Eukaryotic cell

Work in pairs to discuss the cell structure. Eg. student A reads
the introduction of chloroplast, and student B reads the intro of
mitochondria, then students A&B share ideas with each other.
When you tell the description of the cell structure, please
include at least:
• one feature of the structure
• one function of the structure
• identify whether it is single membrane or double membrane

or else?

•

All cells are surrounded by a cell
surface membrane which controls
the exchange of materials between
the internal cell environment and the
external environment The
membrane is described as being
‘partially permeable’

•

The cell membrane is formed from a phospholipid
bilayer(磷脂双层) of phospholipids spanning a diameter
of around 10 nm

The structure of the cell surface membrane – although the structure looks static
the phospholipids and proteins forming the bilayer are constantly in motion

•

Microvilli (singular: microvillus) are finger-like
extensions of the cell surface membrane.

Ø typical of certain animal cells, such as

epithelial cells

Ø greatly increase the surface area of the cell

surface membrane

Ø useful for reabsorption in the proximal

convoluted tubules of the kidney and for
absorption of digested food into cells lining
the gut

Ø Cell membrane projections that

increase the surface area for
absorption

•

Largest cell organelle, surrounded by two
membranes forming the nuclear envelope, many
nuclear pores

•

out of pores: mRNA, tRNA, ribosomes

•

enter pores: proteins, nucleotides, ATP, some
hormones such as thyroid hormone T3 (甲状腺激素)

•

Chromatin= DNA + protein (especially histone)

chromatin also contain some RNA
chromatin →chromosome
•

Usually, at least one or more darkly stained
regions can be observed – these regions are
individually termed ‘nucleolus’ and are the sites
of ribosome production

The basic repeating structural (and functional) unit of chromatin is the nucleosome (核
小体), which contains eight histone proteins and about 146 base pairs of DNA.

The outer membrane of the nuclear envelope is continuous with the endoplasmic reticulum.