Chapter 2 Cell Structure and organisation Flashcards
Define nucleus
An organelle that contains genetic information.
What are the different membranes surrounding the nucleus and what are there functions?
The nucleus is bounded by two membranes : the nuclear envelope with pores that allow the passage of large molecules and the outer membrane is continuous with the endoplasmic reticulum .
What are the 3 principles of cell theory?
- All living organisms are composed of one or more cells.
- The cell is the basic unit of life.
- Cells can only arise from pre-existing cells.
What is the mitochondria?
The site of ATP production during aerobic respiration.
What are the components of the mitochondria? (3)
- The mitochondria has two membranes.
- An organic matrix containing compounds such as lipids and proteins.
- 70S ribosomes and a small circle of DNA which enable it to create proteins and to self replicate.
What is a cristae?
The inner membrane of the mitochondria which fold to provide a large surface area for the attachment of enzymes for respiration.
What is a chloroplast?
The site of photosynthesis within a cell.
What are the components of a chloroplast? (2)
- Chloroplasts are surrounded by two membranes.
* They contain 70S ribosomes and a small circle of DNA to enable self replication.
What are the stroma?
The stroma are fluid filled sacs in the chloroplasts and contains lipids and starch used for photosynthesis.
What are thylakoids?
Thylakoids are located within the stroma and are small flattened sacs which stack together to make a granum.
What is a granum and what is its function?
Granums are stacks of thylakoids and contain photosynthetic pigments such as chlorophyll.
What is the endoplasmic reticulum?
A system of double membranes which allows the transport of materials through the cell
What is the Rough ER?
An ER with ribosomes on the outer surface and transports the proteins that are made there.
What is the Smooth ER?
Membranes that lack ribosomes and is associated with the synthesis and transportation of lipids.
What is a Golgi body?
A complex of vesicles and folded membranes involved in intracellular transport.
What are the functions of the Golgi body? (5)
- produces secretory enzymes packed in the vesicles
- secretes carbohydrates
- produces glycoproteins
- transporting and storing lipids
- forming lysosomes and containing digestive enzymes.
What are lysosomes?
Small temporary vacuoles surrounded by a single membrane.
How are lysosomes formed?
Lysosomes are formed by being pinched off the Golgi body.
What are the functions of lysosomes? (2)
- They contain and isolate digestive enzymes from the cell.
* They release these enzymes when the cell needs to recycle worn out organelles.