7-2 Eukaryotic Cell Structure

Eukaryotic Cell Structures Organelles - Structures in a eukaryotic cells that perform important cellular

functions. eukaryotic cell divided into two major parts:

Nucleus cytoplasm.

o portion of the cell outside the nucleus.

Plant Cell

Nuclear envelope Ribosome (free)

Ribosome (attached)

Mitochondrion

Golgi apparatus

Vacuole

Nucleolus Nucleus

Smooth endoplasmic reticulum

Rough endoplasmic reticulum

Cell wall Cell membrane

Chloroplast

Smooth endoplasmic reticulum

Ribosome (free)

Ribosome (attached)

Golgi apparatus

Mitochondrion

Rough endoplasmic reticulum

Cell membrane

Nucleus

Nuclear envelope

Nucleolus

Centrioles

Animal Cell

Nucleus What is the function of the nucleus?

control center of the cell.

contains nearly all the cell's DNA

coded instructions for making proteins and other important molecules.

Nucleolus Nuclear envelope

Nuclear pores

Chromatin

nuclear envelope - surrounds nucleus made of two membranes. dotted with nuclear pores allow material to move in and out of

the nucleus.

Nuclear envelope

Nuclear pores

Chromatin granular material in the nucleus. made of DNA bound to protein. When a cell divides, condenses to form chromosomes. contains the genetic information that is passed from one generation of

cells to the next

Chromatin

Most nuclei also contain a nucleolus. where the assembly of ribosomes begins.

Nucleolus

Ribosomes small particles of RNA and protein found throughout the cytoplasm. Proteins are assembled on ribosomes. following coded instructions from the nucleus. Cells active in protein synthesis often packed with ribosomes.

Ribosome (free)

Ribosome (attached)

Endoplasmic Reticulum (ER)

internal membrane system

lipid components of the cell membrane are assembled

proteins and other materials that are exported from the cell.

Ribosomes

Endoplasmic Reticulum

two types of ER—rough and smooth. rough endoplasmic reticulum - rough ER. involved in protein synthesis Ribosomes are found on the surface of rough ER. abundant in cells that produce large amounts of protein for export.

Smooth ER does not have ribosomes on its surface. contains collections of enzymes that perform specialized tasks

synthesis of membrane lipids detoxification of drugs.

Smooth endoplasmic reticulum

Golgi Apparatus The Golgi apparatus looks like a stack of stack-like membranes . Proteins produced in the rough ER move into the Golgi apparatus.

modified sorted, and packaged o for storage in the cell o or secretion outside the cell.

Lysosomes small organelles filled with enzymes. break down lipids, carbohydrates, and proteins

So that they can be used by the rest of the cell. break down organelles that have outlived their usefulness.

Vacuoles saclike structures store materials such as water, salts,

proteins, and carbohydrates.

plant cells single, large central vacuole filled

with liquid. The pressure of the central vacuole

allows plants to support heavy structures such as leaves and flowers.

Vacuole

Vacuoles are also found in some unicellular organisms and in some animals.

The paramecium contains a contractile vacuole that pumps excess water out of the cell.

Contractile vacuole

Mitochondria in nearly all eukaryotic cells convert chemical energy in food into

compounds that are easier for the cell to use. enclosed by two membranes - outer and inner inner membrane is folded up inside the organelle.

Mitochondrion

Chloroplasts Found in plants and some other

organisms capture energy from sunlight convert it into chemical energy

photosynthesis.

surrounded by two membranes. contain the green pigment chlorophyll.

Chloroplast

Cytoskeleton Gives eukaryotic cells shape and internal organization network of protein filaments that helps the cell to maintain its shape also involved in movement. made up of:

microfilaments microtubules

Microfilaments: threadlike structures made up of the protein actin. form extensive networks in some cells. produce a tough, flexible framework that supports the cell. help some cells move.

Microtubules: hollow structures made up of proteins known as tubulins. maintain cell shape. are important in cell division. build projections from the cell surface cilia and flagella - allow some cells to swim

Centrioles In animal cells formed from tubulin. Found near the nucleus help to organize cell division.

Centrioles