Diagram of a longitudinal section of a cryptophyte

Sieve elements of Nereocystis

Diagram of a brown algal cell

Pyrenoids of a brown algal cell

Chloroplast of Fucus

Electron micrograph of a cryptophyte

-The large ejectosomes seen here line the wall of the gullet

-Part of a smaller ejectosome is visible just beneath the plasmalemma on the lower left side of the cell

A Cryptophyte eyespot

-These eyespots may be one or several layers thick

- they are located with in the chloroplast but not close to the flagella

- the eyespot operates by either intercepting light (shading) or reflecting light (increasing the illumination) onto the photoreceptor pigment

- which is probably localized in either the plasma membrane or chloroplast membranes over the eyespot

Interphase nucleus and chromosomes of a

dinoflagellate

-The chromosomes lack histones, are permanently condensed and have a characteristic banded appearance

-There is a large nucleolus within the nucleus

Interphase nuclei of a green alga and a

euglenophyte

-Note the condense chromosomes of the euglenophyte

Eyespot of a euglenophyte

-The eyespot is composed of loosely packed globules lying outside the chloroplast, next to the reservoir, opposite of the flagellar swelling

- the swelling is usually on the longer, emergent flagellum and is thought to be the site of the photoreceptor pigment

Euglena

- Diagrammatic longitudinal section

Euglena longitudinal section

- Note the distinctive outer covering, the pellicle

Outer view of a haptophyte

- The cell surface is completely encased in coccoliths , special organic scales encrusted with calcium carbonate

Electron micrograph of Chrysochromulina

- This photograph shows the two flagella and a haptonema, the latter lightly coiled at the tip

Several cross-sections through a haptonema

- Note the outer sheath of three concentric membranes and the inner circle of 6 or 7 microtubules

Sections through parts of chloroplasts from 3 algal

groups-upper photo: chrysochromulina(haptophyte)

-PER surrounds chloroplast

- chloroplast envelope has 2 membranes

-Middle photo: dinobryon(chrysophyte)

- has a girdle lamella

- PER surrounds chloroplast

- chrloroplast envelope has 2 membranes

- lower photo: trachelomonas(euglenophyte)

- chloroplast envelope has 3 membranes

-All three groups share stacking of thylakoids in three

Chlamydomonas

Upper: diagrammatic

Lower: electron micrograph

Chloroplast of a desmid

-Note the pronounced stacking of the thylakoids

-The 2 membranes of the chloroplast envelope and the scattered light areas containing fibrils of DNA

- green algal chloroplasts are similar in many respects to those of high plants

Chloroplast of a ‘higher plant’

-Compare to previous slide

- note the arrangements of the thylakoids into grana stacks (dark areas) which are connected by stromalamellae

- the scattered areas containing chloroplast DNA (in between the grana stacks) (NA)

- RUBISCO in higher plants is found in the stroma of the chloroplast (S)

Portions of sections through chloroplasts of

the Chlorophyta

-This is the only algal phylum in which starch is stored in the chloroplast

-It may be in a sheath surrounding the pyrenoid and/or in other parts of the chloroplast

Section through the eyespot of

Chlamydomonas

-These eyespots may be one or several layers thick

- they are located within the chloroplast but not close to the flagella

- the eyespot operates by intercepting (shading) and/or reflecting (increasing the illumination) light onto the photoreceptor pigment, which is localized in either the plasma or chloroplast membranes over the eyespot

- note the stacking of the thylakoids

Location of chloroplast DNA in the Phaeophyta

Left: is a perpendicular section through a disc-shaped chloroplast, showing sections of the ring nucleoidbeneath the girdle lamella, at both ends

Right: is a section parallel to the face of the same chloroplast, showing the entire ring of DNA