B3 Flashcards
What is osmosis
Net movement of water from an area of higher water potential to an area of lower water potential
Diffusion of water
Down a concentration gradient
Across a partially permeable membrane
What is a turgid cell?
Water enters by osmosis, vacuole swells and pushes against cell wall
What is a flaccid cell?
Water lost from cell, vacuole shrinks, cell loses shape
What is active transport?
Does require energy
Particles move against a concentration gradient
Movement of particles from an area of lower concentration to an area of higher concentration-therefore it requires energy
The energy is needed to make “pumps” move particles the wrong way
Movement of substances against a concentration gradient across a partially permeable membrane
What is diffusion?
Net movement of particles from an area of higher concentration to lower concentration area
Down a concentration gradient (difference in number of particles on either side)
What affects the rate of diffusion?
Surface area
Concentration gradient
Thickness of gas exchange surface
How is the blood capillary involved in diffusion in the gut?
Dense capillary network-inside each villus are many capillaries which take away the absorbed molecules
How is the epithelial membrane involved in diffusion in the gut?
Is a thin layer(only one cell thick). This provides a short diffusion path for digested food molecules
How is the lacteal involved in diffusion in the gut?
At the centre of the villus absorbed fats and carries them away from the villus. This maintains concentration gradient for absorption
Why does the rate of active transport depends on the rate of respiration, why?
As more respiration occurs, more energy is available and therefore more active transport takes place
State the ventilation path
Nose + mouth Trachea Bronchus Bronchiole Alveoli Blood
What is ventilation?
Scientific term for breathing where air is constantly moving in and out of the lungs
What is inspiration?
Occurs when air pressure in the atmosphere is greater than that of the lungs forcing the air into the alveoli
What is expiration?
Occurs when air pressure in the lungs is greater than that in the atmosphere forcing air out the alveoli
What are xylem?
Cells that transport water and minerals up the stem from the roots to the shoots and leaves. This transport occurs in one direction only
What is phloem
Cells transport sugars produced in the leaves up and down the stem to growing and storage tissues
How are the phloem and xylem arranged
In plants as vascular bundles
Both form continuous systems connecting roots, stems and leaves
What is transpiration
The release of water vapour from a plant through the leaves causing water to move through the plant
What is stage one of transpiration
Water diffuses through osmosis from soil to roots
Roots are covered in tiny projections called root hair cells
These structures increase the surface area of he roots and therefore increases the rate of water up take/ diffusion by osmosis
What is stage two of transpiration
Water travels up the stem in the xylem
It diffuses from an area of high concentration to an area of low concentration
It’s higher in the roots because that’s where the water is absorbed it’s lower in the leaves because it’s used for photosynthesis
What is stage three of transpiration
Water travels through veins into leaves. It then diffuses out of the veins and into cells and from these airspaces, water diffuses by osmosis through the stomata into the air where it is evaporated
What is stage four of transpiration
The loss of water through transpiration in the leaves sets up a concentration gradient, continuously pulling water from the soul into all parts of the plant. Capillary action also encourages the water movement up the plant
What factors affect transpiration
Light intensity
Temperature
Humidity
Wind
What makes up the blood
Plasma
Platelets
White blood cells
Red blood cells
What are blood vessels
Arteries carry blood away from the heart (high pressure) Carry oxygenated blood Thick muscular walls Small lumen Has a pulse No valves
What are Capillaries?
Penetrate all tissues
Very narrow
Allows transport of oxygen and nutrients into body cells and water out of cells
What are veins?
Carry blood towards the heart Low pressure Carry deoxygenated blood Thinner more flexible walls Large lumen Doesn't have a pulse Valves present
What’s homeostasis
Maintaining internal body conditions
What are kidneys
Proteins digested by amino acids and absorbed by blood
Excess amino acid carried in the blood to the liver
Your liver cells convert them to ammonia
The ammonia reacts with the carbon dioxide to make urea
The urea passes through the kidneys to be removed from the body as urine
What’s the role of the kidneys
Help clean the blood
What is the cortex?
Filters large molecules from the blood
What is the renal artery
Brings blood to kidney
What is the pelvis?
Collects urine
What is the renal vein
Takes blood away from kidney
What is the ureter
Takes urine from kidney to bladder
What is the medulla
Where water salt and urea are removed from the blood
What is selective reabsorbtion
All sugars absorbed by active transport
However the amount of water and mineral ions are absorbed depends upon the body’s needs
What are kidney stones
High salt and minerals in your diet can lead to stone precipitating out
Have to be excreted from the body in the urine
Kidney no longer able to filter blood effectively
What is dialysis
The clinical purification of blood by dialysis as a substitute for the normal function of the kidney
Artificial process used to remove water and waste substances from the blood when kidneys fail to function properly
Transplantation
Organ removed from either dead person or living
Inserted to patient
Damaged organs removed
Donor organs not always connected into position of old organ
What is glucose
A sugar used in respiration to make energy
What is glycogen
A storage substance made of glucose it is stored in the liver
What is insulin
A hormone, it tells your body to change glucose into glycogen. Made by pancreas
What is glucagon
A hormone that tells your liver to change glycogen back into glucose. Made by pancreas
How does blood sugar levels change after eating
Level of blood glucose increases
Pancreas releases insulin into blood
Insulin causes liver to store excess glucose as glycogen
How do blood sugar levels change during exercise
Blood glucose decreases
Pancreas releases glucose into blood
Glucagon causes the liver to release glucose into the blood from glycogen
What is eutrophication
Occurs when fertilisers applied to soils run off into freshwater a systems making them rich in nutrients
What is deforestation
Removal of forests by felling or burning
What are biofuels and biogas
Made from living or dead organisms
Pros= renewable
Reduce CO2 in atmosphere
Cons=removing plants that take in co2
=less farm land to grow food
Mycoprotein
Fusarium grows and reproduces very rapidly based on cheap energy supply in a large fermenter
It requires oxygen for anaerobic respiration
