Enzymes and Homeostasis:-
* For the body to function properly it needs constant internal conditions. The nervous system and the endocrine system monitor the body and maintain a constant internal environment.
* Enzymes are large protein molecules which speed up chemical reactions. Each type of enzyme is involved in one type of chemical reaction.
* Enzymes work best at specific PH and a particular temperature. The human body has a temperature of 37 degrees, so this will be the optimum temperature for the functioning of enzymes in humans.
* Body fluids, such as blood, are constantly changing their temperature and chemical composition. This process helps organs respond to correct or adjust these changes.
* Changes in body fluids are detected by cells called receptors. These cells send messages to the brain. Organs in the body respond to the brain and restore the fluids to normal.
* In humans, the hypothalamus in the brain detects change in blood temperature. The hypothalamus sends messages to the adrenal glands in skin.
* Humans have a number of cooling and heating mechanisms so that they can maintain a constant temperature.
Enzymes:-
•Needed for metabolism
•Need constant internal conditions
•Reaction would be to slow to maintain without them
•They’re proteins that speed up chemical reactions – without changing or being used themselves.
•All chemical reactions in cells are controlled by enzymes
•They’re specific for each chemical reaction
•Work best as a specific PH – optimum PH
•Low PH means high acidity
•Work best at particular temperatures – optimum temperature
•Low temperature inactive enzymes
•High temps destroy enzymes so they can’t work again.
Homeostasis:-
•Process of keeping internal environment constant. Temperature increases �* Body sweats �* Temperature decreases.
•Body continually monitors and regulates temperature and composition of body fluids.
•Changes in chemicals in blood are detected by chemoreceptors
•Thermoreceptors detect temperature changes
•Receptors send message to brain to body parts which counteract the change
•Hypothalamus in brain is temperature control centre
•Hypothalamus activates adrenal glands and skin to regulate temperature.
Organisms and temperature:-
•All organisms have an optimum temperature range for survival. Outside this temperature range enzymes are inactive and the body does not function adequately
•The temperature of ectothermic organisms will rise and fall with the temperature of the surrounding environment. In water, ectotherms have a very low metabolism, and a number of behavioural activities to help them survive the low temperatures.
•Endotherms can regulate their body temperature so that it remains the same, even though the day may be hot or cold.
•Temperatures on land fluctuate more than in water. The ocean temperature does not vary much in one location, but shallow lakes and rock pools may heat up considerably over a day. Air temperatures on land change constantly. In vast areas like desserts, temperature variations can be extreme.
•Animals rapidly lose heat when in cold water. Aquatic ectotherms, eg fish, function best at the temperature of the surrounding water. Endotherms functions at higher temperatures and they need mechanisms to maintain high body temperatures, eg, whales have blubber to insulate themselves and reduce heat loss.
•Land animals show a variety of adaptations to control temperature. Polar bears have a small SA:V ratio and this reduces heat loss. Sunbaking animals with a large SA:V, eg snakes will absorb heat readily.
•Plants need warmth for germination and flowering. If the temperature is too high, seeds and tissues dehydrate. Plants cool themselves by transpiration, or reflecting heat from leaves.
•Plants have the same temperature as their surroundings. They require particular temperature to survive and breed, eg date palms may survive in cooler temperatures but will not produce seeds.
•Plants control heat with transpiration which lowers the temperature of a plant several degrees lower than the ambient temp
•Hairy leaves relflect 20% more heat then smooth ones.
•Dormancy in winter, losing leaves to avoid damage.
•Underground reproductive structures, eg, bulbs and rhizomes
•Radiation and convection are important in heat control.
Transport in Animals:-
•Plants and animals need energy for growth and maintenance. This energy is produced in cells in a process called respiration which requires oxygen and carbohydrates. Water and waste carbon dioxide are formed.
•In animals, oxygen enters the blood through the lungs, sugars needed for respiration pass into the blood from the small intestines. In plants, oxygen enters via stomates in leaves and diffuses into cells.
