Surface Area, Gas Exchange, Digestion, and Transport

Flashcards about surface area to volume ratio, gas exchange in different organisms, digestion and obsorption, mass transport in animals and plants

What is the relationship between size and surface area:volume ratio?

As the size of an organism/structure increases, its surface area to volume ratio decreases.

How do larger organisms adapt to a reduced surface area:volume ratio?

Larger organisms have adaptations like changes to body shape or development of systems to facilitate exchange.

What four factors maintain rapid diffusion rates in fish gills?

A large surface area, short diffusion pathway, concentration gradient, and counter current flow.

What are the three main components of the insect tracheal system?

Spiracles, tracheae, and tracheoles.

Which layer in plant leaves contains the gas exchange surface?

The mesophyll layer.

What are two plant adaptations to reduce water loss?

Waxy cuticle and closure of stomata.

What are five adaptations of xerophytes to reduce transpiration?

Rolled leaves, sunken stomata, stomatal hairs, needle-like leaves, and thicker waxy cuticle.

What three factors maintain rapid diffusion rates in human lungs?

Millions of alveoli and capillaries, thin alveolar and capillary walls, and constant circulation and breathing.

What is the basic process of digestion?

Hydrolysis of large, insoluble molecules into small, soluble molecules.

What are the four main carbohydrase enzymes involved in starch digestion?

Amylase, maltase, sucrase, and lactase.

What are the three types of protease/peptidase enzymes involved in protein digestion?

Endopeptidases, exopeptidases, and dipeptidases.

How do bile salts and lipases aid in lipid digestion?

Emulsification by bile salts increases the surface area for lipase action to hydrolyze ester bonds in triglycerides.

How are monosaccharides and amino acids absorbed in the ileum?

Sodium ions are actively transported out of the ileum epithelial cells, creating a concentration gradient for facilitated diffusion of sodium ions and co-transport of glucose or amino acids.

How are triglycerides absorbed in the ileum?

Micelles transport monoglycerides and fatty acids to the ileum epithelial cells, where they diffuse across the cell membrane, reform into triglycerides, and are combined with protein/cholesterol to form chylomicrons. Chylomicrons are then transported out of the cell by exocytosis and absorbed into lacteals.

What are the main functions of the atria, ventricles, and coronary arteries in the heart?

Atria receive blood, ventricles pump blood, coronary arteries supply cardiac muscle.

What are the three main stages of the cardiac cycle?

Diastole, atrial systole, and ventricular systole.

What are the primary roles of arteries, veins, and capillaries in blood circulation?

Arteries carry blood away from the heart, veins return blood to the heart, and capillaries are the site of exchange.

How is tissue fluid formed and reabsorbed in capillaries?

High hydrostatic pressure at the arteriole end forces water, ions, and small molecules out, forming tissue fluid. Osmosis draws water back in at the venule end due to water potential gradient.

How does transpiration leads to water movement in xylem?

Water evaporates from mesophyll cells, reducing their water potential. A water potential gradient is formed across the leaf. Water leaves the xylem vessels in the leaf and diffuses into mesophyll cells by osmosis, replacing the lost water

Explain the mass flow hypothesis for the translocation of sugars in plants.

Sugars are actively loaded into sieve tube cells, lowering water potential and causing water to enter by osmosis, increasing hydrostatic pressure. Sucrose is actively unloaded at sinks, increasing water potential and causing water to exit by osmosis, decreasing hydrostatic pressure. A hydrostatic pressure gradient is maintained between the source and the sink.