iii.overview of eukaryotic cell structure and function

III. Overview of Eukaryotic cell structure and function

A. Plasma membrane - regulates the flow of materials into and out of cell, protection

for the cell, gives the cell shape. Made of a double layer of phospholipids imbedded with proteins, carbohydrates and lipids for various functions, such as communication between cells and cell recognition.

B. Nuclear envelope - double layer around nucleus, regulates movement into and out of nucleus

Nuclearmembrane

C. Nucleus – spherical structure that contains DNA (In the form of chromosomes). Usually the largest

organelle in a cell. Contains the nucleolus also.

D. Nucleolus – “mini- nucleus” in the nucleus, contains RNA

nucleus

nucleolus

DNA

RNA

E. Endoplasmic reticulum - (ER) complex of membranes for production

and transport materials through cell * smooth ER (lipids produced) *rough ER (proteins produced)

F. Ribosome – small spherical structures, site of protein synthesis, can be free floating in the cytoplasm or attached to the RER

-rough ER - w/ribosomes -smooth ER - w/out ribosomes

RER

SER

G. Golgi apparatus

-smooth stack of membranes for modification, packaging and transport of materials

-the small spheres (vesicles) can carry various substances. ex: lysosomes, peroxisomes

.

H. Lysosomes

Vesicles -“digestive sacs” that containenzymes to destroy foreign material orcell itself.

I. PeroxisomesVesicles that contain catalase forhydrogen peroxide metabolism

J. Mitochondria - "power house", aerobic respiration, producing

energy (ATP) from glucose and other organic molecules

K. Vacuoles

Sac-like structures for storage of water, minerals and other substances.

Animals: very small vesiclesPlants: Very large, can fill ½ of a plant cell

L. Chloroplast (only plants)

Use sunlight to produce glucose in a process called photosynthesis, contains the green pigment, chlorophyll that absorbs the sunlight.

M. Cell Wall (only plants) Thick layer of interconnecting and

overlapping cellulose fibers surrounding the plant cell for protection and support.

Cellulose of the wall

N. Cytoskeleton

A network of protein fibers throughout the cytoplasm for structural support and motility

1.Microfilaments: the protein actin, twisted double chain for support in the cell membrane. involved in movement-attached to protein motors

2. Intermediate fibers: many protein fibers supercoiled, cell shape and anchors to organelles.

3. Microtubules: straight hollow tubes globular proteins called tubulin, act as “tracks” for organelles

Cilia ( many small hairs)Flagella (few long hairs)

*microtubules wrapped in cell membrane

O. Centrioles - active in animal cell division, always in pairs perpendicular to each other.

*made of microtubules, protein actin…similar to cytoskeleton in clusters like straws

P. The Extracellular Matrix

Produced by animal cells, helps to hold cells in tissues, protect membrane.

* glycoproteins; like collagen *integrins bind proteins to membrane like snaps, transmit signals to loosen or tighten connections

.

Q. Junctions between cells

Cells need to interact, adhere, andcommunicate

Animal cells: 1. Tight junctions: a “seal” between cells

to prevent fluid from leaking, proteins attach like gluing paper together.

2. Anchoring junctions: protein “snaps” to keep cells together, good for stretching tissue, allows for movement, butkeeps the cells connected.Ex: skin

3. Gap Junctions : small molecules move across from one channel protein in one cell to the channel in other cell. The channels do not touch and have a gap.

Plant cells

Plasmodesmata: openings in the cell wall where ERs connect between cells to pass substances back and forth.

Super website for basic info onanimal and plant cell organelles

http://www.sheppardsoftware.com/health/anatomy/cell/index.htm