Session 1 - The Cell and its Components Flashcards
What is the role of the nucleus?
The nucleus is the site of DNA transcription and gene expression it is bound by a double membranes nuclear envelope which is perforated by many nuclear pores that regulate the entry and exit of proteins and RNAs
What is the role of the nucleolus?
This is present in a non dividing cell. It is the site of rRNA synthesis
What is the role of ribosomes
A complex of rRNA and proteins that carry out protein synthesis. They can either be bound to ER or are free floating in cytoplasm
What is the function of RER?
Proteins are produced on the membrane bound ribosomes which release the proteins into the lumen of the ER. Here they are carbohydrates are covalently bonded to them and they are released by budding in the transport vesicles budded off of the transitional ER.
What is the function of the SER?
These are important in the synthesis of lipids such as oils, steroids and new membrane phospholipids as well as many hormones.
They also contain many enzymes that are crucial in the detoxification of drugs and poisons (like in the liver).
What is the role of the Golgi apparatus?
It can be seen as a warehouse for receiving, sorting, shipping and some manufacturing. It is here that products of the ER are modified and the sent to other destinations.
What are the two main sides of the Golgi apparatus and what is there role?
Cis/Convex face - transport vesicles from the ER fuse to this side.
Trans/Convex face - this is the face where the vesicles are pinched off and transport to other sites.
What is the role of lysosomes?
These are sacs of hydrolytic enzymes that digest macromolecules such as those brought in by phagocytosis
What is the role of mitochondria?
They are the site respiration and produce ATP for active processes within the cell
What is the role of Peroxisomes?
They are used to remove hydrogen from various substrates via oxidation and produce peroxide as a by-product. Can be used to break fatty acids down for use in respiration or to detoxify substances in the liver.
What role do microtubules play in the cytoskeleton?
They maintain cell shape by resisting compression and allow for cellular transport
What is the role of microfilaments in the cytoskeleton?
They maintain cell shape by bearing tension
What is the role of intermediate filaments in the cytoskeleton?
Again used in maintaining cell structure as they rebar tension. However they are much more persistent than microtubules and micro filaments and as such can persist after the cell death. This is evident in skin cells as keratin.
What is the role of the centrosome?
This is the cite from which microtubules grow out from. It is usually located near the nucleus
