Chapter 11 - Regulation of water, salts and gases

Question 1

Osmoregulation

Answer 1

The active regulation of an organism’s water content. It maintains the fluid balance (water gain and loss) and the concentration of electrolytes (salts in solution) to keep internal fluids from becoming too diluted or concentration

Question 2

Turgid

Answer 2

Describes a cell into which water had diffused, so that the walls are stretched and the cell is fairly rigid

Question 3

what are the three functions of the kidney

Answer 3

• Removal of nitrogenous wastes
• Regulation of water concentration in the blood
• Maintaining ion levels in the blood

Question 4

Nephrons

Answer 4

The basic structural and functional unit of the kidney that filters the blood in order to regulate chemical concentrations, produce urine and eliminate nitrogenous waste

Question 5

bowmans capsules

Answer 5

A cup shaped structure found at one end of each nephron, in the cortex of the kidney. It surrounds a group of capillaries called a glomerulus

Question 6

glomerulus

Answer 6

A group of capillaries surrounded by a bowmans capsule

Question 7

filtration

Answer 7

A process that starts in the glomerulus, where fluid and solutes are filtered out of the blood to form a glomerular filtrate

Question 8

reabsorption

Answer 8

Process of substances in the filtrate being absorbed back into the blood

Question 9

what animals secrete which nitrogenous waste of urea, ammonia and uric acid

Answer 9

• Aquatic animals (Fish and amphibians) can’t afford to lose water. Ammonia (most toxic)
• Mammals, most adult amphibians, sharks need to conserve water. Urea (less toxic)
• Birds, insects, many reptiles, snails need to conserve water. Uric acid (least toxic)

Question 10

ADH

Answer 10

Antidiuretic hormone. A hormone that regulates the level of water reabsorption in the collecting duct of the kidneys nephron

Question 11

How does ADH reduce the urine output

Answer 11

By acting on the collecting duct of the kidney. The main functions of the collecting ducts are reabsorption of water and carrying a urine to the ureter. ATH increases reabsorption of water and the collecting ducts

Question 12

Negative feedback loop for low water volume

Answer 12

• Stimulus: Decrease in the blood water content below optimal range
• Receptor: Osmoreceptors cells in the hypothalamus detect the change in the blood water content and send a message to the coordinating centre
• Modulator: The hypothalamus receives a message from the receptor, coordinator response and sent a message to the effector. (The thirst centre is also activated.)
• Effector: The pituitary gland releases ADH, which travels through the blood to the kidney nephron, increasing the permeability of the collecting duct wall, which increases water reabsorption
• Response: An increase in the blood water content, a lower volume of urine and a higher urine concentration
• Negative feedback: The blood water content returns to the normal value. The response count acts the stimulus

Question 13

Osmoregulators

Answer 13

An organism that has specialised mechanisms for regulating internal water and solute concentration, despite concentration changes in the external environment.

Question 14

osmoconformers

Answer 14

An organism in which the internal solute concentration changes with the concentration of solutes in the external environment. Eg, Most marine invertebrates, cartilaginous fish such as sharks and rays and some fish

Question 15

Structural features to maintain water balance in Osmoregulators

Answer 15

Waterproof or impermeable outer layer, reducing water loss. (The scale of reptiles, the hair of mammals, the feathers of birds). The waterproof surface acts as a barrier preventing loss via osmosis or evaporation.

Question 16

Physiological processes to maintain water balance in Osmoregulators

Answer 16

Many reptiles and birds reabsorb water from their cloaca, Excreting nitrogen as wastes as uric acid is affective in saving water, slowing down the production of urine by reducing the rate of glomerular filtration, concentrate it’s a urine (water is conserved when it’s reabsorbed in the descending portion of the loop of henle). Some animals can use water stored in fats or carbs

Question 17

Behaviour maintain water balance in Osmoregulators

Answer 17

Borrowing in the sand for several months at a time after filling its bladder, aestivation, burrowing (Lower temperatures and higher humidity so water loss is reduced also traps exhaled water vapour)

Question 18

why is transpiration important

Answer 18

• Supplies photosynthesis with the water it needs
• cooling affect
• Distributing mineral salts throughout the plant

Question 19

how is water transported up a plant

Answer 19

Roots have fine root has attached to them (high SA:V) So they can achieve high rates of osmosis and diffusion, as well as active transport of dissolved substances (salts) To be transported to the stem of a vascular plants (via xylem and phloem). Water is pulled from the roots through the xylem to the leaves due to the set of forces known as the transformation pull. Including cohesion and adhesion. As water evaporates from the leaves, columns of water are drawn up through the xylem vessels

