biodiversity

Essay by saniahussainHigh School, 12th gradeA-, September 2013

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Biodiversity and natural resources Chapter 4.1 Plant Structure

The structure of a plant cell - I can compare the ultrastructure of plant cells with that of animal cells:

Plant cells have different organelles from animal cells

Organelle

Description

Function

Cell Wall

Arigid structure that surrounds plant cells. It's made mainly of the carbohydrate cellulose

Supports plant cells.

Middle lamella

The outermost layer of the cell.

This layer acts as an adhesive, sticking adjacent plant cells together. It gives the plant stability

Plasmodesmata

Channels in the cell walls that link adjacent cells together

Allow transport of substances and communication between cells.

Pits

Regions of the cell wall where the wall is very thin. They're arranged in pairs - the pit in one cell is lined up with the pit in the adjacent cell

Allow transport of substances between cells.

Chloroplast

A small, flattened structure. It's surrounded by a double membrane, and also has membranes inside called thylakoid membranes. These membranes are stacked up in some parts of the chloroplast to form grana. Grana are linked together by lamellae - thin, flat pieces of thylakoid membrane.

The site where photosynthesis takes place. Some parts of photosynthesis happen in the grana, and other parts happen in the stroma (a thick fluid found in chloroplasts)

Amyloplast

A small organelle enclosed by a membrane. They contin starch granules.

Storage of starch grains. They also convert starch back to glucose for release when the plant recquires it.

Vacuole and Tonoplast

The vacuole is a compartment surrounded by a membrane called the tonoplast.

The vacuole contains the cell which is made up of water, enzymes, minerals and waste products. Vacuoles keep the cells turgid - stops the plant wilting. They're also involved in the breakdown and isolation of unwanted chemicals in the cell. The tonoplast controls what...