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Organelles in a Eukaryotic Cell (Golgi Apparatus (stack of membrane bound…
Organelles in a Eukaryotic Cell
Cytoplasm
chemical reactions take place here
made up of cytosol and insoluble suspended particles
Cytosol = water and anything that is soluble and dissolved in it
eg. ions and soluble proteins
Nucleus
largest organelle
consists of chromatin
contains DNA and proteins
shows up darker when stained
some proteins regulate cell's activity
makes ribosomes
nuclear pores allow exchange of substances
Nucleolus
most obvious structure in the nucleus
produces ribosomes
move out of nucleus to latch onto the outside of the rough endoplasmic reticulum where they produce ribosomes
Nuclear Envelope
dense, spherical structure
surrounds nucleoulus
double membrane with fluid separating two layers
nuclear pores allow exchange of relatively large substances
Chromatin
complex of DNA and protein
DNA coils around histones
chromatin coils and condenses to form chromosomes
Mitochondria
energy generating organelles
2 membranes
inner layer folds inwards to form cristae
projects into a liquid called the matrix
inner membrane coated in enzymes, which catalyses aerobic respiration
has it's own DNA to create new enzymes
Ribosomes
tiny organelle found in cytoplasm or bound to rough endoplasmic reticulum
each ribosome has two sub units
site of protein synthesis
Endoplasmic Reticulum
Rough ER
consists of a series of flattened membrane
bound sacs called cisternae
studded with ribosomes
transports proteins that are made in the ribosomes
some of these proteins secreted by cell whilst others placed on cell membrane
Smooth ER
same structure as rough ER but no ribosomes
involved in making lipids
Golgi Apparatus
stack of membrane bound flattened sacs
single membrane with two layers
membrane surrounds an area of fluid where complex molecules are stored and changed
receives proteins from ER and modifies them
may add sugar molecules to proteins
packages modified proteins into vesicles that can be transported
some modified proteins may go to surface of the cell so they can be secreted
Lysosomes
spherical sacs that have a single membrane
specialised vesicles
contain powerful digestive enzymes
their job is to break down materials
Cytoskeleton
hold organelles in place and controls cell movement and organelle movement within the cell
Made up of 3 components
Microfilaments - contractile fibres formed from the protein actin. Responsible for cell movement and contraction during cytokinesis
Microtubules - used to form scaffold-like structure that determines the shape of the cell. Act as tracks for organelle movement. Spindle fibres made of microtubules
Intermediate Fibres - give mechanical strength to cells and help maintain integrity
Cilia
Mobile Cilia
beat in rhythmic manner to cause fluids or objects adjacent to cell to move
Stationary Cilia
present on the surfaces of most cells and have an important function on sensory organs
Structure
Two central microtubules surrounded by nine pairs of microtubules arranged like a 'wheel'
Flagella
enable cell's motility
sometimes used as sensory organelle, detecting chemical changes
stick out from cell surface and are surrounded by plasma membrane
inside, there are 2 microtubules in the centre and nine pairs around the edge, which contract
Centrioles
Centrosome is involved in the assembly and organisation of spindle fibres during cell division