•In animals, substances in the blood are carried in vessels called arteries, veins and capillaries. Arteries carry blood away from the heat to the lungs and body tissues. Blood in arteries is under high pressure and the walls are thick.
•Arteries branch into a network of capillaries, which penetrate the tissues and have very thin walls. Substances pass through these walls into and out of cells. Veins take the blood back to the heart.
•Mammalian blood is composed of red blood cells, white bloods cells and platelets in a yellow liquid called plasma. White blood cells are involved in the immune system and the body’s defenses.
•Red blood cells are the most common cells in blood. They carry the red pigment called haemoglobin. This pigment attaches to oxygen and transports it to the cells.
•The plasma is mainly composed of water. It carries a number of substances around the body. Salts and most of the carbon dioxide are transported as ions.
Changes in the blood:-
•The composition of blood changes as it moves through the body. Blood passes through the lungs collects oxygen and releases waste carbon dioxide. As blood travels though the tissues, it passes oxygen and digested food to the cells and collects carbon dioxide from them.
•Humans must maintain a constant acidity in the blood. Carbonic acid is formed when carbon dioxide enters the blood and combines with the water in plasma.
•PH is a measure of acidity. Chemicals with a low PH between 1 and 6 are acidic. Substances with a PH between 8 and 14 are alkaline. A PH of 7 is neutral. Carbon dioxide makes blood acidic.
•AN increase of carbon dioxide in the blood triggers release of oxygen, which is attached to haemoglobin in blood. Cells use the oxygen in respiration.
•The presence of oxygen in blood triggers the release of carbon dioxides into the lungs. Carbon dioxide is a waste and needs to be removed from the body.
•Mountain air has less oxygen then air at sea level. Mountain dwellers respond to this by breathing at a faster rate They also have more red blood cells and larger hearts.
Transport in Plants:-
•In plants, gases diffuse into and out of stomates, which are mainly found in leaves. These gases are needed for photosynthesis and respiration.
•Xylem and phloem transport substances in plants. Xylem consists of hollow, dead cells, and carries water from roots to tissues in leaves.
•Phloem carried sugars made in leaves to growing trees and storage organs, such as fruits. This is called translocation. Phloem is living tissue composed of siev tubes and companion cells.
•Water movies in xylem because of transpiration pull, osmotic pressure and capillary. The plant does not supply energy to do this, so the process is called passive transport.
•The plant provides energy, in the form of ATP, to move substances in the phloem. This process is called active transport.
Kidneys:-
•Metabolic reactions are chemical reactions occurring in cells. These reactions produce wastes which are toxic and must be removed. The human organs which excrete these wastes are the kidneys and bladder, lungs and skin.
•Fish are marine invertebrates excrete nitrogenous wastes in the form of ammonia. Land animals produce urea or uric acid.
•Chemical reactions occurring in cells require water as a soluble. Chemicals dissolve in a solvent. Kidneys help the body to balance water and it’s substances, such as salts.
•Osmo regulation is the way the body maintains the balance of ions, small molecules and water. The kidneys of fish function mainly in osmo regulations, whereas the human kidney functions as an osmo regulator, as well as excreting nitrogenous wastes.
•Blood containing wastes and other substances, passes into the kidneys and into the filtering units called nephrons, there wastes and excess substances are removed, and useful substances are reabsorbed into the blood.
•In diffusion and osmosis, a substance moves from where it is concentrated to where it is less concentrated. This does not need energy. It is passive transport.
•Hormones determine how much water and salt will be reabsorbed from the kidney nephrons into the blood. Antidiuretic hormones regulate water and are produced by hypothalamus in the brain.
•Different animals excrete different wastes. When protein is broken down or deaminated ammonia is formed. It is very toxic and needs to be removed rapidly. Fish excrete ammonia mainly through the gills. It dissolves readily in water.
•Mammals convert ammonia to urea. Urea is soluble and dissolves in water to form urine. Urea is less toxic so can stay in the body longer. Mammals who need to conserve water produce very concentrated urine. It contains lots of waste and little water.
