CSF: recap Flashcards
Size and general purpose of the Nucleus
- the largest distinct structure inside the cell
- house and protect DNA (euk)
- RNA and ribosome production
How does the nucleus regulate movement
via the pores
the nucleus and molecules
molecule segregation to allow temporal and spatial control
what affects DNA accessibility
the extent of coiling
Ribosome function
protein production (translation)
where is the ribosome found
free, making proteins in the cytosol OR
attached to ER - making secreted membrane or organelle proteins
do ribosomes have a membrane?
no
where does translation occur?
the ribosome
Rough ER structure
continuous with the nuclear envelope, dotted with attached ribosomes
what 3 things do the rough ER help with the production of?
- secreted proteins
- membrane proteins
- organelle proteins
smooth ER structure
- extends from the RER
- lack ribosomes - doesn’t make proteins
smooth ER function
synthesizes lipids and steroids, storage of cell-specific proteins
Golgi function
- modify, sort, package and transport proteins from RER
what happens to proteins in the golgi
enzymes modify them in each cisternae
Lysosomes function to digest three things
- substances that enter a cell
- cell components e.g. organelles - autophagy
- entire cells autolysis
mitochondria functions
generation of ATP through cellular respiration
Cytoskeleton is
structural support of the cell
three types of cytoskeleton fibres
- microfilaments
- intermediate filaments
- microtubules
Microfilament composition
7nm, Actin
Intermediate filaments composition
10nm, Keratin
microtubules composition
25nm, Tubulin
transcription
from RNA to DNA
processing
of the pre-mRNA transcript
Translation
of the mRNA transcript to a protein
SRP
signal recognition particle
Signal peptide
at N terminus of the protein (~20aa)
where does translation commence
on free ribosomes for ALL proteins
endomembrane system
RER, golgi, vesicles, membrane
what happens to proteins
will be secreted or will form parts of the membrane
DNA sequence determines
protein sequence
protein sequence determines
its structure and function
DNA mutations can affect
the ability of the protein to function
how do cells communicate?
cells respond to signals from other cells and from the environment
what stage and how many proteins are activated
during transduction multiple proteins are activated, usually via phosphorylation
receptors are
specific
what determines function
conformational changes
how are signals relayed in signal transduction
signals relayed from receptors to target molecules within the cell via a ‘cascade’ of molecular interactions
mitosis is
somatic cell division (2n»»2n)
purpose of mitosis is
growth and development
result of mitosis
two daughter cells that are genetically identical to parent cells
MPF does what
phosphorylates many other proteins allowing mitosis to commence
what happens if the cell cycle is uncontrolled?
CANCER
no brakes =
deactivation of tumour suppressor genes
over accelerators =
over-activation of proto-oncogenes
how many mutations typically form a malignant tumour
5 :)
