Yr9 Stuff

Question 1

Factors affecting the movement of substances into and out of cells:

Answer 1

• Temperature
• Distance
• Particle size
• Diffusion Medium

Question 2

How does temperature affect the movement of substances into and out of the cells?

Answer 2

The higher the temperature, the more kinetic energy the particles have, the faster the rate of diffusion

Question 3

How does particle size affect the movement of substances into and out of the cells?

Answer 3

The bigger the particle, the slower the diffusion will be (depending on the mass of the atoms in the particle)

Question 4

How does the diffusion medium affect the movement of substances into and out of the cells? (What particles are travelling through)

Answer 4

The bigger the gaps between the particles, the faster the rate of diffusion (in a vacuum, diffusion is instantaneous, in a gas, diffusion happens very quickly and in a liquid, diffusion happens much slower

Question 5

Why does a simple unicelleur organism consisting of 1 cell not need a transport system?

Answer 5

• It can rely on diffusion to move substances i to and out of the cells
• It’s surface area is large compared to its volume, so nutrients and other substances can pass quicker through the membrane and around its body

Question 6

Why does a multicelleur organism (such as a plant or an animal) need a transport system?

Answer 6

• Because the surface area is small compared to its volume
• As a result, multi cellular organisms need specialised exchange surfaces (such as lungs or gills) and transport systems

Question 7

What are some abiotic factors affecting the population size and distribution of organisms?

Answer 7

• Light intensity
• Temperature
• Moisture levels
• Soil pH
• Soil mineral content
• Wind intensity and direction
• Carbon dioxide levels for plants
• Oxygen levels for aquatic animals
• Availability of Food
• New predators
• New pathogens
• Out competition (e.g. native red squirrels unable to compete with newer, larger grey squirrel)