cell respiration sl Flashcards
Cell Respiration
the controlled release of energy from organic compounds in cells to form ATP
Cellular respiration: uses of ATP
- what are the 3 main types? (SMA)
- Chemical energy (ATP) produced by an organism through cellular respiration can be converted into a number of different forms of energy with only little being lost to heat:
- Chemical energy stored in ATP can be converted into electrical energy when transmitting a nerve impulse, into kinetic energy during muscle contractions, into light energy in bioluminiscence, into other forms of chemical energy in the synthesis of molecules or when transporting materials.
- synthesizing macromolecules, movements, active transport
- Define Redox rxn
- OIL RIG
- Reducing agent
- Oxidizing agent
- a type of chemical rxn that involves the transfer of electrons between 2 species
- substance that loses an electron; the substance that caused the reduced atom to become reduced
- substance that gains the electron; substance that causes the oxidized atom to become oxidized
ATP as the molecule that distributes energy within cells
- Include the full name of ATP (adenosine triphosphate) and that it is a nucleotide.
- Why do we burn up so much during physical activity?
- Students should appreciate the properties of ATP that make it suitable for use as the energy currency within cells.
- Energy in cellular respiration is transferred in small quantities rather than one big release. If energy would be all given out in one go most of it would be lost as heat to the surrounding. Instead, energy is transferred to ATP in many small steps with only little heat loss.
- It contains chemical energy locked up in its structure
- The energy can be released in small managable quantities by hydrolysing ATP into ADP – useful for many energy requiring processes in the cell
- It is a very reactive molecule, taking part in cell respiration and metabolism
- It is small and can be moved easily into cells by facilitated diffusion
- It cannot move simply through cell membranes, keeping it under control
- Renewable energy source
- Soluble (most active processes happen in aqueous environments)
Life processes within cells that ATP supplies with energy
- Include active transport across membranes, synthesis of macromolecules (anabolism), movement of the whole cell or cell components such as chromosomes.
- EXAMPLES
- synthesizing macromolecules: synthesis of starch from glucose in plants/synthesis of proteins/DNA replication
- movement: muscle contraction
- active transport: transport of substances against concentration gradient (sodium-potassium pump/root hairs of plants to absorb mineral ions)
Energy transfers during interconversions between ATP and ADP
- Students should know that energy is released by hydrolysis of ATP (adenosine triphosphate) to ADP (adenosine diphosphate) and phosphate, but energy is required to synthesize ATP from ADP and phosphate. Students are not required to know the quantity of energy in kilojoules, but students should appreciate that it is sufficient for many tasks in the cell.
- During cellular respiration the energy from food is used to form ATP from ADP and Pi. Energy requiring processes in the body can then use ATP together with enzymes as energy source converting it back into ADP.
- Hydrolysis of ATP splits it into ADP by removing one phosphate group using water. Energy contained in the covalent bond is released.
- The reverse process, where water is released and energy required to form ATP from ADP and Pi, is referred to as condensation.
- In many metabolic reactions ATP reacts with other metabolites with the help of enzymes to form phosphorylated intermediates.
- This phosphorylation makes them more reactive for the process in which they need to take part in.
- When muscles contract, they shorten in length as a result of actin and myosin protein filaments in muscle cells sliding in and out of each other. The sliding depends on the hydrolysis of ATP and the energy released is used for the “power stroke”.
Cell respiration as a system for producing ATP within the cell using energy released from carbon compounds
- What are principle substrates for cellular respiration?
- how is ATP formed?
- Students should appreciate that glucose and fatty acids are the principal substrates for cell respiration but that a wide range of carbon/organic compounds can be used.
- ATP is produced by attaching a phosphate group to ADP. This step requires energy – ultimately coming from food. The covalent bond created stores energy until it is released again for processes required by cells. ADP is therefore recycled again.
- Students should be able to distinguish between the processes of cell respiration and gas exchange.
- mention place
- Breathing is the intake of oxygen into the lungs and release of carbon dioxide from the lungs to enable gas exchange and to provide the body with oxygen for cellular respiration.
- Cell respiration is the controlled release of energy from organic compounds to produce ATP. It takes place in the mitochondria of all cells.
define aerobic and anaerobic respiration!
Differences between anaerobic and aerobic cell respiration in humans
- Aerobic: When oxygen is present the two pyruvate molecules now enter a mitochondrion and are further metabolized (substrates are gradually reduced using oxygen as the final electron acceptor.)
- Anaerobic:
Alcoholic fermentation: where carbon dioxide and ethanol (C2H6O) are produced in yeast.
Lactic acid fermentation: takes place in humans and other animals. Lactate can be converted back to pyruvate when oxygen is present. (Without oxygen pyruvate will be converted into lactic acid during anaerobic respiration)
Differences between anaerobic and aerobic cell respiration in humans
- Include which respiratory substrates can be used, whether oxygen is required, relative yields of ATP, types of waste product and where the reactions occur in a cell.
- Students should be able to write simple word equations for both types of respiration, with glucose as the substrate.
- Students should appreciate that mitochondria are required for aerobic, but not anaerobic, respiration.
- Use of oxygen (as electron acceptor)
- Substrates used
- Waste products
- Yield of ATP
- Location of reactions in the cell
- Word equation for reaction
- Purpose of reaction
why and when to use anaerobic respiration?
- When a short and rapid burst of ATP is needed (high intensity exercises b/c the supply of energy needs to be fast and quickly available so that power can be maximized./not enough time to deliver O2 to the cells for aerobic respiration.)
- When oxygen supplies run out in respiring cells
- In environments which are oxygen deficient (e.g. waterlogged soil)
Variables affecting the rate of cell respiration
- Students should make measurements allowing for the determination of the rate of cell respiration. Students should also be able to calculate the rate of cellular respiration from raw data that they have generated experimentally or from secondary data.
GLYCOLYSIS
- initial and end products
- info about inhibitors
