Movement Of Substances Flashcards
Explain how a root hair cell carries out its function
-Mineral ions are taken up by active transport
-The water potential inside the root hair cell decreases
-Water enters the root hair cell by osmosis
Describe two effects that the accumulation of waste products would have on cells. (2)
-Waste products would be toxic to cells/would denature enzymes
-Waste products would cause water to move out of cells by osmosis
-Waste products would take up storage space inside cells
What are the excretory products of the lungs?
-Lung excreted carbon dioxide
-as a waste product of aerobic respiration via exhalation
What are the excretory products of the kidney?
-Kidney excretes excess water, salts and urea
-by producing urine via osmoregulation
What are the excretory products of the skin?
-Skin excretes excess water and salts
-Through sweat glands of skin by producing sweat
What are the two main functions of the kidney?
-They regulate the water content of the blood (vital for maintaining blood pressure)
-They excrete the toxic waste products of metabolism (such as urea) and substances in excess of requirements (such as salts)
How does the kidney carry out its roles of excretion?
- Renal Artery carries oxygenated blood to Glomerulus in Bowman’s Capsule at high pressure
- High pressure due to wider afferent arteriole and narrow efferent arteriole
- Blood filtered at high pressure produces Glomerular Filtrate: water, glucose, salts, urea
- Proteins and red blood cells too large to filter through base membrane, remain in blood
- Glomerular Filtrate enters Proximal Convoluted Tubule (PCT), where glucose selectively reabsorbed
- Remaining filtrate moves to Collecting Duct, where water reabsorbed based on ADH levels
- Excess water, salts, and urea form urine
- Urine transported via ureter to bladder for storage and excretion
What are the key functions of the urinary system?
-Filter and remove waste products
-Control water levels
Describe the structure of the Bowman’s capsule
- Cup-shaped sac collects Glomerular Filtrate
- Filtrate enters tubules for filtration
Describe the structure of the glomerulus
- Tuft of capillaries filters blood under high pressure
- Produces Glomerular Filtrate: water, glucose, salts, urea
Describe the structure of the convoluted tubules
- Nephron section: Proximal Convoluted Tubule (PCT) and Distal Convoluted Tubule (DCT)
- Purpose: Selective reabsorption of glucose into blood capillaries
Describe the structure of the loop of Henle
- U-shaped nephron section regulates body water concentration
- Filters out salts for homeostasis
Describe the structure of the collecting duct
- Long, narrow tube
- Reabsorbs water
- Maintains water balance
- ADH levels regulate process
Describe the process taking place in the glomerulus (2)
-Small molecules are forced out of the capillaries (of the glomerulus) into the Bowman’s capsule
-Due to the high pressure in the capillaries (of the glomerulus)
-During the process of ultrafiltration
Ultrafiltration
-Occurs between the glomerulus and Bowman’s capsule
-High pressure created by: blood from renal artery, narrowing of capillaries in glomerulus
-Filtrate is formed when small molecules are forced into the Bowman’s capsule
What are the components of the filtrate?
-WATER reabsorbed at loop of henle and collecting duct
-SALTS reabsorbed at loop of henle
-GLUCOSE reabsorbed at proximal convoluted tube (PCT)
-UREA is not reabsorbed
Complete the following sentences on the reabsorption of glucose:
As the filtrate moves through the —————-, glucose is reabsorbed by ————–. The cells are adapted for this process by containing many ———- where energy is released. (3)
As the filtrate moves through the PROXIMAL CONVOLUTED TUBULE, glucose is reabsorbed by ACTIVE TRANSPORT. The cells are adapted for this process by containing many MITOCHONDRIA where energy is released.
What does glucose in the urine indicate?
Indicated conditions such as diabetes.
Explain free water molecules
When the sugar dissolves water molecules are attracted to the sugar molecules. These water molecules are now not considered free.
Explain a partially permeable membrane
A membrane that only allows certain particles through. The free water molecules can move through however the sugar-water complexes are too big.
E.g. There are 22 free water molecules on the left and 10 free water molecules on the right. So the overall movement of water will be towards the right hand side. (Overall movement as particles move randomly, in all directions.)
Water potential in cells
A measure of the concentration of free water molecules in a solution.
-Pure water has a water potential of zero.
-As solute is added, WP falls as there will be a lower conc of free water molecules.
-Conc solutions have a very LWP
Why do animals and plant cells react diffferently when being placed in different concentrations?
Plant cells have a cell walk which can withstand a large amount of water pressure
Isotonic solution
-The solution outside the cell has the same WP as inside the cell- no net movement
Hypotonic solution
-The solution outside the cell has a higher WP then inside the cell- net movement of free water molecules into the cell
Hypertonic solution
-The solution outside the cell has a lower WP then inside the cell- net movement of free water molecules out of the cell
Why do plants wilt?
There is not enough water to fill their cells + so the cytoplasm shrinks from the cell wall
Animal cell in hypotonic solution
Lysed
Animal cell in isotonic solution
Normal
Animal cell in hypertonic solution
Shriveled
Plant cell in hypotonic solution
Turgid (normal)
Plant cell in isotonic solution
Flaccid
Plant cell in hypertonic solution
Plasmolyzed
Visking tubing
Only allows small soluble molecules to pass through through, so osmosis can occur
Onion cells- turgid
Soaked in pure water
Onion cells- turgid
Soaked in pure water
Onion cells- plasmolysed
Have been soaked in a concentrated salt or sugar solution
