IB DP Biology HL B3.2 Transport Flashcards

[q] B3.2.2—Structure of arteries and veins.

[a] Application of skills: Students should be able to distinguish arteries and veins in micrographs from the structure of a vessel wall and its thickness relative to the diameter of the lumen.

[q] B3.2.3—Adaptations of arteries for the transport of blood away from the heart.

[a] Students should understand how the layers of muscle and elastic tissue in the walls of arteries help them to withstand and maintain high blood pressures.

[q] B3.2.4—Measurement of pulse rates.

[a] Application of skills: Students should be able to determine heart rate by feeling the carotid or radial pulse with fingertips. Traditional methods could be compared with digital ones.

[q] B3.2.5—Adaptations of veins for the return of blood to the heart.

[a] Include valves to prevent backflow and the flexibility of the wall to allow it to be compressed by muscle action.

[q] B3.2.6—Causes and consequences of occlusion of the coronary arteries.

[a] Application of skills: Students should be able to evaluate epidemiological data relating to the incidence of coronary heart disease.
NOS: Students should understand that correlation coefficients quantify correlations between variables and allow the strength of the relationship to be assessed. Low correlation coefficients or lack of any correlation could provide evidence against a hypothesis, but even strong correlations such as that between saturated fat intake and coronary heart disease do not prove a causal link.

[q] B3.2.7—Transport of water from roots to leaves during transpiration.

[a] Students should understand that loss of water by transpiration from cell walls in leaf cells causes water to be drawn out of xylem vessels and through cell walls by capillary action, generating tension (negative pressure potentials). It is this tension that draws water up in the xylem. Cohesion ensures a continuous column of water.

[q] B3.2.8—Adaptations of xylem vessels for transport of water.

[a] Include the lack of cell contents and incomplete or absent end walls for unimpeded flow, lignified walls to withstand tensions, and pits for entry and exit of water.

[q] B3.2.9—Distribution of tissues in a transverse section of the stem of a dicotyledonous plant.

[a] Application of skills: Students should be able to draw plan diagrams from micrographs to identify the relative positions of vascular bundles, xylem, phloem, cortex and epidermis. Students should annotate the diagram with the main functions of these structures.

[q] B3.2.10—Distribution of tissues in a transverse section of the root of a dicotyledonous plant

[a] Application of skills: Students should be able to draw diagrams from micrographs to identify vascular bundles, xylem and phloem, cortex and epidermis.

[q] B3.2.11—Release and reuptake of tissue fluid in capillaries.

[a] Tissue fluid is formed by pressure filtration of plasma in capillaries. This is promoted by the higher pressure of blood from arterioles. Lower pressure in venules allows tissue fluid to drain back into capillaries.

[q] B3.2.12—Exchange of substances between tissue fluid and cells in tissues.

[a] Discuss the composition of plasma and tissue fluid.

[a] Limit to the presence of valves and thin walls with gaps in lymph ducts and return of lymph to the blood circulation.

[q] B3.2.14—Differences between the single circulation of bony fish and the double circulation of mammals.

[a] Simple circuit diagrams are sufficient to show the sequence of organs through which blood passes.

[q] B3.2.15—Adaptations of the mammalian heart for delivering pressurized blood to the arteries.

[a] Include form-function adaptations of these structures: cardiac muscle, pacemaker, atria, ventricles, atrioventricular and semilunar valves, septum and coronary vessels. Students should be able to identify these features on a diagram of the heart in the frontal plane and trace the unidirectional flow of blood from named veins to arteries.

[q] B3.2.16—Stages in the cardiac cycle.

[a] Application of skills: Students should understand the sequence of events in the left side of the heart that follow the initiation of the heartbeat by the sinoatrial node (the “pacemaker”). Students should be able to interpret systolic and diastolic blood pressure measurements from data and graphs.

[q] B3.2.17—Generation of root pressure in xylem vessels by active transport of mineral ions.

[a] Root pressure is positive pressure potential, generated to cause water movement in roots and stems when transport in xylem due to transpiration is insufficient, for example when high humidity prevents transpiration or in spring, before leaves on deciduous plants have opened.

[q] B3.2.18—Adaptations of phloem sieve tubes and companion cells for translocation of sap.

