body.
Cardiac Muscle
Striated Muscle
Smooth Muscle
Outline the relationship between skeletal muscles, muscle fibre cells and myofibrils.
Skeletal muscles are composed of muscle fiber cells, which in turn contain myofibrils responsible for muscle contraction.
Compare and contrast cardiac muscle tissue and skeletal muscle tissue.
Striated muscle : attached to the skeleton and is involved in the movement of bones
Cardiac muscle : located in the heart and responsible for the continued beating of the heart
Both contain contractile myofibrils
Describe how the Y-shape, intercalated discs and gap junctions of cardiac muscle cells allow for propagation of the stimulus to contract.
They allow rapid transmissions of electrical impulses which trigger contraction of the cardiac muscle cells
State the function of gamete cells.
To reproduce
Compare the size, and motility of egg and sperm cells.
Sperm : streamlined shape, adapted to swimming, contain 3 sections , a head, a midpiece and a flagellum
Eggs (Ova) : large cells with protective layers and low mobility
State the function of each of the following egg structures: haploid nucleus, binding proteins, zona pellucida, cortical granules, yolk, mitochondria and centrioles.
Haploid nucleus : has the maternal genetic information which will be combined with the male genetic informationat fertilization
Binding proteins : assists in sperm-egg recognition and binding during fertilization
Zona pellucida : prevents polyspermy after fertilization
Cortical granules : make the zona pellucida impenetrable to sperm after fertilization
Yolk : provides nutrients for early embryonic development
Mitochondria : provides energy for cellular processes (fertilization, embryonic development, cell division)
Centrioles: Organize the spindle fibers during cell division and are involved in the formation of the mitotic spindle.