•Land animals such as reptiles, birds and insects, convert ammonia to uric acid, which is not very soluble and is non-toxic. This is the white substance commonly seen in bird poo. Uric acid is solid, so animals producing uric acid as a waste lose less water from the body.
•All living things need water. The water inn the body contains substances needed for chemical reactions. The body needs to maintain a particular concentration of these for it to work properly.
•Kidneys regulate the composition of the body fluids to ensure water balance and correct concentrations.
•The human kidneys excrete nitrogenous wastes as well as regulating the ions in the fluids. Blood is filtered by the kidneys.
•In fish, gills excrete the nitrogenous wastes. The kidneys are mainly involved in osmoregulation. Aquatic organisms like fish have the perpetual problem of their tissues being dehydrated on flooded by osmosis. This upsets the ion-water balance, the kidney is involved in regulating this water flow.
•The human kidney contrains over a million nephrons, or filtering units. Contents of the blood pass into the Bowman’s capsule and down the tubule. In the tubule, useful substances like water and glucose are reabsorbed into the blood.
•Reabsorption of substances into the blood from the nephrons tubule involves active and passive transport. Active transport requires energy. It occurs if the substance is too large to pass through the membrane, and the substances moving against a concentration gradient.
•Osmosis and diffusion in the mammalian kidney are passive processes, which involve substances moving from where there are many particles to where there are few particles.
•Hormones regulate the Reabsorption of water from kidney nephrons go little water in the blood is registered by the hypothalamus in the brain. It produces ADH which causes the kidneys to pass more water back into the blood. If there is too much water the opposite happens.
•Aldosterone controls the amount of salt reabsorbed. Low salt concentration in the blood causes production of aldosterone. This increases salt reabsorption from the nephrons to the blood. High salt concentrations cause the opposite reaction.
Organisms living in water:-
•Osmosis is the movement of water across a semi-permeable membrane. Water moves from where it is concentrated to where it is less concentrated. This means that water moves from a dilute solution to a concentrated solution, to even out the concentrations.
•Animals in salt water tend to lose water because there is a higher concentration of water inside the tissue than in the ocean. These animals will become dehydrated unless they have special mechanism or adaptation to reduce water loss.
•When an animal is surrounded by fresh water, the animals tissues may become flooded. Water moves into the tissues by osmosis, because water is more concentrated in the river than in the tissues.
•Animals in bays, coastal swamps and estuaries have an environment with changing salt levels. When surrounded by fresh slightly salty water, the animals tissues tend to be flooded. In very salty water, the tissues tend to lose water and become more concentrated.
•Many estuarine animals are very tolerant of the fluctuating salt content in their environment and tissues. Some animals swim away when salinity changes. Others burrow and shell dwellers such as oysters tightly close their shells.
•Plants living in salty environments are called halophytes. They have special adaptations to control salt levels in their tissues. Many of these plants, such as mangroves excrete salt from their leaves.
Plants in dry habitats:-
•Many Australian plants grow in hot dry conditions. For plants to survive in these habitats, they need to increase water uptake or reduce water loss. They have a variety of adaptations to assist with survival in the harsh Australian environment.
•Plants in dry areas often have a thick, waxy cuticle which covers the surfaces. It is waterproof and reduces water loss.
•Plants have small pores, called stomates on their leaves and stems. Stomates open to allow gases into and out of the plant. Water is also lost from them. In dry environments stomates may open in early or late parts of the day when it is cooler.
•Stomates may be sunken in cavities in the leaves. These stomates are deep inside the leaf tissue. This reduces evaporation and water loss. Often the cavities contain tiny hairs, which also slow down the water loss from the plant.
•Leaf surfaces may be small so that little water is lost from them. Some plants, like spinifex and banksias roll up their leaves to reduce SA and therefore water loss.
•Shiny or hairy leaves like those of spinifex reflect heat. This keeps plants cool and reduces evaporation and water loss.
•As well as reducing water loss, plants in dry habitats may increase the uptake of water by having extensive root systems.