[a] Include sieve plates, reduced cytoplasm and organelles, no nucleus for sieve tube elements and presence of many mitochondria for companion cells and plasmodesmata between them. Students should appreciate how these adaptations ease the flow of sap and enhance loading of carbon compounds into phloem sieve tubes at sources and unloading of them at sinks.

[q] sieve element cells

[a] these cells transport water and solutes. To be efficient at transport, they have reduced quantities of cytoplasm and no nucleus, ribosome, or vacuole.

[q] companion cells

[a] these cells are “life support” for the sieve element cells as they perform certain metabolic functions for sieve elements.

[q] parenchyma

[a] parenchyma acts as packing material between other cell types and helps transfer materials to the sieve elements and companion cells.

[q] fibers of sclerenchyma cells

[a] fibers of sclerenchyma cells provide structural support for the plant.

[q] how are sieve tubes structured to function?

[a] -the rigid cell walls of the sieve tube allow for the building of the high pressures needed to generate hydrostatic pressure.
-the ends of sieve element cells are connected with other sieve elements and together they form a sieve tube.
-sieve plates contain large pores for speeding the transport of substances between sieve element cells.

[q] active translocation

[a] -moving food around, occurs in the phloem.
-plants produce their own carbohydrates in the leaves through photosynthesis. For the plant to grow and reproduce, this food needs to be translocated (transported) to the tissues that need it.
-the movement of phloem sap requires energy – it is an active process, so we call it active translocation.

[q] source

[a] site of production or storage

[q] sink

[a] destination/site of use

[q] sugars

[a] -source: green leaves and stems, storage tissues in seeds
-sink: growing roots and stem, roots absorbing minerals, fruit production or other energy storage

[q] amino acids

[a] -source: roots or tubers, rhizomes, storage in germinating seeds.
-sink: growing roots and stem, developing leaves, fruits, flowering and reproduction.

[q] sucrose

[a] -sucrose is actively transported into the phloem.
-concentration of sucrose in phloem cells is relatively high.
-consequently the water concentration is relatively low.
-water moves down the concentration gradient from the xylem, through the membrane, into phloem cells, by osmosis.

[q] hydrostatic pressure

[a] -phloem transports water and solutes along hydrostatic pressure gradients.
-relatively high concentration of sucrose and water in phloem sieve tubes.
-water is incompressible and the walls of the sieve tubes are rigid.
These 2 factors cause a build-up of hydrostatic pressure at the source.
-water and the solutes flow down the hydrostatic gradient to the sink where pressure is relatively low.
-this is due to the active unloading of sucrose and hence loss of water by osmosis at the sink.

[q] aphids

[a] -only group of insects that have evolved the ability to feed primarily on plant sap
-possess a stylet, a piercing and sucking mouthpart that is inserted into the plant sieve element to allow the sap to be extracted
-sap is sampled by cutting the stylet after feeding has commenced.

[q] platelets

[a] help blood clot; travels in blood stream, seals puncture in vein/artery, attract clotting factors.

[q] clotting factors

[a] proteins that travel through blood stream; binds to platelets sealing puncture, produces thrombin enzyme.

[q] prothrombin

[a] type of clotting factor, produces thrombin enzyme

[q] thrombin

[a] enzyme that converts soluble protein fibrinogen to insoluble protein fibrin during coagulation.

[q] Fibrinogen

[a] plasma protein that converts into fibrin.

[q] fibrin

[a] forms a meshwork that traps RBCs and forms the basis of the clot, turns into scab when exposed to air.

[q] systolic pressure

[a] peak pressure exerted against arterial walls as the ventricles contract and eject blood, storing potential energy.

[q] diastolic pressure

[a] end of heartbeat causes pressure in arteries to fall enough for stretched fibers to squeeze blood in the lumen

[q] lumen

[a] center space of blood vessels, veins, and arteries

[q] vasoconstriction

[a] contraction of the circular muscles in the wall of the artery reduce the circumference of the lumen and BP increases.

[q] asodilation

[a] the circular muscles in the wall of the artery increases circumference of the lumen and BP decreases.

[q] veins

[a] return deoxygenated blood to the heart.

[q] valves

[a] located in veins, prevents back-flow, allows for one-way circulation.

[q] capillaries

[a] smallest blood vessels that receive 02 and nutrients from arteries and exchange it with cells.