BLG 143 Study Guide - Final Guide: Nuclear Membrane, Ribosomal Rna, Nuclear Lamina
27 Apr 2018
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7.2 Eukaryotic Cells Structure and Their Functions
The relatively large size of the eukaryotic cell makes it difficult for molecules to diffuse
across the entire cell.
This problem is partially solved by breaking up the large cell volume into several smaller
membrane-bound organelles.
Compartmentalization offers 2 benefits:
1. Incompatible chemical reactions can be separated
2. Chemical reactions become more efficient
Key differences
• Eukaryotic chromosomes are found inside a membrane-bound compartment called
the nucleus
• Cells are often much larger
• Cells contain extensive amounts of internal membrane
• Cells feature a particularly diverse and dynamic cytoskeleton
Eukaryotic Cell Structure
Structure correlates with function.
Nucleus
• Contains chromosomes
• Functions as an information storage and processing centre
• Ribosomal RNA synthesis (in the nucleolus)
• One of the largest and most organized of all organelles
• Enclosed by a complex double membrane nuclear envelope
• Nuclear lamina stiffens structure and maintains its shape; fibrous proteins that
form a lattice-like sheet
• Nucleolus RNA molecules found in ribosomes are manufactured and the large and
small ribosomal subunits are assembled
• Nuclear envelope is continuous with an extensive series of membrane-bound sacs
called the endoplasmic reticulum
Rough Endoplasmic Reticulum
• Knobby like structures are ribosomes that attach to the membrane
• Ribosomes synthesize proteins that’ll be inserted into the plasma membrane,
secreted to the cell exterior or shipped to an organelle
• Continuous with the nuclear envelope
• Lumen interior of any sac-like structure in a cell/body; where newly
manufactured proteins undergo folding and other types of processing
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Document Summary
The relatively large size of the eukaryotic cell makes it difficult for molecules to diffuse across the entire cell. This problem is partially solved by breaking up the large cell volume into several smaller membrane-bound organelles. Compartmentalization offers 2 benefits: incompatible chemical reactions can be separated, chemical reactions become more efficient. Key differences: eukaryotic chromosomes are found inside a membrane-bound compartment called the nucleus, cells are often much larger, cells contain extensive amounts of internal membrane, cells feature a particularly diverse and dynamic cytoskeleton. Smooth endoplasmic reticulum: lack ribosomes associated with the rough er, enzymes within may synthesize fatty acids and phospholipids, or break down poisonous lipids, reservoir for ca2+ions. Peroxisomes: globular organelles bound by a single membrane, centre of oxidation reactions, glyoxysomes specialized peroxisomes in plants; packed with enzymes that oxidize fats to form a compound that can be used to store energy for the cell.
