Eukaryotic cell structure - 2.4 (5) Flashcards
Module 2, Chapter 2, 2.4, Page 29 & 30
What are centrioles a component of?
the cytoskeleton present in most eukaryotic cells with the exception of flowering plants and most fungi
What are centrioles composed of?
microtubules
What do two associated centrioles form?
the centrosome
What is the centrosome involved in the assembly and organisation of?
the spindle fibres during cell division
In organisms with flagella and cilia, what are centrioles thought to play a role in?
the positioning of these structures
What is flagella (whip-like) and cilia (hair-like)?
extensions that protrude from some cell types
Flagella are longer than cilia but…
cilia are usually present in much greater numbers
Where is flagella used primarily?
to enable cells motility
In some cells, what is flagella used as?
a sensory organelle detecting chemical changes in the cell’s enviroment
What can cilia either be?
mobile or stationary
Where is stationary cilia present?
on the surface of many cells
What does stationary cilia have an important function in?
sensory organs such as the nose
Mobile cilia beat in a rhythmic manner, creating a…
current, and cause fluids or objects adjacent to the cell to move
Mobile cilia are present in the trachea to move mucus away from lungs helping to keep…
the air passages clean
Mobile cilia is present in the falopian tubes to move…
egg cells from the ovary to the uterus
What does each cilium contain?
two central microtubules (black circles)
What are the two central microtubules surrounded by?
nine pairs of microtubules arranged like a “wheel”
What is the nine pairs of microtubules arrangement also known as?
the 9+2 arrangement
Pairs of parallel microtubules slide over each other causing…
the cilia to move in a beating motion
What is the key function of a cell?
to synthesize proteins for internal use and for secretion (transport out of the cell)
To synthesis proteins, what is required?
a significant proportion of the internal structure of a cell
The ribosomes, the endoplasmic reticulum, and the Golgi apparatus are all closely linked and coordinate the…
production of proteins and their preparation for different roles within the cell
What does the cytoskeleton play a key role in?
coordinating protein synthesis
What is the endoplasmic reticulum (ER)?
a network of membranes enclosing flattened sacs called cisternae
Where is the endoplasmic reticulum connected to?
the outer membrane of the nucleus
What are the two types of endoplasmic reticulum?
smooth endoplasmic reticulum and rough endoplasmic reticulum
What is the smooth endoplasmic reticulum responsible for?
lipid and carbohydrate synthesis, and storage
What is the rough endoplasmic reticulum responsible for?
it has ribosomes bound to the surface and is responsible for the synthesis and transport of proteins
Secretory cells, which release hormones or enzymes, have more rough…
endoplasmic reticulum than cells that do not release proteins
