B2 Flashcards
What is mitosis
When a cell reproduces itself by splitting to form two identical offspring
What is an example of a specialised cell
Palaside leaf cells do most of the photosynthesis in plants so they are packed with chloroplasts their tall shape means they have a lot of surface area good for absorbing co2
What is diffusion
The gradual movement of particles from places where there are lots of them to places where there are fewer of them
Why are the subtances able to move in and out
The cell membrane allows very small molecules to diffuse things like glucose and water
What is active transport
The movement of particles across a membrane against a concentration gradient from an area of low to high concentration using atp released during respiration
What is osmosis
The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
What are the three main factors that affect the movement of substances
Surface area to volume ratio
Temperature
Concentration gradient
Where does gas exchange take place
The alveoli
What are the role of the valves
To make sure blood flows in the right direction
What is the role of the arteries
Carry the blood away from the heart
What is the role of the capillaries
Involved in the exchange of materials at the at the tissues
What is the role of the veins
Carry blood to the heart
What type of blood do the arteries carry
High pressure so the artery walls are thick and elastic
They contain thick layers of muscle to make them strong
Why are capillaries really small
Carry the blood really close to every cell in the body to exchange subtances with them
Permeable walls so subtances can diffuse in and out
What type of the blood do veins carry
Low pressure blood so the walls don’t have to be thick
They have valves to keep the blood flowing in the right direction
