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Slide 1

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 gulletPart 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 appearanceThere is a large nucleolus within the nucleusInterphase 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


- Diagrammatic longitudinal sectionEuglena longitudinal section

- Note the distinctive outer covering, the pellicleOuter view of a haptophyte

- The cell surface is completely encased in coccoliths , special organic scales encrusted with calcium carbonateElectron micrograph of Chrysochromulina

- This photograph shows the two flagella and a haptonema, the latter lightly coiled at the tipSeveral cross-sections through a haptonema

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


Upper: diagrammaticLower: electron micrograph

Chloroplast of a desmid

Note the pronounced stacking of the thylakoidsThe 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 plantsChloroplast of a higher plant

Compare to previous slide note the arrangements of the thylakoids into grana stacks (dark areas) which are connected by stroma lamellae 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 chloroplastIt may be in a sheath surrounding the pyrenoid and/or in other parts of the chloroplastSection 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 nucleoid beneath the girdle lamella, at both ends

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

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