B2 Flashcards
What is diffusion ?
The movement of particles from an area of high concentration to an area of low concentration.
How does the concentration gradient affect the rate of diffusion?
The greater the difference in concentration, the fater rate of diffusion
How does temprature affect the rate of diffusion ?
The greater the temprature , the greater movement of particles.
How does the surface area of the membrane affect the rate of diffusion ?
The greater the surface area, the more space for parcticles to move through
What is osmosis?
Osmosis is the movement of water from a low concentration to a high concentration through a partially permeable membrane.
What is active transport ?
Active transport is the movement of particles from an area of low concentration to an area of high concentration
What is mitosis ?
Mitosis is a type of cell division where 1 cell divides to form 2 identical daughter cells.
What happens in the first stage of cell division (Interphase)
In this stage the cell grows, organells grow and increases in number. All 46 chromosones are replicated.
What happens in the third stage of cell division (cytokinesis)
2 identical daughter cells form cytoplasam and cell membranes divide, each containing the same 46 chromosones as the origional cells.
How do cells specalise ?
By undergoing differentiation : a process that involves the cell ganining new sub-cellular structures in order for it to be suited to it’s role.
What are stem cells ?
An undifferenciated cell which can undergo division to prodice many more similar cells. Some will differentiate to have different funtions.
What is an embryonic stem cell ?
A cell that can differenciated into any type of cell in the body
How does surface area : volume ratio impact exchange surfaces & transport systems
If the surface area : Volume ratio is large, the organisim is less likley to require specalised exchange surfaces and a transport system because the rate of diffusion is sufficient in supplying and removing the gases
What does system 1 of the double circulatory system do ?
Deoxygenated blood flows into the left atrium then into the left ventricle which pumps oxygenated blood around the body.
What does system 2 of the double circulatory system do ?
Oxygenated blood flows into the left atrium then into the left ventricle which pumps oxygenated blood to the body.
How does the blood move through the vessels ?
Vena cava –> Pulmonary artery –>Pulmonary vein –> Aorta —>
What are the charcteristics of arteries ?
- Carry blood away from the heart
- Layers of muscle to make the walls strong
- Elastic fibres
- Carry blood at a high pressure
What are the charcteristics of veins ?
- Carry blood towards the heart
- The lumen is wide to let blood flow through
- They have vaulves to stop blood from flowing in the wrong direction
What are the charcteristics of capillaries ?
Allow the blood to flow very close to the cells
The wall is 1 cell thick
What are the elements of the blood ?
Red blood cells - have haemoglobin - biconcave shape
Plasma- liquid that carries components of the blood i.e. platelets
What is transpiration ?
The loss of water of water vapour from the leaves and stems of the plants
What is the xylem ?
They transport water and minerals around the plant. They replace water that has been lost due to transpiration
What do guard cells do ?
They control the opening and closing of the stomata
What are the 4 factors affecting water uptake ?
- Light instensity
- Temprature
- Wind (air movement)
- Humidity
What is translocation ?
The movement of food substances made in the leaves or up & down the phloem
