Movement in and out of cells and membrains

Question 1

What are ways in which subrstances go through membrains?

What does it need? Does it need energy or not? What does it transport?

Answer 1

• Passive transport: no energy required, transports ions and other molecular substances within the cells along the concentration gradient
• Diffusion: No energy is required, transports substances
• Facilitated diffusion: no energy needed, transports aquaporins like glucose and water, channel proteins are needed
• Osmosis: no energy needed, need a semi-permiable membrain, transports water
• Active transport: requires energy, transports large molecules and high concentrations of molecules that the cell needs, such as ions, glucose and amino acids, needs channel proteins and goes against the concentration gradient
• Ion pumps: requires ATP, againsed the concentration gradient, transport ions

Question 2

What are the charactaristics for efficient diffusion?

Answer 2

• Small particles
• Hotter temperature
• High concentration gradient
• Gas is best state for particles
• Large surface area

Question 3

What are the definitions of isotonic, hypertonic and hypotonic

Osmosis and cells

Answer 3

• Isotonic: equal concentration gradient from cell and the outside
• Hypertonic: too less water in cell
• Hypotonic: too much water in cell

Question 4

What is active transport? Define

Answer 4

• Active transport uses energy to transport molecules againsed their concentration gradient, across a partially permiable membrain
• Enegy is used to move molecules/ions across a cellular membrain from a region of low concentration to a region of high concentration using transport proteins

Question 6

What are the three types of active transport?

With examples

Answer 6

• Endocytosis: bring substances into the cell. For example phagocytosis used by white blood cells to engluf bacteria (penocytosis, liquid/pheocytosis. solid)
• Exocytosis moving sybstances outside of the cell (too large to pass through plasma membrain. For example neurotransmitters and the golgi apparatus usses exocytosis.
• Ion pumps and co-transport:Example s the sodium-potassiom pump is a transmembreain protein that uses energy to move ions across a membrain againsed their concentration gradient. this is importrant for the transmission of nerve impulses.

Question 7

What are the differences of diffusion and osmosis

Answer 7

Question 8

What is the equasion for surface area to colume ratio

Answer 8

Surface area divided by volume

Question 9

Why are leaves ussually long and flat

Answer 9

Leaves are long and flat to increase their surface area, which enhances their ability to absorb sunlight for photosynthesis and facilitates efficient gas exchange through stomata. This shape also supports effective water regulation via transpiration, crucial for plant health and growth.