Cells - Cell structure Flashcards
What is a eukaryotic cell?
A cell that contains a nucleus.
What are the structures in an animal cell ultrastructure?
Nucleus, cell membrane, rough ER, smooth ER, golgi apparatus, mitochondria, centrioles, ribosomes and lysosomes.
What is the structure of the nucleus?
It consists of a double membrane called the envelope containing nuclear pores that enable molecules to enter and leave. It also contains chromatin and a nucleolus which is the site of ribosome production. A granular jelly like material called nucleoplasm makes up the majority of it.
What is the rough endoplasmic reticulum?
A series of flattened sacs enclosed by a membrane with ribosomes on the surface.
What is the function of the rough endoplasmic reticulum?
To fold and process proteins made on the ribosomes.
What is the structure and function of smooth endoplasmic reticulum?
SER is a system of membrane bound sacs that produces and processes lipids.
What is the structure of the golgi apparatus?
A series of fluid filled, flattened and curved sacs with vesicles surrounding the edges.
What is the function of the golgi apparatus?
Processing and packaging proteins and lipids, and producing lysosymes.
What is the structure and function of the mitochondria?
They are oval shaped, bound by a membrane called the envelope. The inner membrane is folded to form projections called cristea with a matrix on the inside containing enzymes. Mitochondria are the site of respiration.
What are the centrioles and what is their function?
They are hollow cylinders containing a ring of microtubules arranged at right angles to each other. They are involved in producing spindle fibres for cell division.
What is the structure and function of ribosomes?
They are composed of two sub-units and are the site of protein production.
What is the structure and function of lysosomes?
Vesicles containing digestive enzymes bound by a single membrane.
What are the structures only found in plants?
Chloroplasts and the permanent cell vacuole.
What is the function of the permanent vacuole?
Contains cell sap, helps maintain pressure by pushing the cytoplasm against the cell wall, and to isolate harmful chemicals. It is surrounded by a membrane called the tonoplast.
What is the function of chloroplasts?
They are the site of photosynthesis.
Which structures are present in prokaryotic cells?
Cell wall, capsule, plasmids, flagellum, pili, ribosomes and mesosomes.
How do prokaryotic cells differ from eukaryotic cells?
- Smaller
- Lack membrane-bound organelles
- Don’t have a nucleus, instead have circular DNA in the cytoplasm
- They have a cell wall.
What is the cell wall of bacteria made of?
peptidoglycan
What is the capsule of a bacterial cell?
A protective, slimy layer which helps the cell to retain moisture and adhere to surfaces.
What is a plasmid?
A circular piece of DNA.
What is the flagellum?
A tail like structure which rotates to move the cell.
What are pili?
Hair-like structures which attach to other bacterial cells.
What are mesosomes?
Infoldings of the inner membrane which contain the enzymes needed for respiration.
What are viruses?
Non-living structures which consist of nucleic acid enclosed in a protective protein coat called the capsid, sometimes covered in a lipid layer called the envelope.
What is the organisation of multicellular organisms?
Cells organised into tissues, tissues into organs, and organs into organ systems.
