Cell Types
Prokaryotes
single-celled organisms that have a simple cell structure without compartmentalisation (they do not possess any membrane-bound organelles)
Prokaryotic Cell Structure
Nucleoid
Plasmids
70s Ribosomes
Cell Wall
Cell Capsule
Cell Membrane
Pili
Flagella
Prokaryotes are classified into 2 main domains:
Bacteria: A large and diverse range of organisms including many pathogenic (disease-causing) forms
Archaea: Include a variety of extremophiles (organisms living in extreme environments), but also exist in normal habitats
Eukaryotes
Organisms whose cells contain a nucleus and are compartmentalised by numerous membrane-bound organelles
Eukaryotes have been classified into distinct kingdoms
Animal: Have no cell wall and undertake heterotrophic nutrition (via ingestion)
Plant: Have a cell wall (made of cellulose) and undertake autotrophic nutrition (via photosynthesis)
Fungi: Have a cell wall (made of chitin) and undertake heterotrophic nutrition (via absorption)
Protist: Any eukaryotic organism that does not belong to the animal, plant or fungal kingdoms
Eukaryotic Cell Strucutre
Nucleus
Nucleoulus
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum
Mitochondria
Plasma Membrane
Lysosome
Golgi Apparatus
Ribosomes 80s
Cytoskeleton
Peroxisome
What additional organaelles do plant eukaryotic cells have?
Chloroplast
Cell Wall
Central Vacuole
Key distinguish feature of eukaryotic cells
Have Nucleus
Nucleus
The nucleus is a double membrane structure with pores that stores the genetic material (DNA)
Within the nucleus, a specific region called the nucleolus is responsible for ribosome assembly
Mitochondria
Mitochondria are responsible for ATP production via the process of aerobic cell respiration
It has an inner membrane that is highly folded into cristae in order to increase the SA:Vol ratio
Endoplasmic Reticulum
The ER is a membranous network that synthesises and transports materials via vesicles
The smooth ER synthesises lipids, while the rough ER synthesises proteins (via ribosomes)
Golgi Complex
The golgi apparatus is an assembly of folded membranes responsible for material secretion
Material is sorted, stored, modified and exported from the cell within vesicles (exocytosis)
Vesicles
Vesicles are membranous containers involved in the transport and storage of materials
Peroxisomes are involved in the oxidation of lipids and the digestion of toxic metabolites
Lysosomes are responsible for the breakdown of cellular wastes and pathogenic debris
Vacuoles are comparatively larger containers that store excess fluid and regulate pH
Chloroplast
n organelle responsible for photosynthesis (converting light energy into chemical energy)
Chloroplasts use the photosynthetic pigment chlorophyll to absorb and utilise light energy
Centrosome
Centrosomes function as microtubule-organising centres composed of paired centrioles
They contribute towards cell division in animal cells (plants and fungi use other structures)
Not organelles but part of the cell
Cell Wall
Cytoplasm
Cytoskeleton