CH 3 Eukaryotic Cell Structure

Eukaryotic Cell Structures

Eukaryotic Cell Structures

Structures within a eukaryotic cell that perform important cellular functions are known as organelles.

Cell biologists divide the eukaryotic cell into two major parts: the nucleus and the cytoplasm.

The Cytoplasm is the portion of the cell outside the nucleus.

Eukaryotic Cell Structures

Plant Cell

Nuclear envelope

Ribosome (free)

Ribosome (attached)

Mitochondrion

Golgi apparatus

Vacuole

Nucleolus

NucleusSmooth endoplasmic reticulum

Rough endoplasmic reticulum

Cell wall

Cell membrane

Chloroplast

Eukaryotic Cell Structures

Smooth endoplasmic reticulum

Ribosome (free)

Ribosome (attached)

Golgi apparatus

Mitochondrion

Rough endoplasmic reticulum

Cell membrane

Nucleus

Nuclear envelope

Nucleolus

Centrioles

Animal Cell

Comparing the Cell to a Factory

Organelles

Specialized structures

Cytoplasm

Portion of the cell outside the nucleus Consists mostly of water

Nucleus

Main Office Contains nearly all the cell’s DNA & w/ coded

instructions for making proteins & other important molecules

Nucleus

The Nucleus

Nucleolus Nuclear envelope

Nuclear pores

Chromatin

Nucleus

Nuclear Envelope Surrounds the nucleus Composed of two membranes Allows messages to enter & leave the main

office

Nucleus

Chromatin Granular material seen in the nucleus Consists of DNA bound to protein Condenses to form chromosomes when a cell

divides

Nucleus

Nucleolus Small, dense region in the nuclei Where assembly of ribosomes begins

Ribosomes

Small machine in the factory Proteins are assembled on the ribosomes Small particles of RNA and protein are found

throughout the cytoplasm

Endoplasmic Reticulum (ER)

The site where lipid components of the cell membrane are assembled, along w/ proteins & other materials that are exported from the cell

There are 2 types of ER:

1. Rough Endoplasmic Reticulum

Rough ER Portion of ER involved in

the synthesis of proteins Named b/c ribosomes

attach to it Newly made proteins

leave these ribsomes & are inserted into the rough ER, for chemical modification

2. Smooth Endoplasmic Reticulum

Contains enzymes that perform specialized tasks

Golgi Apparatus

Customization Shop – finishing touches & then shipped

Modifies, sorts, & packages proteins & other materials from the ER for storage in the cell or secretion outside the cell

Lysosomes

Clean up crew, removes “junk”

Small organelles filled w/ enzymes

Functions include digestion or breakdown of carbohydrates, lipids & proteins

Vacuoles

Storage center Sac-like

structure that stores water, salts, proteins & carbohydrates

Vacuoles

In many plant cells there is a single, large central vacuole filled with liquid.

Vacuole

Vacuoles

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 & Chloroplasts

Mitochondria Power plant Organelles that convert chemical energy stored in

food into compounds that are more convenient for the cell to use

Chloroplasts Solar power plant Organelles that capture the energy from sunlight &

convert it into chemical energy in a process called photosynthesis

Mitochondria & Chloroplasts

Cytoskeleton

Support beams Network of protein filaments that helps the

cell to maintain its shape Also involved in movement

The cytoskeleton is made up of: microfilaments microtubules

Copyright Pearson Prentice Hall

Cytoskeleton

Cytoskeleton

Ribosomes Mitochondrion

Endoplasmic reticulum

Cell membrane

Microtubule

Microfilament

Cytoskeleton

Centrioles are located near the nucleus and help to organize cell division.

Cell Organelle Interactive

Plant and Animal Model Interactive

The Cell

Eukaryotic vs. Prokaryotic

Has a nucleus Organelles to carry out

specialized functions Flagella or cilia

Single celled organism Lacks a nucleus & other

compartments Can not carry out many

specialized functions Flagella

Comparison of Plant and Animal Cells

Plant has:Chloroplast

Cell Wall

Regular/Box-like shape

Large Central Vacuole

Animal Cell has:Centrioles

Irregular shape

Small vacuoles called vesicles

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