SA : V
(simple) diffusion
Name the process by which oxygen reaches the cells inside the body of a tubifex worm.
increased metabolism / respiration OR less oxygen
suggest why the volume of water passing over the gills increases if the temperature of the water increases
diffusion
what is the process of which fatty acids and glycerol enter the intestinal epithelial cells
Width / size / diameter of blood cell
What factor limits the minimum internal diameter of the lumen of a capillary?
1. Flattened cells OR Single layer of cells; Reject thin cell wall/membrane
2. Reduces diffusion distance/pathway;
3. Permeable;
4. Allows diffusion of oxygen/carbon dioxide;
Describe and explain one feature of the alveolar epithelium that makes the epithelium well adapted as a surface for gas exchange. Do not refer to surface area or moisture in your answer
1. (Epithelium is) single cell layer
OR (Epithelium contains) thin/flat cells
OR Epithelium is thin;
2. (So) short diffusion pathway/distance;
Describe and explain one adaptation of a single alveolus for gas exchange.
1. (Maintains/generates) a concentration/diffusion gradient for Na+ (from ileum into cell);
2. Na+ moving (in) by facilitated diffusion, brings glucose with it OR Na+ moving (in) by co-transport, brings glucose with it;
explain how the movement of Na+ out of the cells allows the absorption of glucose into the illeum epithelial cells
1. carry / wash sharp instruments by holding handle OR pointing away from body
2. disinfect instruments / surfaces
3. disinfect hands OR wash hands with soap and water
4. Put organ in a seperate bin / Bag
Describe two precautions that the student should take when clearing away after the dissection
1. tracheole wall is one cell thick
2. rapid diffusion / short diffusion pathway
explan the importance of one adaptation of the gas exchange surface in the tracheal system of an insect
As surface are to volume ratio increases , metabolic rate increase.
a larger surface are to volume ratio will lose more heat
a higher rate of respiration replaces the heat / maintains the body tempertaure
Describe and explain the relationship between surface are to volume ratio of the human body and metabolic rate
Diaphragm (muscle) contracts pulling diaphragm down;
2. External intercostal muscles contract pulling/moving ribs upwards/outwards;
3. (Causes) volume increase and pressure decrease in thoracic cavity
Describe how we breathe in
1. droplets increase surface area
2. so faster hydrolysis / digestion
3. micelles carry fatty acids and glycerol / monoglycerides to memebrane / epithelial cells
Explain the advantages of lipid droplet and micelle formation
1. aorta is directly linked to the heart / pressure is higher
2. aorta has elastic tissue
3. stretch / recoil
the rise and fall in blood pressure in the aorta is greater than in the small arteries. suggest why
1. (Allows unbroken) water column OR (So) no barrier to (water) movement;
2. Cohesion from H bonds between (all) water (molecules) OR Cohesion from (polar) attraction between (all) water (molecules);
3. Evaporation/transpiration creates tension (in column) OR Water moves from xylem (into cells) creates tension OR (To) pull up water creates tension (in xylem);
Explain the importance of the xylem being kept open as a continuous tube
1. mention the tracheae and bronchi and bronchioles
2. down a pressure gradient
3. down diffusion gradient
4. across the alveolar epithelium
describe how oxygen in the air reaches capilaries surrounding alveloi in lungs
1. hydrolysis of peptide bonds
2. endopeptidases act in the middle of the protein / prodce shorter polypeptides
3. exopeptidases act at the end of the protein / produce dipeptides
4. dipeptidases acts on dipeptides / produce a single amino aid
describe the role of enzymes in the digestion of proteins in mammals
1. plasma proteins remain
2. creates a water potential gradient OR reduces water potential
3. water movves to blood by osmosis
4. then it returns to the blood by lymphatic system
explain how water from tissue fluid is returned to the circulatory system
1. in source / leaf sugars are actively transported into the phloem
2. by companion cells
3. lowers water potential of seive cell / tube and water enters by osmosis
4. increase in hydostatic pressure causes mass movement
5. sugars used / converted in the root for respiration for storage
describe the mass flow hypothesis fro the mechanisms of translocation
1. Named structures – trachea, bronchi, bronchioles, alveoli;
2. Above structures named in correct order OR Above structures labelled in correct positions on a diagram;
. 3. Breathing in – diaphragm contracts and external intercostal muscles contract;
4. (Causes) volume increase and pressure decrease in thoracic cavity (to below atmospheric, resulting in air moving in);
5. Breathing out - Diaphragm relaxes and internal intercostal muscles contract;
Describe the gross structure of the human gas exchange system and how we breathe in and out.
1. Micelles contain bile salts and fatty acids/monoglycerides;
2. Make fatty acids/monoglycerides (more) soluble (in water) OR Bring/release/carry fatty acids/monoglycerides to cell/lining (of the iluem) OR Maintain high(er) concentration of fatty acids/monoglycerides to cell/lining (of the ileum);
3. Fatty acids/monoglycerides absorbed by diffusion;
4. Triglycerides (re)formed (in cells); Accept chylomicrons form
5. Vesicles move to cell membrane;
describe the processes involved in the absorption and transport of digested lipids from the illeum inro lymph vessels
1. haemoglobin is affected by pH change
2. changes tertiary structure
3. changes shape
4. less oxygen binds to haemoglobin
5. fewer es complexes form
explain the importance of maintaining a constant blood pH
1. Sucrose actively transported into phloem (cell); OR Sucrose is co-transported/moved with H+ into phloem (cell);
2. (By) companion/transfer cells;
3. Lowers water potential (in phloem) and water enters (from xylem) by osmosis;
4. (Produces) high(er) (hydrostatic) pressure; OR (Produces hydrostatic) pressure gradient;
5. Mass flow to respiring cells OR Mass flow to storage tissue/organ;
6. Unloaded/removed (from phloem) by active transport;
Describe the transport of carbohydrate in plants.