Comparing Eukaryotes & Prokaryotes | A-level Biology | OCR, AQA, Edexcel

Common Ancestor

Common Ancestor

An organism from which two or more different species have evolved.

Cytoplasm

The gel-like substance within a cell where various cellular activities occur.

Cell Membrane

A semipermeable membrane that surrounds the cell, controlling the passage of substances in and out.

Ribosomes

Cell organelles responsible for protein synthesis or translation.

Eukaryotes

Organisms with cells that have a true nucleus and membrane-bound organelles like mitochondria and nucleus.

Prokaryotes

Organisms with cells lacking a true nucleus and membrane-bound organelles.

Cell Wall Composition

Eukaryotes can have a cell wall made of cellulose or chitin, while prokaryotes have a cell wall made of peptidoglycan.

Size Difference

Prokaryotes are smaller in size (0.1 to 5 micrometers) compared to eukaryotes (10 to 100 micrometers).

Ribosome Types

Prokaryotic ribosomes are 70s, while eukaryotic ribosomes are 80s.

Organelles Presence

Eukaryotes have membrane-bound organelles like mitochondria and nucleus, which prokaryotes lack.

Capsule Presence

Prokaryotes may have a waxy capsule outside the cell wall.

Flagella Presence

Prokaryotes have flagella for movement, while eukaryotes do not have flagella.

Prokaryotic cytoskeleton

Simpler compared to eukaryotic cytoskeleton.

Cytoskeleton

Provides structure and strength to the cell.

Pili structures

Found in prokaryotes for various functions.

Prokaryotic Cell Features

Organelles have simpler functions

Prokaryotic Cell Features

Division of the cell during cell division is a primary function

Prokaryotic Cell Features

Presence of pili, different from cilia in eukaryotes

Eukaryotic Cell Features

Epithelial cells have cilia for various functions

Eukaryotic Cell Features

Cilia increase surface area for absorption or secretion

Eukaryotic Cell Features

Eukaryotic DNA packaged in the nucleus with histone proteins

Eukaryotic Cell Features

DNA arranged in linear chromosomes with a start and end

DNA Packaging Differences

Eukaryotic DNA associated with histone proteins in the nucleus

DNA Packaging Differences

Prokaryotic DNA is naked, not associated with any other molecule

DNA Packaging Differences

Eukaryotic DNA packaged tightly due to more DNA content

DNA Packaging Differences

Prokaryotic DNA is circular and free in the cytoplasm

Circular vs

Eukaryotic DNA is linear, arranged in discrete units as chromosomes

Circular vs

Prokaryotic DNA is circular, forming a loop without a distinct beginning or end

Circular vs

Prokaryotic cells have plasmids, extra loops of DNA, which eukaryotic cells lack