Biology 10.4 Plant Cell Structure.

Plants = eukaryotic cells - have a distinct nucleus and membrane-bound organelles e.g. mitochondria and chloroplasts.

Leaf palisade cell

Leaf palisade cell = typical plant cell, carries out photosynthesis so has these features:

• Long thin cells, form continuous layer to absorb sunlight.
• Many chloroplasts, arrange themselves to get maximum amount of sunlight.
• Large vacuole, pushes cytoplasm and chloroplasts to the edge of the cell.

Chloroplasts

Vary in size and shape but typically are disc-shaped. Other main features:

• Chloroplast envelope = double plasma membrane that surrounds organelle, highly selective in what it allows in and out of chloroplast.
• Grana (granum sing.) = stacks of up to 100 disc-like structures called thylakoids, where first stage of photosynthesis takes place.
• Thylakoids = contain photosynthetic pigment called chlorophyll, some have tubular extensions that join thylakoids with adjacent grana.
• Stroma = fluid filled matrix, where second stage of photosynthesis takes place, conatin other structures e.g. starch grains.

Chloroplasts are adapted to their function of harvesting sunlight in these ways:

• Granal membranes provide large surface area…