Cellular physiology I Flashcards
describe cellular level of organisation
cells are made up of organelles that carry out specific metabolic tasks
membrane bound:
mitochondria
nucleus
golgi apparatus
lysosome
ER
peroxisome
non-membrane bound:
ribosome
centrioles
flagella
purpose of membranes in cells in general
protection of organelle, control of what enters and leaves the organelle
structure of nucleus
surrounded by nuclear envelope
- double membrane, perforated by nuclear pores formed by rings of proteins
contains nucleolus
function of nucleus and nucleolus
nucleus: contains genetic material of cell
nucleolus: site of ribosome biogenesis
function of nuclear envelope
- controls what substances enters and leaves nucleus
- holds membrane layers together
IN: materials for DNA RNA synthesis, hormones and enzymes to change gene expression
OUT: RNA
cells with no or many nucleus
RBC: small, nucleus takes up a lot of space, only has 1 function, be able to fit more haemoglobin proteins for oxygen transport
skeletal muscle cells: long and thin, requires large amounts of protein production, many nuclei allow rapid localised production of proteins
structure and function of ribosome
small, made up of 2 subunits, found on membranes (rough ER), in cytoplasm, in organelles
site of protein synthesis
ER structure
- continuation of outer membrane of nuclear envelope
- series of channels surrounded by membranes
- rough ER has ribosomes
smooth ER function
- synthesises lipids
- synthesises steroid hormones
- detoxifies alcohols
- stores calcium
rough ER function
- packages proteins into vesicles to be protected and transported to golgi apparatus
- produces phospholipids for bilayer
structre of golgi apparatus
- membranes
- has a cis side (facing ER) and trans side (facing plasma membrane)
function of golgi apparatus
- receives protein from rough ER via endocytosis
- modifies protein by adding sugars and phosphates to increase solubility (post translational modification)
- packages protein in vescicles
- targets and transports proteins to their destinations (lysosome, plasma membrane, secreted from cell)
- ALSO synthesises carbs
structure and function of vescicles
- membrane bound
- endocytosis (phagocytosis, pinocytosis)
- exocytosis (can be constitutive or regulated with ATP –> important for neurotransmission)
structure of cytoskeleton
microtubules are bigger and made of tubulin
microfilaments are smaller and made of actin
intermediate filaments
function of cytoskeleton
cell shape and movement position of organelles
transport within cell
cell division
intermediate filaments hold cells together, mechanical strength
structure and function of lysosome
- produced in golgi apparaus
- membrane bound, contains enzymes
digests all 4 macromolecules for recycling of monomers - phagocytose bacteria
- used to break down surplus or old organelles also
structure and function of autophagosome and proteosome
transient structures
1) forms
2) engulf protein/organelle 3) fuses with lysosome to break down the contents
structure and function of peroxisome
found in liver and skeletal muscles
detoxifies alcohol with H2O2 (oxidation)
neutralises free radicals
breaks down fatty acids into acetyl groups for ATP synthesis
structure and function of mitochondria
double membrane
inner membrane has folds called cristae, space between cristae is called the mitochondrial matrix
contains mtDNA, enzymes for ATP synthesis, ribosomes
ATP synthesis, site of aerobic respiration by driving proteins across inner membrane to convert ADP to ATP with ATP synthase