Question 20

Adhesion

Answer 20

The attractive force between water molecules and the inner walls of a vessel (e.g. the xylem vessels)

Question 21

cohesion

Answer 21

The attractive force between water molecules

Question 22

Capillary action

Answer 22

The movement of water within the spaces of a porous material or a narrow tube due to the forces of adhesion and cohesion

Question 23

root pressure

Answer 23

A force pushing on the water in the xylem, resulting from the active transport of salt ions into the root hairs, which causes osmosis to occur and water to move in from the soil into the room hairs. Is one of the forces involved in the transpiration stream

Question 24

Transpiration pull

Answer 24

The set of forces that pull water from the roots to the leaves, including cohesion and adhesion. As water evaporates from the leaves, columns of water are drawn up through the xylem vessels

Question 25

Transpiration stream

Answer 25

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

Question 26

Xylem

Answer 26

A form of vascular tissue that contains tubes within which water is transported from roots to leaves in a vascular plant

Question 27

Phloem

Answer 27

A type of vascular tissue (tubes) within which sugars and other dissolved organic substances are transported in a vascular plant

Question 28

Xerophytes

Answer 28

A plant that is adapted to live in arid environments. It has developed specialised features that minimise water loss, while maintaining gas exchange

Question 29

Halophytes

Answer 29

A plant adapted to live in environments with high soil salinity (i.e. a high salt concentration), such as salt marshes and the mudflats of estuaries

Question 30

5 structural and physiological adaptations of Xerophytes

Answer 30

- Sunken stomata, which prevent water loss by increasing the relative humidity near each stoma, decreasing the concentration gradient and reducing evaporation and diffusion. This creates a microclimate - Deep roots to reach water sources underground such as the water table which increase water uptake preventing dehydration of the plant - Rolled leaves, With the stomata inside and the inner surface covered in hairs. The rolled leaf and hairs serve to trap moist and thus reducing the concentration gradient of water vapour, the diffusion rate of water vapour out of the leave, the evaporation rate and the transpiration rate, creating a humid micro climate and reducing water loss - Thick, waxy leaf cuticle that is impermeable to water, preventing evaporation and water loss. The cuticle is also shiny and can reflect light, reducing the amount of light absorbed that could transform into heat and increase transpiration rate - Shallow spreading roots to collect the occasional rainfall and increase water uptake and reduce the risk of dehydration of the plant

Question 31

5 structural and physiological adaptations of Halophytes

Answer 31

- Filtration at the roots to regulate the amount of salt entering the plant. Root cells that are in permeable to prevent salt from entering the plant - Secretion of salt by special salt glands on leaves, stems and roots. This reduces the amount of salt in the plant - Succulence, the development of water storage structures in the leaves and other parts of the plant, dilutes the salt content of the cells - Accumulation of salt in older leaves, salt bladders or bark which can later to be discarded. This reduces the amount of salt in the plant (Physiological) - Vacuoles in root cells to store salt which increases the salt concentration of the roots so it is a greater than that of the soil. This allows water movement into the roots. Storing salt in vacuoles rather than in the cytoplasm stops it from interfering with cell functioning (Physiological)

Question 32

Transpiration

Answer 32

The evaporative loss of water from plants usually through small pores called stomata found on the surface of a plant, mostly on the underside of leaves. The evaporation and diffusion out of the stomata occurs because of the concentration gradient in the water vapour between the inside and outside of the leaf. Water vapour moves down the concentration gradient from an area of high water content to an area of low water concentration. The transport of water through the plant results in water loss

Question 33

nitrogenous waste pathway

Answer 33

Ammonia (highly toxic) --> urea (moderately toxic) --> uric acid (least toxic, little water, energy cost)

Question 34

hypotonic

Answer 34

(water enters cell) At a lower concentration than another solution. When a cell is surrounded by a hypotonic solution, water moves into the cell via osmosis to dilute the cell, so the cell swells. (animal cells which have no cell wall sometimes burst)

Question 35

hypertonic

Answer 35

(water leaves cell) At a higher concentration than another solution. When a cell is surrounded by a hypertonic solution, water moves out of the cell via osmosis to dilute the surroundings, so the cell shrinks