* For the body to function properly it needs constant internal conditions. The nervous system and the endocrine system monitor the body and maintain a constant internal environment.
* Enzymes are large protein molecules which speed up chemical reactions. Each type of enzyme is involved in one type of chemical reaction.
* Enzymes work best at specific PH and a particular temperature. The human body has a temperature of 37 degrees, so this will be the optimum temperature for the functioning of enzymes in humans.
* Body fluids, such as blood, are constantly changing their temperature and chemical composition. This process helps organs respond to correct or adjust these changes.
* Changes in body fluids are detected by cells called receptors. These cells send messages to the brain. Organs in the body respond to the brain and restore the fluids to normal.
* In humans, the hypothalamus in the brain detects change in blood temperature. The hypothalamus sends messages to the adrenal glands in skin.
* Humans have a number of cooling and heating mechanisms so that they can maintain a constant temperature.
Enzymes:-
•Needed for metabolism
•Need constant internal conditions
•Reaction would be to slow to maintain without them
•They’re proteins that speed up chemical reactions – without changing or being used themselves.
•All chemical reactions in cells are controlled by enzymes
•They’re specific for each chemical reaction
•Work best as a specific PH – optimum PH
•Low PH means high acidity
•Work best at particular temperatures – optimum temperature
•Low temperature inactive enzymes
•High temps destroy enzymes so they can’t work again.
Homeostasis:-
•Process of keeping internal environment constant. Temperature increases �* Body sweats �* Temperature decreases.
•Body continually monitors and regulates temperature and composition of body fluids.
•Changes in chemicals in blood are detected by chemoreceptors
•Thermoreceptors detect temperature changes
•Receptors send message to brain to body parts which counteract the change
•Hypothalamus in brain is temperature control centre
•Hypothalamus activates adrenal glands and skin to regulate temperature.
Organisms and temperature:-
•All organisms have an optimum temperature range for survival. Outside this temperature range enzymes are inactive and the body does not function adequately
•The temperature of ectothermic organisms will rise and fall with the temperature of the surrounding environment. In water, ectotherms have a very low metabolism, and a number of behavioural activities to help them survive the low temperatures.
•Endotherms can regulate their body temperature so that it remains the same, even though the day may be hot or cold.
•Temperatures on land fluctuate more than in water. The ocean temperature does not vary much in one location, but shallow lakes and rock pools may heat up considerably over a day. Air temperatures on land change constantly. In vast areas like desserts, temperature variations can be extreme.
•Animals rapidly lose heat when in cold water. Aquatic ectotherms, eg fish, function best at the temperature of the surrounding water. Endotherms functions at higher temperatures and they need mechanisms to maintain high body temperatures, eg, whales have blubber to insulate themselves and reduce heat loss.
•Land animals show a variety of adaptations to control temperature. Polar bears have a small SA:V ratio and this reduces heat loss. Sunbaking animals with a large SA:V, eg snakes will absorb heat readily.
•Plants need warmth for germination and flowering. If the temperature is too high, seeds and tissues dehydrate. Plants cool themselves by transpiration, or reflecting heat from leaves.
•Plants have the same temperature as their surroundings. They require particular temperature to survive and breed, eg date palms may survive in cooler temperatures but will not produce seeds.
•Plants control heat with transpiration which lowers the temperature of a plant several degrees lower than the ambient temp
•Hairy leaves relflect 20% more heat then smooth ones.
•Dormancy in winter, losing leaves to avoid damage.
•Underground reproductive structures, eg, bulbs and rhizomes
•Radiation and convection are important in heat control.
Transport in Animals:-
•Plants and animals need energy for growth and maintenance. This energy is produced in cells in a process called respiration which requires oxygen and carbohydrates. Water and waste carbon dioxide are formed.
•In animals, oxygen enters the blood through the lungs, sugars needed for respiration pass into the blood from the small intestines. In plants, oxygen enters via stomates in leaves and diffuses into cells.
