homeostasis Flashcards

Question

salts (outside of cell)

Answer 1

Increase - water leaves cell, leads to cell shrinkage and dehydration Decrease - water enters cell, cell swells, leading to weakness, fatigue, confusion.

Answer 2

CO2 dissolves into blood, forming carbonic acid (H2CO3) and later into hydrogen and bicarbonate ions too High CO2 - leads to inc in H+ conc. Which lowers pH, creating acidic blood. Too Low CO2 - leads to lower ventilation rate in mammals, lower rate of photosynthesis in plants too High O2 - can be toxic, gas can diffuse straight into cell, can cause: cell damage, nausea, dizziness and breathing problems Too low O2 - leads to reduction in the respiration rate and thus the rate of ATP (energy) prod.

Answer 3

Occurs in plants cell membrane of a plant has pulled away from the cell wall due to water moving out of cell

Answer 4

functional processes performed by organisms

Answer 5

physical features that have a function

Answer 6

action performed in response to a stimulus

Answer 7

cold climate - thick, waxy leaves reduce heat loss by providing insulation against the cold climate Hot climate - its narrow, vertical leaves minimise the amount of direct sunlight hitting them and thus minimise heat absorption during hot desert days.

Answer 8

Animals that use metabolic processes to generate their own heat to maintain their internal temp within tolerance range Body generates heat loss and gain.

Answer 9

Animal whose body temp is determined by the external enviro body temp fluctuates wt external enviro No physiological adaptations

Answer 10

conduction - transfer of heat from a hotter object to a cooler object by direct contact Convection - transfer heat when hot air/liquid rises and is replaced by cooler air/liquid evaporation - occurs when liquid turns to vapour, cooling the skin Radiation - transfer of heat by infrared waves.

Answer 11

In cool of night plant increases its metabolic heat prod, and in heat of day, evaporative cooling is used

Answer 12

High surface-area-to-volume ratio of bv close to surface to facilitate conduction sweat glands for evaporation Increased blood flow to skin Fur can reflect heat from radiation ectotherms - adjusts skin colour, temp rises, colour becomes lighter

Answer 13

Shelter from high temps reduce physical activity Licking body parts emerge in water Open mouths burrow into ground

Answer 14

vasodilation sweating panting Decrease metabolic activity pilorelaxation - muscle attached to follicle relax to flatten hair, and decrease layer of air acting as an insulator

Answer 15

Insulation (fur, feathers, blubber) piloerection - muscle attached to follicle contracts so that hairs stand up Darker shading (fur/scales) aquatic animals - countercurrent heat exchange Larger size

Answer 16

The exchange of heat between two fluids flowing in opposite directions in vessels that are in close proximity heat in the blood travelling in the arteries to the foot or fin warms the blood returning to the body in the adjacent veins Traps heat in the body core, reducing heat loss in the extremities

Answer 17

Minimising amount of surface area exposed to the surroundings basking in the sun Lay on hot surface (rock)

Answer 18

Vasoconstriction inc. metabolic rate Shivering torpor Hibernate aestivation

Answer 19

physiological state of decreased metabolic rate and physical activity Reduces energy and water costs

Answer 20

Spending a long period of time in Torpor the metabolic rate falls to a level that just sustains life

Answer 21

seasonal dormancy Done in dry conditions

Answer 22

Active regulation of the organism’s water content

Answer 23

a cell into which water was diffused so that the walls are stretched and the cell is fairly rigid.

Answer 24

the passive diffusion of water across a membrane in response to a concentration gradient caused by an imbalance of molecules on either side of the membrane

Answer 25

1. Removal of nitrogenous wastes 2. Regulation of water conc in the blood 3. Maintaining ion levels in the blood

Answer 26

individual filtering units Filter blood in order to regulate chemical concentrations and produce urine

Answer 27

Surrounds glomerulus cup-shaped structures

Answer 28

a group of capillaries Plasma is forced out through the walls of the glomerulus, then in the outer layers of the Bowman’s capsule to its interior, being filtered in the process. Where filtration occurs

Answer 29

Glomerulus -> bowman’s capsule -> proximal convoluted tubules -> loop of henle -> distal convoluted tubules -> collecting ducts -> ureter

Answer 30

Occurs at proximal/distal tubules, loop of hence and collecting ducts process of water, ions and other substances in the filtrate being absorbed back into the blood.

