Eukaryotic cell structure - 2.4 (3) Flashcards
Module 2, Chapter 2, 2.4, Page 28
What does the nucleus contain?
coded genetic information in the form of DNA molecules
What does DNA direct?
the synthesis of all proteins required by the cell (although it occurs outside of the nucleus at ribosomes)
What does the DNA control through directing the synthesis of proteins?
the metabolic activites of the cell
As many of these proteins are the enzymes…
necessary for metabolism to take place
What is the nucleus often?
the biggest single organelle in the cell
What is DNA contained / packaged within?
a double membrane called a nuclear envelope
What is the purpose of the nuclear envelope?
to protect the DNA from damage in the cytoplasm
What does the nuclear envelope contain?
nuclear pores that allow molecules (substances) to move into and out of the nucleus
What is DNA too large to leave?
the nucleus to the site of protein synthesis in the cell cytoplasm
What is DNA instead transcribed into?
smaller RNA molecules, which are exported via the nuclear pores
What does DNA associate with?
proteins called histones to form a complex called chromatin
What does chromatin do?
it coils and condenses to form structures known as chromosomes
When do chromosomes become visible?
when cells are preparing to divide
What is the nucleolus?
an area within the nucleus
What is the nucleolus responsible for producing?
ribosomes
What is the nucleolus composed of?
proteins and RNA
What is RNA used to produce?
ribosomal RNA which is then combined with proteins to form the ribosomes necessary for protein synthesis
What is mitochondria?
they are essential organelles in almost all eukaryotic cells
What is mitochondria the site of the final stages in?
cellular respiration, where the energy stored in the bond complex, organic molecules is made available for the cell to use by the production of the molecule ATP
What is the number of mitochondria in a cell generally a reflection of?
the amount of energy it uses
What do very active cells usually have a lot of?
mitochondria
What has a double membrane?
mitochondria
The inner membrane is highly folded to form structures called…
cristae and the fluid interior is called the matrix
What does the membrane forming the cristae contain?
the enzymes used in aerobic respiration
What does mitochondria contain a small amount of?
DNA called mitochondrial (mt)DNA
What can mitochondria produce?
their own enzymes and reproduce themselves
