Cell Structure Flashcards
What is the name of the membrane around the nucleus?
Nuclear membrane
How do chromatins turn into chromosomes?
Chromatin threads condense to form thicker, shorter structures called chromosomes
What are found in the nucleolus?
DNA, rRNA and proteins
What is the endoplasmic reticulum?
It is an extensive network of membranous tubules and sacs called cisternae
What are the 2 types of endoplasmic reticulum?
Rough and smooth endoplasmic reticulum
What does the rough endoplasmic reticulum synthesize?
Proteins, enzymes or glycoproteins
What does the smooth endoplasmic reticulum synthesize?
A variety of carbohydrates and lipids
What is the function of the rough endoplasmic reticulum?
- Proteins are synthesized by bound ribosomes. When it enters cisternal space, it folds into its native 3D conformation.
- Carbohydrates may be added to protein by glycosylation to from glycoproteins.
- Transport proteins in transport vesicles that bud off the RER
What is the function of the smooth endoplasmic reticulum?
Many embedded enzymes catalyse synthesis of a variety of carbohydrates and lipids
What are the differences between smooth and rough endoplasmic reticulum?
- Cisternae is more flattened in RER than cisternae in SER
- RER has ‘bound’ ribosomes while SER does not
What is the Golgi apparatus?
it is a stack of cisternae associated to vesicles called Golgi vesicles. It has a convex or ‘cis’ face where vesicels from ER fuse and a concave or ‘trans’ face giving rise to vesicles which pinch off
What is the function of the Golgi apparatus?
- Adds short sugar chains, via glycosylation, to proteins and lipids to form glycoproteins and glycolipids
- Modify existing glycoproteins and glycolipids made in ER by modifying their sugar chains
- Formation of lysosomes
- Sorts and targets completed materials
What is a lysosome?
A small spherical vesicle enclosed by single membrane containing hydrolytic enzymes used to digest macromolecules. Contents are acidic.
What is the function of lysosome?
- Digestion of material taken in by endocytosis
- Autophagy -> breakdown of unwanted structures
- Release of enzymes outside the cell by exocytosis -> breakdown of extracellular content
- Autophagy - Contents of lysosome released to allow cell to undergo self-digestion
What structures are found in cells?
Plasma membrane, Mitochondria. Endoplasmic Reticulum, Nucleus, Cell Wall (Plant cell), Chloroplast, Vacuole, Centrioles, Microtubules
