B2 Topic 2 - Life Processes Flashcards
What is the equation for Cardiac Output?
Cardiac Output = Heart Rate x Stroke Volume
cm^3pm = bpm x cm^3
Why do humans do use anaerobic respiration when it produces less energy than aerobic?
If the cells cannot get enough oxygen, the body can’t respire aerobically. Rather than not producing any energy at all, it respires anaerobically to produce a little energy until enough oxygen arrives. After you finish exercising, you need to repay your oxygen debt, or EPOC (excess post-exercise oxygen consumption), to convert the lactic acid in your muscles into CO2 and water.
Define respiration.
Respiration is the process of breaking down glucose to release energy, which goes on in every living cell.
What is the equation for aerobic respiration?
Glucose + Oxygen -> Carbon Dioxide + Water (+ Energy)
How do the raw materials and waste get to and from the cells?
The circulatory system carries glucose, oxygen and CO2 around the body. The glucose comes from breaking down food in the digestive system. The oxygen comes from air inhaled into the lungs, while the CO2 is exhaled. The blood vessels nearest to the cells are called capillaries and the reactants and products of respiration get to the cells through diffusion. The particles move to the area with the lowest concentration. Oxygen and glucose are used up in the cells and so the concentration is low.
Define diffusion.
Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.
What is the equation for anaerobic respiration?
Glucose -> Lactic acid (+ energy)
How do plants produce their own food?
The photosynthesise using the chloroplasts in their leaves, which use carbon dioxide, water and sunlight to produce glucose and oxygen.
How are plants’ leaves adapted to be efficient at photosynthesis?
They are broad, so they have a larger surface area to absorb sunlight.
They contain a lot of chlorophyll in their palisade cells, which are long to absorb light and also compacted together so no space is wasted
Leaves also have stomata which open and close to allow CO2 and oxygen to pass in and out of the plant, as well as water vapour to escape, which is known as transpiration.
What are the three limiting factors of photosynthesis?
Light
Carbon dioxide concentration
Temperature
What is osmosis?
Osmosis is the movement of water molecules across a partially-permeable membrane from a region of high water concentration to an area of low water concentration.
A partially permeable membrane allows small particles such as water to pass through, but not larger ones such as glucose etc. so the water molecules move across randomly from one side to the other, but the net movement of water is towards the area with a lower concentration of water.
If one side contains more sucrose, for example, water molecules are attracted to these molecules due to their slight polarity, so less water molecules are free to move and the concentration of ‘free’ water molecules is lower on that side. So the net movement of water would be towards the high sugar concentration in an attempt to dilute the solution.
How do root hair cells take in water and minerals into the plant?
Water by osmosis - the water concentration is usually higher outside the root so water naturally moves into the plant by diffusion (osmosis).
Minerals by active transport - concentration of minerals is usually higher inside the plant, so roots use energy from respiration to take in minerals from the soil.
The minerals inside the plant further speed up osmosis as the water outside tries to dilute them.
What is transpiration?
As water rises up the plant in the xylem and into the leaves only 10% is used for photosynthesis, the other 90% leaves the leaves through the stomata, this creates a vacuum that sucks more water from the roots up the plant and into the leaves.
What does the xylem and phloem transport in a plant?
Xylem - water and minerals up the plant only
Phloem - sugars from leaves, up and down to rest of plant
Name four different methods of collecting organisms.
Pooters- collecting ground insects
Pitfall traps - collecting ground insects
Sweep nets - collecting animals in long grass or flying insects
Pond nets - collecting small aquatic organisms
