Lecture 9 Flashcards
What are ribosomes made of
Ribosomal RNAs and proteins
Where are bound ribosomes found
attatched to the rER
Where are free ribosomes found
in the cytoplasm
What is the function of ribosomes
To carry out translation
How large is the nucleus in diameter
5-10um
What is found in the nucleus
Most of the cells genes
What is the function of the nucleus
Serves as repository of inherited genetic information
It is the cell’s control centre
What parts make up the nucleus structure
Nuclear envelope
Nucleous
DNA
Nuclear pore
What is the perinuclear space
The space between the inner and outer membranes that make up the nuclear envelope
What two things make up the Nuclear envelope
It is composed of two membranes
The inner and outer membrane
(Each membrane is a phospholipid bilayer)
What organelle is the outer membrane of the nuclear envelope continous with
It is continous with the ER
What is nuclear lamina
It lines the inner surface of the nuclear envelope and is composed of intermediate filaments
What is the role of the nuclear lamina
To maintain shape of the nucleus and help organise the packing of DNA within the nucleus
What are nuclear pores and what is their function
They are channels made of proteins (nucleoporins) that from the nuclear pore complex.
Their function is to controlle the movemtn of molecules. (nucleo-cytoplasmic exchange)
What does mRNA carry
it carries information from a gene
What are tRNA (transfer RNA) and ribosomal subunits needed for?
They are needed to build proteins
What is the nucleolus
A prominent nuclear structure within non-dividing cells. It is a Non-membrane bound specialised
region within the nucleus
What is the role of the nucleolus
Responsible for making ribosomal RNA & ribosomal subunits
What is the width of the fibre that forms DNA
10nm
How wide in diameter is the DNA double helix
2nm
What is the name of the proteins that the helix interacts with
Histones
Which is more electron opaque, Euchromatin or Hetrochromatin
Hetrochromatin
What is the function of Histone
It causes the 10nm fibre of DNA to coil and form a 30nm Fibre
(this then loops to form 300nm fibre. During cell division the 300nm fibre coils to form metaphase chromosomes)
