Chapter 25 - Eukaryotic Cells

Cytoskeleton

scaffolding of dynamic proteins

endomembrane system

regulates protein traffic and performs metabolic functions in the cell

Phagocytosis

engulf, package, transport, and digest food particles

heterotrophs

An organism that obtains organic food molecules by eating other organisms or their by-products.

reasons for diversity in eukaryotes

- Membrane dynamics

- Compartmentalized metabolism

- Genome organization

- Genetic diversity by means of sex

- Life cycle variations

haploid

An organism or cell having only one complete set of chromosomes.

diploid

containing two complete sets of chromosomes, one from each parent.

multicellular eukaryote life cycle (animals)

meiosis -> fusion -> growth by mitosis

- 1 multicellular phase: diploid

multicellular eukaryote life cycle (vascular plants)

meiosis -> growth by mitosis -> fusion -> growth by mitosis

- 2 multicellular phases: 1 haploid and 1 diploid

chloroplast endosymbiosis

• Chloroplasts are derived cyanobacteria

• No longer need a big genome since they are not independent (not free-living)

• Some genes lost due to duplication in function of nuclear genes

• Some genes migrated to the host nucleus

• This has happened at least three times that we know of so far...

- Red algae

- Green algae

- Photosynthetic amoeba

Mitochondria Endosymbiosis

theory that an oxygen-using, ATP-producing bacterium was engulfed by a larger bacterial host cell and evolved into the mitochondria

opisthokonta

- all unicellular protists

- all have microvilli ring with single flagellum

- sister group to animals

- example: choanoflagellates

amoebozoa

the eukaryotic supergroup that contains the amoebas and slime molds

coenocytic cells

a single cell with many nuclei

plasmodia

structure with many nuclei formed by acellular slime molds

cellular slime molds

- Soil amoeboid-style living, eat bacteria, free-living.

- When starved of food, amoebas (up to 100,000!) form aggregations called a slug. Slug can locomote using actin and myosin. It can then form sporangia.

archaeplastida

supergroup from which land plants arose

red algae

mostly marine, walls of cellulose, chlorophyll a and biliproteins. Used in toothpaste, ice cream and agar. Emulsification

glaucocystophytes

FW, single-celled, the highest number of features linking to the ancestral cyanobacteria endosymbiont. Peptidoglycan and biliprotein pigments that are photosynthetic

green algae diversity

differences in form

chlorophyll a and b

2-membrane chloroplasts

phytoplankton

worldwide distribution

LAND PLANTS!!!

stramenopila

Giant kelp, algae and protozoans, free-living and parasitic. Odd flagellum with stiff hairs, some with second flagellum that is not hairy. Diatoms and brown algae are both Stramenopiles

alveolata

A protistan clade that includes dinoflagellates, apicomplexans, and the ciliates. Alveolates have small membrane-bounded cavities called alveoli under their cell surfaces.

rhizaria

the eukaryotic supergroup that contains organisms that move by amoeboid movement

excavata

defined by a feeding groove, allowing organisms to ingest small particles of food in their aquatic habitats by phagocytosis (phagotrophy)