2.Structure And Functions In Living Organisms Flashcards
What is the role of enzymes?
To speed up rates of reaction, biological catalysts in metabolic reactions.
How does temperature affect enzyme function?
As temperature increases, so does the rate of reaction because the enzymes and substrates have more kinetic energy so move faster and collide more. However, at a certain temperature the active site of the enzyme denatures and is no longer complimentary to the substrate so rate of reaction slows.
How des pH affect enzyme function?
The rate of reaction will increase up to the optimum pH of the enzyme.after the optimum pH of the enzyme the rate of reaction will decrease again.
What is diffusion?
The net movement of particles from an area of high concentration to an area of low concentration down a concentration gradient.
What is osmosis?
The net movement of water across a partially permeable membrane from an area of high water potential to an area of low water potential down a water potential gradient.
What is active transport?
The net movement of particles from an area of low concentration to an are of high concentration, against a concentration gradient, using ATP
What factors affect the rate of movement of particles?
.surface area
.diffusion distance
.temperature
.concentration
How does surface area affect rate of movement of particles?
Larger the surface area, the mor particles can move through in the amaze period of time.
How does diffusion distance affect the rate of movement of particles?
Further distance to travel mean a longer time for diffusion
How does temperature affect rate of movement of particles?
Higher temp, more kinetic energy, particles move faster
How does concentration gradient affect rate of movement of particles?
The larger the concentration, the faster diffusion occurs
What form is energy produced in for living organisms when respiring?
ATP
What does ATP do?
Provide energy for cells
What is the difference between aerobic and anaerobic respiration?
Aerobic respiration uses oxygen, anaerobic doesn’t
What is the word equation for aerobic respiration?
Glucose + oxygen —> carbon dioxide + water
C6H12O6 + 6H20 —> 6CO2 + 6H20
What is the word equation or anaerobic respiration in animals?
Glucose —> lactic acid (+energy)
What is the word equation for anaerobic respiration in plants?
Glucose —> ethanol + carbon dioxide (+energy)
What is the role of diffusion in gas exchange?
.to remove the waste products of photosynthesis out of the leaf
.to bring oxygen into the leaf for photosynthesis
How is the structure of the leaf adapted for gas exchange?
Stomata- open and close when needed
Guard cells- open and close stomata
Spongy mesophyll- gas diffuses faster in air than through membranes
What is the role of the stomata in gas exchange?
To allow gasses to diffuse in and out of the leaf for photosynthesis and respiration
What is the role of the xylem
.xylem tubes transport water and minerals
.the xylem carry water and mineral salts from the roots up too the shoot to the leaves in the transpiration stream.
How is water absorbed by root hair cells?
.the hairs on the root hair cells increase its surface area for absorption of water
.water is absorbed by osmosis as there is usually a higher water potential in the soil than in the plant
What is transpiration?
The evaporation of water from the surface of a plant
What factors affect the rate of transpiration?
Humidity, wind speed, temperature, light intensity
How does humidity affect the rate of transpiration?
Higher the humidity, lower the rate of transpiration as the concentration gradient from inside the leaf to outside the leaf is lower so less water will diffuse out of the leaf
How does wind speed affect rate of transpiration?
Higher the wind speed, higher the rate of transpiration because the water vapour that is exiting the leaf is being swept away allowing a high concentration gradient to be maintained between the inside and the outside of the leaf so the rate of transpiration is higher
How does temperature affect the rate of transpiration?
The warmer it is the higher the rate of transpiration
When it is warm the water particles have more energy to evaporate and diffuse faster out i of the stomata
How does light intensity affect the rate of transpiration?
The brighter th light the higher the rate of transportation as stomata begin to close when it gets darker so when it i bright the stomata will be more open.
What are the excretory products of the lungs?
Carbon dioxide and water vapour
What are the excretory products of the kidneys?
Urea, ions and water
What are the excretory products of the skin?
Sweat - water and salts
How des the kidney carry out its role in excretion?
- Ultrafiltration: .blood from the renal artery flows through the glomeulus
.a high pressure is built up which squeezes water, urea, ions and glucose oit of the blood and into the bowman’s capsule
.the membranes between the glomerulus and the bowman’s capsule act like filter so bigger molecules like proteins cannot pass through. - Reabsorption: .as the filtrate flows along the nephron, useful substances get selectively reabsorbed back into the blood:
.all the glucose is reabsorbed from the PCT so that it can be used for respiration. This uses active transport.
.sufficient ions are reabsorbed, excess ions aren’t
.sufficient eater is reabsorbed from the collecting duct into the bloodstream by osmosis - Release of wastes: the remaining substances (water ions and urea) continues out of the nephron, through the ureter and down to the bladder, where it is stored before being released by the urethra.
How does the kidney carry out its role in osmoregulation?
.The amount of water reabsorbed bin the kidney nephrons is controlled by ADH (anti-diuretic hormone)
.ADH makes the collecting duct mire permeable to water so more water gets reabsorbed back into the blood.
.the brain monitors the water content of the blood and instructs the pituitary gland to release ADH into the blood according the how much is needed
Describe the structure of the urinary system
Consists of two kidneys, two ureters, which connect the kidneys to the singular bladder which excretes urine through the urethra
Describe the structure of the nephron
Glomerulus —> basement membrane —> bowman’s capsule —> PCT —> loop of Henle —> DCT —> collecting duct
What is globular filtrate composed of?
Urea, water, ions, glucose
Why does selective réabsorptions of glucose occur?
Because glucose is needed for respiration
Was is urine composed of?
Urea, ions, water
How are organisms able to respond to changes in their environment?
Hormones and nervous control
What is homeostasis?
The maintenance of a constant internal environment and the body water content and body temperature are both examples of homeostasis
What are the differences between nervous and hormonal control?
Hormonal:
.slower response
.longer lasting
.affect whole organs (more general)
.uses the blood
.involves hormones
Nervous:
.faster response
.shorter lasting
.affects specific parts
.uses nerves or neurones
.involves nerve impulses
What is the CNS made up of?
Brain and spinal chord
How is the CNS linked to sense organs?
Nerves
When a receptor is stimulated, what happens?
It sends electrical impulses along nerves in an out of the CNS resulting in rapid responses
