Cell Structures + Functions Flashcards
What are the main similarities between prokaryotic and eukaryotic cells?
- All cells are bound by a cellular membrane (plasma membrane)
- All cells contain cytosol, a jelly-like fluid in which all the cell’s components are suspended within
- All cells contain chromosomes
- All cells have ribosomes which make proteins
What is the major difference between prokaryotic and eukaryotic cells?
The main difference between prokaryotic and eukaryotic cells is the location in which they contain their DNA
Prokaryotic cells contain their DNA in a small region of the cell which is not enclosed by any membrane, referred to as the nucleoid
Eukaryotic cells contain their DNA within an organelle known as the nucleus, a double membrane-bound structure
what are some common differences between prokaryotic and eukaryotic cells?
- Eukaryotic cells consist of membrane-bound organelles, all of which are not found in prokaryotic cells
- Eukaryotic cells tend to be much larger than prokaryotic cells
How do metabolic requirements set a limit on cell size?
A cell’s size greatly reflects the cell’s capability to meet its metabolic requirements for survival.
The plasma membrane which is known to be a semi-permeable barrier may only allow a certain amount of substance to cross per second and therefore with a greater volume, comes greater metabolic requirements which the small surface area of the cell may not be able to provide for.
Define the term nuclear envelope.
The double membrane is a lipid bilayer which encloses nucleic acids within.
What does the nuclear lamina do for the nucleus?
The nuclear lamina is a lining found on the nuclear side of the nucleus made up of a net-like array of protein filaments which maintains the shape of the nucleus and provide mechanical support to the nuclear envelope
What role does the nuclear pore complex play in the cell?
The pore complex is a protein structure which ranges the entire nuclear envelope. these pores play a large role in the regulation of entering and exiting proteins and RNA
Where in the nucleus is ribosomal RNA synthesized?
Ribosomal RNA is synthesized within the nucleolus, a structure within the nucleus composed of a compact arrangement of densely stained granules using genes from DNA
What is the nucleolus responsible for?
The nucleolus is responsible for synthesizing ribosomal RNA using genes present in DNA and also plays a role in controlling cell division
How does the nucleus direct protein synthesis?
The nucleus synthesizes mRNA (messenger RNA) which carries instructions for protein synthesis from the DNA into the cytoplasm where ribosomes will translate the mRNA into the primary structure of polypeptide.
How are ribosomes assembled after synthesis?
After synthesis in the nucleolus, rRNA is then grouped with proteins imported from the cytosol making up large and small ribsome subunits. The subunits then exit the nucleus through its nuclear pores, in the cytosol, the small and large subunits assemble to make up ribosomes
What are the major components which make up ribosomes?
Ribosomes are made up of small and large subunits of rRNA and proteins which are assembled in the cytosol after synthesis inside the nucleolus
What is the major function of ribosomes?
Ribosomes are known as protein factories for their main function is to carry out protein synthesis through mRNA, tRNA
What does it mean for a cell to have a large number of ribosomes?
This means that the cell undergoes high rates of protein synthesis
What is the difference between free and bound ribosomes?
While free ribosomes are found suspended in the cytosol, bound ribosomes are found attached to the outer surface of the endoplasmic reticulum or the nuclear envelope. Function-wise, either or can play both roles but free ribosomes generally produce more proteins which are beneficial within the cytosol such as enzymes whereas proteins produced by bound ribosomes are meant to enter the the membranes of the organelles they are bound to.
