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Higher Biology - Unit 2
Terms in this set (120)
What is dormancy?
A period where organisms have a reduced metabolic rate.
What is predictive dormancy?
When organisms become dormant before the onset of adverse conditions.
What is consequential dormancy?
When organisms become dormant after the onset of adverse conditions.
Where is consequential dormancy more common?
In regions where conditions change suddenly and unpredictably.
What is hibernation?
A form of dormancy that helps an organism survive cold temperatures.
What happens to organisms during dormancy?
Rate of metabolism decreases, heart rate and breathing rate decreases and body temperature decreases
What is aestivation?
A form of dormancy that helps an organism survive hot temperatures / drought.
What happens to organisms during aestivation?
Rate of metabolism decreases, heart rate and breathing rate decreases and body temperature decreases Rate of metabolism decreases
Give an example of an organism that uses hibernation?
Give an example of an organism that uses aestivation?
What is daily torpor?
An organism's metabolic rate is greatly reduced for a period of time in every 24 hour cycle.
Give an example of an organism which uses daily torpor?
Birds - hummingbird
What is migration?
The regular movement by members of a species from one place to another.
Why do organisms migrate?
To avoid periods of metabolic adversity like food shortages or low temperatures.
Why do we study migration?
To find out: When organisms migrate, where they go, how long they stay, how long they live and when they return to their territory
Which specialised techniques can be used for studying migration?
Ringing / banding, electronic tagging, colour marking and using transmitters which send GPS signals
What is innate behaviour?
Behaviour which is inherited and inflexible.
What is learned behaviour?
Behaviour which is gained by experience and is flexible.
Which type of behaviour is thought to play a primary role in migration?
What is an extremophile?
An organism which can survive in extreme conditions.
How are extremophiles able to survive?
They usually have enzymes which function well at high temperatures; They can remove electrons from inorganic molecules to generate ATP.
What is a conformer?
An organism which cannot control its metabolic rate and its internal environment is dependent on its external environment.
What are the disadvantages of being a conformer?
Narrow ecological niche and cannot tolerate change
What is an advantage of being a conformer?
Low metabolic costs.
What is a regulator?
An organism which can control its internal environment using physiological mechanisms.
What is an advantage of being a regulator?
Can exploit a wide range of ecological niches
What is a disadvantage of being a regulator?
High metabolic costs.
Give an example of a conformer?
Give an example of a regulator?
What is homeostasis?
Maintaining a stable internal environment.
What is negative feedback control?
A change from the optimum conditions is detected by receptors a corrective mechanism is switched on to bring the conditions back to the optimum.
What is a receptor?
Something which detects change in a condition.
What is an effector?
Something which brings about a change in response to messages from receptors.
How are messages sent between receptors and effectors?
Nerve impulses or hormones.
Why do organisms need to maintain stable body temperatures?
1. To ensure that enzymes have optimum conditions to maintain high metabolic rates. 2. To ensure high diffusion rates of substances. 3. Temperature affects the ability of nerves to send nerve impulses.
Which part of the brain detects changes in blood / body temperature?
What is a thermoreceptor and where are they found?
Detect changes in blood temperature, found in hypothalamus and skin.
How does the hypothalamus receive and send signals?
What are the effectors in thermoregulation?
Sweat glands, skin arterioles, hair erector muscles and skeletal muscles
Describe how sweat glands bring body temperature back to normal when it experiences high temperatures.
increase sweat production, heat energy is used to evaporate the water from the body lowering the body temperature
Describe how metabolic rate changes to bring body temperature back to normal when it experiences high temperatures.
Describe how skin arterioles bring body temperature back to normal when it experiences high temperatures.
arterioles widen increasing blood supply closer to surface of the skin so more heat is lost by radiation.
Describe how hair erector muscles bring body temperature back to normal when it experiences high temperatures.
Relax mean hairs are lowered so less insulating air trapped reducing body temperature
Describe how sweat glands bring body temperature back to normal when it experiences low temperatures.
Decrease sweat production, less heat energy is used to evaporate the water from the body increasing the body temperature
Describe how skin arterioles bring body temperature back to normal when it experiences low temperatures.
vasoconstriction- arterioles narrow decreasing blood supply closer to surface of the skin so less heat is lost by radiation
Describe how hair erector muscles bring body temperature back to normal when it experiences low temperatures.
contract mean hairs stand on end so more insulating air trapped increasing body temperature
Describe how skeletal muscles bring body temperature back to normal when it experiences low temperatures.
shivering which produces heat
Describe how metabolic rate changes to bring body temperature back to normal when it experiences lowtemperatures.
What is meant by metabolic rate?
The quantity of energy used per unit time.
How can metabolic rate be measured?
By measuring the oxygen uptake, heat production or carbon dioxide production.
Which pieces of equipment can be used to measure metabolic rate?
Respirometer or calorimeter.
Where does blood enter the heart?
Where does blood leave the heart?
What do we call the circulatory system of a fish?
Single circulatory system
What do we call the circulatory system of amphibians (and reptiles)?
What do we call the circulatory system of mammals and birds?
Why are incomplete double systems less efficient than complete double?
There is mixing of oxygenated and deoxygenated blood in incomplete so cells are not receiving the maximum quantity of oxygen.
How many chambers does a fish heart have?
How many chambers does an amphibian heart have?
3 - Two atriums, one ventricle
How many chambers do bird and mammal hearts have?
4 - Two atriums, two ventricles.
What is cellular respiration?
A series of enzyme controlled reaction which results in the release of energy from food and regenerates the supply of ATP.
What is aerobic respiration?
Respiration which occurs in the presence of oxygen.
What is fermentation?