•In animals, substances in the blood are carried in vessels called arteries, veins and capillaries. Arteries carry blood away from the heat to the lungs and body tissues. Blood in arteries is under high pressure and the walls are thick.
•Arteries branch into a network of capillaries, which penetrate the tissues and have very thin walls. Substances pass through these walls into and out of cells. Veins take the blood back to the heart.
•Mammalian blood is composed of red blood cells, white bloods cells and platelets in a yellow liquid called plasma. White blood cells are involved in the immune system and the body’s defenses.
•Red blood cells are the most common cells in blood. They carry the red pigment called haemoglobin. This pigment attaches to oxygen and transports it to the cells.
•The plasma is mainly composed of water. It carries a number of substances around the body. Salts and most of the carbon dioxide are transported as ions.
Changes in the blood:-
•The composition of blood changes as it moves through the body. Blood passes through the lungs collects oxygen and releases waste carbon dioxide. As blood travels though the tissues, it passes oxygen and digested food to the cells and collects carbon dioxide from them.
•Humans must maintain a constant acidity in the blood. Carbonic acid is formed when carbon dioxide enters the blood and combines with the water in plasma.
•PH is a measure of acidity. Chemicals with a low PH between 1 and 6 are acidic. Substances with a PH between 8 and 14 are alkaline. A PH of 7 is neutral. Carbon dioxide makes blood acidic.
•AN increase of carbon dioxide in the blood triggers release of oxygen, which is attached to haemoglobin in blood. Cells use the oxygen in respiration.
•The presence of oxygen in blood triggers the release of carbon dioxides into the lungs. Carbon dioxide is a waste and needs to be removed from the body.
•Mountain air has less oxygen then air at sea level. Mountain dwellers respond to this by breathing at a faster rate They also have more red blood cells and larger hearts.
Transport in Plants:-
•In plants, gases diffuse into and out of stomates, which are mainly found in leaves. These gases are needed for photosynthesis and respiration.
•Xylem and phloem transport substances in plants. Xylem consists of hollow, dead cells, and carries water from roots to tissues in leaves.
•Phloem carried sugars made in leaves to growing trees and storage organs, such as fruits. This is called translocation. Phloem is living tissue composed of siev tubes and companion cells.
•Water movies in xylem because of transpiration pull, osmotic pressure and capillary. The plant does not supply energy to do this, so the process is called passive transport.
•The plant provides energy, in the form of ATP, to move substances in the phloem. This process is called active transport.
Kidneys:-
•Metabolic reactions are chemical reactions occurring in cells. These reactions produce wastes which are toxic and must be removed. The human organs which excrete these wastes are the kidneys and bladder, lungs and skin.
•Fish are marine invertebrates excrete nitrogenous wastes in the form of ammonia. Land animals produce urea or uric acid.
•Chemical reactions occurring in cells require water as a soluble. Chemicals dissolve in a solvent. Kidneys help the body to balance water and it’s substances, such as salts.
•Osmo regulation is the way the body maintains the balance of ions, small molecules and water. The kidneys of fish function mainly in osmo regulations, whereas the human kidney functions as an osmo regulator, as well as excreting nitrogenous wastes.
•Blood containing wastes and other substances, passes into the kidneys and into the filtering units called nephrons, there wastes and excess substances are removed, and useful substances are reabsorbed into the blood.
•In diffusion and osmosis, a substance moves from where it is concentrated to where it is less concentrated. This does not need energy. It is passive transport.
•Hormones determine how much water and salt will be reabsorbed from the kidney nephrons into the blood. Antidiuretic hormones regulate water and are produced by hypothalamus in the brain.
•Different animals excrete different wastes. When protein is broken down or deaminated ammonia is formed. It is very toxic and needs to be removed rapidly. Fish excrete ammonia mainly through the gills. It dissolves readily in water.
•Mammals convert ammonia to urea. Urea is soluble and dissolves in water to form urine. Urea is less toxic so can stay in the body longer. Mammals who need to conserve water produce very concentrated urine. It contains lots of waste and little water.