Answer 31

the removal of nitrogenous wastes In mammals, urea removed as part of urine

Answer 32

Extremely toxic affects pH, can denature enzymes - slow metabolic rate Excretion: directly, diluted into water (freshwater fish), or converted to urea or uric acid (requires energy).

Answer 33

Controls maintenance of water balance in mammals reduces urine output Prod. by hypo stored in pit gland acts on collecting ducts of nephrons Increases reabsorption of water in the collecting ducts

Answer 34

Stimulus: decrease in blood water content below optimal range Receptor: osmoreceptor cells in Hypo detect the change in the blood water content and send a message to coordinator centre. Coordinator centre (modulator): hypothalamus receives a msg from a receptor, coordinates a response and sends a msg to effector. Effector: Pit. gland releases ADH, which travels through the blood to kidney nephrons, increasing the permeability of the collecting duct wall, which increases water absorption.

Answer 35

an organism in which the internal solute conc. Changes wt the conc of solutes in external enviro Able to concentrate urea in their bodies to maintain a high soluble concentration, thus matching the ocean’s high conc of solutes

Answer 36

Organism that has specialised mechanisms for regulating internal water and solute conc, despite conc changes in external enviro. Have physiological adaptations

Answer 37

Structural features: waterproof/impermeable outer layer physiological processes: reabsorb water from their cloaca, Excrete nitrogenous wastes as uric acid, retain urine in bladder for use. behavioural adaptation: aestivation and burrowing

Answer 38

used by desert frogs Fills its bladder and pockets under the skin wt water and tucks itself into a water-conserving cocoon created from mucus and sloughed skin. metabolic rate slows down Can survive in cocoon for many months

Answer 39

Carries water

Answer 40

caries the products of photosynthesis (eg. Glucose)

Answer 41

set of forces that pull water up Xylem Cohesion: attractive force that occurs between water molecules. As water evaporates from leaves, columns of water are drawn up through the xylem vessels. Adhesion: attractive force operating between water molecules and inner walls of the Xylem vessels

Answer 42

formed by the combined forces of cohesion and adhesion Drawing up of water creates conc gradient between inside and outside of root hairs active transport of salt ions into the roots can cause osmotic water movement into the root hairs, causes root pressure

Answer 43

force pushing on the water in the Xylem Pushes water upwards

Answer 44

The continuous flow of water from the roots to the leaves via Xylem vessels due to the forces of cohesion, adhesion and root pressure.

Answer 45

The evaporative loss of water from plants, usually through stomata occurs because of the conc gradient of water vapour between the inside and outside of the leaf. The transport of water through the plant results in water loss.

Answer 46

1. Transpiration supplies photosynthesis wt the water it needs 2. The evaporation of water from mesophyll cells in the leaves that accompanies transpiration requires energy therefore cools the leaves in the same way that sweating cools the skin of some mammals. Heat energy is drawn out of the plant, into the water, then out into the external environment. 3. The transpiration stream is also necessary for distributing mineral salts throughout the plant.

Answer 47

light in comb wt CO2 conc and sufficient humidity opens stomata. Using active transport, K+ are purposely moved into guard cells, creating conc gradient. guard cells then take up water and become turgid. Because inner walls are rigid, they are pulled apart, opening the pore. in darkness, water lost, guard cells become flaccid, and their inner walls move together, closing the pore. Stomata opening/closing depends on the changes in the turgor of guard cells.

Answer 48

Increases - guard cell expands. Due to relatively inelastic inner walls of guard cells, they bend and draw away from each other, so the pore opens. decreases - guard cell shrinks. Guard cells lower their water potential to draw in water from the surrounding epidermal cells actively accumulating potassium ions. This requires ATP, which is supplied by chloroplasts in guard cells.

Answer 49

live in dry environment. Evap exceeds precipitation. Adaptations: reduction in leaf surface area sunken stomata Deep roots rolled leaves Thick, waxy leaf cuticle stomata opening at night Shallow, spreading roots

Answer 50

plants that liv in enviro of high soil salinity Adaptations: filtration at the roots - regulates amount of salt entering, impermeable to salt prevents salt to enter. vacuoles in root cells - stores salts, which increases the salt conc of the roots so it is greater than that in the soil. Accumulation of salts - in older leaves, salt bladders or bark, which can later be discarded. secretion of slat by special glands on leaves Succulence - development of water storage structures in the leaves and other parts of the plant, dilutes the salt content of the cells.

Answer 51

Gather and store excess salt in their slat glands or in their central vacuoles

Answer 52

Remove salt by ultrafiltration through cell membrane