This document provides in depth information about cell specialization and all the point, questions and answers mentioned in the syllabus. The document includes resources for exams, past papers, diagrams, pictures and save my exams screenshots on top of explanations. Powerpoint links are also availa...
Microvilli: Microvilli are microscopic cellular membrane protrusions that increase the surface area
for diffusion and minimize any increase in volume.
Diffusion: Diffusion is the net movement of anything generally from a region of higher
concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free
energy or chemical potential.
Gametes: Gametes are haploid sex cells formed by the process of meiosis – males produce sperm
and females produce ova.
Alveoli: Tiny air sacs located at the end of the respiratory tract in the lungs. They allow inhaled
oxygen to enter the bloodstream and carbon dioxide to leave the bloodstream with exhalation.
Nephron: The nephron is the functional unit of the kidney and includes: Afferent arteriole: Brings
blood to the nephron to be filtered.
Tubule: In biology, a tubule is a general term referring to small tube or similar type of structure.
Flagellum: A flagellum (plural: flagella) is a long, slender, whiplike cellular structure used generally
for locomotion. It is like a propeller that spins and pushes the cell forward, allowing it to go where it
wants to go.
Gap junctions: Gap junctions are clusters of intercellular channels that allow direct diffusion of ions
and small molecules between adjacent cells.
Myofibrils: Myofibrils are bundles of protein filaments that contain the contractile elements of the
cardiomyocyte, that is, the machinery or motor that drives contraction and relaxation.
Cardiac muscle: Cardiac muscle (or myocardium) makes up the thick middle layer of the heart. It is
one of three types of muscle in the body, along with skeletal and smooth muscle.
Multinucleate: having more than two nuclei. having more than one nucleus.
Intercalated discs: Intercalated discs, also known as lines of Eberth, are responsible for connecting
the cardiac muscles. It is located at the longitudinal ends of each cardiac muscle cell. It consists of
gap junctions.
Erythrocyte: A cell that contains hemoglobin and can carry oxygen to the body. Also called a red
blood cell (RBC). The reddish color is due to hemoglobin.
Striated muscle fibers: Striated muscle tissue is a muscle tissue that features repeating functional
units called sarcomeres.
,Type I Pneumocytes: A type I pneumocyte is a flattened, branched pneumocyte that covers more
than 98% of the alveolar surface. They have a central nucleus and thin extensions of the cell
membrane called leaflets that cover the capillaries.
Type II Pneumocytes: Type II pneumocytes are identified as the synthesizing cells of the alveolar
surfactant, which has important properties in maintaining alveolar and airway stability. Lung
surfactant can reduce the surface tension and prevent alveolar collapse and the airway walls
collapse.
Acrosome: an organelle covering the head of animal sperm and containing enzymes that digest the
egg cell coating, thus permitting the sperm to enter the egg.
Adaptations to increase the surface area of cells
• Specialized cells involved in the exchange of materials have adaptations to increase surface
area.
• Why is the surface area to volume ratio important for cells: Every cell has a limit of surface
area to volume ratio to ensure that the exchange of resources and waste occurs quickly
enough for the cell to survive. If cells were too big, diffusion would take an extremely long
time, and a cell could die from starvation or poison itself with its waste.
• Red blood cell specialization: Erythrocyte (red blood cells) are thin and flat with a biconcave
shape, which increases their surface area for the exchange of gases. It also contains no
nucleus to increase surface area, to maximize space for oxygen. It also has hemoglobin
which makes it red.
• Why does it need to maximize surface area: Only 1 red blood cell can go through a capillary
at a time (because it’s one cell thick). This is why red blood cells need a big surface area.
• The cells lining the proximal convoluted tubule include extensions of the cytoplasm known
as microvilli.
• Microvili adaptation: They increase the rate of absorption of nutrients and water as filtrate
passes through the nephrons of the kidney. They have a short diffusion distance. Villi have
capillaries inside them for a good blood supply to allow for quick diffusion into the blood.
Villi have a large surface area to allow quicker diffusion. The cells in the walls of the villi
have microvilli to provide an even bigger surface area for quicker diffusion.
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