cells Flashcards
what is the function of the nucleus in a cell?
- acts as cell brain
- contains DNA
- produces RNA for the production of proteins
Describe what a mitochondria is and what is does.
- double membrane bound organelle
- outer membrane site of lipid synthesis and FFA metabolism
- inner membrane site of oxidative phosphorylation for ATP production
- matrix is the site of krebs cycle
- intramembranous space site of nucleotide phosphorylation
what is an endoplasmic reticulum? what does it do?
- highly folded membraneous sac
- can be smooth and rough
- rough = protein production and attached to nuclear pores
- smooth = membrane lipid production and protein synthesis
what is the golgi apparatus? what does it do?
-parallel membrane sheets
-has three parts
cis - receives vesicles from the SER and protein phosphorylation
medial - modify by the addition of sugars
trans - proteolysis to active products and vesicle packaging
what is the purpose of the cytoskeleton?
to maintain the shape of the cell and facilitate the transport of materials
what are the filaments that make up the cytoskeleton?
microfilaments - actin
intermediate filaments - differ from cell to cell
micro tubules - tubulin arise from centromeres
what things make up the phospholipid bilayer?
- phospholipids
- glycoproteins - integral proteins
- glycolipids - communication
- cholesterol - maintain membrane fluidity
what is the function of the phospholipid bilayer?
- compartmentalisation
- regulation of things in and out
- cells response to signals
- insulate - myelin - sphingomyelin
what are the three types of cell junction?
occluding - tight junctions that seal cells together
anchoring - anchor cell to cell or cell to matrix - mainly actin - adherens
communicating junction - gap junctions - allow the movement of water soluble ions between cells
what type of a junction is a desmosome?
it’s an anchoring junction between intermediate filaments of a cell
what type of receptors are there?
- channel - activation opens channels ie neurotransmitter activated channels
- enzyme linked channels - activates intracellular enzymes
- induce second messenger - usually cAMP or G protein
- intracellular receptors - think steroid hormone
what are the characteristics of peptide hormones?
- stored in vesicles
- freely transported in the plasma
- receptors are present on the cell surface membrane
- usually induce a second messenger
- generate a quick response when released
what are the characteristics of a steroid hormone?
- they’re not stored anywhere they are made at response
- transported through the blood attached to plasma proteins
- receptors are found intracellularly usually in the nuclei
- they directly alter transcription
- repsonse time is slow can be hours or days