Respiration which occurs without oxygen.
What is the summary equation for aerobic respiration?
Glucose + oxygen -> carbon dioxide + water + 38 ATP
What is the summary equation for fermentation in animals (and some bacteria)?
Glucose -> Pyruvate -> Lactate
What is the summary equation for fermentation in plants and yeast?
Glucose -> Pyruvate -> Carbon dioxide + ethanol
What is ATP?
A high energy chemical compound with three phosphates.
What is ADP?
A low energy chemical compound with two phosphates.
How is ATP generated in the cell?
ADP is joined to Pi to create ATP which results in energy being stored.
What happens when ATP is broken down?
Energy is released.
How is it that organisms have a fixed quantity of ATP at all times in their bodies?
As ATP is broken down more ATP is regenerated.
What is phosphorylation?
The addition of phosphate to a molecule- acts as a transfer of energy and makes the molecule more reactive.
Where does the first stage of respiration take place?
What happens in the first stage of respiration?
Glucose -> Pyruvate; NAD -> NADH because DEHYDROGENASE releases electrons and hydrogen ions from the intermediates; 2 ATP used in energy investment phase; 4 ATP made in energy payoff phase
What is the second stage of aerobic respiration known as?
Citric acid cycle
Where does the second stage of aerobic respiration take place?
Matrix of the mitochondria
What happens in the second stage of aerobic respiration?
Pyruvate -> Acetyl group + Carbon dioxide.
What is required for the second stage of aerobic respiration to occur?
What is the final stage of aerobic respiration which results in the generation of most of the ATP?
Electron transport chain
Where does the final stage of aerobic respiration take place?
The christae of the mitochondria, proteins which make up the electron transport chains are found in the inner membrane.
What is the role of NADH and FADH2 in the final stage of aerobic respiration?
They deliver high energy electrons and hydrogen ions to the electron transport chain.
What is the function of the high energy electrons in the final stage of aerobic respiration?
They provide the energy to pump hydrogen ions across the membrane.
What is the function of the hydrogen ions in the final stage of aerobic respiration?
The hydrogen ions flow back into the matrix of mitochondria causing ATP synthase to produce ATP from ADP + Pi.
What is the function of oxygen in the final stage of aerobic respiration?
Acts as the final hydrogen and electron acceptor. Combines with hydrogen and electrons to form water.
What is the main respiratory substrate?
Which stage of respiration can sugar molecules enter?
Which stage of respiration can fat molecules enter?
Broken into glycerol which enters in glycolysis and fatty acids which enter into the citric acid cycle.
Which stage of respiration can protein molecules enter?
Broken down into amino acids and are deaminated before entering either glycolysis or citric acid cycle.
Which enzyme is responsible for the synthesis of ATP molecules?
Which enzyme removes hydrogen and electrons from molecules during respiration?
What is metabolism?
All of the enzyme controlled chemical reactions that take place within cells.
What is meant by an anabolic pathway?
Synthesis reaction that requires energy.
What is meant by a catabolic pathway?
Breakdown reaction that releases energy.
What is an example of an anabolic pathway?
Amino acids -> Proteins
What is an example of a catabolic pathway?
Glucose -> Carbon Dioxide and Water (in presence of oxygen)
Why are irreversible steps necessary in some metabolic pathways?
To commit the metabolic pathway to continuing.
Why are reversible steps necessary in some metabolic pathways?
To keep substrates at the required concentrations.
Why are alternative routes necessary in some metabolic pathways?
Allows reactions to proceed with different substrates and enzymes.
What are membranes made out of?
Phospholipids and proteins
Describe the structure of the membrane?
Phospholipid bilayer, flexible, fluid
What are the roles of proteins in the membranes?
Pumps, pores, enzymes, receptors and structural
Why are membranes important?
They increase the rate of reaction.
How are genes and metabolic pathways linked?
Genes need to be expressed to provide the enzymes for metabolic pathways.
What is an enzyme?
A biological catalyst that lowers the activation energy of reactions.
What is activation energy?
The energy required for the reactants to reach the transition state.
What is the transition state?
The point at which the bonds in the substrate(s) are breaking ready to being the reaction to make the product(s).
What is meant by the "induced fit model"?
When the substrate binds to the enzyme the active site changes shape slightly to fit more closely around the substrate.
What is meant by "affinity"?
Why are enzymes specific?
They only work on substrates which have a high affinity for the active site
Which factors can affect the rate of enzyme activity?
Temperature, pH, substrate concentration and presence of inhibitors
Where can signal molecules which control enzyme action come from?
Intracellular environment or extracellular environment.
What is an inhibitor?
A substance which decreases the rate of an enzyme controlled reaction.
What is a competitive inhibitor?
An inhibitor which works by binding to the active site of the enzyme because it has a similar shape to the substrate.
How can the effects of a competitive inhibitor be overcome?
By increasing the substrate concentration.
What is a non-competitive inhibitor?
An inhibitor which works by binding to the enzyme at a site away from the active site which causes the active site to change shape.
How can some enzymes be activated?
Binding of an activator which makes it take on its active shape.
What is end-product inhibition? (Sometimes known as feedback inhibition)
As the concentration of the end product builds up it can bind to the first enzyme in the pathway thus slowing down the pathway.
How is end-product inhibition useful?
It prevents the build up of end products and the wasteful breakdown of intermediates.
What are protein pores for?
Allow diffusion across membranes.
What are protein pumps for?
Active transport across membranes.
THIS SET IS OFTEN IN FOLDERS WITH...
Higher Biology Unit 1
Higher Biology - Unit 3
Higher Biology Unit 2
Higher Biology: Unit 3
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