Specialised Cells

Question 1

How are palisade leaf cells adapted for photosynthesis? (3 points)

Answer 1

1) lots of chloroplasts at the top of the cell (maximum sunlight) for respiration
2) tall shape means lots of surface area to absorb CO2
3) thin so lots can be put at the top of the leaf

Question 2

How are guard cell adapted to open and close pores? (5 points)

Answer 2

1) kidney shape which opens and closes stomata in the leaf
2) lots of water = turgid = open stomata so lots of gas exchange for photosynthesis
3) little water = flaccid = closed stomata so less gas exchange
4) thin outer walls and thicker inner walls to make opening and closing work
5) sensitive to light so at night close when there is no light

Question 3

How are red blood cells adapted to carry oxygen? (3 points)

Answer 3

1) concave shape means large surface area for absorbing oxygen and to move smoothly through the capillaries
2) lots of haemoglobin (pigment that absorbs oxygen)
3) no nucleus so more room for haemoglobin

Question 4

How are sperm and egg cells specialised for reproduction? (4 points)

Answer 4

1) egg cells contain a food reserve for the embryo
2) when a sperm fuses with the egg, the egg’s membrane changes to stop other sperm getting in
3) sperm have long tails for swimming and a streamlined head, and lots of mitochondria for energy
4) sperm have enzymes in their head to break through the egg’s cell membrane