•Land animals such as reptiles, birds and insects, convert ammonia to uric acid, which is not very soluble and is non-toxic. This is the white substance commonly seen in bird poo. Uric acid is solid, so animals producing uric acid as a waste lose less water from the body.
•All living things need water. The water inn the body contains substances needed for chemical reactions. The body needs to maintain a particular concentration of these for it to work properly.
•Kidneys regulate the composition of the body fluids to ensure water balance and correct concentrations.
•The human kidneys excrete nitrogenous wastes as well as regulating the ions in the fluids. Blood is filtered by the kidneys.
•In fish, gills excrete the nitrogenous wastes. The kidneys are mainly involved in osmoregulation. Aquatic organisms like fish have the perpetual problem of their tissues being dehydrated on flooded by osmosis. This upsets the ion-water balance, the kidney is involved in regulating this water flow.
•The human kidney contrains over a million nephrons, or filtering units. Contents of the blood pass into the Bowman’s capsule and down the tubule. In the tubule, useful substances like water and glucose are reabsorbed into the blood.
•Reabsorption of substances into the blood from the nephrons tubule involves active and passive transport. Active transport requires energy. It occurs if the substance is too large to pass through the membrane, and the substances moving against a concentration gradient.
•Osmosis and diffusion in the mammalian kidney are passive processes, which involve substances moving from where there are many particles to where there are few particles.
•Hormones regulate the Reabsorption of water from kidney nephrons go little water in the blood is registered by the hypothalamus in the brain. It produces ADH which causes the kidneys to pass more water back into the blood. If there is too much water the opposite happens.
•Aldosterone controls the amount of salt reabsorbed. Low salt concentration in the blood causes production of aldosterone. This increases salt reabsorption from the nephrons to the blood. High salt concentrations cause the opposite reaction.
Organisms living in water:-
•Osmosis is the movement of water across a semi-permeable membrane. Water moves from where it is concentrated to where it is less concentrated. This means that water moves from a dilute solution to a concentrated solution, to even out the concentrations.
•Animals in salt water tend to lose water because there is a higher concentration of water inside the tissue than in the ocean. These animals will become dehydrated unless they have special mechanism or adaptation to reduce water loss.
•When an animal is surrounded by fresh water, the animals tissues may become flooded. Water moves into the tissues by osmosis, because water is more concentrated in the river than in the tissues.
•Animals in bays, coastal swamps and estuaries have an environment with changing salt levels. When surrounded by fresh slightly salty water, the animals tissues tend to be flooded. In very salty water, the tissues tend to lose water and become more concentrated.
•Many estuarine animals are very tolerant of the fluctuating salt content in their environment and tissues. Some animals swim away when salinity changes. Others burrow and shell dwellers such as oysters tightly close their shells.
•Plants living in salty environments are called halophytes. They have special adaptations to control salt levels in their tissues. Many of these plants, such as mangroves excrete salt from their leaves.
Plants in dry habitats:-
•Many Australian plants grow in hot dry conditions. For plants to survive in these habitats, they need to increase water uptake or reduce water loss. They have a variety of adaptations to assist with survival in the harsh Australian environment.
•Plants in dry areas often have a thick, waxy cuticle which covers the surfaces. It is waterproof and reduces water loss.
•Plants have small pores, called stomates on their leaves and stems. Stomates open to allow gases into and out of the plant. Water is also lost from them. In dry environments stomates may open in early or late parts of the day when it is cooler.
•Stomates may be sunken in cavities in the leaves. These stomates are deep inside the leaf tissue. This reduces evaporation and water loss. Often the cavities contain tiny hairs, which also slow down the water loss from the plant.
•Leaf surfaces may be small so that little water is lost from them. Some plants, like spinifex and banksias roll up their leaves to reduce SA and therefore water loss.
•Shiny or hairy leaves like those of spinifex reflect heat. This keeps plants cool and reduces evaporation and water loss.
•As well as reducing water loss, plants in dry habitats may increase the uptake of water by having extensive root systems.
